KR100430345B1 - Apparatus for generating low temperature plasama at atmospheric pressure - Google Patents

Abstract

The present invention relates to a device for generating a low-temperature plasma at atmospheric pressure, one side is connected to the power supply means, the other side is grounded and provided a pair of electrodes facing each other spaced apart; Mounting a dielectric having one or more discharge gaps opposed to each other on a surface where the electrodes face each other; The power supply means is configured to generate a capillary plasma in the dielectric discharge gap by applying pulsed direct current of 50 Hz to 10 GHz or AC power with an electric field strength of 1 to 100 KV / cm.

Accordingly, the present invention suppresses the transition of the plasma generated at atmospheric pressure into an arc, and can stably generate a plasma having a low temperature and a high density between the two electrodes with a low start of discharge and a sustain voltage, and a power supply device and an electrode. Makes the production easier.

The present invention utilizes the effects that can be usefully used for bonding, polishing, cleaning, thin film deposition, sterilization, disinfection, ozone production, printing, dyeing, etching, purification of tap water and wastewater, purification of air and automobile exhaust gas, and production of high brightness lamps. to provide.

Description

A device for generating low temperature plasma at atmospheric pressure {APPARATUS FOR GENERATING LOW TEMPERATURE PLASAMA AT ATMOSPHERIC PRESSURE}

The present invention relates to an apparatus for generating low-temperature plasma at atmospheric pressure by applying an electric field to the dielectric discharge electrode to generate a high-density plasma with low discharge voltage at low temperature.

Plasma is a locally energized gas that consists of ions, electrons, neutral particles, and radicals, and is a fourth material state having properties different from gas, liquid, and solid. It can be obtained by applying a high temperature, or an electric field, and is extremely chemically or physically reactive.

As a method of generating a low temperature plasma at atmospheric pressure, there is a dielectric discharge (barrier discharge), also called corona discharge (silent discharge).

Corona discharge is a method of obtaining a streamer plasma at an electrode by applying a high voltage between two electrodes using a pointed electrode made of a conductive material such as a metal. When voltage is applied while the spacing between the two electrodes is very narrow, an arc is generated and a linear plasma having a very small diameter is formed. In order to prevent an arc discharge, a method of applying an intermittent voltage or applying an resistance to an electrode is used.

Dielectric discharge is a method of preventing the conversion to arc discharge by becoming a pulse discharge to stop the discharge by forming a reverse potential through charge accumulation using the dielectric polarization phenomenon.

Atmospheric pressure plasma generated through such discharge is used to produce or detoxify ozone. In addition, it is used to increase the bonding strength by changing the surface energy of various materials such as metal, polymer, nylon, etc., and to dye and print wool, plastic, paper and the like. In addition, it is used for depositing various thin films or cleaning process and manufacturing UV discharge lamp.

However, even though there are many applications, corona discharge cannot obtain uniform low temperature plasma at atmospheric pressure, and because the gap between two electrodes is narrow, it is difficult to apply to three-dimensional processing materials and short electrode life. .

On the other hand, the dielectric discharge method can obtain a uniform plasma, but the plasma of a large area cannot be obtained together with the corona contact method. In addition, when a separate means for preventing the switching to arc discharge is provided, the plasma density is low, so that the processing time is long, so the efficiency is low. In addition, in case of high discharge initiation and maintenance voltage such as argon, oxygen, air, and nitrogen, an expensive high voltage power supply device is required, which consumes a lot of power and poses a lot of risks in handling.

The present invention has been made in view of the above-described problems of the prior art, and has been created to solve this problem. The use of a novel electrode structure prevents the plasma from being converted into arc discharge and lowers the discharge voltage to provide a power supply means. Significantly reduce power consumption, significantly reduce power consumption, enable discharge using a wide frequency range of AC and pulsed DC, and discharge all gases with very high discharge initiation voltages such as nitrogen, oxygen, and air. It is an object of the present invention to provide a device for generating a low temperature plasma at high atmospheric pressure with high density at low discharge voltage.

In addition, the plasma generated through the generator according to the present invention is bonded, polished, cleaned, thin film deposition, dyeing of various materials including metals, rubber, fibers, paper, and synthetic resins and semiconductors such as polymers, plastics, nylon, epoxy, etc. It can be used for process such as printing and printing.

In addition, the plasma generated by the generator of this invention is air, sterilization, disinfection of city water of SO _x, NO _x, etc. of automobile exhaust gas and waste water purification, medical and food machine, ozone production, and the automobile, the gas turbine It can also be used for complete combustion.

