CN201518555U - Plasma needle device - Google Patents

Abstract

A plasma needle device belongs to plasma generating devices, and solves the problem that a human body cannot directly touch the prior corona discharge device and the problem in a plasma fluidic device that an electric pole is not safe or arc discharge is probable to occur between the electric pole and the earth. The plasma needle device comprises a pulse power supply and the electric pole, wherein, the electric pole is connected with the pulse power supply through a resistor and a capacitor which are in series connection; the radial cross section of the electric pole is in the shape of one of a round, or circular ring, or a polygon; and an aciform or splinter-shaped bulge is formed at the end part or the outer surface or the inner surface of the electric pole. The plasma needle device has the advantages of easy fabrication, easy maintenance, convenient use, low cost and portability, can generate different temperatures of a plasma needle by selecting the resistors with different resistances and the capacitors with different capacitances and by selecting different driving power supplies and working gas, and can be applied to etch, sedimentation, surface treatment, surface cleaning, purification, food processing, biomedical disinfection, tooth cleaning, root canal therapy, etc.

Description

Plasma needle device

technical field

The utility model belongs to a plasma generating device, in particular to a gas discharge plasma needle device.

Background technique

Plasma is composed of positive ions, neutral particles and electrons. Generally, plasma can be divided into two types: thermal equilibrium plasma and non-thermal equilibrium plasma. The temperature of all particles in thermal equilibrium plasma is the same.

In non-thermal equilibrium plasma, the temperature of electrons can be as high as tens of thousands of degrees, while the temperature of ions and neutral particles is much lower than that of electrons. This "hot cooler" has many advantages, and non-thermal equilibrium plasma can be used as a highly active reactant. Widely used in various fields, such as plasma deposition and coating, etching, surface treatment, chemical purification, biological purification and medical applications.

Under atmospheric pressure, due to the relatively high breakdown voltage of the working gas, the distance of the discharge gap is usually very limited, generally between several millimeters and several centimeters, which directly limits the shape and size of the processed items. If plasma indirect treatment is used, because many active components, such as oxygen atoms and many charged particles, have a very short lifespan, they disappear before reaching the surface of the treated object, resulting in very low treatment efficiency. In order to solve the above problems, recent attention has been paid to the atmospheric pressure single-electrode non-thermal equilibrium plasma device, which can directly generate plasma in the external space. There are no restrictions on the shape and size of the processed items.

The following are several existing non-thermal equilibrium plasma devices:

(1) DC corona discharge device, see Dion S Antao et al. "Atmosphericpressure DC corona discharge: operating regimes and potential applications" Plasma Sources Sci.Technol.18 (2009), which describes a DC negative polarity corona discharge device under atmospheric pressure , the device, as shown in Figure 1, includes an electrode 3, a positively conducting electrode plate 18, a resistor 9 and a power supply 1, and the working gas can be air, nitrogen, helium or a mixed gas of hydrogen and methane; the power supply 1 is a DC power supply, and the electrode 3 Connect to the negative polarity of the power supply. When working, the distance between the needle connected to the cathode of the power supply and the positive electrode plate can be adjusted, placed in different gases, and a conical corona discharge area is generated between the negative electrode and the positive electrode plate. The discharge can be divided into three areas, the corona discharge is near the negative electrode, the glow discharge is on the surface of the positive conductive plate, and there is a dark area between the corona discharge and the glow discharge. Moreover, as the distance between the negative electrode and the positive conductive plate increases, the dark area becomes larger. The gas temperature of the glow discharge generated by the device near the positive electrode plate is close to room temperature, but when the voltage reaches a certain value, the corona discharge is easily converted into a spark discharge, which is not safe for biomedical applications.

