CN108848604A - A kind of portable micro-hollow cathode discharge plasma fluidic device - Google Patents

Abstract

The invention relates to a portable micro-hollow cathode discharge plasma jet device, which comprises a micro-hollow cathode discharge electrode, an excitation source module, a gas supply module and an insulating casing, and the insulating casing combines the above-mentioned micro-hollow cathode discharge electrode, excitation source module and supply The air module is wrapped inside, and the front end of the insulating shell is also provided with a nozzle. The excitation source module includes a rechargeable lithium battery, a low-voltage DC voltage stabilizing circuit, a DC boost circuit, a high-voltage pulse generator, and an impedance matching circuit that are electrically connected in sequence, wherein the impedance matching circuit is connected to the micro-hollow cathode discharge electrode, and the gas supply module is connected to the micro-hole. The hollow cathode discharge electrode is directly powered by a low voltage DC voltage stabilizer circuit. The portable micro-hollow cathode discharge plasma jet device of the present invention uses air as the gas source, can get rid of the problem of rare gas gas supply, and can solve the problem of conversion from glow discharge to arc discharge under high pressure, and generate air glow plasma.

Description

A portable micro-hollow cathode discharge plasma jet device

technical field

The invention relates to a portable micro-hollow cathode discharge plasma jet device.

Background technique

Atmospheric pressure-cooled plasma jet transports the active free radicals, charged particles, highly active molecules and atoms generated in the discharge area to the treated area through gas flow, breaking through the space limitation of traditional cold plasma, and being used in biomedicine, material modification, energy Chemical industry and other fields have broad application prospects. The generation of atmospheric cold plasma requires not only external excitation sources (such as 220V power frequency AC, signal triggers, high-voltage cables and other ancillary equipment) but also working gas supply (such as gas cylinders, mass flow meters, pressure reducing valves, etc.). These complex and necessary auxiliary equipment limit the application of outdoor occasions or emergency situations.

In recent years, the appearance of portable plasma jet devices has made plasma treatment easy to deal with various occasions. Portable plasma jet devices on the market can be roughly divided into power supply modules, gas supply modules, and plasma generation modules. Among them, the plasma generation module and the power supply module determine the characteristics of the generated plasma.

According to different application fields, researchers have designed and developed a variety of plasma generation modules with different structures. The dielectric barrier plasma jet in the form of needle ring and double ring separates the high voltage end from the low voltage end due to the insulating medium, effectively avoiding the conversion of discharge to arc, which is beneficial to applications that are extremely temperature sensitive such as biomedicine and sterilization. Chinese patent CN201410160831.5 discloses a hand-held large-area low-temperature plasma generator. A plasma discharge unit is formed by using a porous disk electrode and a dielectric barrier discharge, and multiple plasma jet devices are arrayed at the same time. Not only safe but also avoid arc discharge. Chinese patent CN201710873449.2 discloses a handheld plasma jet device. Similar to the previous patent, a needle-ring dielectric barrier discharge unit is used to form a jet array unit. The fan provides the air flow rate. The device is easy to carry and does not require an external power supply. Although this dielectric barrier discharge plasma jet has high application safety, it requires a high excitation threshold. Portable plasma jet devices often use air as the working gas for plasma discharge. Air requires a high excitation electric field strength threshold, and dielectric barrier discharge units cannot excite air plasma. Therefore, some plasma generation modules adopt a form similar to dielectric barrier discharge. Chinese patent CN201410236903.X discloses a hand-held portable sliding arc low-temperature plasma generation device, which can use air, simple gas or mixture as the working gas, does not require other excitation devices, and has less equipment failure. Chinese patent CN201110391504.7 discloses a hand-held plasma torch, which adopts a multi-needle bare electrode structure, directly uses air as the excitation gas, but has no blowing device; it is powered by a DC boost, and the maximum power can reach 10W. Dielectric barrier discharge can significantly enhance the discharge intensity and chemical characteristics during material treatment, but this kind of discharge plasma is easily converted into arc discharge, which is not suitable for human medical treatment.

