EP2646373A1

EP2646373A1 - Electrolysis cell for generating ozone for treating a liquid

Info

Publication number: EP2646373A1
Application number: EP11799386.5A
Authority: EP
Inventors: Berthold Conradt; Peter Weidner; Ron Kemmer
Original assignee: Brita SE
Current assignee: Brita SE
Priority date: 2010-12-03
Filing date: 2011-12-02
Publication date: 2013-10-09
Also published as: WO2012072784A1; US20130240458A1

Abstract

An electrolysis cell for generating oxidizing agents, in particular ozone, for treating a liquid comprises a first electrode (12) and a second electrode (14). The first and the second electrodes (12, 14) are spaced apart from one another by a distance (A). A particulate solid electrolyte (20) is arranged between the first and the second electrodes (12, 14) and can have the liquid flowing through it. The solid electrolyte (20) is arranged in a free space bounded by the first and the second electrodes (12, 14).

Description

Electrolysis cell for generating ozone for the treatment of a liquid

The present invention relates to a Elektrolysezel ^¬ le for generating oxidants, in particular ozone, for treating a liquid, comprising

a first electrode and

a second electrode,

wherein the first and the second electrode are arranged at a distance from each other, and

wherein between the first and the second electrode, a particulate solid electrolyte is arranged, which is traversed by the liquid.

Furthermore, the invention relates to a device for treating a liquid comprising

an inlet for supplying liquid into the

Contraption,

an outlet piece for dispensing the treated liquid from the device,

a water treatable treatment area for treating the water.

Moreover, the invention relates to a method for generating ozone for the treatment of a liquid.

Liquid or drinking water-donating devices, such as coolers, chillers, water bars or vending machines ^¬ , usually have elongated piping systems, which have inlets and outlets, via which the drinking water is supplied to the devices and discharged from them. In particular of the outlet pieces, the risk of retrograde bacterial contamination of the drinking water by undesirable and often harmful to health germs such as bacteria, Pro ^¬ tists, fungi, parasites, viroids, viruses, algae or prions, which are in the piping systems of liquid or drinking water are located and can get stuck there. For example, touching the output Sufficient with the hand of a user to enter germs in the outlet piece, which spread against the main flow direction of the drinking water within the device. However, not only is retrograde germination a hazard, but also of the pipeline system itself, in which also harmful germs can be found and spread.

To prevent this germination, it is known to inactivate the germs by various means. Inactivation means measures that act on the germs in such a way that they can no longer multiply. The germs do not necessarily have to be killed. Inactivation of the germs avoids the formation of biofilms. These measures include, for example, the irradiation of the liquid with UV light or the displacement of the liquid with a cleaning agent. The irradiation of the liquid with UV light has the disadvantage that the germs are inactivated only in the radiation range of the UV lamp, so that only a part of the germs are inactivated and the non inactivated ^¬ th germs can spread to other locations of the device on. The use of a cleaning agent which can be conveyed through the entire apparatus, has the disadvantage that it is generally not safe to drink and be ^¬ collected and must be completely removed from the apparatus thus before the device can be used again for dispensing drinking water , This is particularly disadvantageous because the device for a certain time can not fulfill its intended purpose.

Another measure of the inactivation of the germs is the production of oxidizing agents, which are introduced into the liquid or the drinking water. Oxidizing agents are in particular ozone, chlorine, chlorine dioxide, hydrogen peroxide and hydroxyl radicals (OH radicals). The production of oxidation ^¬ forward has the advantage that its concentration in the

Liquid or in drinking water can be controlled so that the germs are safely inactivated and the user is not exposed to health hazards. Furthermore, the Oxidizing agents are conveyed together with the liquid through the entire device, so that all Leitungsab ^¬ cuts applied to the oxidizing agent and germs are inactivated everywhere.

Typically, ozone is generated by means of a so-called Koro ^¬ na-discharge method (corona discharge). With this method, gaseous ozone is generated, which is then introduced into the liquid to be treated. For this purpose, a mixing unit air / water is necessary. A gas separator is needed as residual gases must be destroyed, which are responsible for the

User can be poisonous.

These disadvantages can be circumvented by using an electrolytic cell for generating oxidizing agents and in particular ozone for treating a liquid. The "Fischer cell" known from the prior art, which is suitable for this purpose, comprises areal shaped electrodes which are pressed against a membrane located between the electrodes. The electrodes used are made of lead oxide, which have the disadvantage, especially in the case of non-continuous operation of the device, that they release lead constituents into the liquid to be treated, which is unacceptable in terms of the user's health.

From DE 103 16 759 electrodes are known which have a diamond coating. However, the electrolyte cells disclosed therein serve to treat gases, so that the

Transfer to the present case is not possible. In particular, the problem arises in the treatment of liquids that the volume flow, which can be passed through the maximum through the electrolysis ^¬ cell, due to the

Incompressibility of liquids is a limiting factor.

DE 10 2004 015 680 A1 discloses an electrolysis cell suitable for treating liquids, in which a solid electrolyte is arranged between the electrodes. In order to ensure the stability of the electrolysis cell, the solid electrolyte must be provided in a relatively complex form, whereby a high space requirement is created. The used membranes of a polymer solid electrolyte must be kept permanently moist, so as not to lose their functionality. This is disadvantageous for the storage, the easy transport and the replacement of a spent electrolysis cell.

Flatly prepared electrodes without openings, in which the liquid flows between the first and second electrodes, are easier to produce than flat electrodes, which are traversed by channels, to direct the liquid to the membrane, as described in DE 100 25 167 AI become. This also applies to the grid electrodes described in DE 10 2004 015680 AI.

