This patent application is a national phase filing under section 371 of PCT/EP2020/072762, filed Aug. 13, 2020, which claims the priority of German patent application 102019122930.8, filed Aug. 27, 2019, each of which is incorporated herein by reference in its entirety.
The present invention relates to a device for generating a gas discharge, for example a non-thermal atmospheric pressure plasma.
The requirements for a high voltage supply capable of igniting a discharge in a gas at atmospheric pressure are high.
The high voltage supply is subjected to not inconsiderable mechanical stresses caused by the plasma ignitions themselves as well as by chemical processes generated during plasma ignition. The high voltage supply should be robust against these stresses.
The high voltage supply should have low impedance to avoid high reactive power. The cables used in such a system must therefore be well insulated and must not be subjected to excessive mechanical stress. The connection capacity of a discharge path is considerably increased by the cable capacity.
Embodiments provide an improved device for generating a gas discharge. The device should preferably have a compact design and be robust against environmental influences and stresses caused by the gas discharge.
A device for generating a gas discharge, for example a non-thermal atmospheric pressure plasma, is proposed, comprising a low voltage assembly and a high voltage assembly. The low voltage assembly has an output contact, wherein the low voltage assembly is configured to provide a low voltage at the output contact. The high voltage assembly includes an input contact and a transformer. The low voltage assembly and the high voltage assembly are interconnected by a plug-in connector, wherein the plug-in connector forms an electrical contact between the output contact of the low voltage assembly and the input contact of the high voltage assembly, wherein the low voltage provided at the output contact is applied to the transformer via the input contact, and wherein the transformer is adapted to convert the low voltage to a high voltage.
Accordingly, the low voltage assembly and the high voltage assembly may be constructionally separated into two sub-units of the device. This allows the components to which a high voltage may be applied to be separated from the remaining components of the device.
The high voltage assembly may be designed to provide particularly good protection against environmental influences such as dust or moisture. The high voltage assembly may also provide shielding for the components arranged therein, in particular for the transformer. Since there is no high voltage in the low voltage assembly, the requirements for shielding and/or protection against environmental influences in the low voltage assembly may be lower. By constructionally separating the low voltage assembly and the high voltage assembly, a device can be constructed in which the entire device does not have to meet the high requirements concerning environmental influences or in which the entire device does not have to be shielded, but in which it is sufficient to protect the high voltage assembly particularly well against environmental influences or to shield the high voltage assembly. This allows a compact design of the device.
Since the low voltage assembly and the high voltage assembly are connected to each other by the plug-in connector, the low voltage assembly and the high voltage assembly can be separated from each other by disconnecting the plug-in connector. Accordingly, one of the assemblies can be replaced and the other assembly can continue to be used. In particular, the transformer may be subjected to stresses during gas discharge that limit the life time of the transformer. In the device, the high voltage assembly can be disconnected and replaced by unplugging the plug-in connector so that the assembly having the structure with the lowest life time, namely the discharge structure in unity with the transformer, can be easily replaced.
A low voltage assembly may be defined as an assembly in which only a low voltage is present. For example, low voltage may be defined as any voltage up to 1000 V. A high voltage assembly may be defined as an assembly having the components configured to convert the low voltage to a high voltage. High voltage may be defined as, for example, as any voltage greater than 1000 V.
The device may be, for example, a handheld device. The handheld device may, for example, be intended for use in medical applications. The device may be a module for 3D printing, a module for digital printing, or a module for textile treatment facilities.
The low voltage module may include a housing, and the high voltage module may include a cartridge in which the transformer is arranged and which comprises the input contact. The housing and the cartridge may be latched or clamped together by the plug-in connector.
The cartridge may be a container suitable for insertion into the housing. The cartridge may be encapsulated, i.e., sealed. Alternatively, the cartridge may have an opening.
The cartridge may have a simple and robust construction. A volume enclosed by the cartridge may be smaller than a volume enclosed by the housing. The cartridge may have a small design to ensure that there are short lengths of cable in the high voltage assembly that do not significantly increase an impedance of the high voltage assembly. Thus, a device with a low reactive power can be designed.
