DEVICE FOR GENERATING A NON-THERMAL ATMOSPHERIC PRESSURE PLASMA AND ACTIVE SPACE COMPRISING THIS

Description

[0001] The present invention relates to a device for generating a non-thermal atmospheric pressure plasma. Furthermore, the present invention relates to an active chamber comprising such a device.

[0002] The non-thermal atmospheric pressure plasma will be generated using a piezoelectric transformer. The transformer can, in particular, be a Rosen-type transformer.

[0003] US 2015 / 069911 A1 shows a handheld device 1 for plasma treatment of workpieces. The handheld device has a plasma source with an electrode unit for igniting a plasma stream, which electrode unit can be a piezoelectric transformer.

[0004] WO 2017 / 025923 A1 discloses an air conditioning unit for use in a motor vehicle. A piezoelectric transformer 5 can be used in the air conditioning unit as a plasma generator for generating an excited gas.

[0005] DE 202008008980 U1 describes a device for generating an atmospheric pressure plasma, in which a piezo element is arranged in a housing which is connected to a power supply device via a gas line and a supply line for a voltage supply.

[0006] EP 2638960 A1 describes a plasma generator and a method for its operation in which ozone generation is to be limited.

[0007] The object of the present invention is to provide an improved device for generating non-thermal atmospheric pressure plasma, which, for example, has a long service life. The device should preferably be suitable for use in a working space, for example, a trash can, a garbage bin, a sports bag, a wardrobe, or a garment bag.

[0008] This object is achieved by a device according to claim 1.

[0009] A device for generating a non-thermal atmospheric pressure plasma is proposed, comprising a first housing in which a piezoelectric transformer is arranged, and a second housing in which a drive circuit is arranged, which is configured to apply an input voltage to the piezoelectric transformer. Accordingly, the piezoelectric transformer and the drive circuit can be spatially separated from one another by the first and second housings.

[0010] The control circuit has a timing circuit that applies the input voltage to the piezoelectric transformer for a predefined period of time and that does not apply any input voltage to the piezoelectric transformer during a predefined pause interval between two time periods. The application of the input voltage is prevented for the duration of the pause interval. During the pause interval, it may therefore not be possible to apply an input voltage to the piezoelectric transformer. This allows the amount of ozone that can be generated by the device to be limited to a level that is not harmful to health. Plasma and ozone generation may not be possible during the pause interval.

[0011] The device can be operated in pulsed mode, where the transformer can be activated and deactivated for the duration of the pause intervals based on the timer, without taking other operating parameters into account. In any case, the purely time-based control can limit the ozone generation rate to a level that is harmless to health.

[0012] This arrangement of the piezoelectric transformer in the first housing and the control circuit in the second housing offers numerous advantages. If a plasma is generated using the piezoelectric transformer, irritating gases, such as ozone, can be produced during plasma generation. Some of these irritating gases are aggressive and can damage the control circuit over time. However, since the control circuit is arranged in the second housing, damage to the control circuit by the irritating gases can be prevented. This can increase the service life of the device. The first housing and the second housing can preferably be designed such that gas exchange between the two housings is minimized. Accordingly, an irritating gas generated in the first housing cannot enter the second housing or can only do so in a negligible concentration.

[0013] In the output region of the piezoelectric transformer, high-intensity electric fields can be generated during plasma generation. The spatial separation of the piezoelectric transformer and the control circuit ensures that the control circuit is not undesirably influenced by the electric fields.

[0014] Furthermore, by arranging the transformer in the first housing and the control circuit in the second housing, a user can be better protected from irritating gases. The user will typically operate the second housing to switch on the control circuit or to make changes to the control. Since the piezoelectric transformer is arranged separately in the first housing, irritating gases are only generated near the first housing and therefore not in the immediate vicinity of the user. This can increase safety for the user. This can make it possible to use the device in end products for end users that have high safety requirements.

[0015] By dividing the device into separate housings, it can be easily handled. The device can be designed in a small and compact manner.

[0016] The piezoelectric transformer used here could, for example, be a component marketed by EPCOS under the name CeraPlas™<.

[0017] The piezoelectric transformer can be configured to generate a piezoelectrically ignited microplasma at an output end face of the piezoelectric transformer. This can be a so-called piezoelectric direct discharge plasma (PDD). The plasma can therefore be generated directly at the piezoelectric transformer. No additional dielectric barrier is provided in front of the output end face.

[0018] Alternatively, a dielectric barrier can be arranged directly in front of the output end of the transformer, for example, in the form of an attachment. In this case, the plasma can be generated similarly to a dielectric barrier discharge (DBD). However, unlike a "classical" dielectric barrier discharge, the barrier is not connected to a high-voltage source via a cable, but is located in close proximity to the piezoelectric transformer, allowing a high voltage generated by the transformer to be capacitively coupled into an ignition chamber separated from the transformer by the barrier.

[0019] The first and second housings can be separate from one another. The housings can not be formed as one piece. The first housing is not arranged within the second housing and the second housing is not arranged within the first housing. The housings can be spatially separated from one another. The housings can be arranged next to one another, with the two housings either directly adjoining one another or arranged at a distance from one another. The first and second housings can be designed to ensure a spatial separation between the piezoelectric transformer and the drive circuit. The first and second housings can be designed to ensure that gas exchange between the two housings occurs only to a negligible extent.

[0020] The drive circuit and the piezoelectric transformer can be connected to each other by a cable. The cable can enable an alternating voltage output by the drive circuit to be applied to the outer electrodes of the piezoelectric transformer as an input voltage. The drive circuit can be designed such that it is not affected by the impedance of the cable. Accordingly, the cable can have a length of up to 10 m. The cable can have a length of at least 1 cm. The cable preferably has a length in a range between 10 cm and 100 cm.

[0021] A control element that allows the plasma generation to be controlled can be arranged in the first housing. Alternatively, the control element can be arranged in the second housing. The control element can be, for example, a push button, a rotary dial, a microcontroller-controlled system with or without a touchscreen, a remote control, or a system controlled via USB, WLAN, or Bluetooth. Furthermore, it can be controlled via software, for example an app. The control element can enable a user of the device to control the control circuit and to influence and read out various parameters during plasma generation, such as the input voltage, the amount of process gas supplied to the transformer, the concentration of the components of the process gas, the input power, and the operating time.

[0022] If the control element is located on the second housing, it is spatially separated from the piezoelectric transformer located in the first housing. Accordingly, the safety of a user operating the control element can be increased, as they do not have to be in close proximity to the transformer, which can potentially generate harmful irritant gases.

[0023] In an embodiment not claimed, the first housing may comprise a nozzle arranged in front of an end face of the piezoelectric transformer and configured to form a plasma jet generated by the piezoelectric transformer.

