EP0000773A1 - Irradiation process, multichamber photoreactor - Google Patents

Abstract

Multi-chamber radiation processes and multi-chamber photoreactors for cleaning, in particular disinfection and disinfection of flowable media with UV rays and in the wavelength range from 240 to 320 nm in a flow-through reactor enable extensive use of the UV radiation emitted by the radiation source at high flow rates. The radiation chamber of an annular two-chamber photoreactor (200) with an axially arranged UV lamp (24) is divided by a quartz glass tube (207) into two coaxial radiation chambers (209, 211) which are connected to one another in such a way that the medium is irradiated in the longitudinal direction the radiation source passes through both radiation chambers (209, 211) one after the other while reversing the direction of flow. Other exemplary embodiments for multi-chamber photoreactors and monitoring devices for the flow rate are described, as well as arrangements for the return operation. A modified two-chamber photoreactor (500) has separate radiation chambers (509, 511) through which the medium is conveyed in parallel, such as for water purification by reverse osmosis. Areas of application: Stationary and mobile drinking water supply; Beverage and food industry; Pharmaceutical and cosmetic companies, chemistry and biotechnology; Ultrapure water for clinics, analytics, electronics, photo processing; Climate washer; Swimming pool; Aquaristics; Absasser treatment.

Description

The invention relates to a method for cleaning, in particular for disinfecting and disinfecting flowable media in a flow reactor with a predetermined minimum radiation, i.e. Minimum dose, ultraviolet radiation predominantly in the wavelength range from 240 to 320 nm, at which the medium is conveyed through a flow reactor from at least one radiation room and is thereby exposed to UV radiation from a radiation source consisting of at least one lamp.

The invention also relates to a device for carrying out the method, consisting of a radiation source with at least one radiator which emits ultraviolet radiation predominantly in the wavelength range from 240 to 320 nm, and a flow reactor with at least one radiation chamber, which has a feed line and a discharge line for the medium to be irradiated and a monitoring device for the ultraviolet radiation.

Methods and devices for cleaning, in particular for disinfection or disinfection by ultraviolet rays, are advantageously used instead of chemical agents in order to remove pathogenic, toxic or otherwise disruptive components which are sensitive to ultraviolet rays from water. These can be microorganisms such as bacteria, spores, yeasts or fungi, algae etc., but also are viruses or bacteriophages. It can also be pollution that pollutes the environment, such as carcinogenic aromatics, various halogen compounds, especially chlorine compounds, for example also chlorophenols, etc. Irradiation can be used in drinking water treatment and is particularly useful in connection with ion exchange or reverse osmosis. Investments. You can also swim _- pool water disinfection hygienic drinking water quality. However, the UV radiation process can also be used for circulating water, for example in air conditioning systems in hospitals, and can lead to significantly higher degrees of disinfection than required for drinking water, which is a prerequisite, for example, for use in ophthalmological preparations or when used as a detergent in the operating room. Further areas of application can be found, for example, in the brewery and beverage industry, in the food, pharmaceutical and cosmetics industry, in the purification of waste water or in the production of the purest sea water for biotechnical purposes.

Photochemical disinfection, disinfection and detoxification reactions follow the well-known basic principles of photochemical reactions, the validity of which must be observed in practice. In general, the concentration of pathogenic and other contaminants to be removed by UV radiation is very low. In practice, therefore, the absorption of the medium to be irradiated is determined by other ingredients whose absorption competes with that of the microorganisms etc. The highest possible utilization of the available photon current should be aimed for. Layer thicknesses in which 90% of the incident photons are absorbed are generally sufficient for this purpose, since if this layer thickness is doubled, only a further 9% of the incident photons can be additionally absorbed. In UV disinfection technology, the layer thickness characterized by 90% absorption is referred to as "effective depth of penetration". At a wavelength of 254 nm, this can be 10 cm in particularly pure water, but also only a fraction of a millimeter in milk.

If the ultraviolet radiation is carried out up to a conversion (inactivation) of 90 to 99% of the microorganisms or impurities initially present, an exponential course similar to that of kinetically analogous photochemical reactions can be seen. The aforementioned conversion of 90 to 99% takes place in a fraction of the time that is generally required for sterilization or detoxification reactions. The absolute amount of sales achieved, which asymptotically approaches the number of inputs (number of germs / volume), is no longer of interest here. Rather, only the amount of cleaned medium of a required degree of cleaning (e.g. 10) is now of interest. Here it can be seen that the work suggested by photochemical considerations with a layer thickness corresponding to 90% absorption, ie with the so-called "effective penetration depth", does not provide an optimal result. As a result of the exponential Lambert absorption law, there is an inhomogeneous speed distribution of the cleaning in the irradiated layer. Because of the predominantly laminar flow characteristics of the irradiated medium in the high-performance radiation sources used in the flow reactors, a logarithmic distribution of the degrees of purification occurs in this, the much less cleaning predominating at a greater distance from the radiation source.

For the killing (inactivation) of microorganisms as an example of cleaning in the dose ranges necessary for water disinfection, the simple dose effect principle applies. Thereafter, the microorganism input concentration (input number per ml) N _o by the dose E. t (E = irradiance; t = duration of irradiation) reduced to the microorganism concentration N _t at time t according to a sensitivity constant k characteristic of each species:

In the case of parallel radiation, the irradiance E decreases exponentially with the layer thickness of the irradiated medium even according to Lambert's law of absorption. Overall, the following relationship therefore results for the reduction in the number of bacteria N after the irradiation time t

In this equation, α is the logarithmic absorption measure of the irradiated medium and d is its layer thickness in cm.

If the irradiation is not directed in parallel, an additional change in the irradiance occurs in accordance with the geometry of the flow reactor, which is taken into account in the aforementioned equation by a corresponding geometry factor G.

A photoreactor with approximately parallel radiation is known, in which the radiation source is arranged in a reflector above the surface of the medium to be irradiated (M. Luckiesh, Applications of germicidal, erythemal and infrared energy, Van Nostrand, New York, 1946, p 257-265; company publication "Germicidal lamps and applications", LS-179, General Electric Company). However, photoreactors of this type can only be used in connection with free-flowing media, but not in connection with printing systems in which the medium to be irradiated is conveyed through the photoreactor under pressure.

For such devices, it has been proposed to design the photoreactor in a ring shape and to accommodate the radiation source in the interior of the ring; the source of radiation is a high-pressure mercury lamp (W. Buch, water disinfection device "Uster", AEG-Mitteilungen 1936, No. 5, pp. 178-181), but also a low-pressure mercury lamp (K. Wuhrmann, "disinfection of water using ultraviolet radiation" , Gas / Wasser / Wärme 1960, Volume 14, pp. 100-102) or bundles of low-pressure mercury lamps (P. Ueberall, "The chemical-free drinking and process water disinfection with ultraviolet rays", Dieforce 1969, Volume 21, p. 321-327). In order to compensate for the sharp decrease in the irradiance in a ring-shaped photoreactor caused by the Lambert absorption law and the geometry of the photoreactor, it has been proposed to build up the radiation source from a plurality of lamps which are arranged in individual reflectors which concentrically surround a ring-shaped flow reactor from the outside (German Offenlegungsschrift No. 2 119 961), whereby additional lamps can optionally be arranged in the interior (German Offenlegungsschrift 2 205 598). The photoreactors with a radiation source with radial radiation also include those whose emitters are accommodated in a suitable flow-through container, one or more times, in the manner of a diving lamp (L. Grün, M. Pitz, "UV rays in nozzle chambers and air ducts of air conditioning systems in Hospitals ", Zbl. FürHygiene, I. department Orig. 1974, volume ^{B 1} 59, pp. 50-60).

Although the effective penetration depths for 90% absorption are known for many media, the known photoreactors generally have layer thicknesses which only make up a fraction of the effective penetration depth. For the disinfection of drinking water on seagoing ships, there is even a requirement that the layer thickness of the medium to be irradiated should not exceed 7.62 cm (Department of Health, Education, and Welfare, Public Health Service; Division of Environmental Engineering and Food Protection; "Policy Statement on Use of the Ultraviolet Process for Disinfection of Water", April 1, 1966). This restriction in the reactor diameter, which is carried out for safety reasons, means that in many cases of high transmission factors the possibility of economic disinfection is wasted because then a substantial part of the photon energy radiated into the medium leaves the medium unused and is destroyed on the wall. Attempts to remedy this with mirrored walls have not proven to be particularly effective.

If one irradiates (with parallel irradiation) in a layer with 90% absorption and with such a high dose that the disinfection in the first layer with 10% absorption reaches at least 10 ^-10 , then the above equation results in an inhomogeneity of the degree of disinfection, which ranges from 10 ^-9 in the first shift to 10-1 in the last shift. As a mean result, a degree of disinfection of the order of magnitude of 10-2 is achieved, which is unsatisfactory if one takes into account that the degree of disinfection theoretically achievable, assuming a log radiation that does not decrease logarithmically, but rather average, is in the order of 10 ^-4 .

Devices of the type mentioned at the outset are also known, in which the radiation source consists of a plurality of emitters and the flow reactor consists of a plurality of radiation chambers, each provided with an emitter and connected in the flow direction perpendicular to the emitter axis by connecting chambers (German Offenlegungsschriften No. 2 422 838, 2,622,314). Such devices have radiation chambers of relatively small layer thicknesses (for example less than 6.35 mm), so that the inhomogeneity of the degree of disinfection in the radiation chambers do not reach the degree as in other known devices with larger layer thicknesses. Although a small fraction of the radiation emitted by the emitters reaches the connection chambers, a considerable proportion (approx. 75-95%) of the radiation is lost in this arrangement, for example when sterilizing drinking water with the above-mentioned layer thickness, without being usable for disinfection become.

The object of the present invention is accordingly to provide a method and a device for its exercise, which allow optimal utilization of the UV radiation emanating from the radiation source with the highest possible power.

According to the invention, the object is achieved in relation to the method in that the medium is conveyed through separate radiation chambers which are assigned to the radiation source and are arranged one behind the other in the radiation direction, and is exposed in each radiation chamber to a fraction of the total radiation emanating from the radiation source.

The invention is based on the knowledge that when the photoreactor is subdivided, the layer thickness of the radiation chambers can be selected in such a way that the change in the irradiance in the layer thickness does not have an unfavorable effect on the radiation economy. This results in a less inhomogeneous distribution of the degree of disinfection in each irradiation chamber. With a layer thickness for 90% absorption, a four to five-fold subdivision can result in the differences in the degree of sterilization within each irradiation chamber being less than 3 orders of magnitude, while the differences in the non-subdivided photoreactor are over 8 orders of magnitude. So the principle is based on that the efficiency of the photoreactor, which goes through an optimum with increasing layer thickness and then again sharply decreases, is set in such a way that one works with a layer of only partial absorption and then uses the photons leaving this layer in subsequent layers of similar or identical, only partial absorption. The favorable effect achieved by the subdivision is largely independent of the radiation geometry of the respective photoreactor. It is found both in photoreactors in which the radiation source is formed by diving lamps, and in ring-shaped photoreactors in which the radiation source is mounted inside and / or outside; it is also found in photoreactors, the radiation source of which is arranged above the surface of the medium.

A closer analysis has shown that the irradiation economy is particularly badly affected by the inhomogeneity of the degree of sterilization in the layers of the irradiated medium which are exposed to the highest irradiance. In order to use as much as possible of the high irradiance in the immediate vicinity of the radiation source, which is particularly favorable for the effectiveness of the disinfection, and on the other hand to lose as little as possible of this beneficial effect due to the inhomogeneity in the distribution of the degree of disinfection, the radiation source immediately adjacent should be used Irradiation chamber does not absorb more than 60% of the incident radiation.

Advantageously, at least 50% of the radiation penetrating into the medium in the radiation chamber immediately adjacent to the radiation source falls into the medium in the immediately following radiation chamber and no more than 50% of the penetrating radiation is absorbed in the medium in the radiation chamber immediately adjacent to the radiation source; in the medium are absorbed in a flow reactor with up to 5 radiation chambers not more than (1 - 0.5 ⁿ ) · 100% of the total penetrating radiation, where n is the number of radiation chambers. It is not necessary for the incident radiation to be attenuated by the same fraction in each radiation chamber. As has already been explained above, the efficiency of cleaning or disinfection is determined by the gradient of the irradiance between the entrance and exit of the respective irradiation chamber. In the multi-chamber photoreactor, this applies to each individual radiation chamber, which is why, for example, in two radiation chambers, the total absorption of the incident radiation should not exceed 75% in order to keep this gradient sufficiently small for each radiation chamber and to keep the overall efficiency as high as possible.

In the known single-chamber photoreactors, attempts have already been made to reduce the harmful effects resulting from the gradient of the irradiance in the radiation chamber by mixing the medium as intensively as possible during the residence time in the single-chamber photoreactor (French Patent No. 1 560 780; German Offenlegungsschrift No. 1 937 126). Even with the highest turbulence, however, ideal mixing, in which all particles of the medium would be exposed to the same average irradiance, cannot be achieved. However, even ideal mixing cannot cancel out the influence of the gradient of the irradiance in the medium, since the mean irradiance decreases with increasing layer thickness. As a calculation shows in detail, the gradient only has an effect at layer thicknesses in which no more than 60%, preferably no more than 50%, of the incident radiation is absorbed to the extent that this influence is acceptable for practical purposes. Therefore, the efficiency of cleaning or disinfection is already in one Two-chamber photoreactor considerably higher than with a single-chamber photoreactor with the same total layer thickness. Another advantage of the multi-chamber photoreactor is that under such circumstances the flow characteristics of the medium in the radiation chambers lose their influence on cleaning or disinfection. In the multi-chamber photoreactor, special means for generating turbulent flow in the radiation chamber can therefore be dispensed with.

To increase the degree of sterilization, it may be advantageous to add an oxidizing agent to the medium before or during the irradiation. The oxidizing agent can be, for example, oxygen, ozone, halogen or a hypohalite. This not only favors the oxidative degradation of impurities contained in the medium, but also the disinfection is favorably influenced by additional secondary bactericidal effects.

The sensitivity of microorganisms to ultraviolet radiation is very different; for example, the sensitivity of fungi or algae is more than 2 orders of magnitude lower than the sensitivity of bacteria. When using flow reactors for disinfection, this results in a wide dose range, the full extent of which cannot be determined simply by increasing the radiation flow of the radiation source and / or reducing the flow of the medium to be irradiated. According to the invention it is therefore provided that at least a partial stream of the irradiated medium is returned to the flow reactor after the passage. In this way, the medium to be irradiated is passed through the reactor several times and thus irradiated with the corresponding multiple of the dose of the single pass. This procedure is also recommended in cases where the sterilized medium is removed from an ultraviolet sterilization system in varying amounts.

