KR101150387B1 - Atmospheric pressure plasma jet generator with a capillary electrode - Google Patents

Abstract

In order to provide a plasma jet generator operable in a wide range of driving conditions to enable a biomedical application, the present invention comprises a main body; A capillary tube extending in a first direction and accommodating at least a portion of the body and connected to a driving power source and an oxygen source; A quartz tube accommodating at least a portion of the capillary tube and formed to have an outer diameter at both ends thereof; A teflon accommodated in the quartz tube and into which the capillary tube is inserted; And a gas inlet formed on one side of the main body, and supplying an inert gas into the quartz tube.

Description

Atmospheric pressure plasma jet generator with a capillary electrode}

The present invention relates to a capillary drive electrode type atmospheric plasma jet generator, and more particularly to a capillary drive electrode type atmospheric plasma jet generator operable under a wide range of driving conditions to enable biomedical applications.

The plasma torch may be used to plasma the gas to heat the solid to melt, or to heat or evaporate the solid or liquid, or to heat the gas to increase enthalpy.

Conventional plasma generators using microwaves usually consume more than 100 Watts using magnetrons. Plasma generators implemented with a rectangular waveguide have a disadvantage in that they are difficult to carry because of their bulky size. Although a coaxial microwave plasma torch using a discharge tube using an antenna structure has been proposed, the present invention is merely a replacement for a generator formed by a conventional rectangular waveguide, and is not large enough to be carried.

In the case of plasma generated by applying a potential to fine size needles (less than several cm in length and several mm or less in diameter), the electric field generated near the electrode is very strong to ionize the gas, while the generated plasma is very small. Low temperature In addition, because of the simplicity and mobility of the device, there is an infinite potential for life sciences and medical care. The temperature of the atmospheric pressure plasma is very different from each other depending on the structure, supply energy, operating conditions and the like.

Many sources of atmospheric plasma have been reported to date. In the form of direct current and low frequency discharge, there are a pencil-shaped torch in continuous operation mode, a corona discharge device in pulse operation mode, a dielectric barrier discharge device, an ICP torch, and an atmospheric plasma jet. However, in order to apply these sources to biomedical applications, microsized plasma close to room temperature must be generated, discharge must occur at low voltage to prevent electric shock or electric shock, and there is no toxicity. It should be able to be adjusted to be suitable for the condition.

However, if you want to generate plasma in the discharge gas and driving conditions that require high discharge voltage, high voltage power is required and the temperature of plasma is much higher and it is not suitable for life science application due to the possibility of transition to arc discharge. .

At present, although atmospheric pressure plasma is generated by using various types of power sources, signals in the microwave region, for example, signals having a frequency of several hundred kilohertz, are used to generate plasma without low thermal effect. The method of making is currently under study. Efforts to apply plasma generators to life sciences are in the research stage of the world and are being used as devices to treat wrinkles and pigmentation of skin.

Therefore, there is a need for a plasma jet generator having a simple structure that can be applied to life science and medical fields by generating a plasma jet in a low temperature region of atmospheric pressure.

In order to solve the above problems, the present invention can improve the structure to allow a wide range of operating conditions in consideration of the bio-medical application of the atmospheric pressure micro-plasma and to provide the physical properties of the plasma for each application. Its purpose is to increase its utility as a plasma jet generator.

The present invention body; A capillary tube extending in a first direction and accommodating at least a portion of the body and connected to a driving power source and an oxygen source; A quartz tube accommodating at least a portion of the capillary tube and formed to have an outer diameter at both ends thereof; A teflon accommodated in the quartz tube and into which the capillary tube is inserted; And a gas inlet formed on one side of the main body, and supplying an inert gas into the quartz tube.

In the present invention, it may further include an aluminum foil strip formed to surround at least a portion of one end of the quartz tube.

In the present invention, the driving power source may be connected to a DC or RF power source.

In the present invention, one end of the capillary tube can be processed sharply to concentrate the electric field in the local region.

In the present invention, a plasma plum may be formed by reacting oxygen and the inert gas at one end of the capillary tube.