[0024] Furthermore, the first housing can have a dielectric barrier arranged directly in front of the piezoelectric transformer. The dielectric barrier can separate the piezoelectric transformer from an ignition chamber in which the process medium is arranged. A high voltage generated by the piezoelectric transformer can be capacitively coupled into the ignition chamber via the dielectric barrier and trigger plasma ignition there. Such an embodiment is particularly advantageous for liquid process media or when biological tissue is used as the process medium. In this case, the piezoelectric transformer does not come into direct contact with the process medium. This direct contact would mechanically dampen the transformer and could no longer be used to generate plasma. Since direct contact is prevented by the barrier, mechanical damping can be prevented from the outset.Even with other process media that are very aggressive and could damage the piezoelectric transformer, it is advisable to place a dielectric barrier in front of the transformer.

[0025] The device may have a third housing, which also has a piezoelectric transformer. The first housing may be exchangeable and replaced by the third housing. In this case, after the first housing has been replaced by the second housing, the drive circuit may be configured to apply the input voltage to the piezoelectric transformer arranged in the third housing.

[0026] Accordingly, the piezoelectric transformer can be replaced along with the first housing. The piezoelectric transformer is the component of the device most exposed to wear. The design in which the first housing is replaceable makes it possible to replace only the transformer, while continuing to use the drive circuit and other elements located in the second housing.

[0027] The piezoelectric transformer can be replaced together with the first housing as a module. The first housing and the second housing can be connected to each other by a detachable connection, for example a plug connection, a USB connection, or a bayonet connection. Such a connection is easy for a user to undo, so that the module comprising the first housing and the piezoelectric transformer can be replaced easily. Replacing the piezoelectric transformer without simultaneously replacing the first housing, however, would be considerably more complex, since in this case, the transformer's attachment to the housing would have to be removed.

[0028] The third housing may have a nozzle. The first housing may also have a nozzle. The nozzles may be designed to shape the plasma jet in different ways or to attach a dielectric barrier in front of the transformer. Accordingly, the first and third housings can be interchanged to change the shape of the plasma jet as desired. Replacing only the nozzle separately without replacing the entire first housing would be considerably more complex, as in this case, the nozzle's attachment to the housing would have to be removed and the new nozzle would have to be attached to the housing again.

[0029] In an alternative embodiment, the nozzle can be replaced separately. A nozzle attached to the first housing or the third housing can be exchangeable. The nozzle is preferably attached to the respective housing by an easily removable fastening. For example, the nozzle can be attached to the respective housing by a bayonet connection. The nozzle can also be attached to the respective housing by a snap-in connection or a screw connection.

[0030] The first housing is designed to destroy irritant gases produced during plasma generation. For this purpose, the first housing can have a coating. The coating can, for example, comprise manganese dioxide, iron oxide, other metal oxides, bare metal surfaces, or surfaces or paints coated with metal catalysts. Alternatively or additionally, the housing can have a filter to destroy the irritant gases. The filter can, for example, be an activated carbon filter. The housing is designed in such a way that a closed gas guidance system is created which prevents irritant gases from escaping from the housing. In addition, the housing can have a suction device. This can be designed to suck out irritant gases immediately after they are generated.Furthermore, at most, only partial gas recirculation into the first housing may be provided, wherein the first housing may be appropriately coated to destroy the irritant gas. In an embodiment not claimed, the device may comprise a control mechanism that allows the amount of a process medium supplied to the piezoelectric transformer to be adjusted. Alternatively or additionally, the control mechanism may also allow the composition of the process medium to be adjusted.

[0031] The device may comprise an attachment which is attached to the first housing and which forms a dielectric barrier immediately in front of an output-side end face of the piezoelectric transformer, so that the device is designed to ignite a plasma by a dielectric barrier discharge on a side of the dielectric barrier facing away from the transformer.

[0032] A plurality of piezoelectric transformers may be arranged in the first housing. The drive circuit arranged in the second housing may be connected to each of the transformers and configured to apply an input voltage to each of the transformers.

[0033] The control circuit can include a timing circuit that applies the input voltage to the piezoelectric transformer for a predefined period of time and that does not apply any input voltage to the piezoelectric transformer during a predefined pause interval between two time periods. For example, an input voltage can be applied to the transformer for a period of 15 seconds and no input voltage can be applied during a pause interval of 2 hours. In this way, the device's energy consumption can be minimized and the irritant gas concentration can be limited.

[0034] The first housing and the second housing can be formed by two chambers of an injection-molded part. The first housing and the second housing can be separated from each other in a watertight manner. The first housing and the second housing can be separated from each other in a gas-tight manner.

[0035] Means for supplying power to the device can be arranged in the second housing. The power supply means can be, for example, a battery, rechargeable batteries, which in one embodiment can be charged using contactless inductive charging, or a transformer designed to convert a mains voltage into an operating voltage for the device. Since the power supply means are arranged in the second housing, they can continue to be used if the first housing is replaced.

[0036] The device may be a portable handheld device.

[0037] In an embodiment not claimed, means for supplying process gas can be arranged in the second housing, wherein the device has a hose designed to conduct a process gas from the means for supplying process gas from the second housing to the piezoelectric transformer arranged in the first housing. The hose can be integrated into a cable that connects the first housing to the second housing. If the first housing is replaced, the means for supplying process gas can thus continue to be used. The means for supplying process gas can be, for example, a fan, a compressor, or a connection for various compressed gas containers, optionally using a gas mixer. Furthermore, the means for supplying process gas can have a pressure reducer, a mass flow controller, a gas humidifier, a gas dryer, an atomizer, and a nebulizer.Alternatively, the means for conducting process gas can also be integrated into the first housing.

[0038] The process medium can be the medium in which the plasma is ignited. The process medium can, for example, be the ambient air of the piezoelectric transformer. The process medium can also be any substance that is gaseous at the use temperature and pressure, any conceivable mixture of substances that is gaseous at the use temperature and pressure, an aerosol that contains liquid and / or solid particles suspended in a gas, a liquid, or biological tissue. The use pressure and the use temperature indicate the pressure and temperature, respectively, at which the device for generating the non-thermal atmospheric pressure plasma is typically used. The use pressure can, in particular, be atmospheric pressure. The use pressure can be between 0.2 bar and 1.5 bar, preferably between 0.8 bar and 1.2 bar.The operating temperature may, in particular, be room temperature. The operating temperature may be in a range between -50°C and +155°C, preferably between 0°C and 45°C.