Both a plug-in connection configured as a latching connection and a plug-in connection configured as a clamping connection can protect against accidental disconnection of the respective connection. The latching connection may define a force threshold, where a force greater than the force threshold must be applied to disconnect the plug-in connection.
The high voltage assembly may include a discharge structure configured to affect an electric field generated by the high voltage generated at the transformer.
The discharge structure may include conductive structures, such as a metallization, for this purpose, which alter the field routing of the field generated by the transformer. The metallization may be disposed on an outer surface of the cartridge. The discharge structure may be arranged on the cartridge such that it is close to the transformer. This allows the discharge structure to be coupled to the transformer with minimal impedance.
The discharge structure may include a protruding element disposed on the exterior of the cartridge, the protruding element being made of a conductive material. The protruding element may be needle-shaped or blade-shaped. Accordingly, it may be tapered and provide a point-like field elevation at a tip. This may cause a point-like gas discharge, for example a point-like plasma ignition. Alternatively, the protruding element may be rounded at its tip. As a result, a gas discharge, for example a plasma ignition, can be triggered on a small area of the protruding element. Alternatively, the protruding element may have a wire at an end facing away from the transformer that is perpendicular to a longitudinal direction of the cartridge. Such a protruding element may initiate gas discharges, such as plasma ignitions, on a near-linear structure. Accordingly, different discharge structures are possible, resulting in gas discharges with different shapes. Depending on the intended use of the device, the appropriate discharge structure can be selected.
In a further embodiment, the protruding element comprises bristles, wherein at least some of the bristles comprise a conductive material and/or at least some of the bristles comprise an insulating material. The bristles made of the conductive material may provide a point-like gas discharge, such as a point-like plasma ignition. Thus, the discharge structure can initiate a plurality of point-like gas discharges simultaneously. The bristles of the insulating material can mechanically treat a surface and/or act as spacers that prevent the bristles of the conductive material from coming into direct contact with the surface.
The discharge structure may be coated with an insulating material that forms a dielectric barrier. Accordingly, gas discharges, such as plasma ignitions, may be caused by dielectric barrier discharges.
The transformer may be encapsulated within the cartridge. In this regard, the cartridge may be sealed. Encapsulation may provide good protection against dirt, moisture and corrosion. The encapsulation can provide shielding of the transformer from interfering electric fields. The encapsulation in the cartridge can prevent unwanted plasma ignitions, for example at longitudinal edges of a piezoelectric transformer, or flashovers to the high voltage winding of a conventional transformer.
In this regard, the cartridge may be configured to allow the discharge structure and input contacts to exchange energy with the environment or the low voltage structure, and otherwise isolate the high voltage assembly from the environment.
The cartridge may include an opening, such as a plasma exit opening. For some applications of the device, it may be advantageous for the gas discharge to be generated directly at an end face of the transformer and to exit from the opening.
The high voltage assembly may be separable from the low voltage assembly. As discussed above, this may allow replacement of a defective high voltage assembly. Further, a high voltage assembly may be replaced by another high voltage assembly having a different discharge structure. This allows a single low voltage assembly to effect gas discharges in different forms.
The low voltage assembly may include a driver module to drive the transformer.
The transformer may be a piezoelectric transformer. A piezoelectric transformer has a compact design and may thereby enable a construction of a small and compact cartridge. The piezoelectric transformer may be a Rosen-type transformer.
The high voltage assembly may include a gas supply line through which a process gas may be supplied. The process gas may be, for example, air or a noble gas, such as argon. The process gas may be directed through the gas supply to a location in close proximity to the location of the gas discharge, for example, the plasma ignition. The process gas may be ionized during the gas discharge.
The device may be, for example, a plasma generator, an ionizer, an ozone generator, and/or a gas discharge structure.