The biggest obstacle to realizing a portable plasma jet device is the power module design. As an essential part of the device, many patents use a portable DC boost, high-frequency high-voltage AC source as the excitation source. Chinese patent 201210540793.7 discloses a flashlight that can be used in the field of disinfection that can be carried around. The DC voltage provided by the rechargeable battery is oscillated and boosted to form high-voltage AC power; , the temperature of the discharge space is too high, and the sputtered or evaporated electrode substances are seriously polluted; the pulse excitation source greatly improves the electro-optic conversion efficiency. Chinese patent 201710183836.3 discloses a microsecond pulsed plasma jet all-in-one device, the device is integrated with a microsecond power module, which has the advantages of high discharge efficiency and miniaturization of the device, but the entire device is bulky and inconvenient to carry.

Contents of the invention

Aiming at the problems of unreasonable discharge electrode design, bulky excitation source, and high plasma gas temperature in the above-mentioned portable plasma jet device, the purpose of the present invention is to provide a portable micro-hollow cathode discharge plasma jet device to expand atmospheric pressure-cooled plasma body in outdoor or emergency environment applications.

The purpose of the present invention is achieved through the following technical solutions:

A portable micro-hollow cathode discharge plasma jet device, comprising a micro-hollow cathode discharge electrode, an excitation source module, a gas supply module and an insulating casing, and the insulation casing wraps the micro-hollow cathode discharge electrode, the excitation source module and the gas supply module Inside, the front end of the insulating shell is also provided with a nozzle; wherein:

The micro-hollow cathode discharge electrode is a pyramidal structure consisting of three layers of anode, insulating layer and cathode; the anode is located in the inner layer and is hollow inside, forming a hollow tube; the cathode is located in the outer layer and wrapped in the entire micro-hollow cathode discharge Outside the electrode; the insulating layer is located in the middle to separate the anode and the cathode and realize electrical insulation; the nozzle is a discharge hole opened at the front end of the cone of the micro-hollow cathode discharge electrode, and the discharge hole runs through Anode, insulating layer and cathode of the micro-hollow cathode discharge electrode;

The excitation source module includes a rechargeable lithium battery, a low-voltage DC voltage stabilizing circuit, a DC boost circuit, a high-voltage pulse generator and an impedance matching circuit that are electrically connected in sequence, and also includes a battery for controlling charging that is electrically connected to the rechargeable lithium battery. Lithium battery on-off control circuit switch; the impedance matching circuit is connected to the micro-hollow cathode discharge electrode;

The gas supply module includes a gas supply circuit, one end of the gas supply circuit is connected to a DC air pump, and the other end of the gas supply circuit is connected to the internal hollow tube of the anode; the DC air pump is directly powered by a low-voltage DC voltage regulator circuit .

Further, the anode is a hollow cylindrical structure, and the central axis of the anode coincides with the central axis of the micro-hollow cathode discharge electrode.

Further, the diameter of the discharge hole is 0.05-0.8mm.

Further, there are several micro-hollow cathode discharge electrodes arranged side by side to form a porous array glow discharge, and each micro-hollow cathode discharge electrode is connected in series with a ballast resistor.

Further, the rechargeable lithium battery provides a low-voltage DC source with an output voltage of 12V or 24V.

Furthermore, the high-voltage pulse generator is composed of a solid switch formed by a plurality of MOSFET switches connected in series, an energy storage element and a pulse signal controller; the impedance matching circuit is composed of a capacitor and an inductor.

Further, in the excitation source module, the output voltage of the rechargeable lithium battery is stabilized by a low-voltage DC voltage stabilizing circuit, and the low-voltage DC is raised to a high-voltage DC through a DC boost circuit, and the energy storage element is charged; wherein the MOSFET switch The speed adjusts the duty cycle and frequency range of the pulse waveform. When the solid switch is turned on, the energy storage element releases the energy in the form of pulse discharge through the impedance matching circuit and the micro-hollow cathode discharge electrode.