(2) AC non-thermal equilibrium plasma jet device, see Yong Cheol Hong et al. "Microplasma jet at atmospheric pressure" Appl Physics Letter 89, 221504 (2006), which describes a plasma jet with nitrogen as the working gas under atmospheric pressure The device, as shown in Figure 2, includes an electrode 3, a ground electrode 11, a dielectric disc 13, a dielectric container 12 and an (AC) power supply 1, the electrode 3 and the ground electrode 11 are separated by a dielectric disc 13, and are placed together In the medium container 12, the (AC) power supply 1 is connected to the electrode 3 and the grounding electrode 11; during work, the (AC) power supply 1 is adjusted to high voltage, with a frequency of 20 kHz, and the input work to the medium container 12 at a flow rate of 3 liters/second Gas 6 (nitrogen), discharges between the electrode 3 and the ground electrode 11 to generate plasma, and ejects the plasma jet 5 from the gas outlet 16 at a speed of about 255 m/s, the length of the plasma jet 5 is 6.5 cm, and the temperature close to room temperature. Both the electrode 3 and the ground electrode 11 are in direct contact with the plasma jet 5, which is prone to arc discharge, and is not safe for some practical applications such as tooth cleaning, root canal treatment and wound healing.

(3) Radio frequency non-thermal equilibrium plasma jet device, see E stoffels et al. "Plasmaneedle for in vivo medical treatment: recent developments and perspectives" Plasma Source Sci.Technol.15 (2006), which describes a radio frequency plasma needle device , as shown in FIG. 3 , the device includes an electrode 3 , a dielectric container 12 , an insulating dielectric layer 17 , and a power supply (radio frequency) 1 . The insulating medium layer 17 is a ceramic tube with a diameter of 4 mm. The power source 1 is a 10 MHz radio frequency power source, which is connected to the electrode 3 . The electrode 3 is a tungsten wire with a diameter of 0.3 mm, placed in the center of the insulating medium layer 17, the top end is not included in the insulating medium layer 17, exposed in the external space, and is fixed to the medium container 12 by the fixing frame 14 together with the insulating medium layer 17 In the center, the working gas 6 is input from the gas input port 7 . During operation, a plasma jet 5 with a corresponding diameter of 2.5 mm is generated. The top part of the electrode 3 of the device is exposed to the external space and is in direct contact with the plasma jet 5. The generated plasma jet 5 is short in length and high in temperature. The plasma jet 5 at the tip of the electrode 3 is 1.5 mm and 2.5 mm The temperatures were 90 degrees Celsius and 50 degrees Celsius, respectively.

(4) Pulse direct current non-thermal equilibrium plasma jet device, see Xinpei Lu et al. "Dynamics of an atmospheric pressure plasma generated by submicrosecondvoltage pulses" J Appl. Phys 100.063302 (2006), which describes a plasma pen device, the device As shown in FIG. 4 , it includes an electrode 3 , a ground electrode 11 , a dielectric container 12 , a dielectric disc 13 , a dielectric ring 15 , and a power supply 1 . Both the electrode 3 and the ground electrode 11 are metal rings of the same size, which are respectively pasted on two dielectric discs 13 with a dielectric ring 15 in between, and are located at the front end of the dielectric container 12 together. The working gas 6 is helium, and the power supply 1 is a pulsed DC power supply. During operation, a plasma jet 5 with a length of 5 cm can be generated, and the temperature of the plasma jet 5 is close to room temperature.

The generation of plasma by dielectric barrier discharge using pulsed DC power supply is a relatively popular research direction recently. The disadvantage of this device is that under certain conditions, for example, arc discharge may occur between the electrode 3 and the ground electrode 11 when the voltage pulse width is higher than 10 us.

As noted above, existing devices each suffer from similar deficiencies. Similar defects also exist in some recent plasma jet generation methods, devices and systems, such as U.S. Patent No. 5369336 "Plasma Generating Device" Hideomi Koinuma et al, patent No. 6,262,523 "Large area atmospheric-Pressure Plasma Jet" by Gary S. Selwynet al, and Patent No. 7271363 "Portanle microwave plasma systems including asupply line for gas and microwaves" by Lee et al. These factors have greatly limited the wide application of existing plasma jet technology and devices.

Contents of the invention

The utility model provides a plasma needle device that can be used in biomedical applications, which solves the problem that the human body cannot be directly touched by the existing corona discharge device and the electrode in the plasma jet device is not safe or may occur between the electrode and the ground. The problem of arcing.