[0039] If the process medium is a gaseous substance, it can be, for example, a pure gas, e.g., pure He, pure Ar, pure N 2 , pure O 2 , pure CO 2 , pure H 2 , or pure Cl 2 . Furthermore, the process medium can be H 2 O in the supercritical range. The process medium can contain supercritical pure substances, i.e., pure substances that cannot be condensed at the operating temperature and pressure.

[0040] The process medium can comprise one or a mixture of several of the aforementioned pure gases or the following gases: air, shielding gas, and forming gas. The process medium is selected so that the gas state is maintained at the operating temperature and pressure.

[0041] The process medium can be a liquid aerosol in a gas or a gas mixture. This can be, for example, air above the dew point, saturated steam or a gasoline / diesel air mixture. The process medium can be a solid aerosol in a gas or a gas mixture. This can be, for example, soot in exhaust gas or particulate matter in the air. For medical and technical applications, particularly good results can be achieved when using aerosols as a process medium. The aerosol can, in particular, be water droplets in air. It can also be droplets of H2O2 or formaldehyde. OH radicals can be generated by treating the water droplets with plasma. Water droplets can also be used to bind the resulting irritating gases, such as ozone or nitrogen oxide, and thus reduce the ambient pollution with these gases in order to increase application safety.This irritant gas binding can also increase the effectiveness of irritant gas, particularly for sterilization, for example, through ozone dissolved in water droplets. The device could also be used in exhaust streams for particle separation. The device could also be used in steam circuits or sanitary rooms and their ventilation circuits, where aerosols can also form the process medium.

[0042] In an embodiment not claimed, the device may comprise an intake nozzle configured to suck out an irritant gas generated by the piezoelectric transformer, wherein the irritant gas is destroyed in the intake nozzle.

[0043] The device may include a sensor for detecting a fill level, temperature, or humidity. The sensor measures the corresponding parameter inside or in the surroundings of the working chamber.

[0044] The device may include circuit components of a remote control. The circuit components serve to control a control system. The remote control may enable the status of the device to be read or the device to be controlled via a program or app for a computer, e.g., a PC or a mobile communications device.

[0045] The device may include circuit elements for recording parameters such as operating time, errors encountered, status information, or other operating parameters. A memory makes it possible to store values ​​in a log file.

[0046] The device may comprise one or more displays for optically or acoustically signaling one or more operating parameters.

[0047] The device may be intended and suitable for enabling, accelerating or catalyzing chemical reactions.

[0048] The device may be intended and suitable for activating or sterilizing surfaces.

[0049] The device can be intended and suitable for treating or cleaning living and biological tissue. In particular, it can be used for treating or cleaning open or closed or poorly healing wounds inside or outside the living human or animal body. Application to skin wounds is particularly preferred, whereby these wounds can be poorly healing, poorly supplied with blood, or infected with germs.

[0050] A fan and a catalyst are arranged in the first housing, wherein the fan is designed to effect a recirculation mode in which a process medium ionized by the piezoelectric transformer is circulated in the first housing and is thereby passed through the catalyst before the process medium is fed again to the piezoelectric transformer.

[0051] The first housing may include a heat exchanger arranged and configured to dissipate heat from the interior of the first housing to an environment.

[0052] The input region of the piezoelectric transformer can rest on a first support element, wherein the device has at least one projection that is spaced from the piezoelectric transformer when the transformer is in a rest state and that forms a stop against transverse movements of the piezoelectric transformer. The projection can be arranged halfway along the length of the transformer. The projection can be spaced from the piezoelectric transformer when the transformer is in a rest state. The distance of the projection is selected such that the piezoelectric transformer does not strike the projection in its rest state, even with normal manufacturing tolerances and thermal expansion.The projection is arranged in such a way that it limits movements of the transformer due to deformations of the transformer during operation and / or due to impacts on the device and forms a stop for the transformer during such movements.

[0053] The device can have a second projection that is spaced apart from the piezoelectric transformer when the transformer is at rest, and that forms a stop against transverse movements of the piezoelectric transformer, wherein the second projection is arranged at an input-side end of the transformer. The distance of the second projection is selected such that the piezoelectric transformer does not strike the second projection in its at-rest state, even with normal manufacturing tolerances and thermal expansion. The second projection is arranged such that it limits movements of the transformer due to deformation of the transformer during operation and / or due to impacts on the device, and forms a stop for the transformer during such movements.

[0054] According to a further aspect, the present invention relates to an active chamber comprising the device described above and a gas volume. The gas volume can be sealed or leaky. The device can be used to treat the gas present in the gas volume with plasma and / or ozone, for example, to prevent or reduce an odor.

[0055] The effective space can also be referred to as the effective volume. The effective space can be a spatially defined area whose contents are treated with the plasma generated by the device. The effective space can be a container, for example. The effective space does not necessarily have to be a closed volume. Rather, in an effective space with a leaky gas volume, a constant gas exchange can occur, so that the gas in the effective space is continuously renewed or replaced.

[0056] For example, a trash can, a garbage bin, and a plastic bag can form an active space with a dense gas volume. A sports bag or a cotton sack can form an active space with a leaky gas volume. Furthermore, use in cabinets, such as wardrobes, is conceivable. Use in garment bags or shoe bags is also possible.

[0057] If the device is used in an active chamber with a leaky gas volume, precautions can preferably be taken to limit the concentration of irritant gas and to reduce it quickly. In particular, the first housing, which contains the transformer, as already discussed above, is designed to destroy irritant gases generated during plasma generation. For this purpose, the first housing can have a coating, for example manganese dioxide or iron oxide. Alternatively or additionally, the housing can have a filter to destroy the irritant gases. The housing is designed to create a closed gas supply system that prevents irritant gases from escaping from the housing. Alternatively or additionally, the housing can have a suction device designed to extract irritant gases immediately after they are generated.Alternatively, the housing may have a partial irritant gas guide or (gas) recirculation, whereby the housing may be appropriately coated to destroy the irritant gases. Furthermore, the device may have an acoustic and / or visual warning device designed to alert a user in the event of a critical irritant gas concentration. Alternatively or additionally, the device may be designed to automatically switch off when the irritant gas concentration exceeds a threshold value. The device may further be designed to switch on again when the irritant gas concentration falls below the threshold value.

[0058] The device can be compactly integrated into the active chamber and have a perforation for the ozone discharge. The device can be removable from the active chamber. Alternatively, only the first housing can be mounted inside the active chamber. The second housing can be located outside the active chamber.

[0059] The active chamber can, for example, have a lid, with the device or at least the first housing being arranged on the lid. In one embodiment, a plasma outlet opening of the device can point away from the lid. The plasma outlet opening points toward an active chamber or an active volume. Alternatively, the device can be installed at a different position in the active chamber, for example, in a side wall.