US 6,254,762 discloses a two compartment electrolytic cell for the production of hydrogen peroxide. This system can be released ozone by selecting a suitable catalyst. A main body of the electrolytic cell is divided into an anode chamber and a cathode chamber by means of an ion exchange membrane. The ion exchange membrane has on a side facing the anode chamber on a gas diffusion anode, which is in close contact with her. In the

Cathode chamber is a gas diffusion cathode spaced apart from the Io ^¬ nenaustauschermembran located, so that the cathode is connected to the upper side and the lower side of the main body of the electric ^¬ lysezelle is in contact to the cathode chamber in a

Divide solution chamber on the anode chamber side facing and a gas chamber on the opposite side. The solution chamber is completely filled with ion exchange resin particles. The upper and lower side of the solution chamber wei sen ^¬ a supply ultrapure water or a

Dispensing opening for an aqueous hydrogen peroxide solution. The supply and discharge ports each have a plug to prevent the ion exchange resin particles from flowing out. The anode chamber has a hydrogen gas supply port and a gas excess discharge port formed in lower and upper parts of the anode chamber, respectively. Further, the cathode chamber has an oxygen gas supply port and a gas excess discharge port located in lower and upper, respectively Parts of the cathode chamber are formed. When a voltage is applied to the two electrodes, while hydrogen gas is supplied to the anode chamber, an oxygen-containing gas is supplied to the cathodic chamber, and ultrapure water is supplied to the solution chamber, an electric current flows at a relatively high current density through the cathode and the anode, although the electric

Conductivity of the ultrapure water is practically zero. This is due to the fact that the two electrodes are electrically connected to one another via the ion exchange membrane and the ion exchange resin particles, which both have electrical conductivity.

However, the known electrolytic cell only works with ultrapure water. If you were to use tap water, it would quickly lead to deposits in the solution chamber.

Object of the present invention is therefore to provide an electrolytic cell, which is suitable for the treatment of other liquids as ultrapure water.

The object is achieved with an electrolytic cell of the type mentioned, in which the solid electrolyte is arranged in a limited by the first and the second electrode space.

In this context, a particulate solid electrolyte is to be understood as meaning an electrolyte which comprises a large number of solids with small dimensions. In particular, the predominant particle size of the solid ^¬ electrolyte should be less than 1 mm. The particulate

Solid electrolyte can be present as a granulate, a suspension or a powder. Furthermore, the particulate solid electrolytes may also become a larger unit

For example, be connected using a binder. Here, particles with a mean diameter of 1 mm and more can be generated.

For the generation of a sufficient amount of ozone and in particular a high ozone yield compared to other oxidants such as chlorine, a certain current density is required. The ozone yield describes the Proportion of ozone in the total amount of oxidants generated. As the current density increases, so does the ozone yield. However, the conductivity of the liquid decreases with increasing purity. As a consequence, a higher voltage is needed to generate the required current density. In comparison with other oxidizing agents, ozone has the advantage that it decomposes into odorless oxygen and has a higher ef ^¬ fectivity in the inactivation of germs and possibly existing biofilms. Furthermore, the formation of disinfection by-products (DNP) such as chloroform is reduced.

By means of the through-flow of liquid, particle ^¬ shaped solid electrolyte may have high current densities are generated, without the two electrodes are short-circuited. The solid electrolyte promotes the conduction of ions through the liquid from the first to the second electrode, so that

Generation of the necessary current density lower voltages sufficient than in known electrolysis cells, the no

having particulate solid electrolyte. The electrolyzer ^¬ sezelle can therefore be operated more economically. Since it is possible to work with lower voltages in this embodiment, this contributes to the safety of the electrolysis cell. Furthermore, the electronics can be simplified.

Moreover guarantee particulate solid electrolytes good flowability through the space between the electrodes so that a sufficiently high airflow can be added with the oxidizing agent without the flow resistance ^¬ or the pressure loss in the electrolytic cell becomes too large.

Because the free space is empty except for the solid electrolyte, ie no further objects are arranged in the free space between the electrodes, the electrodes can be arranged at a very small distance from each other and yet be flowed through with a sufficiently high volume flow. As the distance decreases, the first and second surfaces of the electrodes can be reduced. Furthermore, the space requirement of the electrolytic cell decreases with decreasing distance of the two electrodes, so that they also in areas with low construction can be arranged, for example, directly in the inlet or outlet of a device for the treatment of a liquid.

The fact that the space is not divided into other rooms, the electrolytic cell can be reversed in operation, that is, each of the first and second electrodes can act alternately as the anode or cathode. As a result, deposits on the electrodes are largely avoided. This is not possible in an electrolytic cell with separate supply ports for different gases without a relatively complex arrangement of automatically controlled valves.

The electrolysis cell thus comprises a housing having we ^¬ nigstens an inlet for the liquid to be treated and at least one outlet for the treated liquid, are located where ^¬ at all inlets and outlets between the first of or defined by the second electrode surfaces. The

As a result, the electrolysis cell can be relatively compact, since no chamber has to be arranged on the side of each electrode facing away from the other electrode. In this sense, the electrolysis cell can be symmetrical with respect to an imaginary surface between the electrodes, so that a polarity reversal during operation is easily possible.

In one embodiment, the particulate solid electrolyte is in one of the powder form, the granulated form, the sintered form and the extruded form. By definition, the powder should comprise particles of very small particle size, in particular less than 0.5 mm. As a result, the specific surface is increased, so that the contact surface with the liquid to be enriched with ozone is increased. The enrichment with ozone is therefore carried out more effectively.

When sintering, one starts from the particulate solid electrolyte, wherein the grain size can also be chosen so that it corresponds to that of a powder. By a Temperaturbe ^¬ treatment and alternatively using a binder, the particulate solid electrolyte is converted into the sintered form. As a result, the particulate solid electrolyte ^¬ takes on a solid shape, so that it is easier to handle. Thus, the particulate solid ^electrolyte can be represented in disk or plate form.

Furthermore, the solid electrolyte may be in extruded form. Again, the solid electrolyte after leaving a solid form, which corresponds in cross section to that of Extru ^¬ DERS. This can also be tubular. Again, the handling is improved. The extruded shape can be reduced in size by a further process step in ^¬ example by cutting the extruded form.

In one embodiment, the free space is completely filled with solid electrolyte.