Furthermore, the impedance matching circuit is composed of capacitors and inductors.

Further, the operating voltage of the DC air pump is 5V or 12V, and the gas flow rate of the gas supply path is 0.5-5 slm/min.

Further, the insulating shell is pistol-shaped, cylindrical, conical or elliptical; the material of the insulating shell is polytetrafluoroethylene or PMMA.

Further, when the insulating casing is a pistol type, the insulating casing is provided with an insulating handle; the rechargeable lithium battery is provided inside the insulating handle, and the control circuit switch is located outside the insulating handle.

The beneficial effects of the present invention are:

Compared with the traditional portable plasma generator, the portable micro-hollow cathode discharge plasma jet device of the present invention can solve the problem of conversion from glow discharge to arc discharge under high pressure, and generate air glow plasma. The device adopts a portable pulse excitation source. On the one hand, it avoids heating the discharge gas, on the other hand, it affects the energy distribution of electrons, increases the number of high-energy electrons and the excitation coefficient, and improves the discharge power. The gas temperature can be lowered to room temperature, and the plasma is rich in active free radicals, which can be widely used in the fields of biomedicine, materials, environmental protection and chemical defense.

Description of drawings

Fig. 1 is a schematic structural view of the portable micro-hollow cathode discharge plasma jet device of the present invention;

Fig. 2 is the micro-hollow cathode discharge electrode structure schematic diagram of the present invention;

Among them, 1-nozzle, 2-impedance matching circuit, 3-air supply circuit, 4-high voltage pulse generator, 5-DC air pump, 6-rechargeable lithium battery, 7-insulated handle, 8-control circuit switch, 9- Low-voltage DC voltage stabilizing circuit, 10-DC step-up circuit, 11-insulating shell, 12-cathode, 13-anode, 14-insulating layer.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

A portable micro-hollow cathode discharge plasma jet device, as shown in FIG. 1 , includes a micro-hollow cathode discharge electrode, an excitation source module, a gas supply module and an insulating casing 11 . The insulating shell wraps the micro-hollow cathode discharge electrode, the excitation source module and the gas supply module inside. The insulating shell can be pistol-shaped, cylindrical, conical or elliptical, and the material of the insulating shell is polytetrafluoroethylene or PMMA (polymethyl methacrylate). In this embodiment, the insulating casing 11 is selected as a pistol type, and the insulating casing 11 is provided with an insulating handle 7, which is convenient to hold.

As shown in FIG. 2 , the micro-hollow cathode discharge electrode is a pyramidal structure composed of an anode 13 , an insulating layer 14 and a cathode 12 . The anode 13 is located in the inner layer and is hollow inside, forming a hollow tube shape. In this embodiment, the anode 13 is a hollow cylindrical structure, and the central axis of the anode 13 coincides with the central axis of the micro-hollow cathode discharge electrode. The cathode 12 is located on the outer layer and wrapped around the entire micro-hollow cathode discharge electrode. The insulating layer 14 is located in the middle to separate the anode 13 and the cathode 12 and realize electrical insulation. A nozzle is provided at the front end of the insulating shell 11, specifically, the nozzle 1 is a discharge hole opened at the front end of the cone of the micro-hollow cathode discharge electrode, and the discharge hole runs through the anode 13, the anode 13 of the micro-hollow cathode discharge electrode The insulating layer 14 and the cathode 12, and the diameter of the discharge hole is 0.05-0.8mm.

According to the actual application, if you want to increase the discharge area, multiple micro-hollow cathode discharge electrodes can be arranged side by side to realize high-pressure porous array glow discharge, and each micro-hollow cathode discharge electrode is connected in series with a ballast resistor to limit the large current of a single hole .