In this case, as the flow rate of oxygen supplied to the capillary tube increases, the length of the plasma plum may decrease.

Here, the temperature of the plasma plum may increase as the voltage applied to the driving power increases.

Here, the temperature of the plasma plum may decrease as the supply amount of the inert gas increases.

In the present invention, the inert gas may include helium or argon gas.

In the present invention, one or more holes may be formed in the teflon to allow gas to enter and exit.

In the present invention, the capillary tube may include a stainless steel material.

In the present invention, the outer diameter of the end disposed farther from the main body of the both ends of the quartz tube may be formed smaller than the outer diameter of the end disposed closer to the main body.

In the present invention, the Teflon is formed with a hole having a diameter substantially the same as the outer diameter of the capillary tube, the capillary tube may be inserted through the hole.

In the present invention, the Teflon may be a dielectric substance.

The plasma jet generator according to the present invention can implement stable discharge at various power sources (low frequency pulse, low frequency alternating current, high frequency), and at low frequency (several kHz to several tens of kHz) discharge, plasma having a temperature close to room temperature that can be applied to living organisms Can be generated. The plume of the elongated plasma and the particle species present in the plasma can act as bactericidal, induce bacterial phagocytosis, and induce cancer cell natural death. Various combinations of plasma forming gas and additive gas may be utilized for thin film deposition, operate at atmospheric pressure, and the device may be easily and mobilely secured.

1 illustrates a capillary drive electrode type atmospheric plasma jet generator according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view schematically illustrating the capillary driving electrode type atmospheric plasma jet generator of FIG. 1.
3 is a cross-sectional view taken along line AA of FIG. 1.
4 shows an example of the use of a capillary drive electrode type atmospheric plasma jet generator according to an embodiment of the present invention.
5 illustrates waveforms of voltage and total current according to an embodiment of the present invention.
FIG. 6 shows the plume length change as a further effect of (a) gas flow rate and (b) oxygen flow rate in accordance with one embodiment of the present invention.
FIG. 7 illustrates a temperature change of a plume according to (a) an applied voltage and (b) a gas flow rate according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a combined perspective view schematically showing a capillary driving electrode type atmospheric plasma jet generator according to an embodiment of the present invention, Figure 2 is an exploded perspective view schematically showing a capillary driving electrode type atmospheric pressure plasma jet generator of Figure 1, 3 is a cross-sectional view taken along the line AA of FIG. 1.

1, 2 and 3, the capillary driving electrode type atmospheric pressure plasma jet generator 100 according to an embodiment of the present invention is the main body 110, tube receiving portion 120, capillary tube 130, The quartz tube 140, the teflon 150, the oxygen inlet 160, the gas inlet 170, and the power supply unit 180 are included.

The main body 110 is formed in a hollow box shape, the tube receiving portion connecting portion 111 is connected to the tube receiving portion 120 is formed on one side, the oxygen inlet connection portion (200) is connected to the oxygen inlet (160) 112 is formed, a gas inlet connection portion (not shown) to which the gas inlet 170 is connected is formed on one side, and a power supply connection portion (not shown) to which the power supply unit 180 is connected is formed on the other side. do.

The tube accommodating part 120 is formed in a hollow cylindrical shape and is coupled to the tube accommodating part connecting part 111 of the body 110 described above, and the capillary tube 130 and the quartz tube 140 are accommodated therein.

Here, although the main body 110 and the tube receiving part 120 are shown as being formed by combining each of the separate members, the spirit of the present invention is not limited thereto, and the main body and the tube receiving part may be integrally formed. will be. In this case, the main body and the tube accommodating part of FIG. 1 may be collectively referred to as a main body.

The capillary tube 130 is accommodated in the body 110 and the tube receiving portion 120 connected thereto. Capillary tube 130 is formed extending along the central axis (C) direction of the tube receiving portion (120). One end of the capillary tube 130 is connected to a driving power source (not shown) through the power supply unit 180, and is also arranged to be connected to an oxygen source (not shown) through the oxygen inlet 160.