One effect is that the electrical resistance of the electrolytic cell is relatively constant from the beginning, which simplifies the Be ^{¬ operation of} the electrolysis cell. Otherwise, the electrical resistance after the first contact with the liquid ^¬ ness would decrease by swelling the particles because the swelling of the particles would cause a better coverage and a firmer contact Zvi ^¬ rule the particles and the electrode surfaces.

In one embodiment, the distance between the two electrodes using the particulate solid electrolyte is 1.5 to 2.5 mm. The first and second surfaces of the electrodes can be reduced as the distance decreases. The space requirement of the electrolysis cell decreases with decreasing distance between the two electrodes, so that it can also be arranged in areas with a small installation space. The current density between two electrodes increases with the conductivity of the liquid between the electrodes and the applied voltage, but decreases with increasing distance of the two electrodes to each other. If the distance of the electrodes from each other is reduced, the current density increases at the same voltage, whereby the current increases, which increases with the current density and the electrode surface. To return to the original current, the electrode area can be reduced. Thus, the smaller the distance between the two electrodes, the more compact the electrolytic cell can be configured. The production of oxidants also increases with increasing current. It turned out that with one to the

Electrolytic cell applied average current density of more than 0.1 A / cm ^2, the amount of ozone generated is sufficient to effectively disinfect liquids with a conductivity of 10 μΞ / αη or more. In the cell itself, significantly higher current densities can be achieved. This ensures that the majority of the drinking water with the inventive electrolysis cell without ^¬ additional measures such as softening or a full or partial desalination can be treated.

Although the electrolytic cells according to the invention are mainly used for the production of ozone, but it can not be avoided that other oxidizing agents in the form of chlorine, chlorine dioxide, hydrogen peroxide and hydroxyl radicals (OH radicals) are formed. Since these also kill or at least inactivate germs, the formation of these is another

Oxidizing agent in this respect not disadvantageous. However, they lead to taste adverse changes in the liquid and can produce an unpleasant odor. As mentioned above, the formation of these and other oxidants and their disinfection by-products can not be prevented, however, using an increased current density, the ozone yield compared to the yield of the other oxidizing agents can be increased ge ^¬ .

The particulate solid electrolyte may be an ion exchanger, in particular a proton-conducting

Ion exchangers, more particularly a zeolite or a polymer, still more particularly a tetrafluoroethylene polymer. In particular, a sulfonated tetrafluoroethylene polymer such as Nafion has been found to be suitable. It is particularly effective if the ion exchanger is an acidified zeolite or a polymer. A proton-conducting

Ion exchanger is a cation exchanger that provides protons. Acidified zeolites provide protons available so that a kind of "proton chain" is formed between the two electrodes, which contributes to increasing the conductivity ^¬ ness between the electrodes. With a

proton-conducting ion exchangers are compared with elec- rolysis cells without a proton-conducting solid electrolyte, the current flow and thus the current density at the same ^¬ bender voltage increases. A special feature of the sulfonated tetrafluoroethylene polymer, that he does not need to be kept moist to its functionality to be ^¬ true.

Furthermore have acidified zeolites, and poly ^¬ mers have the property that they are resistant to oxidation in comparison with other cation exchangers. In addition to cation exchangers, the use of anion exchangers is conceivable, but the ozone yield generated with them is lower in comparison to cation exchangers, since the best way to increase the conductivity is with protons.

The acidified polymer may be a sulfonated tetrafluoroethylene polymer, such as e.g. Nafion, his. The polymer can be extruded and then particulated.

The electrolysis cell can be further developed by a retaining device for retaining the particulate solid electrolyte in the electrolysis cell. This ensures that the particulate solid electrolyte is not flushed out of the space between the electrodes. This is particularly important when the partikelför ^¬-shaped solid electrolyte as a powder or powder of small

Grain size is present. The retaining device can, for example, as a sieve with a particle size to the particle size

Be adapted to solid electrolyte mesh size or as a nonwoven fabric. Also together with a binder ^¬ ne solid ^electrolyte crystallites form the retaining device. The flow resistance or the pressure loss of the retaining device are thus kept low, so that the

Electrolytic cell can be penetrated with a large volume flow.

In one embodiment, the first and second electrodes comprise a carrier core and a diamond coating. As a carrier core may be any suitable material and in particular

Metal are used. The diamond coating is very durable, giving the electrodes a very long life because the diamond coating protects the electrodes greatly from corrosion by the oxidants such as ozone. Furthermore, it is prevented that components of the electrodes are discharged into the liquid, which may be harmful to the user, as may be the case with lead oxide electrodes, in particular in non-continuous operation of the electrolysis cell. Diamond as such is a very good insulator, so that no current density could be introduced into the liquid to be treated. Therefore, the diamond ^coating does not consist of pure diamond, but is doped,

so that the diamond coating is elekt ^¬ driven conductive for example with boron. The diamond coating is about 5 to 10 μπι and can be applied to the carrier core with a vapor deposition process.

If both the first and the second electrode have ei ^¬ ne diamond coating, a polarity reversal is possible, which should be done at regular intervals. Umpolung means that not only one electrode always acts as an anode and the other as a cathode. At the cathode, a Be ^¬ lag, in particular by limescale, form, which is significantly reduced by the polarity reversal and distributed more uniformly on the two electrodes, so that the life of the electrolysis cell is increased. Otherwise, the electrolysis cell would cease to function after a shorter period of time, when a lime- ^containing liquid, for example tap water, is supplied to it.

Not only the coating on the electrodes can lead to problems, also deposits in the disposed between the first and the second electrode solid electrolyte can adversely affect the function. In this case, regular rinsing with liquid containing substances that degrade the deposit can increase the life. For example, limescale deposits with CO ₂ added liquid can be removed. Such liquid is available eg in many drinking water dispensing devices. Thus, no additional harmful chemicals are used. Another way to avoid deposits is the installation of a filter unit in front of the electrolysis cell, which removes the deposition-generating substances from the drinking water. This can be done, for example, with an ion exchanger for demineralizing the liquid to be treated. In one disclosed embodiment, which is arranged in front of the electrolytic cell filter unit comprising an anion exchanger in ^¬ sulfate form. This can bromite and iodide from the liquid

be removed. As a result, no bromate or iodate can be produced in the electrolysis.

