Apparatus for generating plasma activated liquids, equipment and methods for cleaning and / or sterilization

Abstract

The present invention relates to an apparatus for generating a plasma activated liquid, the apparatus comprising: A first planar electrode (1) and a second planar electrode (2), A first flat electrode (1) and a second flat electrode (2) separated from each other by a discharge space (3); A voltage is applied between the first planar electrode (1) and the second planar electrode (2), thus a voltage source (4) designed to ignite an electric discharge in the discharge space (3) between the first (1) and second (2) planar electrodes; and a liquid supply (5) designed to supply liquid to the discharge space (3) so as to form a liquid film (7) in the discharge space (3) that is exposed to the electric discharge when an electric discharge is ignited in the discharge space (3). Further aspects relate to an instrument comprising such a device and to a method for cleaning and / or sterilization using the device.

Description

[Technical field]

[0001] The present invention relates to a device for generating a plasma active liquid, an instrument including such a device, and a method for cleaning and / or sterilization. [Background technology]

[0002] Transferring the chemical reactivity and energy of gaseous plasma to water or other liquids is a technological approach that can generate liquids with significant, transient, broad-spectrum biological activity. When water is used as the liquid, this process can generate so-called plasma-activated water (PAW). The properties of PAW make it an environmentally friendly solution for a wide range of biotechnological applications, such as water treatment, surface cleaning and biomedicine. The properties of PAW can also be exploited in various household appliances (Haushaltsgeraete).

[0003] However, systems known in the art for producing plasma activated liquids are often very complicated and do not allow easy and reliable setting of the mixing ratio and dosing of the treatment liquid and treatment gas. As a result, these systems often have unstable operation. For example, US 2004 / 0076543 A1 shows a system using plasma treated water. Summary of the Invention

[0004] The problem that the present invention aims to solve is to overcome at least one of the disadvantages of the prior art. A further problem is to disclose an advantageous method for cleaning and / or sterilization.

[0005] The problem is solved by the subject matter of the independent claims. The dependent claims relate to advantageous embodiments and further developments of the invention.

[0006] An apparatus for generating a plasma-activated liquid or plasma-activated fluid is proposed, the apparatus comprising a first and a second planar electrode, the first and second planar electrodes being separated from each other via a discharge space. The apparatus also comprises a voltage source, the voltage source being designed to apply a voltage between the first and second planar electrodes, such that an electric discharge is ignited in the discharge space between the first and second planar electrodes. The apparatus comprises a liquid supply, designed to supply liquid to the discharge space, such that when an electric discharge is ignited in the discharge space, a liquid film is formed in the discharge space which is exposed to the electric discharge.

[0007] A liquid film can be formed on one of the planar electrodes or on an object placed in the discharge space. Here, the term liquid film is used to describe a thin, continuous layer of liquid that wets a surface. A liquid film can differ in its flow properties from bulky or lumpy liquids. If the thickness of the liquid is less than or equal to 1 mm, it can be described as a liquid film.

[0008] Upon discharge in the discharge space, species in the gas in the discharge space, e.g. ozone, NOx and / or peroxides, are activated. These activated species are released into the liquid film, whereby the liquid in the liquid film is plasma activated.

[0009] A liquid film is particularly suitable for use in an apparatus for generating a plasma-activated liquid because, compared to a bulk liquid, the liquid film has a much larger surface area exposed to the discharge in the discharge space, and upon discharge in the discharge space, discharge-induced plasma chemistry and energy transfer to the liquid film occurs at the large surface area of ​​the liquid film.

[0010] During the discharge in the discharge space, an exchange of activated species takes place at the interface between the liquid film and the gas, and the discharge generates activated species in the gas. Due to the large surface area of ​​the liquid film, the exchange of activated species takes place at a high exchange rate. A high exchange rate between the active species is synonymous with a high efficiency of the device. The use of a liquid film makes it possible to generate a plasma-activated liquid with a high concentration of active species in a short time. Due to the small thickness of the liquid film, the diffusion-limited exchange rate in the liquid is high and a new equilibrium of the active species is quickly established in the liquid.