Another aspect relates to an arrangement comprising the device described above and a further high voltage assembly. The low voltage assembly of the device is thereby configured to be interchangeably connected to one of the high voltage assembly of the device and the further high voltage assembly. The two high voltage assemblies may differ in their discharge structure. Accordingly, the two high voltage assemblies may be configured to cause gas discharges in different forms, such as point-like or planar. Alternatively or additionally, the two high voltage assemblies may be configured to cause gas discharges, for example plasma ignitions, in different ways, for example by corona discharge or dielectric barrier discharge. The device is thus variable in use, since a single low voltage assembly can be used to effect gas discharges, for example plasma ignitions, in different forms and in different ways by the possibility of combining it with different high voltage assemblies. The high voltage assemblies may be in a set that includes several cartridges that are different from each other. Such a set may be provided together with the low voltage assembly as a multifunctional kit.
Preferred embodiments are described below with reference to the figures.
Only a low voltage is present in the low voltage assembly 1. The low voltage assembly 1 has a housing 3. All elements of the low voltage assembly may be arranged in the housing 3. In the embodiment shown in
A driver module 6 is arranged in the housing 3. The driver module 6 may be, for example, an ASIC (Application Specific Integrated Circuit) or a printed circuit board on which a drive circuit is formed. The driver module 6 is designed to drive a transformer 7 in the high voltage assembly. In this context, the drive can have a resonance control, a phase control, an amplitude control, a power control, a pulse width modulation or a pulse operation. Likewise, it is possible to monitor the operating state on the high voltage side via the high-frequency signal components generated during discharge ignition.
The low voltage assembly 1 further has two output contacts 8a, 8b. A low voltage can be provided at the output contacts 8a, 8b. In particular, the output contacts 8a, 8b are connected to the mains supply 5 via the driver module 6. The driver module 6 can thereby pass on the voltage provided by the mains supply 5 to the output contacts 8a, 8b.
The housing 3 of the low voltage module 11 has a plug-in connection 9 shown schematically in
In particular, the plug-in connection 9 can be designed such that the low voltage assembly 1 and the high voltage assembly 2 latch together. Alternatively, the low voltage assembly 1 and the high voltage assembly 2 may be clamped together when the plug-in connection 9 is closed. The plug-in connection 9 is designed in such a way that the high voltage assembly 2 rests directly against the housing 3 of the low voltage assembly 1 when the plug-in connection 9 is closed.
In the embodiment schematically shown in
The plug-in connection 9 is designed in such a way that a force threshold must be overcome in order to open the plug-in connection. This can prevent accidental disconnection of the plug-in connection 9. Alternatively or additionally, the plug-in connection 9 can be designed in such a way that a defined movement of the connection partners must be carried out. The plug-in connection 9 can, for example, be designed as a bayonet connection. In this case, the high voltage assembly 2 can only be disconnected from the low voltage assembly 1 if a rotating movement of the high voltage assembly 2, in which the high voltage assembly 2 is rotated relative to the low voltage assembly 1, followed by a pulling movement, in which the high voltage assembly 2 is moved linearly with respect to the low voltage assembly 1, is performed.
The high voltage assembly 2 has the aforementioned input contacts 10a, 10b. Furthermore, the high voltage assembly 2 has the transformer 7. The input contacts 10a, 10b are connected to the transformer 7. The transformer 7 is configured to convert a low voltage applied thereto into a high voltage. The high voltage generated by the transformer 7 is used for gas discharge, for example for plasma generation. The transformer 7 may be a piezoelectric transformer, for example.
The high voltage assembly may include a cartridge 11. The transformer 7 is arranged in the cartridge 11. The cartridge 11 has input contacts 10a, 10b. Thereby, the input contacts 10a, 10b are arranged on an outer side of the cartridge 11. The cartridge 11 is adapted to be plugged into the low voltage assembly 1.