In one embodiment of the invention in which the first electrode having a first surface and the second electrode a second surface, the first and second surfaces are arranged planparal ^¬ lel to one another. This can be a

uniform distribution of the current density between the electrodes cause. It is thus ensured that the current density required for the inactivation of the germs is established everywhere between the electrodes.

Basically, one is free to choose the geometrical shape of the electrodes. The geometric shape of the electrodes has an influence on the current densities. Thus, it is possible einzutau ^¬ chen rod-shaped electrodes in an ion exchange bed. It is also possible to combine electrodes with different shapes to form an electrolytic cell. Thus, a different current density can be generated, with which the ozone yield can be controlled. It has been shown that the ozone yield increases with increasing current density in comparison to the other oxidizing agents.

The carrier core may be made of ceramic material or more generally comprise the ceramic material. The carrier core can therefore consist exclusively of ceramic material or have other components in addition to the ceramic material and in particular ^¬ sondere be modified with organic components. The

Ceramic material is particularly resistant to corrosion and therefore increases the life of the electrolysis cell. Furthermore, no harmful substances are released into the liquid flowing around the electrodes. Furthermore, it is possible that the first and the second surface have one or more projections. Peak discharges occur at the projections, so that high current densities are occasionally generated without the voltage having to be increased. The production of oxidants is thus made more efficient. In conjunction with the carrier material of a ceramic material, there is also the effect that the projections can be made very uniform, since the ceramics can be formed very precisely. The punctually high

Current densities can be set very precisely both locally and by their propagation.

Another aspect of the present invention relates to an apparatus for treating a liquid comprising

an inlet for supplying liquid into the

Contraption,

an outlet piece for discharging the treated liquid from the device,

a water treatable treatment area for treating the water, and

an electrolysis cell according to the invention for producing oxidizing agents and in particular ozone for the treatment of the liquid.

Because the free space in this embodiment is empty or no objects are arranged in the free space between the electrodes, the electrodes can be arranged at a very small distance from each other and yet be flowed through with a sufficiently high volume flow. With decreasing distance, the first and second surfaces of the

Electrodes are reduced. Furthermore, the space requirement of the electrolytic cell decreases with decreasing distance of the two electric ^¬ so that it can be arranged in areas with little space, for example, directly in the inlet or outlet of the device.

In the device according to the invention, a particulate solid electrolyte is arranged in the free space. The parti ^¬ kelförmige solid electrolyte is good from the liquid to be enriched with the oxidant, durchström- bar. By means of the particulate solid electrolyte, high current densities can be generated without the two ^{electrodes being} short-circuited. The particulate

Solid electrolyte promotes the conduction of ions through the liquid from the first to the second electrode, so that to generate the necessary current density lower voltages sufficient than in known electrolysis cells, the no

having particulate solid electrolyte. The electrolyzer ^¬ sezelle can therefore be operated more economically.

In one disclosed form, the device is adapted to reverse the polarity of the electrolysis cell so that the first and the second electrode yaw alternately as a cathode and as an anode ^¬ fun. As a result, deposit formation is effectively counteracted so that the electrolysis cell remains functional for a reasonable amount of time even when ozone is generated from tap water.

In one variant, the polarity reversal takes place in regular

Intervals.

In one embodiment, the device is set up to apply a voltage above a threshold value to the electrodes. The threshold value is in a variant at least 8 V / mm, based on the distance between the first and the second electrode, in particular at least

9 V / mm, more especially 10 V / mm. These values are insbesonde ^¬ re when the solid electrolyte acid a strong

An ion exchanger, for example a sulfonated fluoropolymer, is suitable for generating ozone from tap water.

Below the threshold value, the current flow can be ^¬ already after a relatively short time to break, so that the

Ozone production is greatly reduced. One possible explanation is that the solid electrolyte is saturated with cations, in particular hardness-forming cations, so that its electrical conductivity decreases sharply. The increase of the voltage above a suitable threshold causes a detachment of the bound cations.

In one embodiment, therefore, the device is configured to detect a drop in current through the electrolytic cell and in response to the detection to increase the voltage at least temporarily to a value above ei ^¬ nes certain threshold value.

In one embodiment, the device comprises a measuring device for determining at least one variable from the group comprising the conductivity, the ozone content and the oxidation-reduction potential of the liquid. By determining the conductivity, the ozone content or the oxidation-reduction potential, the cell can be activated (too little oxidant or ozone in the liquid) or deactivated (too much oxidant or ozone in the liquid). Other determinable events for activating and deactivating the cell may be a time interval or time, or the delivery of untreated fluid into the device. The device may be operated to produce or maintain a concentration of the oxidizing agent necessary to safely inactivate the germs. Thus that a too high concentration of the means of Oxidationsmit ^¬ is generated is prevented, which would cause unnecessary costs

Liquid taste is negatively influenced or limits for liquids (especially drinking water) are exceeded. Furthermore, the formation of disinfection by-products is reduced.

In one embodiment, the device comprises a measuring device for determining the conductivity of the liquid, the device being set up to set a cell voltage as a function of the conductivity.

Thus, a sufficient production of oxidants can be ensured. In this embodiment, the device is also better suited for treating tap water whose conductivity may vary within certain limits.

In one embodiment, the cell resistance can be determined by means of the measuring device, wherein the measuring device comprises a power supply for regulating the voltage as a function of the measured cell resistance. In this embodiment, the

Current density in the electrolysis cell on the basis of the measured Leit ^¬ ability, the ozone content or the oxidation-reduction potential of the liquid changeable. This is done by the current Voltage-regulated power supply, with which the current can be kept kon ^¬ constant and the voltage can be changed depending on the measured conductivity of the liquid. With the power supply, the oxidant production and the ozone content of the oxidants can be adapted to the conductivity of the liquid. It is necessary not separate measuring device so that the number of components and the complexity of the pre ^¬ direction and the space required can be reduced.