[0060] The device can have an outlet opening through which plasma generated by the transformer can escape. The device can be arranged such that the outlet opening is located inside the active chamber. The device can further have an inlet opening through which a gaseous process medium can penetrate into the first housing. The device can be arranged such that the inlet opening is located outside the active chamber. Furthermore, the device can have a carbon filter arranged between the inlet opening and the outlet opening and which separates the interior of the active chamber from the surroundings of the active chamber. The carbon filter can, in particular, prevent an irritant gas generated inside the active chamber from reaching the surroundings of the active chamber.

[0061] Alternatively or in addition to the carbon filter, the device can be provided with a coating that degrades the irritant gas, in particular to prevent the irritant gas generated inside the active chamber from escaping into the surroundings of the active chamber.

[0062] The active chamber can have a sensor configured to detect the opening or closing of the lid, and the device can be configured to generate a plasma after the lid is closed. The sensor can be, for example, an inclination sensor, an acceleration sensor, or a light sensor.

[0063] In the following, the present invention is explained in more detail with reference to the accompanying figures. Figure 1 shows a piezoelectric transformer in a perspective view, Figure 2 shows a device for plasma generation according to a first embodiment, Figure 3shows a piezoelectric transformer arranged in a holder, Figure 4 shows a device for plasma generation according to a second embodiment, the Figures 5 to 7 show a device for plasma generation according to a third embodiment, Figure 8 shows a first part of a device for plasma generation according to a variation of the third embodiment, Figure 9 shows a first housing according to a further embodiment. Figure 10 shows a first housing according to a further embodiment.

[0064] The Figures 11, 12 and 13 show a holder for a piezoelectric transformer.

[0065] Figure 1 shows a perspective view of a piezoelectric transformer 1. The piezoelectric transformer 1 can be used in particular in a device for generating non-thermal atmospheric pressure plasma.

[0066] A piezoelectric transformer 1 is a type of resonant transformer based on piezoelectricity and, unlike conventional magnetic transformers, represents an electromechanical system. Piezoelectric transformer 1, for example, is a Rosen-type transformer.

[0067] The piezoelectric transformer 1 has an input region 2 and an output region 3, with the output region 3 adjoining the input region 2 in a longitudinal direction z. In the input region 2, the piezoelectric transformer 1 has electrodes 4 to which an alternating voltage can be applied. The electrodes 4 extend in the longitudinal direction z of the piezoelectric transformer 1. The electrodes 4 are stacked alternately with a piezoelectric material 5 in a stacking direction x, which is perpendicular to the longitudinal direction z. The piezoelectric material 5 is polarized in the stacking direction x.

[0068] The electrodes 4 are arranged inside the piezoelectric transformer 1 and are also referred to as internal electrodes. The piezoelectric transformer 1 has a first side surface 6 and a second side surface 7, which is opposite the first side surface 6. A first external electrode 8 is arranged on the first side surface 6. A second external electrode (not shown) is arranged on the second side surface 7. The internal electrodes 4 are electrically contacted alternately in the stacking direction x with either the first external electrode 8 or the second external electrode.

[0069] The input region 2 can be controlled with a low alternating voltage applied between the electrodes 4. Due to the piezoelectric effect, the alternating voltage applied to the input side is initially converted into a mechanical oscillation. The frequency of the mechanical oscillation depends significantly on the geometry, mechanical structure, and material of the piezoelectric transformer 1.

[0070] The output region 3 comprises piezoelectric material 9 and is free of internal electrodes. The piezoelectric material 9 in the output region 3 is polarized in the longitudinal direction x. The piezoelectric material 9 of the output region 3 can be the same material as the piezoelectric material 5 of the input region 2, whereby the piezoelectric materials 5 and 9 can differ in their polarization direction. In the output region 3, the piezoelectric material 9 is formed into a single monolithic layer that is completely polarized in the longitudinal direction z. The piezoelectric material 9 in the output region 3 has only a single polarization direction.

[0071] If an alternating voltage is applied to the electrodes 4 in the input area 2, a mechanical wave forms within the piezoelectric material 5, 9, which, through the piezoelectric effect, generates an output voltage in the output area 3. The output area 3 has an output-side end face 10. In the output area 3, an electrical voltage is thus generated between the end face 10 and the end of the electrodes 4 of the input area 2. A high voltage is generated at the output-side end face 10. This also creates a high potential difference between the output-side end face and the area surrounding the piezoelectric transformer, which is sufficient to generate a strong electric field that ionizes a process medium. Furthermore, the generation of radicals, excited molecules, or atoms in the plasma is possible.

[0072] In this way, the piezoelectric transformer 1 generates high electric fields capable of ionizing gases or liquids through electrical excitation. Atoms or molecules of the respective gas or liquid are ionized and form a plasma. Ionization always occurs when the electric field strength at the surface of the piezoelectric transformer 1 exceeds the ignition field strength of the plasma. The ignition field strength of a plasma is the field strength required to ionize the atoms or molecules or to generate radicals, excited molecules, or atoms.

[0073] Figure 2 shows a device for plasma generation, which Figure 1shown piezoelectric transformer 1. The device has a first housing 11 in which the piezoelectric transformer 1 is arranged. In the housing 11, a holder 12 is also arranged, which fastens the piezoelectric transformer 1. The holder 12 will be described later in connection with Figure 3 described in more detail.

[0074] The first housing 1 further includes a plasma outlet channel 13. The plasma outlet channel 13 is arranged in front of the output end face 10 of the piezoelectric transformer 1. If a process medium is ionized by the piezoelectric transformer 1 or if radicals, excited molecules, or atoms are generated by the piezoelectric transformer 1, the plasma generated in this way is guided to a desired location via the plasma outlet channel 13.

[0075] The plasma outlet channel 13 is an optional configuration of the device. Alternatively, the first housing 11 can have a simple opening through which the plasma generated by the piezoelectric transformer 1 can exit. Alternatively, the housing 11 can have a nozzle configured to focus or fan out a plasma jet or that has a dielectric barrier.

[0076] The first housing 11 may further comprise a switch for power and / or gas flow control, which allows the amount of process medium supplied to the piezoelectric transformer 1 to be adjusted. The first housing 11 may comprise a feedback mechanism that can transmit information about the currently generated plasma to a control circuit 14, wherein the control circuit 14 may further be configured to adapt the control of the piezoelectric transformer 1 taking this information into account.

[0077] The device further comprises a second housing 15. Further elements of the device are arranged in the second housing 15. In particular, a drive circuit 14 for the piezoelectric transformer 1 is arranged in the second housing 15. A power supply 16 for the device is also arranged in the second housing 15.