The excitation source module includes a rechargeable lithium battery 6, a low-voltage DC voltage stabilizing circuit 9, a DC boost circuit 10, a high-voltage pulse generator 4 and an impedance matching circuit 2 electrically connected in sequence, and a control circuit switch 8 is connected to the rechargeable lithium battery 6. It is electrically connected and used to control the on-off of the rechargeable lithium battery 6 . The impedance matching circuit 2 is connected to the micro-hollow cathode discharge electrode. The rechargeable lithium battery 6 is located in the insulating handle 7 .

The high voltage pulse generator 4 is composed of a plurality of MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) switches connected in series to form a solid switch, an energy storage element and a pulse signal controller.

The rechargeable lithium battery 6 provides a low-voltage DC source with an output voltage of 12V or 24V. One charge can support the portable micro-hollow cathode discharge plasma jet device of the present invention to work continuously for more than ten hours. The output voltage of the rechargeable lithium battery 6 is stabilized by the low-voltage direct current voltage stabilizing circuit 9, and the low-voltage direct current is raised to a high-voltage direct current by the direct-current booster circuit 10, and the energy storage element is charged. The pulse signal controller is provided with a touch-controllable display screen, and the display screen is embedded in the surface of the insulating shell 11, by controlling the switching speed of the MOSFET to adjust the duty cycle and frequency range of the pulse waveform, when the solid switch is turned on , the energy storage element releases energy in the form of pulse discharge through the impedance matching circuit 2 and the micro-hollow cathode discharge electrode.

The impedance matching circuit 2 is composed of capacitors and inductors to eliminate stray capacitance caused by wires and micro-hollow cathode discharge electrodes and optimize plasma jet discharge power. The entire portable micro-hollow cathode discharge plasma jet device of the present invention does not need to be grounded.

The gas supply module includes a gas supply circuit 3 , one end of the gas supply circuit 3 is connected to the DC air pump 5 , and the other end of the gas supply circuit 3 is connected to the inner hollow tube of the anode 13 . The DC air pump 5 is directly powered by a low-voltage DC voltage stabilizing circuit 9, and the working voltage of the DC air pump 5 is 5V or 12V. The gas flow rate of the gas supply channel 3 is 0.5-5 slm/min.