A plasma needle device of the present invention includes a pulse power supply and an electrode, and is characterized in that:

The electrodes are connected to the pulse power supply through series resistors and capacitors;

The radial cross-sectional shape of the electrode is one of circular, annular or polygonal; the electrode end, outer surface or inner surface has needle-shaped or pointed-shaped protrusions.

The plasma needle device is characterized in that:

There are a plurality of electrodes, arranged in a line or in an array on the conductive electrode plate, and the conductive electrode plate is connected with series resistance and capacitance.

The plasma needle device is characterized in that:

The electrode is placed in a medium container, and the medium container is filled with one of the following gases: helium, argon, mixed gas of helium and nitrogen, mixed gas of helium and oxygen, and methane.

When the utility model works, the resistance and capacitance mainly play the role of controlling the voltage applied on the electrode and the discharge current, the resistance mainly plays the role of current limiting, and the capacitance discharges through the plasma needle during each pulse discharge, and the capacitance and the plasma discharge at the same time The needle equivalent capacitance bears the voltage together and plays the role of voltage divider. By choosing resistors with different resistance values and capacitors with different capacitance values, the space field strength and discharge current at the front of the electrode can be different, and the temperature of the generated plasma needle can be close to room temperature or higher than room temperature; using electrodes with different structures and shapes, the generated plasma The body needle can have various shapes and can diffuse in all directions at the same time, the length of the generated plasma needle can be changed, and the radial section of the plasma needle can be large or small. When the temperature of the generated plasma needle is close to room temperature, the human body can safely touch it. Moreover, the electrode can be placed in a dielectric container, and the dielectric container is filled with working gas. The working gas can be helium, argon, nitrogen, oxygen and other simple gas or mixed gas, or a gaseous compound, such as methane (CH ₄ ), etc. , which is beneficial to increase the type and quantity of active ingredients in the plasma needle.

The utility model is easy to manufacture, easy to maintain, convenient to use, low in cost, easy to carry, and has various practical applications, such as etching, deposition, surface treatment, surface cleaning, purification, food processing, tooth cleaning and root canal treatment. According to different specific applications, choose resistors with different resistance values and capacitors with different capacitance values, as well as different driving power sources and working gases, the temperature of the plasma needle generated can be different. When the temperature of the plasma needle is close to room temperature, the human body can be safe with it. s contact. The type and quantity of the active material contained therein can also be selected according to specific applications, and can realize large-scale and large-area specific applications in the air at normal temperature and pressure.

Description of drawings

Fig. 1 is the schematic diagram of existing DC corona discharge device;

2 is a schematic diagram of an existing AC non-thermal equilibrium plasma jet device;

Fig. 3 is the schematic diagram of existing radio frequency plasma needle;

Fig. 4 is the schematic diagram of existing pulsed direct current plasma jet device;

Fig. 5 is a structural schematic diagram of the first embodiment of the utility model;

Fig. 6 is the structural schematic diagram of the second embodiment of the utility model;

Fig. 7 is the structural representation of the third embodiment of the utility model;

Figure 8(a) and Figure 8(b) are the radial cross-sectional view and side view of the needle electrode, respectively;

Fig. 9 is a schematic cross-sectional view of a blade-shaped electrode;

Fig. 10 is a radial cross-sectional view of a needle electrode socketed on a spherical conductor;

Figure 11 is a side view of a brush-shaped needle electrode;

Figure 12(a) and Figure 12(b) are a side view and a radial cross-sectional view of the multi-electrode, respectively;

Fig. 13 is a radial cross-sectional view of a multi-electrode.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

As shown in Figure 5, the first embodiment of the present utility model comprises power supply 1, resistance 9, capacitor 10, conductive plate 18 and electrode 3, and electrode 3 is connected with power supply 1 by resistance 9 and capacitance 10; Electrode 3 is The acupuncture needle is in the shape of a needle point, and the shape of the plasma needle 5 generated at the tip of the acupuncture needle is also the shape of an elongated needle.