[0078] The control circuit 14 is designed to apply an input voltage to the piezoelectric transformer 1. The control circuit 14 is connected to the piezoelectric transformer 1 via a cable 17. Due to the design of the control circuit 14, there are essentially no significant restrictions regarding the cable length. Furthermore, the control circuit 14 does not need to be cooled by a separate cooling device or a fan. However, a cooling device can be provided alternatively to achieve higher output powers if necessary.

[0079] The cable 17, which connects the control circuit 14 to the piezoelectric transformer 1, can be either permanently connected to the first housing 11 or connected via a detachable connection, for example, a plug connection. If the cable 17 is connected to the first housing 11 via a detachable connection, the first housing 11 can be completely removed from the second housing 15 when the connection is severed and replaced, for example, with another housing. The cable 17 can also be either permanently connected to the second housing 15 or connected via a detachable connection, for example, a plug connection.

[0080] An additional line may also be integrated into the cable 17, via which information for a feedback mechanism is transmitted from the first housing 11 to the second housing 15. This embodiment will be explained in more detail later.

[0081] Alternatively or additionally, an operating element, for example a switch, can be arranged on the cable 17, which makes it possible to regulate a gas flow and in this way to adjust the amount of a gaseous process medium that is supplied to the piezoelectric transformer 1.

[0082] Alternatively or additionally, a hose can be integrated into the cable 17, via which a process medium is transported from the second housing 15 into the first housing 11 and is thus supplied to the piezoelectric transformer 1.

[0083] In the case of energy supply 16 according to the Figure 2In the embodiment shown, batteries are used. The power supply 16 can also be rechargeable batteries. These can optionally be charged using an inductive charging method. Alternatively, the power supply 16 can also be a transformer designed to be connected to a power grid and to transform the grid voltage of the power grid to an operating voltage of the device.

[0084] The first and second housings 11, 15 are spatially separated from one another. The spatial separation of the first and second housings 11, 15 ensures that gas exchange between the two housings 11, 15 is minimized. Accordingly, a gas generated in the first housing 11 cannot penetrate into the second housing 15, or at least only in a negligibly low concentration. In this way, the control circuit 14 arranged in the second housing 15 is protected from irritant gases generated during plasma generation in the first housing 11. Since the control circuit 14 does not come into direct contact with potentially aggressive irritant gases, these have no negative impact on the service life of the device. Accordingly, the spatial separation of the two housings 11, 15 enables a long service life of the device.

[0085] Furthermore, the spatial separation of the piezoelectric transformer 1 and the control circuit 14 and the associated minimization of gas exchange between the two housings also makes it possible to integrate the device into a consumer product. A consumer product is a product that is used by an end customer, for example, for private use. In this case, special safety requirements must be met, according to which a user of the device must be protected from potentially harmful irritant gases. For example, it would be possible to arrange the second housing 15 with the control circuit 14 and with operating elements in an area accessible to the end user and to arrange the first housing 11, which contains the piezoelectric transformer 1 and in which potentially harmful irritant gases can arise, in an area not directly accessible to the end user.Accordingly, the end user can be protected from the irritant gases by the spatial separation of the piezoelectric transformer 1 and the control circuit 14.

[0086] Since the control circuit 14 makes it possible to dispense with separate cooling, the construction of a small and lightweight handheld device in which the device is integrated is made possible.

[0087] During plasma generation, high-intensity electric fields are generated in the output region 3 of the piezoelectric transformer 1. By spatially separating the piezoelectric transformer 1 and the control circuit 14 in two separate housings 11, 15, it can be ensured that the control circuit 14 cannot be disturbed by the electric fields.

[0088] Further elements of the device can also be integrated into the second housing 15. For example, control elements can be accommodated in the second housing 15. The control elements can make it possible to issue commands to the control circuit 14 and thus control the plasma generation by the piezoelectric transformer 1. The control elements can be push buttons, rotary controls, microcontroller-controlled systems with a touchscreen, microcontroller-controlled systems without a touchscreen, a remote control, or systems that can be connected to the control circuit via USB, WLAN, or Bluetooth and can transmit control commands to it. Alternatively or additionally, the control circuit can be operated using an app or other software. The control elements can also be arranged on the cable 17 that connects the first and second housings 11, 15 to one another.

[0089] A gas supply can also be integrated into the second housing 15, which is designed to conduct a gaseous process medium to the piezoelectric transformer 1. A hose can also be integrated into the cable 17, which connects the first housing 11 to the second housing 15, through which the gaseous process medium is introduced into the first housing 11.

[0090] The gas supply may, for example, have a fan. The gas supply may have a compressor. The gas supply may have connections to which various compressed gas containers can be connected. The gas supply may also have a gas mixer to mix different gases. The gas supply may have a pressure reducer and / or mass flow controller (MFC), which enables the amount of process medium to be regulated. The gas supply may also have a gas humidifier or a gas dryer or a nebulizer or an atomizer. It is also conceivable to connect the gas control to a stationary gas supply via appropriate couplings, thereby enabling the supply. The stationary gas supply may, for example, be a compressed air source or gas pressure lines that supply N2, O2 or Ar, for example.

[0091] The control circuit 14 can be configured to regulate a power and / or gas flow concentration. The control circuit 14 can vary the input voltage applied to the piezoelectric transformer 1 and / or the process medium supplied to the piezoelectric transformer 1. With regard to the process medium, variations in the amount of the supplied process medium as well as the composition of the supplied process medium are possible. For example, the device can have several gas cartridges in which different gases are arranged. The process medium can result from a mixture of these gases. By varying the mixing ratio of the gases, the properties of the generated plasma can be changed.

[0092] The device may include a sensor that, for example, detects the amount of ozone generated by the piezoelectric transformer 1. The control circuit 14 may be configured to vary and / or read out at least one of the following parameters, taking into account the values ​​measured by the sensor: the input voltage, the amount of process medium supplied to the transformer 1, the composition of the process medium, the input power, and the operating time.

[0093] Alternatively or additionally, the device can be configured to detect whether a load is located in the immediate vicinity of the transformer 1. The control circuit 14 can be configured to vary at least one of the following parameters upon detection of a load: the input voltage, the amount of process medium supplied to the transformer, the composition of the process medium, the input power, and the operating time.

[0094] The second housing 15 may further include a status indicator. The status indicator may, for example, include an LED. Different colors or different flashing patterns of the LED may convey information about the operating state or battery status of the device. The status indicator may enable status and / or performance monitoring of the device.

[0095] The device may further comprise an optical and / or acoustic irritant gas warning system that warns a user if a predetermined limit value for an irritant gas concentration is exceeded in the immediate vicinity of the device.