Capillary tube 130 is preferably to point one end 131 of the capillary tube 130 to improve the electric field locally. Capillary tube 130 is preferably one end 131 is processed sharply, thereby increasing the concentration effect of the electric field than a wide spread, the plasma plume is generated in this area. Capillary tube 130 may be a variety of materials, but may be preferably formed of stainless steel.

The capillary tube 130 electrode may be connected to various power sources (not shown) (for example, low frequency pulse, low frequency alternating current, and high frequency) to implement stable discharge, and is located in the center of the quartz tube 140.

The quartz tube 140 is formed to receive the capillary tube 130 therein. In detail, the quartz tube 140 is formed in a cylindrical shape and is formed so that the outer diameters of both ends thereof are different. In this case, the quartz tube 140 is disposed such that a second end 142 having a larger outer diameter is positioned at the side of the main body 110, and is located at a side spaced apart from the main body 110 of the first end 141 having a smaller outer diameter.

On the other hand, Teflon 150 is provided so that the capillary tube 130 is positioned in the center of the quartz tube 140 to be supported. The Teflon 150 functions as an insulator and supports the capillary tube 130 to be uniformly positioned within the quartz tube 140. That is, one or more holes having a diameter substantially the same as the outer diameter of the capillary tube 130 is formed in the teflon 150, and the capillary tube 130 is inserted through the hole of the teflon 150 to form a capillary tube. The tube 130 is to maintain a fixed position in the quartz tube 140.

Although not shown in the drawings, an aluminum foil strip (not shown) may be further formed to partially surround the end portion of the quartz tube 140. Such an aluminum foil strip (not shown) is formed to surround the first end 141 of the quartz tube 140 and may function as a ground electrode of the plasma jet generator of the present invention.

4 shows an example of the use of a plasma generator according to one embodiment of the invention. A plume is generated at the end of the plasma generator and is ejected into a local region. The plasma plume generated from the capillary driving electrode atmospheric pressure plasma jet generator 100 of the present invention may be formed in a thin and sharp cylinder shape. Can be.

An inert gas is supplied to the discharge region through the gas inlet 170 provided on the side of the quartz tube 140 separately from the oxygen inlet 160 to generate a plasma. The inert gas preferably includes helium or argon gas. Helium or argon gas, which is a plasma forming gas, is supplied through the gas inlet 170 disposed on the side of the quartz tube. Oxygen, the reaction gas, is supplied to the capillary tube 130 as the driving electrode through the oxygen inlet 160, and in the discharge space with helium or argon gas delivered through the hole of the inner teflon 150 of the quartz tube 140. Are mixed. That is, oxygen and an inert gas react at the end of the capillary tube 130 which is the discharge space.

In detail, the capillary tube 130 is positioned in the center of the quartz tube 140, and the inside of the quartz tube 140 is filled with Teflon 150, and the quartz tube 140 is formed by the Teflon 150. Stable at the center In addition, a plurality of holes are formed in the Teflon 150, through which the plasma forming gas flows into the discharge region.

The length of the plasma plume can be adjusted according to the flow rate of the supplied gas and the intensity of the applied voltage, so that the user can adjust the applied gas flow rate and the applied voltage. In general, as the flow rate of the supplied gas increases or the intensity of the applied voltage increases, the length of the plasma plume may be longer under the same conditions.

However, in the capillary driving electrode type atmospheric plasma jet generator 100 of the present invention, unlike the inert gas, the length of the plasma plume may be shortened depending on the amount of oxygen gas. Because, in order to generate radicals in the gas phase, oxygen gas is introduced into the capillary tube and inert gas (eg, argon or helium gas) is supplied using a quartz tube, which directly supplies oxygen to the oxygen inside the nozzle. The resulting electrons tend to reduce the generation of radicals, and therefore the length of the plume can be reduced if the oxygen flow rate is increased.

By type of inert gas, for example, when argon gas is used, the plume length slightly decreases due to oxygen injection, but when helium gas is used, plume length rapidly decreases.