According to the method according to the invention, the medium is exposed to ultraviolet radiation in the wavelength range from 260 to 280 nm. UV radiation from this wavelength range is particularly effective for photo-disinfection because microorganisms have a maximum sensitivity in this range (LJ Buttolph, "Practical application and sources of ultraviolet energy", Radiation Biology, McGraw Hill, New York, 1955, Volume 2 , Pp. 41-93). Irradiation in this wavelength range also avoids the photochemical formation of precipitates from media containing iron or manganese, which occurs when low-pressure mercury lamps are irradiated with 254 nm. Another particular advantage of the radiation in the wavelength range from 260 to 280 nm is that the absorption of iron- or manganese-containing impurities drops sharply in this wavelength range and therefore to a much lesser extent than in the wavelength range which is emitted by low-pressure mercury lamps. acts as a radiation filter, which reduces the effectiveness of the radiation for photo disinfection.

According to the method according to the invention, the medium is advantageously conveyed successively through the radiation chambers of the flow reactor. As already explained above, this considerably increases the efficiency of cleaning or disinfection. The flow reactor can then be operated with a larger flow, so that the flow rates in the radiation chambers of the multi-chamber photoreactor are increased compared to the flow rate in the single-chamber photoreactor. Such an increase in the flow velocities and the reduction in the cross sections of the radiation chambers prevent flow short circuits which occur in single-chamber photoreactors with high layer thicknesses and low flow velocities. These flow short circuits can lead to a strong difference in the radiation field of the single-chamber photoreactor Liche flow velocities are formed, which become more pronounced when the flow is reduced and can jeopardize the overall result of the irradiation. It is also advisable to work with a multi-chamber photoreactor at a flow rate that is at or above the limit of the turbulence of the medium flowing through. In this way, not only is the formation of precipitates from the irradiated medium effectively suppressed in the multi-chamber photoreactor, but moreover a particularly good heat transfer from the radiation source to the flowing medium is achieved in the chamber of the multi-chamber photoreactor immediately adjacent to the radiation source, so that Overheating can be avoided.

The mentioned considerable increase in the efficiency of the flow reactor due to the subdivision is not tied to the fact that the medium is conveyed successively through the irradiation chambers of the flow reactor. Rather, this is a characteristic property of the multi-chamber photoreactor. If you pass the medium in parallel through the radiation chambers, the flow through each individual radiation chamber can be set so that the same minimum dose is administered in each radiation chamber and thus the same degree of disinfection is achieved and the portions of the medium flowing at different flow rates after leaving the Irradiation chambers can be reunited. The parallel liquid flow is more complex due to its equipment, but can be advantageous for the simultaneous irradiation of different media.

The device according to the invention is characterized in that the radiation space of the flow reactor is separated by partition walls made of material permeable to the ultraviolet radiation into the radiation source radiation chambers that are assigned to one another and are arranged one behind the other in the direction of their radiation, that the radiation incident in the medium at least in the radiation chamber, which directly follows the radiation chamber immediately adjacent to the radiation source, is fractions of the radiation that penetrates into the radiation chamber immediately adjacent to the radiation source, and that the device for maintaining a predetermined minimum dose of radiation consists of flow control means for the medium, which are connected to the feed line or to the discharge line of the flow reactor. The fraction of the radiation entering the radiation chamber directly following the radiation chamber immediately adjacent to the radiation source can be at least 50% of the radiation penetrating into the radiation chamber immediately adjacent to the radiation source and the absorption in the radiation chamber immediately adjacent to the radiation source cannot be more than 50% and the total absorption in a flow reactor with up to 5 radiation chambers is up to (1 - 0.5 ⁿ ) * 100% of the total incident radiation, where n is the number of radiation chambers.

In the simplest case, for example in the photo-disinfection of sea water, such a flow reactor consists of a trough-like vessel which is divided into a lower and an upper radiation chamber by a partition made of quartz glass panes. The radiation source is located above the trough-like vessel in a reflector system which directs the radiation emanating from the radiation source in parallel into the trough-like vessel. The seawater enters one of the two chambers and, after passing through the first chamber, passes through the second chamber. In such an arrangement, the vessel subdivided by quartz glass panes in radiation chambers can itself consist of quartz glass, the radiation source being arranged in pairs on opposite sides of the vessel a system of single reflectors mounted spotlights is formed.

In the field of hospital hygiene, disinfection systems operated in circulation with a radiation source from one or more radiators, each inserted into a container in the manner of an immersion lamp, are known, for example in climate washers. Such arrangements have unfavorable flow conditions which result in part of the water in the container receiving considerably higher radiation doses than necessary, while a large part of the container water remains exposed to low doses. There is therefore a risk of germs being released from this water into the air circulated by the air conditioning system. According to the invention it is provided that each radiator enclosed in a cladding tube in the manner of a diving lamp is surrounded by at least one quartz glass tube and the radiators are inserted in a common container, that the cladding tube and the quartz glass tube each delimit an inner radiation chamber and that the inner radiation chambers each communicate with the inside of the vessel and are connected either on the input side to the feed line or on the output side to the discharge line of the flow reactor. In contrast to the known arrangement, the device according to the invention ensures that the irradiation takes place with the desired minimum dose regardless of the direction of flow through the inner irradiation chambers. If the inner radiation chambers are connected to the inlet on the inlet side, radiation in the presence of oxygen or other gases is facilitated in this way; If you connect the inner radiation chambers on the outlet side to the discharge of the flow reactor, you get optimally sterilized water at the spray nozzle of the climate washer.

According to the invention is a device in which the beam lungsquelle and the flow reactor are arranged in a ring to each other, constructed so that the flow reactor consists of two closure parts provided with connecting means, which limit the irradiation chambers on the front side, and consists of pipe sections of different diameters attached to these, which are arranged coaxially one inside the other and the radiation chambers along the side limit. The closure parts for each radiation chamber can have a connection piece which is connected to the associated radiation chamber via at least one inner channel. In this way, a ring-shaped, multi-chamber photoreactor of simple construction consisting of quartz glass tubes held coaxially between the end closure parts is obtained, in which the radiation chambers can be connected in parallel or in series, depending on the requirements.

In the series connection, adjacent radiation chambers are connected to one another at opposite ends. The particular advantages of such a series connection are that, owing to the changed flow paths and velocities, a more favorable distribution of the irradiated energy to the medium flowing through and thereby a substantially improved efficiency of the desired cleaning or disinfection processes is achieved. With the same flow rate, the mean flow rate in an m-chamber photoreactor is approximately m times the average flow rate of a single-chamber photoreactor. In the multi-chamber photoreactor, a volume part of the medium passes through all the radiation chambers in succession, from the highest to the lowest average radiation intensity or vice versa, whereby a much more uniform distribution of the energy supplied to the medium flowing through is achieved. This avoids overexposure in the vicinity of the radiation source and also underexposure in more distant areas, and thus the efficiency of the applied radiation dose increased considerably.

The subdivision of the photoreactor into a plurality of radiation chambers thus permits radiation at lower gradients of the radiation intensity and, through the series connection of the radiation chambers, a summation of the individual energy doses applied in the medium. Overall, the photochemical efficiency of cleaning or disinfection in the multi-chamber photoreactor is significantly increased and an increased effective dose rate in the medium is achieved. This allows the flow to be increased compared to a single-chamber photoreactor with a radiation source of the same UV power. As a result, the mean flow velocities, which are considerably increased in comparison to single-chamber photoreactors, have the additional advantage that the aforementioned flow short circuits are avoided and deposits from the medium occur less easily.

Advantageously, in the device according to the invention, the tube pieces are alternately sealingly held and guided at their ends, and adjacent radiation chambers are connected to each other at the guided ends of the tube pieces. This simplifies the construction of the multi-chamber photoreactor with radiation chambers connected in series, since the connection between the radiation chambers is located within the flow reactor and only internal channels to the connecting pieces that serve as input and output connections have to be provided in the closure parts .

Multi-chamber photoreactors of the type described above with an outer piece of quartz glass tube can be concentrically surrounded in a known manner (German Offenlegungsschrift No. 2 119 961) by a plurality of radiators, each of which has its own paraboloid reflector, so that a optimal efficiency of the irradiation is made possible. proper functioning of a single-chamber photoreactor of this type can only be guaranteed if the short-circuit phenomena discussed above are reliably avoided when flowing through. However, with increasing cross-section and decreasing flow velocity of the medium to be irradiated, the likelihood of such short-circuit phenomena increases, so that photoreactors of this type can generally only be used for narrow areas of application. The subdivision with the formation of the multi-chamber photoreactor ensures that even media with low transmission pass through the flow-through reactor at such a speed that the irradiation with the required minimum dose is ensured and the occurrence of short-circuit phenomena during the flow is excluded.

In the device according to the invention, the inner tube piece can be guided at both ends through corresponding openings in the closure parts and can be held in a sealing manner in the openings. This enables the attachment of a radiation source inside the multi-chamber photoreactor, which can be provided in addition to the radiators surrounding the outside of the multi-chamber photoreactor. As a result, the radiation losses which occur when the radiation passes through the photoreactor are compensated for to a considerable extent, and a suitable approximation to an equally high irradiance in all volume elements of the photoreactor is achieved if the layer thickness is matched appropriately to the transmission factors of the medium.

In the multi-chamber photoreactor according to the invention, the outer tube section can be radiation-impermeable, have an observation opening and can be flanged to the closure parts in a sealing manner. This enables a more stable and further simplified construction of the photoreactor, inside the radiation source is attached. To increase the irradiance in the outer chamber, the outer tube section can be mirrored, preferably so that the medium flowing through cannot act on the mirroring.

In a further embodiment of the device according to the invention, the pipe sections are held in a sealed manner on a closure part, the inner pipe section and every second outwardly following section are closed at the end facing away from the closure part, and each of the second outwardly following pipe sections is close to the closure part serving to hold them Provided through openings, and the closure member has an inner channel, one end of which opens into the inner radiation chamber and the other end into a connecting piece. The one-sided mounting of the pipe sections can facilitate the assembly and disassembly of the multi-chamber photoreactor.

In the multi-chamber photoreactors according to the invention, an irradiation chamber facing away from the radiation source advantageously has a layer thickness which is at least twice the layer thickness of the irradiation chamber immediately adjacent to the radiation source. Such a photoreactor is suitable for all media with transmission factors in the range between T (1 cm) = 0.6 and close to 1. For the disinfection of drinking water with a transmission factor in the low range, the two radiation chambers with a low layer thickness are mainly effective, while with drinking water with a high transmission factor the radiation chamber with a greater layer thickness facing away from the radiation source is also included with good effectiveness. Such a multi-chamber photoreactor can thus be used for the disinfection of drinking water in the entire range of transmission factors occurring, without additional measures being necessary in its construction. By adding the Be Radiation chamber with a large layer thickness when using drinking water with high transmission results in a high output which cannot be achieved with photoreactors with smaller layer thicknesses or with a single-chamber photoreactor with a larger total layer thickness. A total layer thickness of 7.62 cm is recommended for drinking water disinfection on seagoing vessels (Department of Health, Education, and Welfare Public Health Service; Division of Environmental Engineering and Food Protection; "Policy Statement on Use of the Ultraviolet Process for Disinfection of Water", 1. April 1966).

A pressure compensation device is expediently provided in the multi-chamber photoreactor according to the invention. This can have a cover provided with pressure-tight bushings, pressure-tightly connected to the closure part holding the pipe pieces and connected to a barostat, the setpoint of the barostatic pressure control being determined by the inlet pressure of the medium at the flow reactor. Such a device compensates for the pressure acting on the tube sections made of quartz glass during operation of the multi-chamber photoreactor. This prevents mechanical stresses from occurring on the stress-sensitive quartz glass tubes, which could lead to breakage.

In the multi-chamber photoreactors according to the invention, at least one radiation chamber is provided with a compensation element for the flow profile which is effective over the flow cross section. The arrangement of such compensation elements for the flow profile is particularly expedient for the radiation chamber with the highest radiation intensity. The required conditions for the irradiation of the medium flowing through can be adhered to more reliably if the flow profile of the medium passing through the irradiation chamber is uniform, in particular it must be excluded that parts of the medium move through the irradiation chamber at a higher speed. A device according to the invention, in which a partial flow of the irradiated medium is returned to the flow reactor after the passage, is characterized in that the flow reactor is provided on the output side with a flow divider, the one outlet of which is connected to the extraction line and the second output of which is connected by a return flow feed pump and a check valve is connected to the inlet of the flow reactor. The flow rate of the return feed pump can be adjustable in order to bring about a change in the return ratio; however, the return line can also have an adjustable flow restrictor. With such a device, particularly high degrees of disinfection or cleaning can be achieved; it is also suitable for those applications in which there is no continuous removal.

In a device according to the invention, the radiation source is formed by at least one antimony-doped xenon high-pressure lamp which has a strong emission in the wavelength range from 260 to 280 nm. Such a lamp has a bactericidal dose rate per cm of emission length which is at least an order of magnitude higher than the corresponding radiation power of conventional low-pressure mercury quartz lamps. The radiation levels that can be achieved with these emitters are therefore very much higher than the radiation levels that can be achieved with conventional mercury low-pressure lamps, this advantage being further increased by the previously mentioned favorable effects of the radiation in the wavelength range from 260 to 280 nm. With the same flow rate, it is therefore possible to increase the dose range by an order of magnitude; For today's needs in drinking water disinfection, it follows that much higher space-time expansions can be achieved with a radiation source from antimony-doped xenon high-pressure lamps than was previously possible. Next This considerable improvement in performance is based on a further advantage of the use of the antimony-doped xenon high-pressure lamp because, owing to the minimal volatility and toxicity of the antimony, the possibility of dangerous environmental pollution in the event of a lamp break is considerably less than with the otherwise customary mercury vapor lamps.

For applications in which the widest possible range of UV radiation of the effective wavelength range is to be used for cleaning, disinfection and / or disinfection by means of ultraviolet radiation, it can be useful for the radiation source to have at least one mercury vapor lamp in addition to the antimony-doped xenon high-pressure lamp having.

To increase the radiation flow emanating from the radiation source per unit length of the flow reactor, it can be expedient that the radiation source contains at least one coiled radiator.