[0096] In an embodiment not shown, a plurality of piezoelectric transformers 1 can be arranged in the first housing 11. The drive circuit 14 can be configured to apply an input voltage to each of the transformers 1. The piezoelectric transformers 1 can be operated in parallel. In this way, the amount of plasma generated can be increased.

[0097] Figure 3shows the piezoelectric transformer 1, which is fastened in the holder 12. The holder 12 has support elements 18, which are arranged in the longitudinal direction z at a length of one-quarter and three-quarters of the total length of the piezoelectric transformer 1 and bear linearly against it. Furthermore, the holder 12 has two contact elements 19, which are electrically connected to the outer electrodes of the piezoelectric transformer 1. The contact elements 19 are, for example, wires or sheets made of copper, Invar, copper-Invar-copper (CIC), or stainless steel. The contact elements 19 can be fastened to the piezoelectric transformer 1 and form a positive connection with the holder 12. In this way, movement of the transformer 1 in the longitudinal direction z relative to the holder 12 can be prevented.

[0098] As an alternative to the mounting in the holder 12 shown here, the piezoelectric transformer 1 can also be arranged together with a fan and / or a process gas supply in a module. Such a module can be arranged in the first housing 11.

[0099] Figure 4 shows a second embodiment of the device, wherein the first housing 11 and the second housing 15 are arranged directly next to one another. The two housings are separated from one another by a common partition 20. The partition 20 ensures spatial separation of the transformer 1 arranged in the first housing 11 from the elements arranged in the second housing 15, in particular the control circuit 14 and the power supply 16.

[0100] The first housing 11 further has a first opening 21 through which ambient air can be supplied to the piezoelectric transformer 1 as a process medium. The first opening 21 is a slot-shaped grid. The first housing 11 further has a second opening 22 through which a plasma generated by the piezoelectric transformer 1 can exit the first housing 11. The second opening 22 is also a slot-shaped grid. The first opening 21 and the second opening 22 can each be arranged either on a top side or a bottom side of the first housing 11. The second opening 22 is arranged at the end of the plasma outlet channel 13.

[0101] Otherwise, the Figure 4 The device shown essentially corresponds to that shown in Figure 2 device shown.

[0102] An activated carbon filter (not shown) can also be arranged between the first opening 21 of the first housing 11 and the piezoelectric transformer 1. The activated carbon filter absorbs ozone and decomposes it quickly and effectively. The first opening 21 forms an inflow opening through which the gaseous process medium flows to the piezoelectric transformer 1. However, should the gas flow within the first housing 11 reverse, the activated carbon filter can prevent ozone from escaping from the first opening 21. Accordingly, the activated carbon filter increases user safety in the event of any device malfunctions.

[0103] The device can further be designed to prevent the escape of potentially harmful irritant gas from the second opening 22. For this purpose, the device can be provided with a coating, for example made of manganese dioxide or iron oxide, which degrades ozone. The coating can be applied, for example, to the inside of the plasma outlet channel 13. Alternatively, the escape of ozone can also be prevented by a filter system arranged on the output-side end face 10 of the piezoelectric transformer 1. Alternatively, the process medium can also be guided in a closed circuit to prevent the escape of ozone. Alternatively, it is also possible for the device to be designed such that a flow of the process medium can be reversed in order to suck out the irritant gas in a suction mode.

[0104] The Figures 5, 6 and 7show the device according to a further embodiment. The device comprises two parts. In particular, the device comprises a first part 23, which consists of a first housing 11 and a second housing 15, and a second part 24, which consists of a power supply 16.

[0105] Figure 5 shows the first part 23 of the device. The first housing 11 contains the piezoelectric transformer 1. The second housing 15 contains the drive circuit 14. The first housing 11 and the second housing 15 are non-releasably connected to one another. A non-releasable connection here refers to a connection that cannot be separated without damaging the first and / or the second housing 11, 15. The first and second housings 11, 15 are spatially separated from one another. Accordingly, the piezoelectric transformer 1 and the drive circuit 14 are spatially separated from one another.

[0106] The second housing 15 has a USB connector 25, which allows the first part 23 to be connected to the second part 24. In particular, the control circuit 14 can be connected to the power supply 16 via the USB connector 25.

[0107] Figure 6 shows the first and second parts 23, 24 of the device, wherein the two parts 23, 24 are not connected to each other. Figure 7 shows the first and second parts 23, 24 of the device, wherein the two parts 23, 24 are not connected to each other.

[0108] The second part 24 consists of the power supply 16. The power supply 16 has a USB connector receptacle 29, which is designed to be connected to the USB connector 25 of the first part 23. The second part 24 can be connected to the first part 23 via a USB plug connection. When the two parts 23, 24 are connected to each other, the control circuit 14 is supplied with voltage by the power supply 16. In alternative embodiments, the first and second parts 23, 24 can be connected to each other via a different plug connection, for example, a bayonet connection.

[0109] The second housing 15 has no built-in battery, no charging electronics, and no DC / DC converter. Accordingly, the first part 23 of the device can be small and compact. The first part 23 of the device can be insensitive to shock loads.

[0110] The first part 23 of the device can be designed to be connected to any USB accessory via the USB connector 25. For example, a USB extension cable, a USB stand, a USB power bank, or a USB power supply can be connected to the first part 23. Furthermore, the control circuit 14 can be connected to a USB interface of a computer via the USB connector 25. In this case, the device can be configured via the computer. Alternatively or in addition to the USB connection described here, other standardized low-voltage elements or systems are also conceivable for connecting the first part 23 to further accessories, for example micro-USB.

[0111] The Figures 5 to 7The device shown offers the advantage that the first part 23 of the device is easily replaceable. The power supply 16 can be separated from the first part 23 of the device and connected to another part that also includes a piezoelectric transformer 1 and a drive circuit 14 in separate housings 11, 15.

[0112] The first part 23, comprising the piezoelectric transformer 1 and the drive circuit 14, can be replaced as a module. The first part 23 can be replaced by another housing, which also comprises a piezoelectric transformer 1 and a drive circuit 14. The piezoelectric transformer 1 is the component of the device that is subject to the greatest wear. By replacing the first part 23 as a module, it is possible to replace the piezoelectric transformer 1 with a new transformer without having to replace the entire device. In particular, the power supply 16 can continue to be used. By replacing the first part 23 as a module, the replacement can be carried out easily and, for example, by an end customer.

[0113] The first part 23 can be replaced by a part of identical construction. Alternatively, the first part can be replaced by a part in which a nozzle is provided, which is designed to shape a plasma jet generated by the device or to form a dielectric barrier.