In one embodiment of the invention in which the apparatus further comprises a tank for storing the liquid, and guide means for guiding the liquid in the apparatus, the electrolytic cell in the tank, in the inlet, arranged in the Füh ^¬ agent or in the outlet piece. Because the

Inventive electrolysis cell requires little space, it can be arranged in all areas of the device. The location at which the electrolytic cell is located coincides with the introduction of the oxidizing agent into the liquid, so that the electrolysis cell can be arranged at locations of the device which are critical for the microbial contamination, for example at the outlet or at the supply line for untreated liquid.

In one embodiment, the outlet piece comprises a closable opening for selectively discharging the liquid, a supply element for supplying the liquid to the outlet piece, and a discharge element for discharging the liquid from the outlet piece and for guiding into the tank. The outlet piece can be flushed with the treated liquid even if the liquid is not to be dispensed through the outlet piece. The disinfecting effect of the liquid which is ^mixed with the oxidizing agent is used to supply the outlet piece

disinfect. This is therefore particularly effective as that the outlet piece is a critical point for retrograde Ver ^¬ germination, as it represents the interface with the environment in which a high number of germs is located.

The liquid discharged from the outlet piece can be returned to the tank. Furthermore, it is also possible to operate the device so that the liquid is conveyed in the circuit ^¬ run. In this embodiment, a certain Recirculated volume of fluid within the apparatus, repeated with chert ^¬ oxidant and in particular ozone angerei and are brought to a specific concentration.

Since on the one hand less or no fresh liquid ^¬ speed must be supplied, this embodiment has the effect that the amount of spent liquid can be reduced and thus also devices can be operated without outflow. On the other hand, the amount to be generated in the cell becomes

Lowering oxidants, which in turn leads to a reduction in the cost of the supply electronics. Furthermore, the cell can be switched on in dependence upon the determined value of the conductance of the oxidation-reduction potential or the ozone content and off, while the liquid ge ^¬ promotes the circulation, so that a certain concentration is never exceeded.

Furthermore, the oxidant and ozone concentration generated in the electrolysis cell can be adjusted by adjusting the

Current density either choose so that a lot of oxidizing agent and in particular ozone generated and the liquid is not or only partially circulated, or you can produce only a small amount of ozone in the electrolysis cell and circulate the liquid several Ma ^¬ le, so that the ozone concentration in the Device gradually increased and brought to the desired value. The decay time of the ozone must be considered. As already mentioned, can be selectively changed by means of the current density also yield the Ozonaus ^¬, wherein an increasing current density leads to increased ozone yield.

In one embodiment, a conveying device is provided for conveying the liquid within the device. Depending on the configuration of the device, however, the device can also be operated without a conveyor, wherein the pressure of the supply line or the hydrostatic pressure in the tank cause the conveying of the treated liquid.

Furthermore, the enrichment of the liquid in the device with oxidizing agents,

especially with ozone facilitated with the conveyor, since the circulation rate changes independently of the line pressure can be. As already mentioned above, the ozone disintegrates after a while. In order nevertheless to achieve an increase in the ozone concentration, therefore, the circulation speed must be adjusted accordingly to the disintegration time, which can be easily realized by means of the conveyor.

In addition to the promotion in the circulation, the provision of a conveyor, however, offers further possibilities: The liquid can be independent of structural conditions and

existing line pressure to be operated within the device. It is also possible to perform the promotion at regular intervals and / or depending on the amount of liquid removed by the user and to change the delivery rate and thus the pressure within the device.

An embodiment of the device is characterized by a unit for reducing the concentration of the oxidizing agent. This unit can be a UV lamp, activated carbon,

Glass fiber or other catalytically active element umfas ^¬ sen and may for example in the area of the outlet

be arranged. This embodiment makes it possible to produce within the device a concentration of the oxidizing agent which is higher than that which is necessary for the use of the

Liquid, especially as drinking water, acceptable and zuläs ^¬ sig is. Furthermore, a high concentration of

Oxidant unwanted odors verursa ^¬ chen and negatively affect the taste of drinking water.

The unit for reducing the concentration of the oxidizing agent may be disposed outside of the circulation circuit. But it can also be ^¬ classified within the circulation circuit. In this case, the liquid removal is in one disclosed embodiment by the user during the Umwälzpro ^¬ zesses not possible, and the unit is switched off for reducing the concentration of the oxidizing agent.

It is thus possible to generate within the device a concentration of the oxidizing agent which is higher than that which is discharged via the outlet piece, so that Within the device, a very safe and sustainable inactivation of the germs can be effected.

In one embodiment, the device comprises a bypass with a first section and a second section, wherein the electrolysis cell is arranged in one of the sections. As the term bypass indicates, the first and second sections are fluidically connected in parallel. The bypass allows easy replacement of the electrolysis cell, furthermore, with the choice of volume flows through the first and the second section, the enrichment of the liquid with ozone can be easily adjusted. Furthermore, in the bypass a treatment unit, for example, a filter unit may be arranged to condition the flues ^¬ sigkeit upstream of the electrolytic cell. Furthermore, by passing a portion of the fluid through the portion other than the portion which contains the electrolytic cell, and an after ^¬ following blending of the treated with the electrolytic cell liquid with the gas passing the other portion flues ^¬ sigkeit the content of undesired substances such as bromide and iodide are reduced. In general, the ozone content will be sufficient even in the blended liquid for disinfection purposes.