[0011] The use of a liquid film in the device for generating a plasma activated liquid, in which the liquid of the liquid film is plasma activated, also allows the design of a simple device with less complex structure. The liquid can be easily dosed by adjusting the liquid supply and, if necessary, the liquid discharge accordingly. Similarly, the gas used can be dosed by adjusting the flow rate of the gas supply and the gas discharge. In this way, the mixture ratio of liquid and gas in the discharge space can be controlled in a desired manner. The output stoichiometry in the plasma activated gas and in the plasma activated liquid can be easily controlled by a simple and robust dosing system. By selecting the temperature of the entire process in the discharge space, the vapor pressure of the liquid in the gas phase can be adjusted, and as a result, the composition of the chemical species generated under the energy supply can be changed. Easily adjustable parameters such as temperature, liquid flow rate, gas flow rate, etc. make it possible to control the plasma activation of the liquid and the type of activated species generated.

[0012] An electrode may be described as "flat" if it is designed to induce a discharge at its surface. A flat electrode may have a substantially two-dimensional surface to which a voltage can be applied. A flat electrode may be planar and therefore may be arranged substantially in one plane. However, a flat electrode may also have a surface that is not a flat plate but forms the surface of a three-dimensional body, for example the surface of a cylinder. A flat electrode has a surface on which a liquid film can be formed.

[0013] Preferably, the thickness of the liquid film is less than 0.2 mm, more preferably less than 0.1 mm. The thickness of the liquid film can be between 50 nm and 0.2 mm, preferably between 100 nm and 0.1 mm.

[0014] Also, a liquid film less than 50 nm thick is prone to openings in the liquid film, which may not cover one of the planar electrodes or other objects continuously or consistently, resulting in uneven discharge, which may damage the device or shorten its lifespan. This can be avoided by using a liquid film preferably at least 50 nm thick.

[0015] In the case of a liquid film with a thickness of 0.2 mm or less, the ratio of the surface area to the volume of the liquid film is large enough to efficiently exchange active species at the interface between the liquid film and the gas in the discharge space. In addition, a small liquid film with a thickness of 0.2 mm or less has a high diffusion-limited exchange rate in the liquid, allowing a new equilibrium of active species to be rapidly established in the liquid.

[0016] If the liquid film has a thickness in the preferred range of 100 nm to 0.1 mm, the formation of openings in the liquid film is precluded even on poorly wettable substrates and the efficiency of plasma activation is very high.

[0017] The first flat electrode can have a dielectric layer facing the discharge space. Alternatively or additionally, the second flat electrode can have a dielectric layer facing the discharge space. If at least one of the two flat electrodes has a dielectric layer, the discharge is ignited as a dielectric barrier discharge.

[0018] The dielectric layer can cover the flat electrode on which the liquid film is arranged, so that a direct contact of the liquid film with the conductive contact surface of the flat electrode can be avoided. Alternatively or additionally, the dielectric layer can cover the flat electrode on which the liquid film is not arranged. The dielectric layer can optimize the burning behavior during discharge.

[0019] The dielectric layer of the first planar electrode and / or the dielectric layer of the second planar electrode can be porous and / or rough. Porous and rough layers are characterized by good wetting with liquids. In particular, a liquid film can be generated on the dielectric layer. The porous or rough properties of the layer ensure that the liquid film remains on the layer and can be activated with plasma. The roughness or porosity of the layer ensures that the electrode has good wetting properties, facilitating homogeneous dosing of the liquid and distribution of the liquid to form a continuous liquid film. The good wetting properties of the rough and / or porous electrodes ensure that a clear separation of the liquid and gas phases is always ensured.

[0020] A porous layer can have small cavities. A layer can be considered as porous here if the cavity volume of the layer is at least 5% of the total volume of the layer, preferably 10% of the total volume, in particular 20% of the total volume. A layer is considered as rough if the surface of the layer is not flat. The surface of the layer can therefore have microscopic depressions and microscopic protuberances that increase the surface area of ​​the layer and facilitate the formation of a liquid film.

[0021] The liquid supply can be designed to supply the liquid to the discharge space such that the liquid forms a liquid film on a surface of the first planar electrode facing the discharge space. Preferably, this surface of the first planar electrode is formed by a dielectric layer. By forming a liquid film on the electrode, a simple and less complicated device can be constructed in which a large surface of the liquid film is directly exposed to the discharge.