In the case of an annular design of the flow-through reactor, the radiation source can expediently be arranged in the interior of the flow-through reactor in a position close to the axis. Such an arrangement of the radiation source brings about the best radiation distribution in the radial direction. The radiation source can be held independently of the flow reactor; in other versions, e.g. in the case of a pressure flow reactor, on the other hand, the radiation source is held in the flow reactor. The arrangement of the radiation source inside the flow reactor is preferred for flow reactors of smaller volume.

In the case of an annular flow reactor according to the invention, the radiation source can have at least 4 axially parallel and symmetrical emitters arranged between the flow reactor and a reflector system surrounding it. In this case, each radiator is expediently located in a separate, preferably paraboloid, reflector of the reflector system, in order to ensure optimum optical efficiency of the radiation into the flow reactor. With such an arrangement of the radiation source, a more uniform distribution of the radiation over the total volume of the reactor is achieved than with arrangement of the radiation source in the interior of the annular reactor; it is particularly suitable for large-volume flow reactors.

A further improvement in the radiation distribution can be achieved in the flow reactor according to the invention in that some of the radiators forming the radiation source are arranged inside the flow reactor and another part of the radiators, at least 4, are arranged axially parallel and symmetrically between the flow reactor and a reflector system surrounding it. the emitters, as described above, are located in separate reflectors.

In devices of the type described above, it may be expedient to arrange an antimony-doped xenon high-pressure lamp at least inside the flow reactor; this avoids the reflection losses that are unavoidable with reflectors and makes better use of the rays emitted by the highly effective antimony-doped xenon high-pressure lamp; at the same time, special water cooling is not necessary for this heater.

The devices described above for carrying out cleaning, disinfection or disinfection of flowable media in the flow by means of ultraviolet radiation require flow control means in order to maintain a predetermined minimum dose of the ultraviolet radiation, by means of which it is ensured that the medium penetrating the radiation chambers is always irradiated with the required minimum dose . The through according to the invention In the simplest case, flow control means can have a flow restrictor, preferably an adjustable flow restrictor. With constant pressure at the inlet or outlet of the flow reactor, the flow can be adjusted to the required value. In the simplest case, the flow restrictor can consist of a constriction in the feed line or discharge line of the flow reactor, but it can also be formed by a suitable, precisely adjustable valve, the setting of which cannot be changed over time.

However, the flow control means according to the invention can also have a flow limiter which is independent of the inlet pressure. Such flow restrictors are known and their use in connection with the flow reactors described here is particularly advantageous because they prevent a given flow from being exceeded in any case. Such a exceeding of the predetermined flow rate must be avoided, particularly in the case of the flow reactors for photo-disinfection, since an increase in the flow rate must necessarily lead to a drop below the predetermined minimum dose.

According to the invention, the flow control means can also have a pump with an adjustable delivery rate. Such a pump allows the flow to be adapted to the desired radiation dose to the greatest extent possible.

According to the invention, a control device for the pump with an adjustable delivery rate is provided, which is supplied with a control signal originating from the monitoring device with setpoint adjustment. The control device can have a power amplifier and a tachogenerator driven by the pump motor, and the tachogenerator signal can correspond to the control signal of the monitoring device at the input of the power amplifier be countered. Known monitoring devices for flow reactors for photo disinfection contain a radiation detector which is arranged on the flow reactor and responds to the radiation passing through the flow reactor. If the value falls below a preset target value, the detector emits a signal by which a valve is activated, by means of which the medium to be irradiated is passed to a second flow reactor, by which an alarm signal is triggered and by which a cleaning device for the first photoreactor is actuated can (U.S. Patent No. 3,182,193). A monitoring device is also known (US Pat. No. 3,462,597), which closes a solenoid valve in the feed for the medium to be irradiated in the event of failure of the lamp, the lamp transformer or an inadmissibly large drop in the mains voltage. However, these known monitoring devices are only suitable and used to interrupt the operation of the flow reactor immediately in the event of an emergency and by emitting an emergency signal or to switch over to a second reactor. The device according to the invention, on the other hand, connects the pump with adjustable delivery rate to a control device, the output signal of which depends on the radiation intensity measured in each case on the monitoring device. In this way it is possible to adapt the flow to the respective irradiance. This means that when the radiation power decreases, the flow rate decreases in the same ratio, so that it is ensured that the cleaning or disinfection quality (for example the degree of cleaning or disinfection) is maintained. Such a control device allows the influences of aging on the radiation of the radiation source to be taken into account in a simple manner. The described control of the flow with decreasing irradiance to maintain the set dose allows a particularly economical irradiation operation in pairs of multi-chamber photoreactors. One of the photoreactors is put into operation with a new set of lamps, while the second continues to operate for half the life of its lamps. As a result, both are operated optimally in accordance with the respective lamp outputs, and the total output fluctuation due to aging is only half of the previous size. At the same time, however, better use of lamps and electricity is guaranteed and, at the same time, better use of apparatus is achieved.

• Fig. 1 eine perspektivische Ansicht eines ersten Ausführungsbeispiels des erfindungsgemäßen Mehrkammer-Photoreaktors;
• Fig. 2 einen Längsschnitt durch eine Teilanordnung bei einem zweiten Ausführungsbeispiel des erfindungsgemäßen Mehrkammer-Photoreaktors;
• Fig. 2A einen entsprechenden Schnitt durch eine abgeänderte Ausführung der Teilanordnung nach Figur 2;
• Fig. 3 eine perspektivische Ansicht eines Details von Figur 2;
• Fig. 4 einen Längsschnitt durch eine weitere Ausbildung der Teilanordnung;
• Fig. 4A einen entsprechenden Schnitt durch eine abgeänderte Ausführung der Teilanordnung nach Figur 4;
• Fig. 5 eine Ansicht eines Details bei der Teilanordnung nach Figur 4;
• Fig. 6 eine perspektivische Ansicht des zweiten Ausführungsbeispiels des erfindungsgemäßen Mehrkammer-Photoreaktors;
• Fig. 7 eine Draufsicht auf eine weitere Ausbildung des Mehrkammer-Photoreaktors nach Figur 6;
• Fig. 8 eine Schnittansicht eines Details bei dem Mehrkammer-Photoreaktor nach Figur 7;
• Fig..9 einen Längsschnitt durch ein drittes Ausführungsbeispiel des erfindungsgemäßen Mehrkammer-Photoreaktors;
• Fig. 10 einen Teillängsschnitt durch einen Mehrkammer-Photoreaktor nach Figur 9 mit einer Druckausgleichseinrichtung;
• Fig. 11 einen Längsschnitt durch ein viertes Ausführungsbeispiel des erfindungsgemäßen Mehrkammer-Photoreaktors;
• Fig. 12 einen Längsschnitt durch ein fünftes Ausführungsbeispiel des erfindungsgemäßen Mehrkammer-Photoreaktors;
• Fig. 13 ein Fließdiagramm für den Rücklaufbetrieb eines erfindungsgemäßen Mehrkämmer-Photo- reaktors;
• Fig. 13A ein Fließdiagramm für einen modifizierten Rückflußbetrieb entsprechend Figur 13;
• Fig. 14 eine Detailansicht eines Bauteils in dem Fließdiagramm nach Figur 13;
• Fig. 15 ein Blockschaltbild eines Ietails der elektrischen Überwachungseinrichtung für den Betrieb eines erfindungsgemäßen Durchflußreaktors;
• Fig. 16 einen Längsschnitt durch ein für parallelen Durchfluß abgeändertes viertes Ausführungsbeispiel nach Figur 11;
• Fig. 17 einen Längsschnitt durch ein für parallelen Durchfluß abgeändertes fünftes Ausführungsbeispiel nach Figur 12.

Embodiments of the device according to the invention are shown in the figures and are explained and described in detail below. Show it

• Figure 1 is a perspective view of a first embodiment of the multi-chamber photoreactor according to the invention.
• 2 shows a longitudinal section through a partial arrangement in a second exemplary embodiment of the multi-chamber photoreactor according to the invention;
• 2A shows a corresponding section through a modified embodiment of the partial arrangement according to FIG. 2;
• Figure 3 is a perspective view of a detail of Figure 2;
• 4 shows a longitudinal section through a further embodiment of the partial arrangement;
• 4A shows a corresponding section through a modified embodiment of the sub-arrangement according to FIG. 4;
• 5 shows a view of a detail in the sub-arrangement according to FIG. 4;
• 6 shows a perspective view of the second exemplary embodiment of the multi-chamber photoreactor according to the invention;
• FIG. 7 shows a top view of a further embodiment of the multi-chamber photoreactor according to FIG. 6;
• Figure 8 is a sectional view of a detail in the multi-chamber photoreactor of Figure 7;
• 9 shows a longitudinal section through a third embodiment of the multi-chamber photoreactor according to the invention;
• 10 shows a partial longitudinal section through a multi-chamber photoreactor according to FIG. 9 with a pressure compensation device;
• 11 shows a longitudinal section through a fourth exemplary embodiment of the multi-chamber photoreactor according to the invention;
• 12 shows a longitudinal section through a fifth exemplary embodiment of the multi-chamber photoreactor according to the invention;
• 13 shows a flow diagram for the return operation of a multi-chamber photo-reactor according to the invention;
• FIG. 13A is a flow chart for a modified reflux operation corresponding to FIG. 13;
• 14 shows a detailed view of a component in the flow diagram according to FIG. 13;
• 15 shows a block diagram of an detail of the electrical monitoring device for the operation of a flow reactor according to the invention;
• 16 shows a longitudinal section through a fourth exemplary embodiment according to FIG. 11 modified for parallel flow;
• 17 shows a longitudinal section through a fifth exemplary embodiment according to FIG. 12 modified for parallel flow.

Figure 1 shows a two-chamber photoreactor 1 from a flow reactor in the form of a trough-like vessel 2 with a lid 3 which is pivotally hinged to the trough-like vessel 2 and is held in the closed position by a snap lock. The vessel 2 is made of metal such as stainless steel, but can also be made from any other UV-resistant and other requirements, for example food regulations, sufficient material (stoneware, enamelled sheet metal, etc.). The lid 3 carries a series of parallel paraboloid reflectors with a particularly UV-reflecting surface. Within the reflectors, UV emitters 6 are arranged perpendicular to the flow direction so that the flow cross section of the trough-like vessel 2 is irradiated evenly, including the edge areas. Water-cooled, antimony-doped xenon high-pressure lamps are used for the purpose of disinfection; alternatively, low-pressure mercury quartz lamps of known design are also suitable for this. High-pressure mercury lamps or other emitters of suitable emission ranges can also be used for cleaning in the presence or absence of oxidizing agents. The snap lock is connected to a safety circuit by means of which the radiators 6 are automatically switched off when the snap lock is opened. The trough-like vessel 2 is divided in the flow direction by quartz glass panes 7 into two radiation chambers 8 and 9; the irradiation chamber 9 is defined as a lower irradiation chamber through the quartz glass plates 7 on a fixed layer thickness of 2 cm, while the layer thickness of the medium in the irradiation chamber 8 by means of the level controller ¹ .7 described below can be varied. The quartz glass panes 7 are in one removable stainless steel frame 10; the quartz glass panes 7 are fastened to the face frame 10 and this itself is fastened in a sealing manner to the inner wall of the trough-like vessel 2 by means of a cement which is resistant to UV radiation. Instead of cementing, the seal can also be made using preformed and UV-resistant seals. The radiation chambers 8, 9 communicate with one another at their end facing away from the entrance and exit of the trough-like vessel 2. The upper radiation chamber 8 is connected to a flow limiter 12 via a feed line 11. The flow limiter serves to limit the flow to the permissible maximum value even when the inlet pressure is increased; such flow restrictors are sold, for example, by Eaton Corp., Controls Division, 191 East North Ave., Carol Stream, Illinois 60 187, USA. The feed line 11 opens into the radiation chamber 8 via a perforated plate 13, which represents a compensation element for the flow profile and extends over the entire width of the radiation chamber 8. The radiation chamber 9 opens via a similar perforated plate 15, which also acts as a compensating element for the flow profile, into a discharge line 16 with a level controller 17, which carries an air-permeable cover 18, for example made of cotton wool, for protection against contamination.

The perforated plates 13, 15 consist of material which is resistant to UV radiation and the medium flowing through and does not itself emit any disturbing impurities to the medium flowing through (stainless steel, coated metals, plastic, ceramic, quartz, glass). The width of the holes is so large that the flow is not significantly impeded, but a flow profile which is uniform over the passage area is nevertheless produced. For the same purpose, the holes can also be replaced by openings of a different shape, such as slots. The perforated plates 13, 15 are one with the trough-like vessel 2 on the one hand and the transition piece of the feed line 11 or the drain 16 on the other hand sealingly cemented in a suitable manner.

The level controller 17 has an inner tube 19, which is guided in a sealed manner in an overflow vessel 20 and is vertically displaceable and forms the outlet of the trough-like vessel 2. By vertically displacing the inner tube 19 in the level controller 17, different layer thicknesses can be adjusted in the upper radiation chamber 8 in adaptation to the optical density of the medium entering the flow reactor through the feed line 11.

The two-chamber photoreactor 1 has 20 mercury low-pressure quartz lamps (15 W, NN 15/44 Original Hanau Quarzlampen GmbH, Hanau) perpendicular to the direction of flow, which are distributed equally over the radiation chambers 8, 9 of 80 cm in length, each radiator in an assigned reflector and the lamp-reflector combinations are arranged at the smallest possible distance from each other.The total UV radiation flux reaching the surface of the medium (taking into account the reflection losses of at most 45% and the edge losses) is approx. 60 W with an average irradiance E = 25 mW / cm ² . Table 1 below shows a comparison of the two-chamber photoreactor 1 with a single-chamber photoreactor of the same total layer thickness; Table 1 shows values for the flow Q-40 (m ³ / h) for a minimum dose of 40 mWs / cm ² for different transmission factors T (1 cm) and different layer thicknesses of the upper radiation chamber 8.

60 W UV-254 nm at 30 80 = 2400 cm ² irradiation area; average irradiance E = 25 mW / cm ² . Influence of the transmission factor T (1 cm) and the layer thicknesses 2 in the radiation chambers.

According to Table 1 above, the two-chamber photoreactor is suitable for the range of transmission factors T (1 cm) from 0.95 to 0.5; with T (1 cm) ≥ 0.9 the layer thickness of the upper layer should be 4 cm and more, with T (1 cm) <0.6 approx. 1 cm.