In the above-described options for optimizing the sterilization process of the liquid and the flüssigkeitsführen ^¬ the parts is namely to be noted that the Oxidationsmittel- or ozone concentration does not necessarily have to be chosen so high that almost all germs are killed. Rather, one can speak of a safe disinfection, when the oxidant and ozone concentration at regular intervals by a corresponding activation of the electrolytic cell to a comparatively low value held ^¬ th is sufficient to inactivate the germs in many cases already. A certain number of germs can be tolerated, only it may not come to an increase. Thus, with a low oxidizing agent and ozone concentration and thus low energy consumption, the formation of biofilms can be counteracted. Another aspect of the present invention relates to a process for producing ozone for the treatment of a liquid, comprising the following steps:

Determining the conductivity, the oxidation-reduction potential or the ozone concentration of a liquid present in a device according to the invention by means of a measuring device,

Activating a generator for generating an oxidizing agent, in particular ozone, depending on the specific conductivity, the oxidation-reduction potential, the ozone concentration or a detectable event by means of the measuring device, and

Treating the liquid and the liquid-carrying parts of the device with the oxidizing agent,

especially of ozone.

Liquid-carrying parts are understood as meaning all parts of the device which come into contact with the liquid.

The generator for producing oxidizing agents, and in particular ozone, is an electrolytic cell according to one of the exemplary embodiments presented above.

The discussion of the apparatus and the OF INVENTION ^¬ dung modern electrolysis cell advantages therefore apply to the novel process alike. The stated sequence of the method steps is not to be understood as a definition of this, but also a different sequence is conceivable.

In one embodiment, the determinable event is the exceeding or falling below a certain threshold value of the oxidation rate measured by the measuring device.

Reduction potential or ozone concentration. The oxidation ons-reduction potential varies with the concentration of the oxidizing agent generated, so that for example the Erzeu ^¬ supply of the oxidizing agent and can in particular be started by ozone when a predetermined threshold value can be exceeded, and stopped when a predetermined threshold is exceeded , The concentration of the oxidizing agent, in particular, the ozone in the liquid can be held in wählba ^¬ ren thus limits, so that the device is operated efficiently and economically and permissible Maximalkonzentra ^¬ functions are not exceeded.

The determinable event may be the supply of unbehan ^¬ delter liquid in the device. Usually, the untreated liquid has a high number of germs, so that the supply of untreated liquid into the device is an event that makes it necessary to increase the concentration of the oxidizing agent, in particular the ozone. So with ^¬ can also be a reliable inactivation caused crossing of germs without a measurement of the oxidation-reduction potential or the ozone concentration.

The determinable event may be a time interval or a time. It is thus possible to activate the electrolytic cell regularly for a certain period of time. For example, the electrolytic cell can be activated for a certain duration every two hours. Alternatively, a particular time may be chosen, for example during the night when the device is not usually used to activate the electrolytic cell.

In an embodiment, the method includes applying a voltage above a threshold to the

Electrodes. The threshold is in one variant at least 8 V / mm, based on the distance between the first and second electrodes, especially at least 9 V / mm, more in particular ^¬ sondere 10 V / mm. These values are especially if the

Solid electrolyte comprises a strongly acidic ion exchanger, for example a sulfonated fluoropolymer, suitable for generating ozone from tap water.

Ozone production is greatly reduced. One possible explanation is that the solid electrolyte is saturated with cations, in particular hardness-forming cations, so that its electrical conductivity decreases sharply. The increase of tension up above a suitable threshold causes detachment of the bound cations.

In one embodiment, the method includes detecting a decrease in a current through the

Electrolysis cell and at least temporarily increase the voltage across the electrodes to a value above a certain threshold value in response to the detection.

In one disclosed embodiment of the method the Elect ^¬ rolysezelle is reversed, so that the first and second electrodes alternately function as a cathode and anode.

This increases the suitability of the process for producing ozone from liquids other than ultrapure water, such as tap water. The formation of deposits on the electrodes is counteracted.

The polarity reversal can take place in particular at regular intervals. Ozone production thus remains relative

constant .

The invention will be explained below with reference to the accompanying drawings in detail. Show it

Figure 1 is a schematic representation of an electrolytic cell according to the invention according to a first

In the form of a guide,

Figure 2 is a schematic representation of an electrolytic cell according to the invention according to a second

embodiment,

Figure 3 is a schematic representation of an electrolytic cell according to the invention according to a third

In the form of a guide,

Figure 4 is a schematic representation of an inventive device, and

Figure 5 is a schematic representation of a bypass according to the invention.

The electrolytic cell 10i illustrated in Figure 1 to ^¬ holds a first electrode 12 having a first surface Fi and a second electrode 14 having a second area F _2, which face each other and are arranged at a distance A from each other. The Elect ^¬ clear 12,14 each have a carrier core 17 on which a Diamond coating 28 is applied. In order to make the diamond coating 28 electrically conductive, it is doped. Furthermore, the electrolytic cell 10 comprises a measuring ^device 26 for determining the cell resistance and for

Activating the electrolytic cell 10 in response to a ^¬ be determinable event. The measuring device 26 is connected to a

Power supply 18 is connected for controlling the voltage as a function of the precisely measured ^¬ NEN cell resistance.

The two electrodes 12, 14 form a free space 15 which can be flowed through by liquid, for example water, and filled with a particulate solid electrolyte 20, which can be embodied as an ion exchanger 22 or as an acidified zeolite 24 or as a polymer 24. As polymer 24, in particular, a sulfonated tetrafluoroethylene polymer has been found suitable, for example, available under the trade name Nafion ^¬. It may the example extruded and then ground to the desired particle size ^¬. The mean particle size diameter of the

Solid electrolyte 20 is selected so that the liquid can flow with a sufficiently large volume flow between the two electrodes 12,14. It can the

Particle size diameter in the range of 10 μπι to 0.5 mm. To prevent the particulate

Solid electrolyte is flushed out of the free space by the flowing liquid, a retainer 25 is provided. This can for example be designed as a sieve having a mesh width ent ^¬ speaking or as a nonwoven layer. It is important that the pressure loss generated during the flow through the retaining device 25 or the

Flow resistance can be kept low.