[0022] The first planar electrode may have a transport layer of a porous material. The transport layer may form a surface of the first planar electrode facing the discharge space. The porous material of the transport layer may be dielectric. The liquid may move within the transport layer or may form a liquid film on the surface of the transport layer. The transport layer has a high porosity such that capillary forces allow the liquid to move within the transport layer.

[0023] Preferably, the liquid supply is designed to supply the liquid to the transport layer such that the liquid migrates through the transport layer and forms a liquid film on the surface of the transport layer. The use of such a liquid supply, which does not apply the liquid directly to the surface of the first electrode but introduces it into the transport layer, allows a particularly accurate dosing of the liquid. The liquid can be continuously re-dosed via the liquid supply, so that a liquid film of constant thickness can be maintained on the surface of the transport layer.

[0024] A porous body may be arranged in the discharge space, separated from the first and second planar electrodes by gaps. The liquid supply may be designed to generate a liquid film on the surface of the porous body. Thus, no porous film is generated on the electrodes themselves. Also, the liquid film in the gap between the first electrode and the porous body and the liquid film in the gap between the second electrode and the porous body may be plasma activated, respectively. By using an additional porous body in this way, more plasma-activated liquid may be generated in one discharge space in this embodiment.

[0025] In one embodiment, a porous body can be arranged in the discharge space, separated from a first planar electrode and a second planar electrode by a gap, and the liquid supply is designed to generate a liquid film on a surface of the porous body facing the first planar electrode and a further liquid film on a surface of the porous body facing the second planar electrode, where no liquid film is generated on the first and second planar electrodes. The porous body can be arranged in the gap between the first and second electrodes.

[0026] The device may comprise a reaction chamber arranged in the discharge space. The reaction chamber may comprise a liquid outlet designed to release the plasma activated liquid. The liquid outlet may for example be a valve. The liquid outlet may allow for the removal of the plasma activated liquid from the reaction chamber in a controlled manner.

[0027] The device can have a liquid reservoir for containing the liquid. The liquid supply can be designed to take the liquid from the liquid reservoir and to supply it to the discharge space, and the device has a liquid return channel designed to return the liquid from the reaction chamber into the liquid reservoir. In this way, the liquid can be used in a circuit and activated multiple times. Furthermore, the plasma-activated liquid can also be stored in the liquid reservoir. The plasma-activated liquid can be produced at a different place from the place of use. It is not necessary to use it immediately after production, but the activated liquid can also be stored and used later. The plasma-activated liquid maintains its antibacterial effect for several months.

[0028] The apparatus may have a gas reservoir, and the gas supply is designed to take gas from the gas reservoir and supply it to the reaction chamber. The apparatus is designed to activate the gas in the discharge space upon discharge. The gas is circulated between the gas reservoir and the reaction chamber and can be activated multiple times. In this way, activated gas can be stored in the gas reservoir.

[0029] The reaction chamber may be provided with a gas outlet designed to release an activated gas, which may be used, for example, for cleaning or sterilization.

[0030] The apparatus may have a recirculation channel designed to return the activation gas from the reaction chamber to the gas reservoir.

[0031] The liquid reservoir and the gas reservoir can be connected to each other and the outlet of the recirculation channel can be arranged in the liquid reservoir, so that the activated gas released at the outlet of the recirculation channel flows through the liquid in the liquid reservoir. For example, the activated gas can be released in the form of bubbles. When flowing through the liquid in the liquid reservoir, the activated gas can release at least a part of its active species into the liquid, which is then enriched with the active species.

[0032] The first and second planar electrodes can be planar or cylindrically symmetric. When the first or second planar electrodes are cylindrically symmetric, the respective electrodes form a surface of a cylinder, which can be the inner or outer surface of a hollow cylinder.

[0033] The liquid can be moved within the device solely by utilizing free convection, i.e. the device can dispense with active pumping elements and rely solely on capillary forces and gravity to move the liquid, allowing the device to operate in an energy-efficient manner.

[0034] When the liquid film is generated on the first or second planar electrode, the liquid film can cool the respective electrode, thus avoiding overheating of the discharge space. Furthermore, the liquid can also be cooled by a cooling mechanism before being supplied to the discharge space.

[0035] A further aspect relates to an appliance comprising the above-mentioned device for generating a plasma activated liquid, which can be a household appliance, for example a floor care appliance, a cleaning robot, a coffee maker, a dishwasher or a dryer, or it can be another appliance, for example a water treatment appliance or a medical appliance used in biomedicine.