For the areas of lower transmission factors, the layer thicknesses of the lower radiation chamber 9 are also chosen to be lower, for example 1 cm at T (1 cm) = 0.4. At T (1 cm) = 0.4 one then obtains Q-40 = 3.02 m ³ / h for each 1 cm lower and upper layer under the other conditions of the table above and the increase factor is then 1.75. With a layer thickness of the lower irradiation lungskammer 9 of 1 cm, the two-chamber photoreactor is optimally adaptable to the transmission areas occurring in the disinfection of waste water. The losses of effective UV radiation caused by the use of reflectors are more than compensated for by the subdivision of the photoreactor, as a result of which a more energetically favorable result for disinfection is achieved in comparison with the single-chamber photoreactor. Two-chamber photoreactors of this type are also used for the disinfection of sea water.

Figures 2 to 8 show the design of a multi-chamber photoreactor, in which the radiation source is designed in the manner of a diving lamp.

FIG. 2 shows in longitudinal section a first embodiment of a partial arrangement of the multi-chamber photoreactor with an emitter 24 in a cladding tube 25 made of quartz glass, which is inserted into a separating tube 35 likewise made of quartz glass. The radiator 24 is an antimony-doped xenon high-pressure lamp for the purpose of disinfection; alternatively, low-pressure mercury quartz lamps of known design are also suitable for this. High-pressure mercury lamps or other emitters of suitable emission ranges can also be used for cleaning in the presence or absence of oxidizing agents. The radiator 24 rests on a support 27 at the lower end of the cladding tube 25, which can be made of glass wool, for example. At its upper ends, the cladding tube 25 and the separating tube 35 are connected to one another via cuts 26, 36, which are held in tight engagement by suitable, known securing means (from Schott & Gen., Mainz). The separating tube 35 carries two diametrically opposite connections 37 near its upper end. At the lower end of the sub-arrangement, a spacer is provided, by means of which the cladding tube 25 and the separating tube 35 are held at the same distance from one another over their length. The spacer consists of two concentrically arranged spring washers 29, which are connected by three in the angle of 120 ⁰ staggered webs 30 of resilient material (see Figure 3). The spring rings 29 are mounted between the small projections 28, 38, the adjusted at angular intervals of about 120 ⁰ and in the corresponding dimension of the spring ring 29 axial distance are arranged on the outside of the cladding tube 25 or on the inside of the shroud pipe 35th This spacer can also be provided with a perforated plate for setting a flow profile which is uniform over the passage area, as will be explained in connection with FIG. 5.

FIG. 4 shows a converted partial arrangement similar to FIG. 2. In a quartz glass cladding tube 45 there is a radiator 24 of the aforementioned type. It is surrounded by a quartz glass separating tube 55 which has a narrowing at its upper end which is slightly wider than the cladding tube 45, and near its upper end carries two diametrically opposite connections 57. The cladding tube 45 and the separating tube 55 are arranged concentrically to one another and are sealingly connected to one another at their upper ends by an overlapping sealing sleeve 46 made of an elastic plastic, which is resistant to the UV radiation and the medium flowing through. The sealing sleeve 46 is secured by ligatures 48, which are designed in the manner of hose clips. At the lower end of the sub-arrangement, a spacer 67 is provided, by means of which the cladding tube 45 and the separating tube 55 are held at the same distance from one another over their length. The spacer 67 (FIG. 5) is arranged according to FIG. 2 between projections 28 on the cladding tube 45 and projections 68 on the separating tube 55 and initially consists of a double spring ring 29 with resilient webs 30. The outer spring ring 29 is axially projecting upward from its circumference Supports 69, the ends 70 of which are bent radially inwards and there hold in contact with the spring ring 29 by means of a plate 71 which has through openings 72. The passage openings 72 in the plate 71 are assigned to the radiation chamber 49 formed by the cladding tube 45 and the separating tube 55 and are distributed uniformly over the respective passage area. The plate 71 consists of material which is resistant to UV radiation and the medium flowing through and which does not give off impurities to the medium flowing through (stainless steel, coated metals, plastic, ceramic, glass, quartz). The width of the passage openings 72, which may have a circular or other cross section, is so large that they do not substantially impede the flow, but nevertheless produce a flow profile which is uniform over the passage area. The whole arrangement is such that the supports 69 are each located between the projections 68 on the inner wall of the separating tube 55.

A number of modifications are possible compared to the embodiments described above. In the embodiment shown in FIG. 2A, the open end of the separating tube 35A is fused to the cladding tube 25A to form a unitary component, which is complex to manufacture and sensitive to use. In a simpler embodiment, the spacer can also be formed solely by the plate 71 provided with through openings 72; the upper rim of the projections 28 and 68 then falls away, and the plate 71 is held in contact with the lower rim of the projections 28 and 68 by a snap ring.

4, an additional quartz glass tube 52 (see FIG. 4A) is arranged coaxially to the quartz glass tubes 45 and 55. The quartz glass tube 52 is closed at the lower end; the upper open end tapers and is sealed with an overlapping sleeve 51 secured with ligatures 50 Quartz glass tube 55 connected in a similar manner as the quartz glass tubes 45 and 55. The tapered end is fastened to the separating tube 55 just below the connections 57. At least two through openings 53 in the wall of the quartz glass tube 52 near its tapered end are evenly distributed over its circumference. The separating tube 55 extends up to a holder lying on the inside of the bottom of the quartz glass tube 52 and consists of a ring 59, from which a number of leaf springs 60 projecting and holding the end of the separating tube 55 protrude. Between the edge of the separating tube 55 and the ring 59 and the leaf springs 60 there is sufficient space for the unimpeded flow of the medium between the radiation chambers separated by the separating tube 55. However, the edge of the separating tube 55 can also be provided with cutouts for the connection between the radiation chambers and then lie directly on the ring 59. The ring 59 and the leaf springs 60 are made of material which is resistant to UV radiation and the medium flowing through and does not itself emit any disturbing impurities to the medium flowing through (stainless steel, coated metals, preferably with fluorinated hydrocarbon polymers, plastics, ceramics, quartz , Glass).

The partial arrangements for the radiator 24 shown in FIGS. 2, 2A, 4 and 4A together with a tank 21 form the flow reactor 41 of the two-chamber photoreactor 20. According to FIG. 6, the tank 21 has supports 22 on its longitudinal walls, on each of which one of the tubes shown in FIGS Figure 2 shown subassemblies is attached. The tank 21 and the carrier 22 are made of stainless steel and are welded together. The tank 21 and the carrier 22 can, however, also consist of different materials which are suitably firmly connected to one another; the tank 21 is made of a material that is UV-resistant and meets all other requirements, such as food law provisions. In the open to the top Tank 21 opens into a source (not shown) for the medium to be irradiated; the tank 21 can optionally also be connected to the source of the medium to be irradiated via a connecting piece and a connecting line.

In the combination of the sub-arrangement according to FIG. 4A with the tank 21, the outflow expediently consists of an overflow pipe extending from the bottom of the tank 21, which extends to the height of the passage openings 53. This ensures the desired constant fill level of the tank 21.

The sub-arrangement according to one of FIGS. 2 to 4 is held on the carrier 22 by suitable means; For this purpose, a sleeve 31 is provided with a locking screw 32, which carries a chain 33, possibly covered with a protective coating, which surrounds the partial arrangement and is suspended on the sleeve 31 in accordance with its circumference. Such holders in connection with radiation devices are known and commercially available, so that they do not have to be described in detail here. The sub-arrangement is only shown schematically in FIG. At the bottom of the tank 21 there are supports 34, on which the sub-assembly is seated, whereby additional security of the holder is achieved.

For the operation of the flow reactor 41, the connections 37 and 57 of those held on the carriers 22; Partial arrangements according to one of Figures 2 to 4 connected together to form a common (not shown) derivative. The entering medium first passes through the tank 21 forming the first radiation chamber 23; it then exits through the inner radiation chamber 39 or 49 formed by the cladding tube 25 or 45 and the separating tube 35 or 55 and its connection 37 or 57 into the discharge line (not shown).

FIGS. 7 and 8 show a further embodiment of the flow reactor 41 for a two-chamber photoreactor 40 corresponding to FIG. 6, in which the tank 21, which supports a connection 91, is closed by a cover 80 which is provided with passages 81 and holders 82 , on which the sub-arrangement shown in Figure 2 is held sealed. The brackets 82 each consist of a collar 83 projecting from the cover 80, in which the respective outer quartz glass tube 35 is guided. The quartz glass tube 35 carries an O-ring 84 which abuts an inclined surface 85 on the upper inner edge of the collar 83 and is secured by a pressure ring 88 held with screws 86 which engage in threaded bores 87 on the top of the collar 83. The connections 37 of the sub-arrangements according to FIG. 2 are connected to a common derivation 90 via connecting lines 89. In the same way, the sub-arrangements according to FIG. 4 or the other sub-arrangements described above can be held in a sealing manner on the cover 80.

The open arrangement of the multi-chamber photoreactor 20 is advantageously used, for example, in climate washers, the outlet of which is located directly above the tank 21; The closed arrangement of the multi-chamber photoreactor 40 enables other applications in which the medium is to be irradiated in a circulation process without excess pressure. In order to reliably avoid falling below the required minimum dose, a flow limiter of the type described above is also expediently installed in the feed line here. In the case of the multi-chamber photoreactors 20, 40, the disadvantage of the inhomogeneity of the irradiance distribution in the first irradiation chamber 23 formed by the tank 21 is compensated for by the fact that the medium is passed through the inner irradiation chamber 39 or 49, in which, under defined conditions, it is mixed with a lower gradient of the irradiance is exposed to a high minimum irradiance. Depending on the requirements, a smaller or larger number of the partial arrangements according to FIGS. 2 and 4 can be used in the multi-chamber photoresctor 20, 40. The direction of flow is not critical for the function of the multi-chamber photoreactor 20, 40. If you want to achieve high degrees of disinfection with certainty, it should be expedient to pass the medium through the inner radiation chamber 39 or 49 last. However, if you want to fumigate the medium with eg oxygen during the irradiation, the reverse flow direction is recommended.

For the cleaning, in particular for the disinfection or disinfection of media which are to be conveyed at high power through a flow reactor with a UV radiation source emitting predominantly in the range between 240 and 320 nm, devices in which the flow reactor and the Radiation source are arranged in a ring to each other. An annular flow reactor can surround a radiation source arranged inside; however, an external radiation source can also be provided in the form of a series of emitters in respectively assigned reflectors, which surround the flow reactor in a ring shape, or both types of radiation sources can also be provided. The flow reactor can also be tubular and is then combined with an external radiation source. The following Table 2 shows for an annular flow reactor with an inner diameter d _i = 4 cm and an outer diameter D _a = 6 to 14 cm the drop in the internal irradiance E when radially irradiating a medium with a transmission factor T (1 cm) = 0.6. If there is a mercury low-pressure quartz lamp of 1 m effective length in the interior of this flow reactor in the axial position, its radial emission radiates 15 watts UV-254 nm at this length radiated the inner surface of the flow reactor into the medium.

With an effective irradiation area of π · D _i · 100 cm ² = 1256.6 cm ² , the average irradiance in this area is E _i = 11.94 mW / cm ² . The columns in Table 2 show the diameters D and layer thicknesses d, for this the geometry factors G and the transmissions-T as well as their product G. T = E _rel the relative irradiance in the layers; Column _Ed shows the internal irradiance in the layers; column V _d shows the associated annular chamber volumes. The last column in Table 2 shows the associated flow rates Q-40 in m ³ / h while maintaining a minimum radiation dose of 40 mWs / cm ² , calculated for a uniform flow.

It can be seen from Table 2 that the internal radiation intensity E _d decreases sharply with increasing layer thickness d, while in contrast the annular chamber volume V _d increases considerably. With a transmission factor of the medium to be irradiated of T (1 cm) = 0.6, Q-40 = 0.73 m ³ / h is found as the maximum with a layer thickness of d = 2 cm (see Table 2). With larger layer thicknesses d, Q-40 decreases because the influence of the large annular chamber volumes, which are only exposed to a relatively low internal irradiance E _d , predominates. For media with other transmission factors, the achievable flow maxima for Q-40 with other layer thicknesses are d: at T (1 cm) = 0.7, Q-40 (max) = 1.32 m ³ / h with 2 cm layer thickness; at T (1 cm) = 0.8, Q-40 reaches a maximum value of 1.95 m ³ / h at d = 4 cm, at T (1 cm) = 0.9 Q-40 = 3.42 m ³ / h at a layer thickness of 5 cm . With a constant layer thickness d = 5 cm of the single-chamber photoreactor, T (1 cm) = 0.9; 0.8; 0.7 flows Q-40 = 2.56; 1.42; 0.73 m3 / h obtained.

The following Table 3 shows the conditions for a medium also with T (1 cm) = 0.6, but for a multi-chamber photoreactor with the same dimensions, which is subdivided by UV-transparent partition walls (with neglected dimensions) into radiation chambers each with a layer thickness of 1 cm . The first 6 columns of Table 3 contain the same information as Table 2. Column V _k shows the volumes of the individual radiation chambers and column Q-40 (k) the flow rates for which the minimum radiation dose of 40 in each individual radiation chamber mWs / cm ² acts. The last column of Table 3 shows the radiation doses E · t (k) in mWs / cm ² , which the medium flowing through all the radiation chambers successively receives at a flow of 1.61 m ³ / h in each individual radiation chamber.

The penultimate column of Table 3 shows that with a parallel flow through the radiation chambers in such a way that the minimum radiation dose of 40 mWs / cm ^{2 is} maintained in each layer, a total flow of Q-40 (total) = 1.61 m ³ / h is possible. Correspondingly, it can be seen from the last column of Table 3 that when the radiation chambers are connected in series and at a flow of 1.61 m ³ / h, the medium has been irradiated with a total dose of approx. 40 mWs / cm ² . For a medium with a transmission factor T (1 cm) = 0.7, Q-40 (total) = 2.28 m ³ / h, for T (1 cm) = 0.8 the corresponding value Q-40 (total) = 3.15 m ³ / h h, for T (1 cm) = J.9 Q-40 (total) = 4.37 m ³ / h.

overall, the discussion above in connection with Tables 2 and 3 shows that the division of the photo reactor brings a significant increase in performance. This result is summarized in Table 4. For transmission factors T (1 cm) = 0.6 to 0.9, the lines in Table 4 contain the flow rates Q-40 (max) with the optimum layer thicknesses in each case, the flow rates Q-40 of the single-chamber photoreactor according to Table 2 with a layer thickness of d = 5 cm and the flow rates Q-40 (total) for a multi-chamber photoreactor with 5 radiation chambers each with a layer thickness of 1 cm (total layer thickness d = 5 cm), as well as the increase factors F of the flow rates Q-40 of the multi-chamber photoreactor compared to the single-chamber photoreactor.