Resistor 9 is 8 kilohms, capacitor 10 is 36 picofarads; power supply 1 is a pulse power supply with a voltage amplitude of 6 kilovolts and a frequency of 4 kilohertz; due to the high field strength of the external space at the front end of electrode 3, gas discharge occurs, resulting in The temperature of the needle-shaped plasma needle 5 is close to room temperature, and people's hands can directly touch it.

As shown in Figure 6, the second embodiment of the utility model includes a power supply 1, a resistor 9, a capacitor 10, a conductive plate 18 and a plurality of electrodes 3, and the electrodes 3 are connected to the power supply 1 through a resistor 9 and a capacitor 10; An electrode 3 composed of acupuncture needles is sleeved on a conductive electrode plate made of copper; a needle-like plasma needle 5 is generated at the front end of each acupuncture needle.

The resistor 9 is 8 kΩ, the capacitor 10 is 36 picofarads; the power supply 1 is a pulse power supply with a voltage amplitude of 6 kV and a frequency of 4 kHz.

As shown in Figure 7, the third implementation case of the utility model includes a power supply 1, a resistor 9, a capacitor 10, a working gas 6, a gas flow control valve 8, a gas input port 7, a medium container 12, a gas output port 6, a conductive The pole plate 18 and a plurality of electrodes 3, the electrodes 3 are acupuncture needles in the shape of needle points, and the plasma needles 5 are generated at the front ends of the acupuncture needles.

The resistor 9 is 8 kΩ, the capacitor 10 is 36 picofarads; the power supply 1 is a pulse power supply with a voltage amplitude of 6 kV and a frequency of 4 kHz.

Fig. 8(a) and Fig. 8(b) are the radial cross-sectional view and side view of the needle-shaped electrode that can be used in the above embodiments, respectively. The radial cross-section of the electrode is circular, and the side view is needle-shaped.

FIG. 9 is a schematic cross-sectional view of a blade-shaped electrode that can be used in each embodiment.

Fig. 10 is a radial cross-sectional view of a needle electrode socketed on a spherical surface that can be used in each embodiment.

Fig. 11 is a side view of a brush-like needle electrode that can be used in each embodiment.

Figure 12(a) and Figure 12(b) are the side view and radial cross-sectional view of an acupuncture needle electrode respectively. The radial cross-section of the electrode is circular, and there are 6 needle electrodes on the conductive plate, which are arranged in parallel in two rows. .

Fig. 13 is a radial cross-sectional view of an acupuncture needle electrode. There are 15 needle electrodes arranged in a circular shape on the conductive plate.

In the above embodiment, the electrode is pointed needle-shaped or very thin sheet, or is the needle-shaped or sheet-shaped protrusion on the surface (inner surface or outer surface) of the electrode of other shapes; the radial cross-sectional shape of the electrode can be One of circular, annular, zigzag, or polygonal, determined according to specific practical applications.

When the power supply 1 is a pulsed DC power supply, the range of applied pulsed DC voltage ranges from 220V to 10KV, the frequency is 50Hz to 100MHz, and the pulse width is greater than or equal to 1 nanosecond. The resulting plasma jet has a length greater than 0.1 mm and a temperature close to or above room temperature.

Claims (3)

1. A plasma needle device, comprising a pulse power supply and an electrode, is characterized in that: The electrodes are connected to the pulse power supply through series resistors and capacitors; The radial cross-sectional shape of the electrode is one of circular, annular or polygonal; the electrode end, outer surface or inner surface has needle-shaped or pointed-shaped protrusions. 2. The plasma needle device according to claim 1, characterized in that: There are a plurality of electrodes, arranged in a line or in an array on the conductive electrode plate, and the conductive electrode plate is connected with series resistance and capacitance. 3. The plasma needle device according to claim 1 or 2, characterized in that: The electrode is placed in a medium container, and the medium container is filled with one of the following gases: helium, argon, mixed gas of helium and nitrogen, mixed gas of helium and oxygen, and methane.

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