[0036] A further aspect relates to a method for cleaning and / or sterilization, in which a plasma activated liquid and / or a plasma activated gas can be generated using the device described above, and the liquid and / or gas is used for cleaning and / or sterilization. [Brief description of the drawings]

[0037] In the following, preferred embodiments of the present invention will be described with reference to the drawings.

[0038] [Figure 1] FIG. 1 shows a first example embodiment of an apparatus for generating a plasma activated liquid. [Diagram 2] FIG. 2 shows a second embodiment of the device. [Diagram 3] FIG. 3 shows a third embodiment of the device. [Figure 4] FIG. 4 shows a fourth embodiment of the device. [Diagram 5] FIG. 5 shows a fifth embodiment of the device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] 1 shows a first embodiment of a device for generating a plasma activated liquid. The device comprises a first planar electrode 1 and a second planar electrode 2. The two planar electrodes are separated from each other by a discharge space 3.

[0040] Furthermore, the device comprises a voltage source 4, which is connected to the first planar electrode 1 and the second planar electrode 2. The voltage source 4 is designed to apply a voltage between the two planar electrodes 1, 2. The voltage can be an alternating voltage or a pulsed voltage. When the voltage source 4 applies a voltage between the two planar electrodes 1, 2, an electric field is formed in the discharge space 3 between the two planar electrodes 1, 2, with a field strength sufficient to ignite a discharge.

[0041] The apparatus comprises a liquid supply 5 which supplies liquid to the discharge space 3. The liquid can be, for example, water or another process liquid. In the example embodiment shown in Figure 1, the liquid is applied from the liquid supply 5 to a first edge of the surface 6 of the first planar electrode 1. The liquid flows along the surface 6 of the first planar electrode 1 and forms a liquid film 7 on the surface 6 of the first planar electrode 1.

[0042] A liquid outlet 8 is provided at a second end of the surface 6 of the first planar electrode 1 opposite to the first end. At the liquid outlet 8, liquid can be taken out from the first planar electrode 1. Between the liquid supply 5 and the liquid outlet 8, the liquid flows through the discharge space 3 as a liquid film 7. In the discharge space 3, the liquid is exposed to a discharge and is thereby plasma activated.

[0043] The first flat electrode 1 has a conductive contact surface 1a and a dielectric layer 1b. The conductive contact surface 1a may be a metal surface. The conductive contact surface 1a is connected to a voltage source 4, by which a potential can be applied to the conductive contact surface 1a.

[0044] A dielectric layer 1b covers the conductive contact surface 1a such that the dielectric layer forms a surface 6 of the first planar electrode 1 facing the discharge space 3. A liquid film 7 is formed on the surface 6 of the dielectric layer. During discharge, the dielectric layer 1b acts as a barrier and the discharge is ignited as a dielectric barrier discharge (DBD).

[0045] The dielectric layer 1b is preferably rough and / or porous. A rough and / or porous layer is characterized by good wetting with the liquid. The rough and / or porous design of the dielectric layer 1b ensures that a liquid film 7 can be formed on the dielectric layer and that the dielectric layer remains wet with the liquid.

[0046] The second planar electrode 2 has a conductive contact surface 2a, which contact surface is connected to a voltage source 4. The conductive contact surface 2a of the second planar electrode 2 is not covered with a dielectric layer.

[0047] The apparatus also comprises a gas supply 9 and a gas outlet 10. Gas is introduced into the discharge space 3 from the gas supply 9 and extracted from the discharge space 3 from the gas outlet 10. The flow direction of gas from the gas supply to the gas outlet can be opposite to the flow direction of liquid from the liquid supply 5 to the liquid outlet 8. The gas can be air or other process gas.

[0048] Due to the discharge in the discharge space 3, chemical species, such as ozone, NOx or peroxides, are generated in the gas in the discharge space 3. The interface of the liquid film 7 is in contact with the gas and absorbs the chemical species generated from the gas phase of the gas at the interface. The gas is enriched with the generated species by the discharge and can also absorb vapour, such as water vapour, by exchange with the liquid film.