Table 4 shows the advantages of the multi-chamber photoreactor compared to the known single-chamber photoreactors. Simply by dividing the radiation chamber of the single-chamber photoreactor into a multi-chamber photoreactor as described above, performance increases of over 100% can be achieved without additional radiation sources or other measures. This means that the flow rate or, with the same flow rate, the applied radiation dose can be doubled for the same radiation dose. Such effects cannot be achieved by any combination of single-chamber photoreactors. The performance increases achieved are both in the examples when the irradiation chambers are connected in parallel and when the irradiation chambers are connected in series equal. In practice, however, series connection offers considerable additional advantages. The series connection of the radiation chambers offers a significantly increased security against flow short circuits and additionally a significantly improved mixing of the medium to be treated in the entire radiation field. Through the series connection of radiation chambers, the flowing medium is guided through the radiation zone in alternating directions, the liquid particles being reoriented on the way through the radiation chambers by the forced reversal of the flowing layers. Since the series connection also works with relatively higher flow speeds, especially in the inner radiation chambers, flow conditions with significantly higher Reynolds numbers are possible compared to the single-chamber photoreactors. In addition to the better mixing, this has a favorable effect in suppressing precipitation.

Table 4 also shows in particular that the increase factors F increase sharply with decreasing transmission factors but constant layer thickness. This results from the fact that the single-chamber photoreactor has an optimum layer thickness for each transmission factor, ie such photoreactors are only slightly adaptable to media with variable or different transmission factors. In contrast, a multi-chamber photoreactor has the great advantage that it provides favorable performance even with media with highly variable or different transmission factors. The result of the radiation in the multi-chamber photoreactor is therefore not impaired in the case of media with a low transmission factor by the fact that considerable portions of the overall layer: receive only minimal radiation doses, and on the other hand the multi-chamber photoreactor with a high transmission factor of the medium allows the use of the given radiation flow through the high total layer thickness of all Radiation chambers.

Multi-chamber photoreactors with an annular arrangement of radiation source and flow reactor are constructed from a plurality of tube pieces made of quartz glass, which are arranged one inside the other and whose diameters are selected such that coaxial radiation chambers of the desired layer thickness are formed. Such quartz glass tubes can be produced with the desired accuracy of the dimensions and are commercially available with suitable diameters and wall thicknesses. The quartz glass tubes are centered to one another in a known manner and held between closure parts (see below) which close off the flow reactor at the end. The closure parts have e.g. mounting grooves for the quartz glass tubes sealed by stuffing box packings and are provided with internal channels and connecting pieces through which the supply and discharge of the medium are effected when the radiation chambers are connected in parallel and in series connection. Figures 9 to 12 show examples of annular multi-chamber photoreactors with internal radiation, with a pressure compensation device and with external radiation.

A three-chamber photoreactor 100 set up for internal irradiation is shown half in longitudinal section in FIG. 9. It contains a radiator 24 of the aforementioned type, which can be single or multiple turns to increase the irradiance in the photoreactor 100. The radiator 24 is arranged near the axis in the interior of a flow reactor 101, which is formed by a radiation-impermeable outer jacket 102, by a first closure part 103 and a second closure part 104 and by a radiation-permeable inner cladding tube 105 which is held in the first closure part 103. The inner cladding tube 105 is a quartz glass tube which is closed on one side and at the closed end of which the radiator 24 is on a Glass wool pack 27 rests. The flow reactor 101 is divided into three radiation chambers 109, 110, 111 by a quartz glass tube 106 and a quartz glass tube 107 which is closed on one side and has through openings 108 ih of the wall at its open end, both of which are also held in the first closure part 103

For connection to the closure parts 103, 104, the outer jacket 102 is provided at both ends with ring flanges 112 which have bores 113 distributed along their circumference. On the outside of the ring flanges 112 there are recesses 114 for receiving sealing 0-rings 115. The closure parts 103 and 104 carry flanges 116 with holes 117 distributed along their circumference, the number and diameter of which correspond to the holes 113 in the ring flanges 112 of the outer casing 102 . The outer casing 102 and the closure parts 103, 104 are arranged with the ring flanges 112 and the flanges 116 so that the bores 113 and 117 are aligned so that these parts are threaded bolts 118 which extend through the bores 113 and 117 and nuts 119 can be firmly connected.

The outer jacket 102 is provided with an opening 120 in the area of the radiation field of the emitter 24 for observation or control purposes, into which an aperture 121 with an outer ring flange 122 is fitted. When not in use, the tube 121 is closed by a cover 123 which is connected tightly and tightly, for example by screwing, to the ring flange 122. In use, the tube 121 is connected via a quartz window to the photodetector of a monitoring device for the radiation passing through the flow reactor 101. The outer jacket 102 can be provided with a material reflecting the UV rays into the medium in order to utilize the UV power radiated onto the outer jacket 102 when the medium has a high transmission factor. When using an outer jacket made of quartz, the reflective upper can Arrange the surface on the outside as well, which prevents the medium from influencing the reflectivity.

The outer jacket 102 and the closure parts 103, 104 consist of metal such as stainless steel, of metals with a protective coating of glass, enamel or plastic, of galvanized iron sheet, of ceramic; it can find for each _'material of suitable mechanical strength use, which is resistant to UV radiation and emits no foreign substances or pollutants to the flowing medium. In order to increase the mechanical strength and to facilitate processing and handling, the cladding tube 105 and the quartz glass tubes 106, 107 can be fused with extension pieces, for example made of sintered quartz, in the areas that lie outside the radiation field of the radiator 24.

The closure part 103 is generally ring-shaped and has an inner diameter which is closely matched to the outer diameter of the cladding tube 105. The annular closure part 103 carries two axial parts 124, 125, which extend on both sides of the flange 116 on its inner edge and serve to hold the cladding tube 105 or the quartz glass tubes 106 and 107. The first axial part 124 is provided on its outer end with a counterbore 126 into which a stuffing box packing 127 is inserted. The stuffing box packing 127 consists of two 0-rings 128, 130 separated by a guide ring 129, which by a pressure ring 131 with an annular flange 132, which is fastened by screws 133 to the outer surface of the first axial part 124, against which at the end of the counterbore 126 trained shoulder 134 are pressed. As a result, the cladding tube 105 is held firmly and sealed on the first axial part 124. The second axial part 125 is provided from the inside with three concentric annular grooves 135, 136 and 137, the depth of which decreases from the inside to the outside and the annular webs 138, 139, Train 140 and 141. The webs 138 and 139 have small and different axial depths and delimit the innermost, deepest ring groove 135. The middle ring groove 136 is delimited by the web 139 and the longer web 140, while the outermost, shallowest ring groove 137 by two webs 140 of the same depth. 141 is included. The central annular groove 136 serves to receive the quartz glass tube 106, the end of which lies against the bottom of the annular groove 136 via an O-ring 142; a bushing 143 surrounds the O-ring 142 and the upper end of the quartz glass tube 106. The quartz glass tube 106 is held firmly and sealed in the central ring groove 136 by a stuffing box packing 127, which is fastened to the outer surface of the web 140 with screws 133. The outer annular groove 137 serves to receive the quartz glass tube 107, which is closed on one side, the open end of which lies against the bottom of the annular groove 137 via an O-ring 144; a bushing 145 surrounds the O-ring 144 and the open end of the quartz glass tube 107, which is closed on one side. The quartz glass tube 107 is tightly and sealed above the passage openings 108 in the through a gland packing 127, which is fastened to the outer surface of the web 141 with screws 133 outer annular groove 137 held.

The closure part 103 has two radial channels 146 which open diametrically opposite in the peripheral surface of the flange 116 and which end in connecting pieces 147. At its inner end, the radial channels 146 are connected to an axial channel 148 which branches off at a right angle and opens into the bottom of the annular groove 135. This creates a connection between the connecting piece 147 and the inner radiation chamber 109. The flange 116 additionally has an axially extending ventilation channel 149, which connects the outer radiation chamber 111 to a ventilation valve 150 on the outside of the flange 116.

The closure part 104 consists of a plate 151 with a central connecting piece 152. The inner surface of the plate 151 there is a ring 153 which lies circumferentially against the inner wall of the outer casing 102.

The flow through the three-chamber photoreactor 100 takes place between the connecting pieces 147t and 152 through the radiation chambers 109, 110 and 111, the radiation chambers 110 and 111 communicating with one another through the through openings 108 in the wall of the quartz glass tube 107 closed on one side. Annular perforated plates 154, 155 are provided to produce a uniform flow profile. The perforated plate 154 is fastened to the web 139 of the second axial part 125 of the first closure part 103 and acts on the flow passing through the inner radiation chamber 109. The perforated plate 155 lies against the ring 153 lying on the inner surface of the plate 151 of the second closure part 104 and acts on the flow passing through the outer radiation chamber 111; the quartz glass tube 107 bears on its inner edge, which is additionally guided at its closed end. The perforated plates 154, 155 consist of material which is resistant to UV radiation and the medium flowing through and does not itself emit any foreign or harmful substances to the medium (stainless steel, coated metals, plastic, ceramic, quartz, glass). The width of the holes is so large that the flow is not significantly hindered, but a flow profile which is uniform over the passage area is produced. For this purpose, the holes can also be replaced by openings of another suitable shape such as slots.

The direction of flow does not play a role for the continuous operation of the three-chamber photoreactor 100. However, there may be significant differences when starting up the business. In the event of repeated interruptions in operation, it may be desirable to obtain medium of the required degree of purity or sterilization after a very short start-up time. Then it is expedient to remove the medium from the external radiation chamber via the connection piece 152 111 to flow through the inner radiation chamber 109 to the connecting piece 147. With the same direction of flow, in cases of precipitation formation, it can be achieved that the disruptive effect initially remains limited to the outer radiation chambers and does not question the overall result too quickly. For reasons of lamp cooling, however, the flow direction from the inside to the outside will generally be preferred, likewise in the case of fumigation.

Es ergibt sich aus der Tabelle 5, daß die Leistung des Einkammer_-Photoreaktors mit der Schichtdicke d = 5.2 cm für T (1 cm) = 0.7 einen Durchfluß Q-40 = 0.78 m³/ h aufweist; bei ebenfalls 4 cm Hüllrohraußendurchmesser und bei gleichem Transmissionsfaktor erreicht die Leistung des Ein- kammer-Photoreaktors maximal einen Wert von Q-40 (max) = 1 m³/ h bei der Schichtdicke d = 2 cm. Die dreifache Unterteilung in dem in Figur 9 dargestellten Dreikammer-Photoreaktor 100 ergibt dagegen einen Durchfluß Q-40 = 1.75 m³/h, so daß selbst gegenüber der Optimalleistung des Einkammer-Photoreaktors der Steigerungsfaktor immer noch 1.75 beträgt. Dieses Ergebnis wird erzielt, obwohl ein Teil der von der Strahlungsquelle ausgehenden UV-Strahlung von dem Quarzglas absorbiert wird, aus dem die Quarzrohre 106 und 107 bestehen (in der Berechnung berücksichtigt).The three-chamber photoreactor 100 shown in FIG. 9 has an inner radiation chamber 109 with a layer thickness of 0.8 cm, a middle radiation chamber 110 with a layer thickness of 1 cm and an outer radiation chamber 111 with a layer thickness of 3.4 cm. The outer diameter of the cladding tube 105 is 4 cm, the wall thickness of the quartz glass tubes 106 and 107 is in each case 0.4 cm, and the transmission of the quartz glass at 254 nm is T (0.4 cm) = 0.92 at this thickness. In the cladding tube 105 there is a mercury low-pressure quartz lamp (G 36 T g; General Electric) with an effective arc length of 75 cm, the radiation flux of which gives a power of 11 W UV-254 nm to the medium on the irradiated inner surface of the cladding tube 105. For comparison purposes, the values given in Table 5 below are standardized to a radiation flux of 15 W UV-254 nm over an effective length of the irradiation area of 1 m in the radiation chamber 109. The following table shows the flow rates Q-40 (m ³ / h) of the three-chamber photoreactor 100 with a total layer thickness of 5.2 cm and of single-chamber photoreactors with a layer thickness d = 1 cm or d = in an analogous manner to the table 4 above 5.2 cm for media with transmission factors of T (1 cm) = 0.9 to 0.1, and the increase factors F of the flow rates Q-40 of the three-chamber photoreactor 100 compared to the aforementioned single-chamber photoreactors.

It is apparent from Table 5, that the power of the single chamber _- photoreactor with the layer thickness = 5.2 = 0.7 = m / d cm having for T (1 cm) a flow rate Q-40 0.78 ³ h; with an outer tube diameter of 4 cm and the same transmission factor, the performance of the single-chamber photoreactor reaches a maximum of Q-40 (max) = 1 m ³ / h with a layer thickness of d = 2 cm. The threefold subdivision in the three-chamber photoreactor 100 shown in FIG. 9, on the other hand, results in a flow rate Q-40 = 1.75 m ³ / h, so that the increase factor is still 1.75 compared to the optimum performance of the single-chamber photoreactor. This result is achieved even though part of the UV radiation emanating from the radiation source is absorbed by the quartz glass of which the quartz tubes 106 and 107 are made (taken into account in the calculation).

The three-chamber photoreactor 100 shown in FIG. 9 is preferably used in all those cases in which high degrees of disinfection are to be achieved even with relatively low transmission factors, and is therefore not restricted to the disinfection of drinking water or the like.

As Table 5 shows, the single-chamber photoreactor is only adaptable in the region of low layer thicknesses, such as at d = 1 cm, for the region of the transmission factors T (1 cm) = 0.9 to 0.3, but at the expense of performance. With a layer thickness in the range of 5 cm, the single-chamber photoreactor shows such a considerable drop in performance at T (1 cm) = 0.7 that media with even lower transmission factors are often no longer an option for economic disinfection. In contrast, the three-chamber photoreactor 100 described in FIG. 9, see row 1 in Table 5, shows superior performance and adaptability in the range of the transmission factors T (1 cm) = 0.9 to 0.1. The three-chamber photoreactor 100 according to FIG. 9 is suitable for the entire area of drinking water disinfection but also the area of biologically pre-treated wastewater with transmission factors T (1 cm) between 0.6 and 0.25, and thus also that of sugar solutions, colorless vinegar, light wines. The three-chamber photoreactor 100 described by FIG. 9 is also well suited for special purposes, for example water purification with significantly increased radiation doses.

FIG. 10 shows a modification of the three-chamber photoreactor 100 with a pressure compensation device. Only the parts that have been changed compared to the three-chamber photoreactor 100 are shown in accordance with FIG. 9 and are provided with special reference numerals.