The cartridge 11 further includes a discharge structure 12. When a high voltage is generated at the piezoelectric transformer 7, the discharge structure 12 influences the electric field generated, and in this way the shape of a generated gas discharge or plasma discharge is determined in advance. Various discharge structures 12 will be discussed later with reference to
The plug-in connection 9 can be designed in such a way that plugging the high voltage assembly 2 into the low voltage assembly 1 is only possible in one orientation. Alternatively, plugging-in in both orientations may be possible. Accordingly, for example, the output contact 8a can be connected to either of the two input contacts 10a, 10b.
The plug-in connection 9 makes it possible to define a defined state in which the low voltage assembly 1 and the high voltage assembly 2 are firmly connected and can only be separated from each other by applying a force that is greater than the defined force threshold, so that unintentional separation of the two assemblies 1, 2 can be avoided. The plug-in connection 9 can further provide an electrically secure connection between the two assemblies 1, 2.
The transformer 7 is encapsulated in the high voltage assembly 2 in the cartridge 11. As a result, the transformer 7 is protected against dust, moisture and corrosion. Furthermore, the cartridge 11 provides shielding of the high voltage components, in particular the transformer 7, thus preventing unwanted parasitic discharges.
The high voltage assembly 2 can be separated from the low voltage assembly 1 by disconnecting the plug-in connection 9. Depending on the design of the plug-in connection 9, this may require a force threshold to be overcome or a defined movement, for example a linked rotating and pulling movement. The high voltage assembly 2 can then be replaced by another high voltage assembly which is connected to the low voltage assembly 1. The other high voltage assembly may differ from the first high voltage assembly 2, for example, by the discharge structure 12. Accordingly, a single low voltage assembly 1 may be used to generate different types of gas discharges by respectively connecting other high voltage assemblies 2 having different discharge structures 12 to the low voltage assembly 1.
The piezoelectric transformer 7 is a mechanically vibrating component and should therefore be decoupled from the environment, for example by elastic mounting. This can preferably be solved by elastic potting. Preferably, the transformer is encapsulated in unity with the discharge structure. By means of a replaceable high voltage assembly 2, the transformer 7 can be replaced in a simple manner. Replacing the high voltage assembly 2 thus allows the low voltage assembly 1 to continue to be used.
The arrangement of the transformer 7 in the cartridge 11 allows the high voltage assembly 1 to be compact. A simple structure is constructed. The cartridge 11 is robust against damage and interference such as dust, moisture, etc. The high voltage assembly 2 and the low voltage assembly 1 each form functional and mechanically integral subunits of the device.
The compact design of the high voltage assembly 2 in a cartridge 11 makes it possible to keep cable lengths to a minimum. The very short cables used mean that impedance can be minimized. The compact design of the high voltage assembly 2 also makes it possible to arrange the discharge structure 12 in the immediate vicinity of the piezoelectric transformer 7 and thus, under certain circumstances, to dispense completely with the connecting cables on the high voltage side.
The high voltage assembly 2 is designed as a cartridge 11. The piezoelectric transformer 7 is arranged in the cartridge 11. The cartridge 11 has the discharge structure 12 shown in
The low voltage assembly 1 used in the embodiment shown in
In
The piezoelectric transformer 7 is encapsulated in the cartridge 11. Accordingly, the cartridge 11 is sealed in an airtight manner. A discharge structure 12 is attached to the envelope of the cartridge 11. The discharge structure 12 comprises a metallization 14 applied to an outer surface of the envelope. The piezoelectric transformer 7 generates a strong electric field when it generates a high voltage. The metallization 14 of the discharge structure 12 changes the field routings of this electric field. This can affect the nature of a plasma cloud generated by the device.
In the embodiment shown in
The protruding element 15 affects the field distribution of the electric field. If the protruding element 15 is tapered, as in
In the brush-shaped protruding element 15 shown in
In
Although the invention has been illustrated and described in detail by means of the preferred embodiment examples, the present invention is not restricted by the disclosed examples and other variations may be derived by the skilled person without exceeding the scope of protection of the invention.
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102019122930.8 | Aug 2019 | DE | national |
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PCT/EP2020/072762 | 8/13/2020 | WO |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2021/037576 | 3/4/2021 | WO | A |
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