[0049] The liquid in the liquid film 7, enriched with chemical species, becomes the plasma activated liquid. The gas is also enriched with chemical species and water vapor and is therefore plasma activated as well. In this way, the device produces a plasma activated liquid and a plasma activated gas.

[0050] FIG. 2 shows a second embodiment of the device for producing a plasma active liquid.

[0051] According to a second embodiment example, the first flat electrode 1 has a conductive contact surface 1a, a liquid distributor 11 and a porous transport layer 12 which are stacked together, with the porous transport layer 12 forming the surface 6 of the first flat electrode 1 facing the discharge space 3.

[0052] The liquid distributor 11 is connected to a liquid supply 5. The liquid supply 5 supplies liquid to the liquid distributor 11, through which the liquid is supplied to the porous transport layer 12. The liquid distributor 11 can be a volume that is filled with liquid by the liquid supply 5. In the simplest embodiment, the liquid distributor 11 is a container. In alternative embodiments, the liquid distributor 11 can be a structured volume, for example with a meander-like or channel-like distributor structure.

[0053] The porous transport structure 12 draws the liquid from the liquid distributor 11 by capillary forces. In the porous transport layer 12, the liquid is forced through the transport layer 12 by capillary forces and spreads to form a liquid film 7 on the surface of the porous transport layer 12. The liquid can be continuously re-dispensed via the liquid distributor 11. The liquid film 7 on the surface 6 of the porous transport structure is exposed to the discharge in the discharge space 2. As a result, the liquid film 7 is plasma activated as described in connection with the first example embodiment.

[0054] In the embodiment shown in Fig. 2, the second planar electrode 2 is covered with a dielectric layer 2b. The dielectric layer 2b forms a dielectric barrier to the discharge space 3, and thus the discharge is ignited as a dielectric barrier discharge. The liquid in the liquid film 7 formed on the surface 6 of the first planar electrode 1 is activated by the dielectric barrier discharge and can be extracted as activated liquid at the liquid extraction section. In particular, the liquid can move from the surface of the first planar electrode 1 to the liquid extraction section 8 by gravity.

[0055] The liquid in the liquid distributor 11 is located between the conductive contact surface 1a of the first flat electrode 1 and the second flat electrode. This means that during discharge, the liquid in the liquid distributor 11 is present in the current path. In order to ensure that the discharge is not adversely affected by the liquid, it is necessary for the liquid to have a certain electrical conductivity.

[0056] 3 is a diagram showing a third embodiment, which is a modification of the second embodiment, in which the position of the first flat electrode is changed.

[0057] In the third example embodiment, a first planar electrode is disposed between the liquid distributor 11 and the transport layer 12. The first planar electrode has openings through which liquid passes from the liquid distributor 11 to the porous transport layer 12.

[0058] In the third embodiment, the liquid in the liquid distributor 11 is not disposed in the current path during discharge. Therefore, in the third embodiment, there is no restriction on the liquid that can be used.

[0059] FIG. 4 shows an apparatus for producing a plasma activated liquid according to a fourth example embodiment.

[0060] The fourth embodiment differs from the previous embodiments in that the liquid and the gas each circulate in a circuit. The fourth embodiment further differs from the first to third embodiments in that the liquid film 7 is not formed on one surface of the two flat electrodes 1, 2, but is formed on a porous body 13 disposed in the discharge space 3 and separated from the first flat electrode 1 and the second flat electrode 2 by a gap 14.

[0061] Both differences should be considered separately from each other and can also be provided individually in alternative embodiments of the embodiment of Figure 1, 2 or 3. In particular, the liquid film 7 can be formed on the porous body 13 in the discharge space 3 without gas and / or liquid being circulated. Alternatively, gas and / or liquid can be circulated and the liquid film 7 can be formed on one surface of both planar electrodes 1, 2.

[0062] The device shown in FIG. 4 has a reaction chamber 15. A first planar electrode 1 and a second planar electrode 2 are arranged in the reaction chamber 15. A discharge space 3 between the two electrodes 1, 2 is also arranged in the reaction chamber 15. A porous body 13 is arranged in the discharge space 3. A liquid supply 5 supplies liquid to the porous body 13. For this purpose, for example, the liquid can be dripped onto the porous body 13. Alternatively, the liquid supply 5 can have a tube whose outlet abuts against the porous body 13 or is surrounded by the porous body 13.