The flow reactor 171 according to FIG. 10 consists of an outer tube 172, a first closure part 173 and a second closure part 174. The radiator 24 (not shown) and the quartz glass tubes 105, 106, 107, also not shown, are designed and arranged as in the flow reactor 101 .

The outer casing 172 is provided for connection to the closure parts 173, 174 at both ends with ring flanges 182 which have reinforcements 181 running along their inner circumference and bores 183 distributed along their outer circumference. On the outside of the ring flanges 182 there are ridges 184 which interact with seals 185 in recesses 190 on the respective counter flanges 186. The counter flanges 186 of the closure parts 173, 174 have reinforcements 181 running along their inner circumference and bores 187 distributed along their outer circumference, the number and diameter of which correspond to the bores 185 in the ring flanges 182 of the outer casing 172. The outer jacket 172 and the closure parts 173, 174 are arranged such that the bores 183 and 187 are aligned so that they are fixed by threaded bolts 188 which extend through the bores 183 and 187 and nuts 189 and are connected to each other in a pressure-tight manner.

The closure part 173 is provided on the counter flange 186 like the closure part 103 with axial parts, of which only the axial part 124 is shown in a hint. These axial parts are identical to the axial parts 124, 125 of the flow reactor 101 and, like these, serve to hold quartz glass tubes 105, 106, 107; these parts are therefore not shown in detail in FIG. 10. Like the flange 116, the counter flange 186 also has two diametrically opposed radial channels 146 which open in its circumferential surface and end in connecting pieces 147.

On the side facing away from the outer tube 172, the counter flange 186 carries an attachment 191 which is fixedly connected to it or formed from a single piece, to which a rounded cover 192 with a counter flange 186 is flanged in a pressure-tight manner in the manner already described above via an annular flange 182. The cover 192 has a central, pressure-tight, high-voltage and arcing-proof bushing 193 for the connection of the radiator 24 (not shown). A connecting piece 194 is provided for connection to a barostat, which is designed commercially and is therefore not described in detail here.

The closure part 174 consists of a rounded cover 195 with a central connecting piece 196 and with a counter flange 186 for connection to the other ring flange 182 of the outer tube 172 in the manner already described above. A ring 153, not shown here, is supported within the cover 195 and, like in the flow reactor 101, a perforated plate 155 rests on it.

In operation, a pressure gas, preferably an inert gas such as nitrogen, argon or, is fed from the barostat via the connecting piece 194 to the flow reactor 171 Carbon dioxide. A pressure which is equal to the internal pressure of the flow reactor 171 is generated and maintained by the barostat. This prevents pressure differences occurring at the quartz glass tubes 105, 106, 107, which can lead to mechanical stresses and breakage of the quartz glass tubes. I.

FIG. 11 shows a further design of a multi-chamber photoreactor, which differs from the three-chamber photoreactor 100 essentially in the number of radiation chambers and in the design of the cladding tube. FIG. 11 shows a two-chamber photoreactor 200 in the same representation as the three-chamber photoreactor 100 in FIG. 9.

A flow reactor 201 is formed by a radiation-impermeable outer jacket 202, by a first closure part 203 and a second closure part 204 and by a radiation-permeable inner cladding tube 205 which is held by both closure parts 203 and 204. The inner cladding tube 205 is a quartz glass tube that is open on both sides. The flow reactor 201 is divided into two radiation chambers 209, 211 by a quartz glass tube 207, the ends of which are held on the closure parts 203 and 204, respectively.

For connection to the closure parts 203, 204, the outer jacket 202 is provided at both ends with ring flanges 212 which have bores 213 distributed along their circumference. On the outside of the ring flanges 212. There are recesses 214 for receiving sealing O-rings 15. The closure parts 203, 204 carry flanges 216 with bores 217 distributed along their circumference. The outer jacket 202 and the closure parts 203, 204 are firmly and sealingly connected to one another by threaded bolts 218, which extend through the bores 213 and 217 and are secured by nuts 219 connected.

The outer jacket 202, like the outer jacket 102 of the three-chamber photoreactor 100 according to FIG. 9, is provided with an opening 220 and a tube 221 with an annular flange 222 and cover 223 for observation or control purposes. Furthermore, the outer jacket 202 carries a lateral connection piece 224 near the end which is adjacent to the closure part 203. The outer jacket 202, the closure parts 203, 204 and the quartz glass tubes 205, 207 are made of the same material as the corresponding parts of the three-chamber photoreactor 100 .

The closure parts 203, 204 are generally ring-shaped and have an inner diameter which is closely matched to the outer diameter of the cladding tube 205. The closure part 203 has an axial part 225, which extends from the flange 216 on its inside into the interior of the flow reactor 201 and serves to hold the cladding tube 205 or the quartz glass tube 207 at one end of the flow reactor 201. At its outer end, the closure part 203 is provided with a counterbore 226, into which a stuffing box packing 127 is inserted, which is fastened with screws 133 to the outer surface of the closure part 203 and holds the cladding tube 205 firmly and sealingly at this end of the flow reactor 201. At its inner end, the axial part 225 is provided with an annular recess 235 which is delimited on the outside by an annular web 237. The axial part 225 has an outer diameter which is closely matched to the inner diameter of the quartz glass tube 207, so that one end is pushed onto the axial part 225. A sealing sleeve 240, which is optionally secured by ligatures in the manner of hose clips, surrounds the free part of the axial part 225 and the end of the quartz glass tube 207 pushed onto the remaining part. This end of the quartz glass tube 207 is thereby held firmly and sealingly on the closure part 203.

The closure part 203 has a channel 246 opening in its outer surface, which ends in a connecting piece 247. The channel 246 is connected at its inner end to an axial channel 248 which extends through the axial part 225 and opens into the bottom of the annular recess 235. This creates a connection between the connection piece 247 and the inner radiation chamber 209.

The closure part 204 has an axial part 265 which extends away from the flange 216 on the inside of the flow reactor 201 and serves to hold the cladding tube 205 at the other end of the flow reactor 201. At its outer end, the closure part 204 is provided with a counterbore 266 into which a stuffing box packing 127 is inserted, which is fastened with screws 133 to the outer surface of the closure part 204 and holds the cladding tube 205 firmly and sealingly at this end of the flow reactor 201. On its inner surface, a ring 268 is fastened to the closure part 204 with screws 267, from which protruding leaf springs 269 protrude like a crown, between which a protective sleeve 270 surrounding the other end of the quartz glass tube 207 is guided. The closure part 204 has an axially extending drain channel 249, which connects the outer radiation chamber 211 to a drain valve 250 on the outside of the flange 216.

The flow through the two-chamber photoreactor 200 takes place between the connecting pieces 224 and 247 through the radiation chambers 209 and 211, which communicate with one another through the gaps (not shown) between the leaf springs 269 projecting into the flow reactor 201 from the inner surface of the closure part 204. To produce a uniform flow profile, perforated plates 254, 255 are provided, which are designed as in the three-chamber photoreactor 100. The perforated plate 254 is attached to the web 237 of the axial part 225 protruding from the annular recess 235 by the closure part 203 and acts on the flow passing through the inner radiation chamber 209. The perforated plate 255 bears against a ring 251 fastened to the inner surface of the outer casing 202 near the connecting piece 224, which ring can thus also be formed in one piece; on the inside it lies against the end of the sealing sleeve 240. The perforated plate 255 is secured against displacement by locking rings 256; it acts on the flow passing through the outer radiation chamber 211.

The two-chamber photoreactor 200 shown in FIG. 11 has an inner radiation chamber 209 with a layer thickness d = 2.4 cm and an outer radiation chamber 211 with a layer thickness d = 4.6 cm. The outer diameter of the jacket tube 205 is 7.2 cm, the wall thickness of the quartz glass _tubes' 205 and 207 in each case is 0.4 cm, and the transmittance of the silica glass at 254 nm is at that thickness T (0.4 cm) = 0.92. In the cladding tube 205 there is an antimony-doped xenon high-pressure lamp (original Hanau Quarzlampen GmbH, Hanau), whose radiation flow in the range from 260 to 280 nm with an effective length of 80 cm of the irradiation area at the radiation chamber 209 has a power of 100 W to the medium emits the irradiated inner surface of the cladding tube 205. The following table 6 shows in an analogous manner to the above table 5 the flow rates Q-40 of the two-chamber photoreactor 200 with a total layer thickness d = 7 cm and a single-chamber photoreactor of the same layer thickness for media with transmission factors from T (1 cm) = 0.95 to 0.6 and the increase factors F of the flow rates Q-40 of the two-chamber photoreactor 200 compared to the aforementioned single-chamber photoreactor.

The data in the table are given for the transmission of the quartz glass at 254 nm, so as to facilitate comparison with the flow values Q-40 of the same photoreactors when using low-pressure mercury quartz lamps. However, the transmission of the quartz glass is higher in the range from 260 to 280 nm, which results in an increase in the Q-40 values given in the table.

With a layer thickness of the inner radiation chamber 209 of d = 2.4 cm and the outer radiation chamber 211 of d = 4.6 cm, the two-chamber photoreactor 200 corresponds to a total layer thickness of d = 7 cm for high flow rates Q-40 in the range essential for drinking water disinfection Transmission factors T (1 cm) = 0.7 are provided. The performance comparison in Table 6 shows that using two radiation chambers in the range between T (1 cm) = 0.85 to 0.7, an increase factor of 1.55 can be achieved. Because of the target Flow rates Q-40 do without more radiation chambers; for the same reason, the outer diameter of the cladding tube 205 must not be chosen too small. The two-chamber photoreactor 200 is particularly suitable for the purposes of water disinfection in the beverage industry and for UV disinfection in the drinking water supply.

The direction of flow hardly plays a role in the continuous operation of the two-chamber photoreactor 200. For lamp cooling reasons, the flow direction from the inner radiation chamber 209 through the outer radiation chamber 211 will generally be preferred, as well as in the case of fumigation. Because of the high flow rates, there are practically no disturbing start-up phenomena even when there are interruptions in the operation of the two-chamber photoreactor 200. Only if there is a risk of precipitation will the reverse flow direction be selected if necessary.

Another embodiment of a two-chamber photoreactor is shown in FIG. The two-chamber photoreactor 300 is provided for irradiation from the outside with a radiation source (not shown) consisting of 14 emitters (low-pressure mercury quartz lamps NN 30/89 Original Hanau Quarzlampen GmbH, Hanau). The emitters are located in a reflector system made of parabolic reflectors, which is arranged concentrically to a Durohflußreaktor 301, each of which is assigned to one emitter. The entire arrangement is surrounded by a radiation-impermeable housing, which also houses the ballast and operating elements as well as the monitoring device for the operation of the two-chamber photoreactor 300. Such housings and radiation sources are known and commercially available (WEDECO, Society for Disinfection Systems, Düsseldorf, Herford) and therefore do not need to be described in detail here. Otherwise, the representation in FIG. 12 corresponds the representation of the three-chamber photoreactor 100 in FIG. 9.

The flow reactor 301 is formed by a radiation-permeable outer tube 302 made of quartz glass, a holder 30, a closure part 304 and an inner tube 305 made of quartz glass. The inner tube 305 divides the flow reactor 301 into two radiation chambers 309, 311. The outer tube 302 is connected to the holder 303 or the closure part 304 via ring flange pieces 312, which are arranged near its ends, with bores 313 distributed along its circumference. The holder 303 and the closure part 304 carry ring flanges 316 with holes 317 distributed along their circumference, the number and diameter of which correspond to the holes 313 in the ring flange pieces 312. The ring flange pieces 312 and the holder 303 or the closure part 304 are arranged such that the bores 313 and 317 are aligned and the parts are connected to one another by means of threaded bolts 318 secured with nuts 319. The flange parts 312 and 316 have an inner diameter which is closely matched to the outer diameter of the outer tube 302; on the inside they are provided with mutually facing annular recesses 320, against the bottom of which 0-rings 321 are pressed by a guide sleeve 322. In this way, the outer tube 302 is held firmly and sealingly.

The holder 303, the closure part 304 and the inner tube 305 are made of the same material as the corresponding parts of the two-chamber photoreactor 200.

The holder 303 is in the form of an axially stepped ring which in its first step 323 is closely matched to the outer diameter of the outer tube 302 and with a shoulder 358 is closely matched to the inner diameter of the outer tube 302 and is provided with connecting pieces 324; a second step 325 is close in the inside diameter to the outside diameter of the Adapted inner tube 305 and carries a counterbore 326, into which a stuffing box packing 127 is inserted, which is fastened with screws 133 to the outer surface of the holder 303 and holds the inner tube 305 firmly and sealingly in the holder 303. Above the holder 303 there is a further ring flange piece 312, to which a transition piece 328 provided with a ring flange 316 is fixedly and sealingly connected by threaded bolts 31 $ secured with nuts 319 by incorporating 0-rings 321. The transition piece 328 has a clear width which is closely matched to the outer diameter of the inner tube 305; it extends a bit beyond one end of the inner tube 305 and then narrows to a connecting piece 329.

The closure part 304 consists of an axially extending ring 340 which carries the flange 316 and which is fixedly connected to or integrally with a plate 341 which closes the flow reactor 301. The plate 341 carries on its inside an attached ring 342, which is fixedly connected to it or consists of one piece therewith and ends in a raised double ring 343 of U-shaped cross section. The ring 342 runs below the inner tube 305 concentrically thereto; the double ring 343 is adapted to its dimensions, so that the inner tube 305 is guided at its other end in the double ring 343 (with the insertion of an elastic protective ring 344). The ring 342 has through openings distributed around its circumference: 345, through which the radiation chambers 309, 311 communicate. The plate 341 is provided with an axially extending emptying channel 349, which connects the outer radiation chamber 311 with an emptying valve 350 on the outside of the plate 341.

The flow through the two-chamber photoreactor 300 takes place between the connecting pieces 324 and 329 through the Irradiation chambers 309 and 311. In order to produce a uniform flow profile, perforated plates 354, 355 are provided which are designed in accordance with the three-chamber photorepirator 100. The perforated plate 354 lies within the transition piece 328, which is connected to the holder 303, the melting edge of the inner tube 305 and is secured by a snap ring 356. A storage space 357 is formed between the connecting piece 329 of the transition piece 328 and the perforated plate 354, which acts on the flow passing through the inner radiation chamber 309. The perforated plate 355 is held between the melting edge at one end of the outer tube 302 and the shoulder 358, which is formed in the first stage 323 of the holder 303, and acts on the flow passing through the outer radiation chamber 311.