The capillary drive electrode type atmospheric plasma jet generator 100 according to the present invention can generate a plasma at a temperature close to room temperature that is applicable to the application of the organism at low frequency (several kHz to several tens of kHz) discharge. Specifically, the temperature of the plume is usually 25 to 40 ℃, using such a low temperature can be used in a variety of medical applications. Therefore, it is possible to use variously by appropriately adjusting the temperature generated in such a plasma nozzle, the temperature of such plume is affected by the voltage applied to the plasma jet generator and the inert gas introduced.

Specifically, as the voltage applied to the driving power source increases, the temperature of the plume continues to increase. This is because an increase in the applied voltage results in an increase in the plasma volume, which is immediately manifested by the heating of the gas.

Also, the temperature of the plume decreases as the flow rate of the inert gas introduced increases. For example, as the flow rate of helium and argon gas increases, the temperature of the plume decreases.

Capillary driving electrode type atmospheric pressure plasma jet generator 100 according to the present invention can implement a stable discharge in a variety of power sources, radicals of low current, room temperature, biomedical action in order to apply to biological tissues such as bacteria and cancer cell death Provide effective production.

In addition, the capillary driving electrode type atmospheric plasma jet generator 100 according to the present invention serves as a power supply electrode while the capillary tube 130 serves as a passage through which additional gas can be injected separately from the plasma forming gas. The small outer diameter capillary tube 130 sharpens the tip to locally improve the electric field, resulting in a significant reduction in the discharge breakdown voltage. The aluminum foil strip (not shown) serves as a ground electrode and is positioned at the end of the quartz tube 140 to allow the plasma generated inside the quartz tube 140 to extend outwardly.

<Examples>

plasma  Manufacture of Jet Generator

A quartz tube (6 mm i.d. x 8 mm o.d., 20 mm L) was formed as the dielectric barrier layer. A capillary tube (0.4 mm i.d. × 1 mm o.d., 20 mm L) made of stainless steel was installed at the center of the quartz tube and used as a power supply electrode as well as an oxygen supply tube. The end of the capillary tube was sharpened and the outer diameter of the capillary electrode was made small to extend the electric field to some space. This drastically reduced the breakdown voltage.

The distance between the end of the stainless steel capillary tube and the end of the quartz tube was about 2 mm. An aluminum foil strip was installed outside of the small diameter of the quartz tube and the length of the foil was 11 mm, which served as a ground electrode partially covering the outside of the quartz tube. The plasma forming gas helium or argon was supplied through a gas inlet disposed on the side of the quartz tube, and the reaction gas oxygen was supplied to the capillary tube through the power electrode, which was mixed with the helium or argon plasma at the end of the quartz tube.

Three different power sources were applied. The pulsed power supply (PDS4000, FTLab) supplied voltage pulses up to 3 kV at a repetition rate of 10 to 60 kHz. In addition, a sine wave voltage of several tens of kilohertz was applied. An RF power source of 13.56 MHz was applied.

Voltage and current waveforms were measured using a real-time digital oscilloscope (LeCroyWS44XS-A) through a high voltage probe (Tektronix P5100) and a current probe (Pearson 3972).

Results and rating

Figure 5 shows the waveform and total current of an applied voltage in a pulse discharge operation at a repetition rate of 50 kHz in accordance with one embodiment of the present invention. The flow rate of the gas was kept constant at 2 l / m. The peak total current became 0.26 A when the amplitude of the applied voltage was 2.5 kV. The discharge current was about 20 mA, resulting in a cylindrical plasma plume.

FIG. 6 illustrates a plasma plume when oxygen flow rate is added to (a) helium and argon gas and (b) helium and argon gas according to an embodiment of the present invention.

Referring to (a) of FIG. 6, the argon gas showed a decrease in plume from 2 l / min to 4 l / min when the flow rate increased, and then decreased slightly. However, when helium gas is used, the plume length increases continuously when the gas flow rate is increased. In addition, in the experiments with increasing applied voltage, the length of the plume was longer when the applied voltage was increased under the same conditions.