Micro-hollow cathode (Micro-hollow Cathode, hereinafter referred to as MHC) is an electrode structure that can generate micro-discharge plasma under high pressure. Its structure is composed of an anode of any shape and a micro-hollow cathode. The theory of a certain product (p refers to the pressure of the discharge gas component, and D refers to the hollow diameter of the cathode), because the micropore size is on the order of submillimeters, it can realize glow discharge under atmospheric pressure; on the other hand, the microhollow cathode The ring-shaped electrode structure makes the electrons realize the oscillation process under the action of the radial electric field of the cathode, which greatly increases the chance of impact ionization, so the discharge can achieve a high electron density; at the same time, in order to obtain a larger-scale discharge, usually A plurality of micropores are processed on a flat cathode to realize array microhole discharge; finally, due to the small size, the trigger voltage required for discharge is very low, usually only a few thousand volts. The invention is based on the micro-hollow cathode electrode, can solve the problem of conversion from glow discharge to arc discharge under high pressure, and can generate air glow plasma. At the same time, using the high-voltage pulse as the excitation source can effectively reduce the excitation electric field intensity of the air plasma jet.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a portable micro-hollow cathode discharge plasma jet device, is characterized in that, comprises micro-hollow cathode discharge electrode, excitation source module, gas supply module and insulating shell (11), and described insulating shell (11) is described micro The hollow cathode discharge electrode, the excitation source module and the gas supply module are wrapped inside, and the front end of the insulating casing (11) is also provided with a nozzle (1); wherein: The micro-hollow cathode discharge electrode is a pyramidal structure consisting of three layers of anode (13), insulating layer (14) and cathode (12); the anode (13) is located in the inner layer, and the inside is hollow, forming a hollow tube; The cathode (12) is located in the outer layer and wrapped around the entire micro-hollow cathode discharge electrode; the insulating layer (14) is located in the middle to separate the anode (13) and the cathode (12) and realize electrical insulation; the nozzle (1) is the discharge hole that the cone front end of described micro-hollow cathode discharge electrode offers, and described discharge hole runs through the anode (13), insulating layer (14) and cathode (12) of micro-hollow cathode discharge electrode; The excitation source module includes a rechargeable lithium battery (6), a low-voltage DC voltage stabilizing circuit (9), a DC boost circuit (10), a high-voltage pulse generator (4) and an impedance matching circuit (2) electrically connected in sequence, and It includes a control circuit switch (8) electrically connected to the rechargeable lithium battery (6) for controlling the on-off of the rechargeable lithium battery (6); the impedance matching circuit (2) is connected to the micro-hollow cathode discharge electrode; The gas supply module includes a gas supply circuit (3), one end of the gas supply circuit (3) is connected to the DC air pump (5), and the other end of the gas supply circuit (3) is connected to the interior of the anode (13). Empty pipe; the DC air pump (5) is directly powered by a low-voltage DC voltage stabilizing circuit (9). 2. portable micro-hollow cathode discharge plasma jet device according to claim 1, is characterized in that, described anode (13) is hollow cylindrical structure, and the central axis of described anode (13) and micro-hollow cathode discharge electrode The central axis coincides. 3. The portable micro-hollow cathode discharge plasma jet device according to claim 1, characterized in that the diameter of the discharge hole is 0.05-0.8mm. 4. The portable micro-hollow cathode discharge plasma jet device according to claim 1, wherein the micro-hollow cathode discharge electrodes are provided with several, and several micro-hollow cathode discharge electrodes are arranged side by side to form a porous array glow Discharge, each micro-hollow cathode discharge electrode is connected in series with a ballast resistor. 5. The portable micro-hollow cathode discharge plasma jet device according to claim 1, characterized in that the rechargeable lithium battery (6) provides a low-voltage DC source with an output voltage of 12V or 24V. 6. The portable micro-hollow cathode discharge plasma jet device according to claim 1, wherein: The high-voltage pulse generator (4) is composed of a solid switch formed by a plurality of MOSFET switches connected in series, an energy storage element and a pulse signal controller; The impedance matching circuit (2) consists of capacitors and inductors. 7. The portable micro-hollow cathode discharge plasma jet device according to claim 6, characterized in that, in the excitation source module, the output voltage of the rechargeable lithium battery (6) is stabilized by a low-voltage DC voltage stabilizing circuit (9) , the low-voltage direct current is raised to a high-voltage direct current through the direct-current step-up circuit (10), and charges the energy storage element; wherein the MOSFET switching speed adjusts the duty cycle and the frequency range of the pulse waveform, and when the solid switch is turned on, the energy storage The element releases energy in the form of pulse discharge through the impedance matching circuit (2) and the micro-hollow cathode discharge electrode. 8. The portable micro-hollow cathode discharge plasma jet device according to claim 1, characterized in that, the operating voltage of the DC air pump (5) is 5V or 12V, and the gas flow rate of the gas supply path (3) 0.5-5 slm/min. 9. The portable micro-hollow cathode discharge plasma jet device according to claim 1, wherein the insulating casing (11) is pistol-shaped, cylindrical, conical or oval; the insulating casing (11) The material is PTFE or PMMA. 10. The portable micro-hollow cathode discharge plasma jet device according to claim 9, characterized in that, when the insulating casing (11) was a pistol type, the insulating casing (11) was provided with an insulating handle (7) ; The rechargeable lithium battery (6) is provided inside an insulating handle (7), and the control circuit switch (8) is located outside the insulating handle (7).