The two-chamber photoreactor 300 shown in FIG. 12 has an outer radiation chamber 311 with a layer thickness d = 2.5 cm and an inner radiation chamber 309 with an inner diameter of 9.2 cm. The outer diameter of the outer tube 302 is D _a = 15.8 cm, the wall thickness of the quartz glass tubes 302 and 305 is in each case 0.4 cm and the transmission of the quartz glass at 254 nm is T (0.4 cm) = 0.92 at this thickness. 14 low-pressure mercury quartz lamps arranged in paraboloid reflectors (NN 30/89 Original Hanau Quarzlampen GmbH, Hanau) surround the flow reactor 301 concentrically and give an average radiation power of 85 W UV-254 nm over the circumference of the outer tube 302 in the medium over an effective one Length of the radiation chamber 311 of 79 cm. The following table 7 shows the flow rates Q-40 of the two-chamber photoreactor 300 and of a single-chamber photoreactor with analog external radiation with 6 low-pressure mercury quartz lamps of the same type and with an inner diameter of D = 7 cm, and those with a power of 15 W. UV-254 nm standardized values of the flow rates Q-40 with transmission factors T (1 cm) from 0.9 to 0.6. The table also shows the increase factors F, which are calculated from the normalized flows Q-40.

The performance comparison of the two-chamber photoreactor 300 is carried out with a tried and tested cylindrical single-chamber photoreactor with external radiation, since such single-chamber photoreactors are not built with larger diameters because of the risk of flow short-circuits. As an alternative to increasing the power of axial radiation sources, external radiation offers the possibility of achieving significantly increased space-time yields, ie higher Q-40 flow rates with the same apparatus volume. Although such photoreactors with external radiation Because of the positive radiation geometry, the disadvantages of strong radiation gradient gradients in the reactor cross-section are much less, the multi-chamber photoreactor principle also offers considerable increases in performance.

The flow direction does not play an important role in the practical operation of the two-chamber photoreactor 300.

The use of the two-chamber photoreactor 300 for cleaning purposes is shown in the following experimental examples:

1. Removal of residual ozone from water

Ozonated water with a residual ozone content of 0.3 g / m ³ (0.3 ppm) is passed through the two-chamber photoreactor 300 at a flow rate of Q = 40 m ³ / h. The water entering the inner radiation chamber 309 is practically ozone-free (<0.02 ppm) after exiting the outer radiation chamber 311; Detection by Palin's reagent or colorimetric analysis (diethyl-p-phenylenediamine and potassium iodide).

2. Removal of aromatic hydrocarbons from water

An emulsion of approx. 10 g of an aromatic tar oil in 70 m ³ water corresponding to the water content of a swimming pool contains approx. 0.13 mg / 1 aromatics, which are detected by their characteristic UV absorption. The water is circulated through a sand filter system with a delivery rate of 25 m ³ / h. The aromatic content (UV absorption) does not change. If a two-chamber photoreactor 300 is connected downstream of the sand filter system, no aromatic contaminants can be detected in the outlet of the photoreactor (UV absorption, 5 cm cell).

A further increase in output in the two-chamber photoreactor 300 can be achieved if internal radiation is also provided. A photoreactor of this type is obtained in a simple manner by combining the corresponding elements from FIGS. 11 and 12, so that its construction need not be described in detail here. An antimony-doped & xenon high-pressure lamp serves as the internal radiation source, which can also be single or multiple turns to increase the irradiance; mercury vapor lamps of suitable emission areas serve as external radiation sources. Such radiators are commercially available and therefore do not need to be shown and explained in detail.

Further modifications in the structure of the flow reactors 2, 21, 41, 101, 201, 301 result from the fact that a number of known, partly differently designed mounting and guide elements are available to the person skilled in the art for the dividing walls dividing the reactor space. These can be used instead of the devices shown in FIGS. 1 to 12. In many cases, a version with only one side connection piece 147, 224 or 324 is sufficient.

There is a problem in all cases in which the removal of the irradiated medium is subject to fluctuations and is even temporarily interrupted, but a constant high minimum level of cleaning or disinfection is required. In such cases, a multi-chamber photoreactor of the type shown in FIGS. 9 to 12 is operated in the return. FIG. 13 schematically shows a flow diagram for the irradiation operation with return for the three-chamber photoreactor 200; however, a multi-chamber photoreactor 20, 100 or 300 can also be used instead. The two-chamber photoreactor 40, which is already provided for an irradiation circuit, can also be used, which in this mode of operation is used for climate washers is used, but is less suitable for continuous disinfection with partial return than the other multi-chamber photoreactors mentioned. The flow diagram contains the three-chamber photoreactor 200, the connecting piece 224 of which is connected to the supply line of the medium to be irradiated via a supply line 401 and a supply valve 402. The connecting piece 247 is connected via a flow divider 403 with a vent valve 424 and connecting lines 404, 405, each of which carries a flow indicator 406, to a return 407 or a removal valve 408. A flow limiter 12 is connected downstream of the feed valve 402. The return 407 consists of a return feed pump in the form of a one-way feed pump 409 with constant delivery rate, a downstream check valve 410 and a connecting line 411 with flow indicator 406, which opens downstream of the valve 402 into the supply line. The return 407 can instead of the one-way feed pump 409 also contain a return feed pump which is adjustable in its delivery capacity; if necessary, the return 407 can also be equipped with an adjustable flow restrictor. The total volume of the return 407 is small compared to the volume of the respective multi-chamber photoreactor.

The flow divider 403 shown in FIG. 14 is constructed in the manner of a pressure overflow regulator. The sectional view according to FIG. 14 shows a vessel 420, which is provided at the top with a vent valve 424 and whose inlet connection 421 is provided for connection to the two-chamber photoreactor 200. The inlet connection 421 protrudes beyond the bottom of the vessel 420 and into the interior thereof. A first outlet 422 runs from the bottom of the vessel 420 and leads to the return line 407 for connection to the connecting line 404.

• Bei geschlossenem!Entnahmeventil 408 und laufender Einweg-Förderpumpe 409 ergibt sich ein in sich geschlossener Kreislauf des Mediums, das über die Verbindungsleitungen 411, 401.und den Anschlußstutzen 224 des Zweikammer-Photoreaktors 200 in die Bestrahlungskammer 211 eintritt und diese nach Durchtritt durch die innere Bestrahlungskammer 209 über die Anschlußstutzen 247 wieder verläßt. Von dort gelangt es über den Eingangsstutzen 421 in das Innere des Gefäßes 420 des Strömungsteilers 403, den es über den ersten Ausgang 422 verläßt, der über die Verbindungsleitung 404 eingangsseitig an die Einweg-Förderpumpe 409 angeschlossen ist.

A second outlet 423 is arranged on the vessel 420 clearly above the mouth of the inlet connection 421 and serves for connection to the connecting line 405 to the extraction valve 408. The arrangement shown in FIGS. 13 and 14 works as follows, it being assumed that the system is supplied with the medium and vented and that the valves 402 and 408 are initially closed:

• When the extraction valve 408 is closed and the disposable feed pump 409 is running, there is a self-contained circuit of the medium, which enters the radiation chamber 211 via the connecting lines 411, 401. And the connecting piece 224 of the two-chamber photoreactor 200 and passes through the inner chamber Irradiation chamber 209 leaves again via the connecting piece 247. From there it passes via the inlet connection 421 into the interior of the vessel 420 of the flow divider 403, which it leaves via the first outlet 422, which is connected on the input side to the one-way feed pump 409 via the connecting line 404.

The opening of the removal valve 408 is synchronously coupled to the opening of the supply valve 402, through which medium to be irradiated is fed to the two-chamber photoreactor 200 via the supply line 401. The coupling is done by known mechanical, electrical, hydraulic, pneumatic means or the like. Corresponding to the volume of medium to be irradiated, the irradiated medium is now displaced out of the irradiation circuit system by the opened removal valve 408. Since the medium supplied is already diluted by the medium which has already been sterilized before it enters the two-chamber photoreactor 200, a medium with a lower number of incoming bacteria now passes through the photoreactor and a lower number of final bacteria results. It should be borne in mind that the recycled material is subjected to renewed irradiation in a mixture with previously unirradiated medium, which means a change in efficiency as a whole. With this method of operation, therefore, a lower flow rate must be used than be set in operation without return, and this reduction is also based on the reflux ratio.

In order to operate the return radiation with greater effectiveness, however, the medium to be sterilized is expediently added discontinuously in a small amount and passed through. This is done by batch-wise displacement of a large part of the reactor contents with simultaneous stopping of the reflux operation, followed by a period of irradiation in the circuit which, depending on the desired doses, can amount to several revolutions of the reactor volume. For this purpose, a further controlled valve 412 (see FIG. 13A) is provided in the return line 407, which is coupled synchronously in a push-pull manner to the removal valve 408 or the supply valve 402 by one of the aforementioned means. The two last-mentioned coupled valves remain open until the intended portions of the unirradiated medium have filled the photoreactor and the irradiated medium has left the photoreactor. After the valves have been closed, the valve 412 in the return 407 is opened synchronously and the radiation is carried out in the circuit until the next loading period. A continuous removal of the sterilized medium can then be achieved in that the removal valve 408 is connected to an intermediate container with level control and an extraction point equipped with a flow limiter.

The easiest way to carry out the discontinuous supply of the medium is with the aid of a controlled metering pump, the respective metering portions of which must remain just below the reactor volume. The further controlled valve 412 in the return 407 is coupled synchronously in push-pull to the metering pump by one of the aforementioned means, so that the medium is supplied only when the return 407 is closed. The bleed valve 408 and the supply valve 402 can then be omitted. The level control of the above-mentioned continuous removal device with an intermediate container can also be used to vary the period of the metering and thus the average of the flow rate if the need changes within the limits of the performance of the apparatus. In this way it is possible to achieve intended increases in dose while maintaining the function of a given photoreactor.

When cleaning and disinfecting by UV radiation using the described return radiation method, it is advisable to operate multi-chamber photoreactors so that the medium passes through the radiation chamber with the smallest cross-section and the highest radiation intensity last.

Multi-chamber photoreactors with the simple type of return operation are particularly suitable for water disinfection on seagoing ships. The process of portionwise return radiation is particularly suitable for the application of high doses and thus for achieving the highest levels of cleaning and disinfection.

The necessary security in achieving the desired irradiation result is achieved by flow control means which ensure that a certain, maximum permissible flow rate of the medium in the multi-chamber photoreactors according to FIGS. 1 to 12 cannot be exceeded. In the simplest case, a flow restrictor in the feed line to the respective flow reactor is sufficient as a safety element. When the inlet pressure changes, an adjustable flow restrictor, for example in the form of a valve, is recommended, but the more reliable flow restrictor 12 is preferably used here. For safety reasons, its interposition is also carried out when a pump is connected adjustable delivery rate is used, in which the delivery rate can be set immediately and also monitored.

The multi-chamber photoreactors described above are provided with conventional, known monitoring devices of the type mentioned at the outset. This ensures that an alarm is triggered and the entire radiation system is switched off if the irradiance drops below a predetermined target value. In addition, the radiation flow of the emitters decreases over time. Because of the exponential dependency of the irradiation result discussed above and thus also the performance of the multi-chamber photoreactor on the irradiance, a constant adaptation of the flow rate to the instantaneous irradiance is necessary for optimal use of the radiation emitted by the radiation source. For this purpose, a feed pump 450 with an adjustable delivery rate is connected on the input side to a flow reactor 101, 201 or 301, and its delivery rate is adjusted by a controller, which is shown in the block diagram in FIG. 15, in accordance with the respective irradiance. The control consists of a tachogenerator 452 connected to the pump motor 451 and a radiation-sensitive detector 453, which is connected to earth via a discharge resistor 456. And on the tube 121, 221 of a flow reactor 101 or 201 or on the inner tube 302 of the flow reactor 301 (with a suitable implementation) is attached and the output signal is applied to an amplifier 454. The output signals of the tachometer generator 452 and the amplifier 454 are connected in opposition to one another at the input of a power amplifier 455, and the amplified differential voltage present at the output of the power amplifier 455 is used to supply the pump motor 451. In this way, the delivery rate is increased by a control built up from commercially available components the pump 450 adapted to the respective irradiance.

In the multi-chamber photoreactors 100, 200, 300 described above, the respective radiation chambers are connected in series with respect to the direction of flow. This circuit has its particular advantages in better mixing and the passage of the medium through all of the irradiation chambers of the photoreactor. In special cases, however, it may also be advantageous to connect radiation chambers in parallel, specifically when media with high transmission factors are to be processed.

Flow reactors of the type shown in FIGS. 11 and 12 can easily be modified so that the radiation chambers 209 and 211 or 309 and 311 are suitable for parallel flow according to FIGS. 16 and 17. The modified version of the two-chamber photoreactor 200 consists of a flow reactor 501 which surrounds a UV radiation source 24 and essentially contains two radiation chambers 509 and 511, each of which is provided with inlet and outlet connections. FIG. 16 shows a longitudinal section through one half of the flow reactor 501, the other half of which is of mirror-image design, very similar to this.

The flow reactor 501 consists of an outer jacket 202A, which differs from the outer jacket 202 of the flow reactor 201 only in that a further pair of opposing connecting pieces 224 is provided close to the other ring flange 212, not shown in FIG. However, only one observation opening 220 is provided, into which a tube 221 with an annular flange 222 and a cover 223 is inserted.

The flow reactor 501 is provided at both ends by identically designed closure parts 503 with an intermediate _flange. member 504 closed, to which the closure parts 503 are fastened, for example, by means of screw bolts 506 which extend through the flanges 516 of the closure parts 503. The intermediate flange members 504 have flanges 216 with bores 217 which are distributed over the flange 216 near the circumference thereof. The outer jacket 202 and the intermediate flange members 504 are firmly and sealedly connected to one another by bolts 218, which extend through the bores 217 and are secured by nuts 219, with sealing rings 215 being arranged in annular recesses 214.

The closure members 503 are generally ring-shaped and extend axially from an outer end that closely conforms to the outer diameter of the cladding tube 205 to an inner end that closely conforms to the outer diameter of the quartz glass tube 207. At the outer end there is a counterbore 526, into which a stuffing box packing 127 is inserted, which are fastened to flange-like parts by means of bolts 533 and serve to hold the cladding tube 205 firmly and sealingly. In an intermediate area between the axial ends, the axial parts of the closure parts 503 expand to accommodate the quartz glass tube 207. Two diametrically opposed connection pieces 524 are arranged on the enlarged axial part in order to introduce the medium to be irradiated into the inner irradiation chamber 509. A shoulder 552, which bears a perforated plate 554, which is secured by a securing ring 553, is formed on the inner wall of the enlarged axial part, close to the connecting piece 524. The axial inner end of the closure part 503 extends in each case beyond the flange 516 for a purpose explained below.