[0114] Figure 8 shows an alternative embodiment of the first part 23 of the device. The first part 23 here has a first housing 11, in which the piezoelectric transformer 1 is arranged, and a second housing 15, in which the control circuit 14 is arranged. The second housing 15 has a USB connector 25. The second housing 15 can be connected to the power supply 16 via the USB connector 25. The first housing 11 and the second housing 15 are connected to each other via the cable 17.

[0115] Figure 9 shows another embodiment of the device. In Figure 9Only the first housing 11 is shown, which contains the piezoelectric transformer 1. The first housing 11 is designed as a portable handheld device.

[0116] The first housing 11 further includes a fan 26, which serves as a process medium supply. The handheld device further includes an intake nozzle 27 into which air is drawn. The intake nozzle 27 is located near a plasma outlet opening of the first housing 11. The inside of the intake nozzle 27 is coated with an ozone-depleting coating 28, for example, made of manganese dioxide or iron oxide. Irritating gases that inevitably arise during plasma generation are drawn in via the intake nozzle 27, allowing the ozone to be depleted quickly and effectively.

[0117] The first housing 11 may further include a nozzle or nozzle attachment that shapes the shape of the plasma jet generated by the piezoelectric transformer 1. The nozzle may, for example, be configured to fan out the plasma jet or to focus the plasma jet.

[0118] The first housing 11 can be connected to a second housing 15, which contains the control circuit 14. This connection between the two housings 11, 14 is detachable.

[0119] The first housing 11, comprising the piezoelectric transformer 1 and the nozzle, can be removed from the device and replaced as a module. The first housing can be replaced by a third housing, which also comprises a piezoelectric transformer 1 and a nozzle. The piezoelectric transformer 1 is the component of the device that is subject to the greatest wear. By replacing the first housing as a module, it is possible to replace the piezoelectric transformer 1 with a new transformer without having to replace other elements arranged in the second housing. For example, the control circuit 14 can continue to be used. By replacing the first housing as a module, the replacement can be carried out easily and, for example, by an end customer.

[0120] Figure 10shows the first housing 11 according to another embodiment. The piezoelectric transformer 1 is arranged in the first housing 11.

[0121] The first housing 11 has an opening closed by a coupling plate. The coupling plate comprises a non-conductive material. The coupling plate forms a dielectric barrier, allowing plasma to be ignited on the outside of the coupling plate.

[0122] A metallization is arranged on the side of the coupling plate facing away from the piezoelectric transformer 1. The metallization influences the electric field generated by the piezoelectric transformer 1. In this way, the shape of a plasma ignited on the outside of the coupling plate can be influenced. By appropriately shaping the metallization, the plasma can be focused or fanned out.

[0123] The device can have a set of coupling plates, each of which can be connected to the first housing 11. The coupling plates each differ in the shape of their metallization. For example, the device can have a first coupling plate that has a metallization that leads to a focusing of a plasma jet on the outside of the first coupling plate. Furthermore, the device can have a second coupling plate that has a differently shaped metallization that leads to a fanning out of a plasma jet on the outside of the first coupling plate. Depending on the application of the device, the first housing 11 can be connected either to the first coupling plate or to the second coupling plate. The coupling plates 30 can be interchangeable.

[0124] A fan, a catalyst, and a heat exchanger are also arranged in the first housing. The first housing 11 further comprises a tubular housing element in which the piezoelectric transformer 1 is arranged. The fan and the catalyst are also arranged in the tubular housing element.

[0125] The fan is designed to effect a recirculation operation within the first housing 11. In this case, air or another process medium is guided along the piezoelectric transformer 1, then exits the tubular housing element and is drawn back into the tubular housing element at a rear side. The flow of the process medium is in Figure 10indicated by arrows. In the flow direction of the process medium during recirculation mode, the catalyst, the fan, and the piezoelectric transformer 1 are arranged in this order in the tubular housing element. The catalyst is arranged such that the process medium first passes through the catalyst before reaching the piezoelectric transformer 1 again.

[0126] The catalyst is designed to degrade an irritant gas, particularly ozone. The catalyst can be, for example, an activated carbon filter. Alternatively or in addition to the activated carbon filter, the catalyst can comprise a manganese dioxide-based filter or a MnO2-based filter. The manganese dioxide can be present in the form of a coating.

[0127] The process medium is ionized at the piezoelectric transformer 1. Ozone and plasma are generated in the process. Plasma is also generated outside the first housing 11 by a dielectric barrier discharge through the coupling plate. The ozone and other irritant gases remain within the first housing 11 and, due to the recirculation mode, are fed to the catalyst, where they are broken down.

[0128] During operation, the piezoelectric transformer 1 heats up, so that a significant amount of heat is transferred from the transformer 1 to the interior of the housing 11. Ionization of the process medium also generates additional heat within the first housing 11. To prevent overheating of the interior of the first housing 11, the first housing 11 has a heat exchanger. The heat exchanger is arranged at the end of the first housing 11 opposite the coupling plate. The heat exchanger is designed to transfer heat contained in the first housing 11 to the surrounding environment.

[0129] The Figures 11 to 13 show an alternative design of the Figure 3 shown holder 12, to which the piezoelectric transformer 1 can be attached. The holder 12 consists of two identical, interconnectable half-shells 12a, 12b.

[0130] Figure 11 shows a first half shell 12a of the holder 12. Figure 12also shows the first half-shell 12a of the holder 12, wherein the piezoelectric transformer 1 and two contact elements 19 for contacting it are also shown. Figure 13 shows both half-shells 12a, 12b of the holder 12 as well as the piezoelectric transformer 1 fastened in the holder 12 and the contact elements 19 for contacting it.

[0131] In contrast to the Figure 3 The bracket 12 shown has the Figures 11 to 13The holder 12 shown has only one support element 18, on which the piezoelectric transformer 1 rests in its rest state. The rest state is defined as a state in which no electrical voltage is applied to the transformer 1 and in which no external forces, for example as a result of an impact, act on the device. The support element 18 is arranged in the longitudinal direction at a length of one quarter of the total length of the transformer 1. The support element 18 tapers to a wedge shape, so that the transformer 1 rests linearly on the support element 18. The contact elements 19 are arranged and fastened to the first support element 18.

[0132] The device does not have any support elements 18 located in the output region of the piezoelectric transformer 1.