Referring to Figure 6 (b), as the flow rate of oxygen flowing into the capillary tube can be seen that the length of the plume decreases. In the case of using argon gas, the plume length reduction due to the oxygen input was small, but in the case of using helium gas, the plume length reduction due to the oxygen input was more rapid than that of the argon gas. In addition, in the experiments with increasing applied voltage, the length of the plume was longer when the applied voltage was increased under the same conditions.

FIG. 7 shows the temperature of the plasma plume according to (a) applied voltage and (b) gas flow rate of helium and argon gas jets carried out according to an embodiment of the present invention.

Referring to FIG. 7A, as the applied voltage increases, the temperature of the plume also increases continuously. This is the same for both helium and argon gas. This is because an increase in the applied voltage results in an increase in the plasma volume, which is immediately manifested by the heating of the gas.

Referring to FIG. 7B, the temperature of the plume decreases as the flow rate of gas increases. In both helium and argon gas, the temperature of the plume decreases as the flow rate increases, and when the applied voltage is high, the temperature of the plume also appears to be slightly higher.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: capillary drive electrode type atmospheric plasma jet generator
110: main body 120: tube receiving portion
130: capillary tube 140: quartz tube
150: teflon 160: oxygen inlet
170: gas inlet 180: power supply

Claims (14)

A body having a hollow box shape and having a tube accommodating part, an oxygen inlet, a gas inlet, and a power supply on each side;
A capillary tube extending in a first direction, the capillary tube being at least partially accommodated in the main body, connected to a driving power source through the power supply unit, and connected to an oxygen source through the oxygen inlet port;
A quartz tube accommodating at least a portion of the capillary tube and formed to have an outer diameter at both ends thereof;
A teflon accommodated in the quartz tube and into which the capillary tube is inserted; And
And a gas inlet formed on one side of the main body and supplying an inert gas into the quartz tube. The method of claim 1,
Capillary drive electrode type atmospheric plasma jet generator, characterized in that it further comprises a strip of aluminum foil formed to surround at least a portion of one end of the quartz tube. The method of claim 1,
Capillary drive electrode type atmospheric plasma jet generator, characterized in that the drive power source is connected to a DC or RF power source. The method of claim 1,
One end of the capillary tube is sharpened to focus the electric field in a local region capillary drive electrode type atmospheric plasma jet generator. The method of claim 1,
Capillary-driven electrode type atmospheric plasma jet generator, characterized in that the plasma plume is formed by the reaction of oxygen and the inert gas at one end of the capillary tube. The method of claim 5, wherein
Capillary drive electrode type atmospheric pressure plasma jet generator, characterized in that the length of the plasma plume decreases as the flow rate of oxygen supplied to the capillary tube increases. The method of claim 5, wherein
Capillary drive electrode type atmospheric pressure plasma jet generator, characterized in that the temperature of the plasma plume increases as the voltage applied to the drive power is increased. The method of claim 5, wherein
Capillary drive electrode type atmospheric pressure plasma jet generator, characterized in that the temperature of the plasma plume decreases as the supply amount of the inert gas increases. The method of claim 1,
Wherein said inert gas comprises a helium or argon gas. The method of claim 1,
Capillary drive electrode type atmospheric pressure plasma jet generator, characterized in that the teflon is formed with one or more holes (hole) to allow gas to enter. The method of claim 1,
The capillary tube capillary drive electrode-type atmospheric plasma jet generator, characterized in that it comprises a stainless steel material. The method of claim 1,
Capillary drive electrode-type atmospheric pressure plasma jet generator, characterized in that the outer diameter of the end portion disposed further away from the main body of the both ends of the quartz tube is smaller than the outer diameter of the end disposed closer to the body. The method of claim 1,
The Teflon is formed with a hole having a diameter equal to the outer diameter of the capillary tube, the capillary tube capillary drive electrode-type atmospheric pressure plasma jet generator, characterized in that inserted through the hole. The method of claim 1,
And the teflon is a dielectric substance.

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