[0063] The liquid passes through the porous body 13 by capillary forces and moves along the surface of the porous body 13, forming a liquid film 7 on the surface of the porous body 13. Here, a discharge is ignited in the gap 14 between the first flat electrode 1 and the porous body 13 and in the gap 14 between the second flat electrode 2 and the porous body 13. Due to the discharge in the discharge space 3, chemical species are generated in the gas, e.g. ozone, NOx or peroxides. At the interface between the liquid film and the gas, an exchange of chemical species and water vapor occurs. This activates the liquid film with chemical species. Similarly, the gas is enriched with chemical species and water vapor.

[0064] The liquid film 7 flows along the surface of the porous body 13 and drips by gravity into a collection vessel 16 placed below the porous body 13, where the plasma-activated liquid is collected.

[0065] The reaction chamber 15 is gas-tight and liquid-tight to prevent uncontrolled escape of the plasma-activated gases, especially ozone. However, the reaction chamber 15 has inlets and outlets for the gases and liquids described below. The reaction chamber 15 has a liquid outlet 8, through which the plasma-activated liquid can be removed from a collection vessel 16. The removed liquid can be used for any desired purpose, e.g. cleaning, sterilization, activation, etc. The reaction chamber 15 has a gas outlet 10, through which the activated gas can be removed from the reaction chamber 15. The activated gas can also be used for cleaning, sterilization, activation, etc.

[0066] The device shown in Figure 4 also comprises a liquid reservoir 17 and a gas reservoir 18. The gas reservoir 18 and the liquid reservoir 17 may be connected to each other and may for example be formed in a single container.

[0067] The device has a liquid return channel 19, via which the plasma activated liquid can be removed from the collection container 15 and fed to the liquid reservoir 17. The liquid can thus move in a circuit, whereby it is first removed from the liquid reservoir 17 by the liquid feed 5 and fed to the porous body 13. After plasma activation in the discharge space 3, the liquid enters the collection container 15 and is then removed and used at the liquid removal 8 or returned to the liquid reservoir 17 via the liquid return channel 19. In this way, the plasma activated liquid can be collected in the liquid reservoir 17.

[0068] Gas can be taken from the reaction chamber 15 via a recirculation channel 20 and fed to the gas reservoir 18. An outlet 21 of the recirculation channel 20 can be arranged in the liquid reservoir 17. Gas returned from the discharge space 3 to the gas reservoir 18 therefore flows first through the liquid reservoir 17. For example, the outlet 21 of the recirculation channel 20 can have a bubble pattern that ensures that the recirculated gas rises in the liquid in the form of bubbles. At least a part of the active species from the recirculated gas enters the liquid and enriches it in the liquid reservoir 17.

[0069] The gas is guided in a circulation path. It is first in a gas reservoir 18, from where it is taken by a gas supply 9 and supplied to the discharge space 3. In the discharge space 3, the gas is activated by an electric discharge. The gas is then taken at a gas outlet 10 or returned from the discharge space 3 to the gas reservoir 18 via a recirculation channel 10.

[0070] The control of the liquid and gas circuits can be effected by elements whose operation is controlled by differential pressure, in particular pumps, valves, throttles.

[0071] The gas reservoir 18 and the liquid reservoir 17 may each be provided with a re-dosing mechanism 17a, 18a. New, fresh liquid may be supplied to the liquid reservoir via the re-dosing mechanism 17a. New, fresh gas may be supplied to the gas reservoir 18 via the re-dosing mechanism 18a. In this way, the withdrawal of liquid via the liquid outlet 8 and the withdrawal of gas via the gas outlet 10 may be balanced.

[0072] The chemical composition of the circulating liquid and gas can be adjusted via the reintroduction mechanisms 17a, 18a. The volume ratio of fresh non-activated gas to activated gas can be set as required. The volume ratio of fresh non-activated liquid to activated liquid can also be set.

[0073] A pump may also be disposed within the container to circulate the liquid within the liquid reservoir 17 .

[0074] Figure 5 shows a cross section of a device according to a fifth embodiment. In the first to fourth embodiments, the planar electrodes 1, 2 are each substantially two-dimensional surfaces extending on a plane. In the fifth embodiment, the first planar electrode 1 and the second planar electrode 2 are each cylindrically curved. The first planar electrode 1 forms an inner cylinder and the second planar electrode forms an outer cylinder, both cylinders being arranged concentrically with each other. The outer cylinder surrounds the inner cylinder.