Each intermediate flange member 504 is also generally ring-shaped and consists of a flange part and an axial part 537, the inside diameter of which is close to that Outside diameter of the quartz glass tube 207 is adapted. The axial part 537 is provided with a counterbore 536 which extends over a length such that the axial inner end of the closure part 503 and a gland packing made of two sealing rings 538, 540 and a guide bush 539 can be accommodated therein. This arrangement serves together with the flange 516 of the closure part 503, which is fastened to the flange of the intermediate flange member 504 by means of screw bolts 506, for firmly and sealingly holding the quartz glass tube 207 in a manner similar to how the cladding tube 205 is held by the stuffing box packing 127. The end face of the axial part 537 is chamfered inwards in order to facilitate the centered insertion of the quartz glass tube 207 when assembling the flow reactor 501.

The bevelled end faces of the axial parts 537 of the intermediate flange members 504 do not extend into the region of the connecting piece 224 in order to ensure that the flow of the medium through the outer radiation chamber 511 is not hindered thereby. On the other side of the connecting piece 224, an annular shoulder 251 is formed on the inner wall of the outer casing 202A, said ring shoulder abutting a perforated plate 254 which is held by a securing ring 253.

The parts of the flow reactor 501 are made of the same material as the corresponding parts of the flow reactor 201.

FIG. 17 shows a longitudinal section through one half of a flow reactor 301A, which is used in connection with an external radiation source. The two halves of the flow reactor 301A are essentially mirror images of one another and their construction is identical to that part of the flow reactor 301 which is shown in FIG. 12 above the break line. It is therefore no further explanation is required at this point, except that two diametrically opposed pairs of connection pieces 324 form the connections for the inlet and outlet of the radiation chamber 311, while the (middle connection pieces 329 form the inlet and outlet of the radiation chamber 309.

Such flow reactors are used in connection with reverse osmosis plants which are used in numerous areas for the production of pure water, e.g. is used for the production of drinking water from sea water, for special purposes by clinics, electronics laboratories and pharmaceutical companies, as well as in the food industry. For reverse osmosis, various types of membranes, often based on organic materials, are used, which have proven to be susceptible to growth by microorganisms, which endangers the operability of the systems and the hygienic quality of the water produced. For safety reasons, the reverse osmosis system is often followed by UV disinfection. However, the medium introduced into the reversible osmosis is expediently subjected to UV disinfection in order to minimize the microorganism attack on the membranes from the outset. Here, the two-chamber photoreactor with radiation chambers connected in parallel offers a particularly inexpensive technical solution to simultaneously sterilize both the starting medium and the product water using a flow reactor and a radiation source.

To increase the photochemical efficiency of cleaning or disinfection, it is advisable to design at least one of the radiation systems connected in parallel in the manner of the multi-chamber photoreactor with a series connection.

Claims (40)

1. Process for cleaning, in particular for disinfection and disinfection of flowable media in a flow reactor (2, 41, 101, 171, 201, 301, 301A, 501) with a predetermined minimum radiation, ie minimum dose, ultraviolet radiation predominantly in the wavelength range from 240 to 320 nm, in which the medium is conveyed from at least one irradiation room through a flow reactor (2, ... 501) and is thereby exposed to UV radiation from a radiation source consisting of at least one radiator (6, 24),
characterized,
that the medium is conveyed through separate radiation chambers (8, 9; 23, 39; 23, 49; 109, 110, 111; 209, 211; 309, 311; 509, 511), which are assigned to the radiation source and arranged one behind the other in the radiation direction and in each radiation chamber (8, ... 511) is exposed to a fraction of the total radiation emanating from the radiation source. 2. The method according to claim 1, characterized in that at least 50% of the radiation penetrating into the medium in the radiation chamber immediately adjacent to the radiation source (8, 39, 49, 109, 209, 311, 509) into the medium in the immediately following radiation chamber (9, 23, 110, 211, 309, 511) occur that no more than 50% of the penetrating radiation is absorbed in the medium in the radiation chamber (8, ... 509) immediately adjacent to the radiation source, and that the medium be absorbed X 100% of the total of penetrating radiation where n is the number of Bestrahlun ^g s-chambers (8, 9, 23, 39, 49, 109, - in a flow of up to 5 irradiation chambers not more than (0.5 ⁿ 1) 110, 111, 209, 211, 309, 311, 509, 511). ; 3. The method according to any one of claims 1 or 2, characterized in that an oxidizing agent is supplied to the medium before irradiation. 4. The method according to any one of claims 1 to 3, characterized in that an oxidizing agent is supplied to the medium during the irradiation. 5. The method according to any one of claims 1 to 4, characterized in that at least a partial stream of the irradiated medium after the passage in the flow reactor (41, 101, 201, 301) is returned. 6. The method according to any one of claims 1 to 5, characterized in that the medium is exposed to ultraviolet radiation in the wavelength range from 260 to 280 nm. 7. The method according to any one of claims 1 to 6, characterized in that the medium in succession through the radiation chambers (8, 9; 23, 39; 23, 49; 109, 110, 111; 209, 211; 309, 311) of the flow reactor (2, 41, 101, 171, 201, 301) is funded. 8. The method according to any one of claims 1 to 6, characterized in that the medium is conveyed in parallel through the radiation chambers (309, 311; 509, 511) of the flow reactor (301A, 501). 9. Device for carrying out the method according to one of the preceding claims, consisting of a radiation source with at least one emitter (6, 24), which emits ultraviolet radiation predominantly in the wavelength range from 240 to 320 nm, and from a flow reactor (2, 41, 101 , 171, 201, 301, 301A, 501) with at least one radiation chamber which has a feed line (11; 91; 147, 152; 147, 196; 224, 247; 324, 329; 224, 524) and a derivative (16; 37, 37A; 57, 90; - 152, 147; 196, 147; 247, 224; 324, 329; 224, 524) for the medium to be irradiated and a monitoring device for the ultraviolet Has radiation,
characterized,
that the radiation chamber of the flow reactor (2, ... 501) through partitions (7; 35, 35A; 55; 52, 55; 106, 107; 207; 305) of material permeable to the ultraviolet radiation into separate, the radiation source together assigned radiation chambers (8, 9; 23, 39; 23, 49; 109, 110, 111; 209, 211; 309, 311; 509, 511) which are arranged one behind the other in the direction of their radiation, that the in the medium at least in the Irradiation chamber (9, 23, 110, 211, 309, 511), which directly follows the irradiation chamber (8, 39, 49, 109, 209, 311, 509) immediately adjacent to the radiation source, incident radiation is fractions of the radiation that enters the the radiation source (8, 39, 49, 109, 209, 311, 509) immediately adjacent to the radiation source penetrates, and that the device for maintaining a predetermined minimum dose of radiation consists of flow control means for the medium which is connected to the feed line (11; ... 524) or to the derivation (16; ... 524) of the exec flow reactor (2, ... 501) are connected. 10. Apparatus according to claim 9, characterized in that the fraction of the radiation chamber (9, _23,. 110, 211, 309, 511) of the radiation source directly adjacent to the irradiation chamber (8, 39, 49, 109, 209, 311, 509) directly follows, incident radiation at least 50% of the radiation penetrating into the radiation chamber (8, 39, 49, 109, 209, 311, 509) directly adjacent to the radiation source and the absorption in the radiation chamber (8, 39, 49, 109, 209, 311, 509) is not more than 50% and that the Total absorption in a flow reactor (2, 41, 101, 171, 201, 301, 301A, 501) with up to 5 radiation chambers (8, 9, 23, 39, 49, 109, 110, 111, 209, 211, 309, 311 , 509, 511) is up to (1 - 0.5n) 100% of the total incident radiation, where n is the number of radiation chambers (8, ... 511). 11. The device according to claim 9 or 10, characterized in that the partitions (7, 35, 35A, 52, 55, 106, 107, 207, 305) consist of quartz glass. 12. The device according to one of claims 9 to 11 from a radiation source with a plurality of emitters (24) and from a flow reactor (41) with a plurality of radiation chambers (39, 49), each of which is assigned to one of the emitters (24), characterized in that each emitter (24) enclosed in the manner of an immersion lamp in a cladding tube (25, 25A, 45) is surrounded by at least one quartz glass tube (35, 35 ^A ; 55; 52, 55) and the emitter (24) in a common container (21 ) are used that the cladding tube (25, 25A, 45) and the quartz glass tube (35, 35A, 55) each delimit an inner radiation chamber (39, 49) and that the inner radiation chambers (39, 49) each communicate with the interior of the container and are connected either on the input side to the feed line (91) or on the output side to the discharge line (37, 37A, 57, 90) of the flow reactor (41). 13. The apparatus of claim 11, wherein the radiation source and the flow reactor (101, 171, 201, 301,. 301A, 501) are arranged in a ring to one another, characterized in that the flow reactor (101, ... 501) from two with Connection means (147, 152, 196, 224, 247, 324, 329, 524) provided closure parts (103, 104; 173, 174; 203, 204; 303, 304; 303A; 503, 504) which connect the radiation chambers (109, 110, 111; 209, 211; 309, 311; 509) 511) on the end face, and from between the closure parts (103, ... 504) attached to these pipe sections (102, 105, 106, 107; 172, 105, 106, 107; 202, 205, 207; 302, 305 ; 202A, 205, 207) of different diameters, which are arranged coaxially one inside the other and delimit the radiation chambers (109, ... 511) on the long side. 14. The apparatus according to claim 13 for carrying out the method according to claim 8, characterized in that the closure parts (303A; 503, 504) for each radiation chamber (309, 311; 509, 511) at least two connecting pieces (324, 329; 224, 524 ) own. 15. The apparatus according to claim 13 for carrying out the method according to claim 7, characterized in that adjacent radiation chambers (109, 110; 110, 111; 209, 211; 309, 311) are alternately connected to one another at opposite ends. 16. The apparatus according to claim 15, characterized in that the tube pieces (207, 305) are alternately sealingly held and guided at their ends and that adjacent radiation chambers (209, 211; 309, 311) each at the guided ends of the tube pieces (207, 305) are connected. 17. The apparatus according to claim 16, characterized in that the inner tube piece (205) is passed at both ends through corresponding openings in the closure parts (203, 204) and is sealingly held in the openings. 18. The apparatus according to claim 17, characterized in that the outer tube piece (102, 172, 202) is radiation-impermeable and has an observation opening (120, 220) and to the closure parts (103, 104; 173, 174; 203, 204) sealing is flanged. 19. The apparatus according to claim 18, characterized in that the outer tube piece (102, 172, 202) is mirrored. 20. The apparatus according to claim 18 or 19, characterized in that the pipe sections (105, 106, 107) on a closure part (103) are held sealed, that the inner pipe section (105) and every second outwardly following (107) on the the end facing away from the closure part (103) is closed and each of the second outwardly closed tube pieces (107) near the closure part (103) serving to hold them is provided with through openings (108) and that the closure part (103) has an inner channel (146, 148) has one end opening into the inner radiation chamber (109) and the other end opening into a connecting piece (147). 21. Device according to one of claims 13 to 20, characterized in that an irradiation chamber facing away from the radiation source (111; 211; 309; 511) has a layer thickness which is at least twice the layer thickness of the radiation chamber (109; 209; 311; 509). 22. Device according to one of claims 13 to 21, characterized in that a pressure compensation device is provided. 23. The device according to claim 22, characterized in that the pressure compensation device has a pressure-tight bushings (193), pressure-tight with the closure member (173) holding the pipe pieces (105, 106, 107) and connected to a barostat lid (192) , where the setpoint of the barostatic pressure control from the input pressure of the medium at the flow reactor (101) is determined. 24. Device according to one of claims 9 to 23, characterized in that at least one radiation chamber (8, 9, 39, 49, 109, 111, 209, 211, 309, 311, 509, 511) with an effective compensation element over the flow cross section (13, 15, 71, 154, 155, 254, 255, 354, 355) is provided for the flow profile. 25. The device according to one of claims 12 to 24, characterized in that the flow reactor (41, 101, 201, 301) is provided on the output side with a flow divider (403, 420), an outlet (423) to the extraction line (405) and its second outlet (422) with the interposition of a return feed pump (409) and a check valve (410) at the inlet (91; 147, 152; 224, 247; 324, 329) of the flow reactor (41, 101, 201, 301 ) connected. 26. The apparatus according to claim 25, characterized in that the return feed pump (409) is adjustable in its delivery rate. 27. The apparatus according to claim 25, characterized in that the return line has an adjustable flow restrictor. 28. Device according to one of claims 9 to 27, characterized in that the radiation source is formed by at least one antimony-doped xenon high-pressure lamp which has a strong emission in the wavelength range from 260 to 280 nm. 29. The device according to claim 28, characterized in that the radiation source additionally has at least one mercury vapor lamp. 30. The device according to claim 28 or 29, characterized in that the radiation source contains at least one coiled radiator. 31. The device according to any one of claims 13 to 28, characterized in that the radiation source (24) in the interior of the flow reactor (101, 171, 201, 501) is arranged in a position close to the axis. 32. Device according to one of claims 13 to 17 and 22 to 30, characterized in that the radiation source has at least 4 axially parallel and symmetrically arranged between the flow reactor (301, 301A) and a reflector system surrounding this emitter (6, 24). 33. Apparatus according to claim 31 and 32, characterized in that a part of the radiation source forming the emitter (6, 24) inside the flow reactor and another part of the emitter (6, 24), at least 4, axially parallel and symmetrical between the flow reactor and a reflector system surrounding them are arranged. 34. Apparatus according to claim 33, characterized in that an antimony-doped xenon high-pressure lamp is arranged at least in the interior of the flow reactor. 35. Device according to one of claims 9 to 34, characterized in that the flow control means have a flow restrictor. 36. Apparatus according to claim 35, characterized in that an adjustable flow throttle is provided. 37. Device according to one of claims 9 to 34, characterized in that the flow control means have a flow limiter (12) which is independent of the inlet pressure. 38. Device according to one of claims 9 to 34, characterized in that the flow control means have a pump (450) with adjustable delivery rate. 39. Apparatus according to claim 38, characterized in that a control device for the pump (450) is provided with adjustable delivery rate, which is acted upon by a control signal emanating from the monitoring device with setpoint adjustment. 40. Apparatus according to claim 39, characterized in that the control device is a power amplifier (455) and one of the pump motor (451) driven. NEN tachometer generator (452) and that the tachometer generator signal is connected to the control signal of the monitoring device at the input of the power amplifier (455).

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