[0133] The device further comprises two projections that are spaced a few micrometers apart from the piezoelectric transformer 1 when the transformer 1 is in its resting state. If the transformer 1 is moved as a result of a transverse movement, for example due to an impact or deformation caused by an applied voltage, it strikes one or both of the projections, which thus limit the transverse load on the transformer 1 and form a mechanical stop against transverse movements of the transformer 1. A first projection is arranged in the center of the transformer 1. The second projection is arranged at the input end of the transformer 1. List of reference symbols

[0134] 1 Piezoelectric transformer 2 Input area 3 Output area 4 Electrode 5 Piezoelectric material 6 First side surface 7 Second side surface 8 First outer electrode 9 Piezoelectric material 10 Output-side end face 11 First housing 12 Bracket 12a First half-shell 12b Second half-shell 13 Plasma outlet channel 14 Control circuit 15 Second housing 16 Power supply 17 Cable 18 Support element 19 Contact element 20 Partition wall 21 First opening 22 Second opening 23 First part 24 Second part 25 USB connector 26 Fan 27 Intake nozzle 28 Coating 29 USB connector receptacle x Stacking direction z Longitudinal direction

Claims

1. Device for producing a non-thermal atmospheric pressure plasma, comprising a first housing (11) in which a piezoelectric transformer (1) is arranged, and a second housing (15) in which an actuation circuit (14), which is designed to apply an input voltage to the piezoelectric transformer (1), is arranged, wherein a fan and a catalytic converter are arranged in the first housing (11), wherein the fan is designed to effect circulating air operation, where a process medium that is ionized by the piezoelectric transformer (1) in the first housing (11) is guided within a circuit, and is guided through the catalytic converter before the process medium is supplied back to the piezoelectric transformer (1), wherein the first housing (11) is designed to eradicate irritant gases produced during the plasma production, and characterized in that, in order to eradicate the irritant gases, the housing (11) is designed in such a way that a closed gas guidance system is formed, which prevents irritant gases from leaking from the first housing (1).

2. Device according to the preceding claim, wherein the first housing (11) has a coating (28) to eradicate the irritant gases.

3. Device according to the preceding claim, wherein the coating (28) consists of manganese dioxide, iron oxide, other metal oxides, bare metal surfaces or surfaces coated with metal catalysts, or lacquers.

4. Device according to one of Claims 1 to 3, wherein the actuation circuit (14) has a time circuit, which applies the input voltage to the piezoelectric transformer (1) for a predefined period of time and which does not apply any input voltage to the piezoelectric transformer (1) in a predefined pause interval between two periods of time, wherein the application of the input voltage is prevented for the duration of the pause interval.

5. Device according to one of Claims 1 to 4, wherein at least one operator control element, which makes it possible to control the plasma production, is arranged in the first housing (11).

6. Device according to any one of the preceding claims, wherein the piezoelectric transformer (1) is designed to produce a piezoelectrically ignited microplasma on an output-side end face (10) of the piezoelectric transformer.

7. Device according to any one of the preceding claims, wherein the first housing (11) and the second housing (15) are separate from one another.

8. Device according to any one of the preceding claims, wherein the actuation circuit (14) and the piezoelectric transformer (1) are connected to one another by a cable (17).

9. Device according to the preceding claim, wherein the cable (17) has a length of at least 1 cm.

10. Device according to any one of the preceding claims, wherein the device has a third housing comprising a piezoelectric transformer (1), wherein the first housing (11) is replaceable and can be replaced by the third housing.

11. Device according to the preceding claim, wherein the first housing (11) has a filter and / or a suction device to eradicate the irritant gases.

12. Device according to any one of the preceding claims, wherein the device comprises an attachment, which is attached to the first housing (11) and which forms a dielectric barrier immediately in front of an output-side end face (10) of the piezoelectric transformer (1), such that the device is designed to ignite a plasma by means of a dielectric barrier discharge on a side of the dielectric barrier facing away from the transformer (1).

13. Device according to any one of the preceding claims, wherein multiple piezoelectric transformers (1) are arranged in the first housing (11).

14. Device according to any one of the preceding claims, wherein the first housing (11) and the second housing (15) are formed by two chambers of an injection-moulded part.

15. Device according to any one of the preceding claims, wherein the first housing (11) and the second housing (15) are separated from one another in a watertight manner.

16. Device according to any one of the preceding claims, wherein the first housing (11) and the second housing (15) are separated from one another in a gastight manner.

17. Device according to any one of the preceding claims, wherein a power supply (16) of the device is arranged in the second housing (15).

18. Device according to any one of the preceding claims, wherein the device is a portable handheld device.

19. Device according to any one of the preceding claims, further comprising a sensor for determining a filling level, a temperature or a humidity in the interior or in the surroundings of an active space.

20. Device according to any one of the preceding claims, comprising a remote control system, wherein the device further comprises circuit components of a remote control system for actuating an actuation system.

21. Device according to any one of the preceding claims, further comprising circuit elements for recording the operating time, errors, status information, operating parameters.

22. Device according to any one of the preceding claims, further comprising one or more displays for visual or acoustic signalling of one or more operating parameters.

23. Device according to any one of the preceding claims, for enabling, accelerating or catalysing chemical reactions.

24. Device according to any one of the preceding claims, which is intended to activate or to sterilize surfaces.

25. Device according to any one of the preceding claims, which is intended to clean or to treat wounds on a human or animal body.

26. Device according to any one of the preceding claims, wherein the first housing (11) has a heat exchanger, which is arranged and designed to dissipate heat from the interior of the first housing (11) to the surroundings.

27. Device according to any one of the preceding claims, wherein the device has a first support element (18), wherein an input region (2) of the piezoelectric transformer (11) rests on the first support element (18), wherein the device has at least one projection, which is at a distance from the piezoelectric transformer (1) when the piezoelectric transformer (1) is in an inactive state and which forms a stop against transverse movements of the piezoelectric transformer (1).

28. Device according to the preceding claim, wherein the projection is arranged at half the length of the piezoelectric transformer (1).

29. Device according to one of Claims 28 to 29, wherein the device has a second projection, which is at a distance from the piezoelectric transformer (1) when the piezoelectric transformer (1) is in an inactive state and which forms a stop against transverse movements of the piezoelectric transformer (1), wherein the second projection is arranged on an input-side end of the transformer (1).

30. Device according to any one of the preceding claims, wherein the device has a coupling plate, wherein the first housing (11) is sealed by the coupling plate, which comprises a dielectric material, and wherein a metallization is arranged on an outer side of the coupling plate facing away from the piezoelectric transformer (1).

31. Device according to any one of the preceding claims, wherein the device has a first coupling plate and a second coupling plate, wherein the first housing (11) can be connected to the first coupling plate, which comprises a dielectric material and which has a first metallization on an outer side facing away from the piezoelectric transformer (1), or to the second coupling plate, which comprises a dielectric material and which has a second metallization on an outer side facing away from the piezoelectric transformer (1), wherein the first metallization has a different shape to the second metallization.

32. Active space comprising a device according to any one of the preceding claims and a gas volume that is airtight or a gas volume that is not airtight.