[0075] The discharge space 3 is arranged in the cavity between the cylinder formed by the first planar electrode 1 and the cylinder formed by the second planar electrode 2. The discharge space 3 is ring- or sleeve-shaped.

[0076] The fifth embodiment is based on the first embodiment. As described in relation to the first embodiment, the liquid film 7 is generated on the surface of the dielectric layer 1b facing the discharge space 3. Since both flat electrodes 1 and 2 are curved into a three-dimensional cylindrical shape, the area on which the liquid film can be formed is increased, and more plasma active liquid can be generated.

[0077] In another embodiment, the second planar electrode 2 may form an inner cylinder and the first planar electrode 1 may form an outer cylinder.

[0078] Furthermore, in the second, third and fourth embodiment examples, the first planar electrode 1 and the second planar electrode 2 can be curved into a cylindrical shape. The first planar electrode 1 can form an inner cylinder and the second planar electrode 2 can form an outer cylinder. Alternatively, the first planar electrode 1 can form an outer cylinder and the second planar electrode 2 can form an inner cylinder.

[0079] In the fourth example embodiment, in this alternative embodiment the porous body 13 is annular. The annular porous body 13 is arranged in an annular discharge space 3 between a first planar electrode 1 forming a cylinder and a second planar electrode 2 also forming a cylinder.

[0080] The plasma-activated liquid generated by the device according to one of the embodiments shown here can be used in various applications, for example the liquid can be stored in a container and used as a regenerative cleaning agent, the liquid retaining its beneficial cleaning and disinfecting properties for several months.

[0081] The liquid can be poured into a spray bottle and sprayed. It can also be saturated with the liquid into a sponge and applied to the surface to be treated via the sponge. It can also be applied in a dispenser or on a cloth. The liquid can be used to clean, care for or sterilize objects in dry or wet rooms, for example in dishwashers, to sterilize mouth and nosepieces or dental braces.

[0082] The device can be integrated into various household appliances where plasma-activated liquids can be used for cleaning, sterilization and activation. For example, the device can be used in floor care appliances, vacuum robots and coffee makers for cleaning and descaling. The device can be integrated into dishwashers (Spuelmaschine), washing machines and dryers to take advantage of the beneficial properties of plasma-activated liquids and plasma-activated gases. [Explanation of symbols]

[0083] 1. First flat electrode 1a Conductive contact surface 1b Dielectric layer 2 Second flat electrode (zweite flaechige Elektrode) 2a Conductive contact surface 2b Dielectric layer 3 Discharge space (Entladungsraum) 4. Voltage source 5 Fluid supply section 6 Surface of the first flat electrode 7 Fluessigkeitsfilm 8 Fluid outlet (Fluessigkeitsentnahme) 9 Gas Supply Department 10 Gas Extraction (Gasentnahme) 11 Fluidverteiler 12 Transport Layer 13 Porous body 14 Spalt 15 Reaction Chamber (Reaktionskammer) 16 Collection container (Sammelbehaelter) 17 Fluid reservoir 17a Readministration mechanism 18 Gas reservoir 18a Readministration mechanism 19 Liquid return channel 20 Rezirkulation Channel 21 Outlet (Auslass)

Claims

1. 1. An apparatus for generating a plasma activated liquid comprising: A first planar electrode (1) and a second planar electrode (2) separated from each other by a discharge space (3); a voltage source (4) designed to apply a voltage between the first (1) and the second (2) planar electrodes, thus igniting an electric discharge in the discharge space (3) between the first (1) and the second (2) planar electrodes; a liquid supply (5) designed to supply the liquid to the discharge space (3) so as to form a liquid film (7) in the discharge space (3) that is exposed to the electric discharge when the electric discharge is ignited in the discharge space (3); An apparatus comprising:

2. the liquid is plasma activated by the discharge within the liquid film (7); 2. The apparatus of claim 1.

3. The liquid film (7) has a thickness between 50 nm and 0.2 mm.

3. Apparatus according to claim 1 or 2.

4. the first planar electrode (1) has a dielectric layer (1b) facing the discharge space (3), and / or The second flat electrode (2) has a dielectric layer (2b) facing the discharge space (3).