To generate an oxidizing agent, the ^electrodes 12, 14 are subjected to a voltage. In the water, which is located between the first and the second electrode 12,14, adjusts a current density, which ensures that at the anode following the current understanding, the following reactions can take place:

6H ₂ 0 ^ 6H ⁺ + 60H (1) βΟΗ - »βΟΗ ^* + 6e ^~ (2)

where OH ^* OH radicals are called.

Accordingly, ozone is generated as an oxidizing agent, with which the water is enriched in the electrolytic cell 10i. The first time flow through the electrolysis cell 10i, the oxidizing agent and, in particular, the ozone then mixed with the remaining water containing the Elektrolysezel ^¬ le 10i has not flowed through. Is the water already with you?

Been oxidant enriched with ozone, in particular, it is gereichert with additional oxidizing agent and preferably with ozone at ^¬. The volume flow through the electrolytic cell 10i and the concentration of the ozone generated are chosen so that the ozone concentration in the entire liquid in the device 30 is sufficient to safely deactivate the germs present in the liquid and liquid-carrying parts without damaging the health limits on ^¬ steps and / or the water taste adversely modified or an unpleasant odor is triggered. A volume flow of about 30 Lh- ¹ through the electrolytic cell has proved to be suitable. The average ozone concentration in the electrolytic cell is 50 micrograms ^■ L ^~ not exceed ^1, otherwise unwanted by-products are generated to an increased extent in ^¬ play as bromate. However, locally in the

Electrolysis cell also produces a significantly higher ozone concentration, which in the tank to the maximum

desired ozone concentration is diluted. The by-products formed during the Oxida ^¬ tionsmittel- and ozone generation are heavily dependent on the composition of the water to be treated gig, depending on the geological environment, from which the water

is taken, may vary significantly. At an ozone concentration of 50 μg ^■ L ^{~ 1} or less, the formation of

By-products for the water normally supplied by the drinking water networks within an acceptable range. At the same time, the spread of germs in the liquid is prevented.

FIG. 2 shows a second exemplary embodiment of an electrolytic cell IO ₂ . In this case, the free space is 15 empty. Otherwise, the electrolytic cell IO ₂ corresponds to that shown in FIG.

FIG. 3 shows an electrolytic cell 10 ₃ according to a third exemplary embodiment. As a carrier core 17, a ceramic material 29 is provided. The first and the second surface Fi, F ₂ have one or, as shown, several cracks before ^¬ 27, on which high current densities can be produced.

4 shows an inventive device 30 is shown for treating a fluid, comprising a ^¬ genera tor 11 for generating ozone, which in the illustrated

Example is formed as an electrolytic cell 10 according to one of the embodiments shown in the Fi ^¬ gures 1 to 3 embodiments. A control device 31 controls the operation of the electrolysis cell 10. Furthermore, the device 30 comprises an inlet 32, with which an untreated liquid, in particular water, can be guided into the device 30. In the illustrated example, the feed 32 opens into a treatment area 36 in which the liquid, in this case water, is mixed with oxidizing agent and, in particular, ozone. The treatment area 36 comprises a tank 34 in which the water can be stored. Starting from the tank 34, a guide means 37 leads to a

Outlet 38 through which the treated water can be discharged, for example, to be drunk by a user. Furthermore, the outlet piece 38 has a closure element 40 with which an opening 42 for selectively discharging the treated water can be opened and closed. The outlet piece 38 has a feed element 39, which serves to bring the treated water up to the opening 42.

Furthermore, a discharge element 44 is provided in the outlet piece 38, with which the treated liquid from the outlet ^¬ piece 38 can be removed when the opening 42 is closed. In the illustrated example, the removal element 44 is designed from ^¬ that the treated liquid is recycled to the tank 34th

Furthermore, the device 30 comprises a conveyor 46, for example a pump, with which the liquid can be circulated within the device 30. A unit 48 for reducing the concentration of the oxidizing agent is also present, which is arranged in the region of the outlet piece 38 in the example shown. In the example shown, this is activated when fluid is removed via the outlet piece 38. When circulating the liquid, the unit 48 is normally switched off.

The generator 11 or the electrolytic cell 10 is arranged in the guide means 37, but can be mounted at any point of the device 30, for example in the

Tank 32 or in the outlet piece 38. The measuring device 26 for determining the conductivity, the oxidation-reduction potential or the oxidation content of the liquid is not integrated in the illustrated example in the electrolytic cell 10, but disposed upstream of the electrolytic cell 10 and via a line 50 with the Electrolytic cell 10 connected. Thus, the conductivity of the water can be measured anywhere on the device 30, for example in the guide means 37, as shown here.

Now, if the electrolytic cell 10 is activated, the

Liquid, which flows through the electrolytic cell 10, with oxidizing agent, preferably subjected to ozone. After relying ^¬ sen of the electrolytic cell 10, the oxidizing agent, preferably ozone, transported by the fluid within the device 30 is advantage. For this purpose the conveyor means 46 circulates the fluid in the closed closure member 40 within the Führungsmit ^¬ tel 37 in the direction of the arrows in a way, that the ozone is promoted to the outlet piece 38 and back into the tank 34th Thus, it is ensured that both the tank 34 and the guide means 36 and in particular the outlet piece 38 are flushed with the ozone-containing water, so that the necessary number of germs are inactivated and in particular a re ^¬ trograde bacterial contamination of the device 30 and the formation of biofilms in the device 30 is prevented.

The control device 31 is adapted to a

Apply voltage above a threshold at the electrodes 12,14. The threshold value depends on the distance A, in particular sondere proportional to this distance A. Further, the STEU ^¬ ereinrichtung 31 can monitor the current between the electrodes 12,14. If it is detected that this drops sharply, then the voltage is temporarily increased above a threshold value. Subsequently, the normal operation is again aufgenom ^¬ men.

The control device is also set up to carry out a regular reversal of polarity of the electrolytic cell 10. The electrode 12,14, which acted as a cathode before the polarity reversal, becomes the anode. The electrode 12,14, which acted as an anode before the polarity reversal, becomes the cathode.

FIG. 5 shows a bypass 52 which can be used at any point of the device 26 according to the invention. In the illustrated example, the bypass 52 is arranged in the inlet 32, which divides into a first section 53 and a second section 55 and then rejoins. In section 55, the electrolysis cell 10 and a treatment unit 54 are arranged. The Behandlungsein ^¬ standardized 54 is in the embodiment example shown in Figure 5

is shown, upstream of the electrolytic cell 10 angeord ^¬ net. By means of the treatment unit 54, the liquid can be conditioned, for example softened and partially or fully demineralized or mechanically filtered. The bypass 52 further comprises an adjusting device 56 with which the ratio between the volume flow in the first section 53 and the volume flow in the second section 55 can be adjusted. In this way, the oxidizing agent and ozone concentration in the device 26 can be selected. Furthermore, the bypass 52 allows easy replacement of the

Electrolysis cell 10 or the treatment unit 54. The Ver ^¬ steepening 56 may be configured so that all the water flows through the first portion 53. Then, the electrolytic cell 10 or the treatment unit 54 can be replaced without having to shut down the entire device 26. Furthermore, the entire bypass 52 or the second section 55 or the electrolysis cell 10 or the

Treatment unit 54 designed as a replaceable unit which can be very easily separated from the adjacent building units and reconnected with them. For this purpose, a first Abklemmeinheit 58i and a second Abklemmein ^{¬ unit} 58 _{2 are} provided, which can be closed on the one hand to prevent the passage of the liquid and the ^¬ other hand, the assembly and disassembly of lying between them second portion 55 of the bypass 52 together therein angeord ^¬ Neten units, here the treatment unit 54 and the

Electrolysis cell 10, simplify.

LIST OF REFERENCE NUMBERS

10 electrolytic cell

11 generator

12 First electrode

14 second electrode

15 free space

17 carrier core

18 power supply

20 particle-shaped solid electrolyte

22 ion exchangers

24 zeolite, polymer

25 retention device

26 measuring equipment

27 advantage

28 diamond coating

29 ceramic material

30 device

31 control device

32 inlet

34 tank

36 treatment area

37 guiding means

38 outlet piece

39 delivery element

40 closure element

42 opening

44 Abführelernent

46 conveyor

48 unit

50 line

52 Bypass

53 First section

54 filters

55 Second section

56 Adjustment device

58 Clamping unit

Claims

1. electrolytic cell for generating Oxidationsmit- elements, in particular ozone, for treating a liquid, comprising

a first electrode (12) and

a second electrode (14),

wherein the first and the second electrode (12,14) are arranged at a distance (A) to each other, and

wherein between the first and the second electrode (12,14) a particulate solid electrolyte (20)

is arranged, which can be traversed by the liquid, as ^¬ characterized in that

the solid electrolyte (20) is disposed in a free space bounded by the first and second electrodes (12, 14).

2. electrolytic cell according to claim 1,

wherein the first and second electrodes (12, 14) comprise a carrier core (17) and a diamond coating (28).

3. An electrolytic cell according to claim 1 or 2, wherein the first electrode (12) has a first surface (Fl) and the second electrode (14) has a second surface (F2) in contact with the particulate solid electrolyte (20), and wherein the first and the second surface (F1, F2) are arranged plane ^¬ parallel to each other.

4. electrolytic cell according to one of the preceding claims,

wherein the first and second surfaces (Fi, F2) have one or more projections (27).

5. Apparatus for treating a liquid comprising

an inlet (32) for feeding liquid into the device,

an outlet piece (38) for discharging the treated liquid from the device,

a water treatable treatment area (36) for treating the water, and an electrolysis cell (10) for generating oxidants and in particular ozone for the treatment of

Liquid according to one of the preceding claims.

6. Apparatus according to claim 5,

wherein the device is adapted to umzupolen the elec ^¬ rolysis cell, so that the first and the second

Electrode (12,14) alternately as a cathode and as an anode fungie ^¬ ren.

7. Apparatus according to claim 5 or 6,

further comprising a measuring device (26) for determining at least one variable from the group comprising

Conductivity, oxidation-reduction potential and the ozone ^¬ content of the liquid,

wherein the device is adapted to activate the electrolytic cell (10) in response to a detectable event.

8. Device according to one of claims 5-7, wherein the device comprises a measuring device (26) for determining the conductivity of the liquid, and

wherein the device is adapted to adjust a cell h ^¬ lenspannung depending on the conductivity.

9. Apparatus according to claim 7 or 8,

wherein a cell resistance can be determined by means of the Messeinrich ^¬ device (26), and wherein the measuring device (26) comprises a power supply (18) for regulating the voltage in dependence on the gemes ^¬ Senen cell resistance.

10. Device according to one of claims 5-9, wherein the outlet piece (38)

a closable opening (42) for selectively dispensing the liquid,

a feeding member (44) for supplying the liquid to the outlet piece ^¬ ness (38) and

comprises a discharge element (44) for discharging the liquid ^¬ ness from the outlet piece (38) and passing into the tank (34).

11. Device according to one of claims 5-10, further comprising a unit (48) for reducing the concentration of the oxidizing agent.

12. Device according to one of claims 5-11,

further comprising a bypass (52) having a first portion (53) and a second portion (55), the

Electrolysis cell (10) in one of the sections (53,55) is arranged.

13. A process for producing ozone for the treatment of a liquid, comprising the following steps:

Determining the conductivity, the oxidation-reduction potential or the ozone concentration of a liquid present in a device according to one of claims 5-12 by means of a measuring device (26),

Activation of a generator (11) for generating ei ^¬ nes oxidizing agent, in particular of ozone, depending on the specific conductivity, the oxidation-reduction potential, the ozone concentration or a detectable event by means of the measuring device (26), and

especially of ozone.

14. The method of claim 13, wherein the electrolysis cell (10) is reversed, so that the first and the second

Electrode (12,14) alternately act as a cathode and anode.

15. The method according to claim 14, wherein the polarity reversal takes place at regular intervals.