4. Apparatus according to any one of claims 1 to 3.

5. the dielectric layer (1b) of the first planar electrode (1) is porous and / or rough; the dielectric layer (2b) of the second flat electrode (2) is porous and / or rough; 5. The apparatus of claim 4.

6. the liquid supply (5) is designed to supply the liquid such that it forms the liquid film (7) on the surface of the first planar electrode facing the discharge space (3); 6. Apparatus according to any one of claims 1 to 5.

7. the first planar electrode (1) comprises a transport layer of porous material forming a surface (6) of the first planar electrode (1) facing the discharge space (3), 7. Apparatus according to any one of claims 1 to 6.

8. the liquid supply (5) is designed to supply liquid to the transport layer (12) so that the liquid moves through the transport layer (12) and forms the liquid film (7) on the surface (6) of the first planar electrode (1); 8. The apparatus of claim 7.

9. A porous body (13) is disposed in the discharge space (3) and is separated from the first flat electrode (1) and the second flat electrode (2) by a gap (14), The liquid supply unit (5) is designed to generate the liquid film on the surface of the porous body.

9. Apparatus according to any one of claims 1 to 8.

10. A porous body (13) is disposed in the discharge space (3) and is separated from the first flat electrode (1) and the second flat electrode (2) by a gap (14), the liquid supply (5) is designed to generate the liquid film on the surface of the porous body (13) facing the first planar electrode (1) and to generate a further liquid film on the surface of the porous body (13) facing the second planar electrode (2); No liquid film is formed on the first planar electrode (1) and the second planar electrode (2); 9. Apparatus according to any one of claims 1 to 8.

11. The device has a reaction chamber (15) in which the discharge space (3) is arranged, The reaction chamber (15) has a liquid outlet (8) designed to discharge a plasma activated liquid, 11. Apparatus according to any one of claims 1 to 10.

12. The device comprises a liquid reservoir (17) for containing the liquid, the liquid supply (5) is designed to take the liquid from the liquid reservoir (17) and to supply the liquid to the discharge space, The device has a return channel (19) designed to return the liquid from the reaction chamber (15) into the liquid reservoir (17).

12. The apparatus of claim 11.

13. The apparatus includes a gas reservoir (18); A gas supply (9) is designed to take gas from the gas reservoir (18) and supply said gas to the reaction chamber (15); the device is designed to activate the gas in the discharge space (3) during the discharge, 13. Apparatus according to claim 11 or 12.

14. The apparatus has a recirculation channel (20) designed to return plasma activated gas from the reaction chamber (15) to the gas reservoir (18).

14. The apparatus of claim 13.

15. the liquid reservoir (17) and the gas reservoir (18) are connected to each other and the outlet (21) of the recirculation channel (20) is located in the liquid reservoir, so that the plasma activated gas released at the outlet of the recirculation channel (20) flows through the liquid in the liquid reservoir (17), 15. Apparatus according to claims 12 and 14.

16. The reaction chamber (15) has a gas outlet (10) designed to release a plasma activated gas, 16. Apparatus according to any one of claims 11 to 15.

17. said first flat electrode (1) being of planar or cylindrical symmetry; and / or The second planar electrode (2) is of planar or cylindrical symmetry; 17. Apparatus according to any one of claims 1 to 16.

18. The device has no active pumping elements and the liquid within the device moves only by capillary forces and gravity.

18. Apparatus according to any one of claims 1 to 17.

19. the liquid film (7) cools the first planar electrode (1) and / or the second planar electrode (2); 19. Apparatus according to any one of claims 1 to 18.

20. 20. An apparatus comprising a device according to any one of claims 1 to 19.

21. The appliance is a household appliance, for example a floor care appliance, a cleaning robot, a coffee maker, a dishwasher or a dryer, or The device is a water treatment device or a medical device.

21. The apparatus of claim 20.

22. Producing a plasma activated liquid by means of a device according to any one of claims 1 to 19, using said plasma activated liquid for cleaning and / or sterilization, method.

23. 1. A method for cleaning and / or disinfection comprising the steps of: Producing a plasma activated gas by means of a device according to any one of claims 1 to 19, using said plasma activated gas for cleaning and / or sterilization, method.

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