This object of the present invention, one side is connected to the power supply means and the other side is grounded, and provided a pair of electrodes facing each other spaced apart; At least one discharge gap having a thickness of 25 μm to 10 mm on the side of the electrode facing each other, and having one of the dielectrics having a width of 5 μm to 2 mm and a height of 5 to 250 times the width. Has; The discharge gap is provided with a conductor electrode for adjusting the width and height of the discharge gap; It is achieved by applying a pulsed direct current, or alternating current, in a frequency range of 50 Hz to 10 GHz, through a power supply means between the electrodes, at a field strength of 1 to 100 KV / cm and supplying a reaction gas between the electrodes.

1 is a cross-sectional view showing a schematic configuration of an atmospheric pressure low temperature plasma generating apparatus of a plate structure electrode according to a first embodiment of the present invention;

2 is a cross-sectional view showing a schematic configuration of an atmospheric pressure low-temperature plasma generating apparatus of a tubular structure electrode according to a second embodiment of the present invention;

Explanation of symbols on the main parts of the drawings

1, 2, 5: conductor electrode, 3, 4: dielectric,

6: power supply, 7: discharge gap,

a: width, b: height.

Hereinafter, some preferred embodiments according to the present invention will be described in more detail with reference to the accompanying drawings.

[First Embodiment]

1 is a cross-sectional view showing the electrode structure of the apparatus for generating a low temperature plasma at atmospheric pressure according to a first embodiment of the present invention.

The first embodiment shows an example that can generate a low-temperature plasma at atmospheric pressure through the electrode of the plate structure.

As shown, the atmospheric pressure plasma generator according to the present invention has a structure in which the two electrodes (1, 2) face each other.

One of the electrodes 1, 2 is connected to the power supply means 6 and the other electrode 2 is grounded.

If the power supply means 6 is a direct current, the grounded side is preferably the positive electrode 2 and the side connected to the power supply means 6 is the negative electrode 1.

Each electrode (1,2) is preferably formed of a metal, such as a stainless steel, aluminum and copper, and the pair of dielectrics (3,4) are opposed to each other on the surface of the electrode (1,2) facing each other Is mounted.

The dielectrics 3 and 4 preferably have a thickness of 25 μm to 10 mm in order to facilitate plasma generation.

It is preferable that one of the dielectrics 3 and 4 has a gap 7 penetrated perpendicularly to the surface thereof, and the other dielectric 4 has no discharge gap 7.

That is, one dielectric 3 is mounted on the electrode 1 side connected to the power supply means 6, and the other dielectric 4 is mounted on the grounded electrode 2 side so that both are disposed to face each other. .

In particular, the conductive electrode 5 extending from the electrode 1 is disposed in the discharge gap 7 with a predetermined width and height.

In the first embodiment of the present invention, as shown in the drawing, one dielectric 3 is mounted on the electrode 1 side connected to the power supply means 6, and the other dielectric 4 is mounted on the grounded electrode 2 side. Although limited to the above, the present invention is not limited thereto, and the positions of the electrodes 1 and 2 on which the dielectrics 3 and 4 are mounted may be changed.

For example, the dielectric 3 having the discharge gap 7 may be mounted on the electrode 2, and the dielectric 4 without the discharge gap 7 may be mounted on the electrode 1.

In addition, a dielectric having a discharge gap 7 may be provided in either one of the two metal electrodes 1 and 2, and the dielectric may not be mounted in other metal electrodes facing each other.

These dielectrics 3 and 4 are made of alumina (A ₂ O ₃ ), boron nitride (BN), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), quartz (SiO ₂ ), and magnesium oxide It is preferable to use a high-temperature dielectric having high generation efficiency of secondary electrons such as MgO), and the dielectrics 3 and 4 generate arcs generated when a voltage is applied using only the conductor electrodes 1 and 2. Will be suppressed.

In addition, when there is no discharge gap 7 in the dielectric 3, a high voltage may be applied to generate plasma, and the generated plasma has a low density. As described above, the dielectric 3 may be discharged. By having the gap 7, it is possible to lower the voltage for plasma generation and obtain a high density and stable plasma. In addition, the production of the electrode becomes very easy.

The dielectrics 3 and 4 penetrate perpendicularly to the surface thereof to have a width a of 5 µm to 2 mm, and a height b to be in a range of 5 to 250 times the width a. Formation is particularly desirable, and the reason for limiting the size of the gap is that a capillary discharge does not occur when it is out of the range, so that the discharge initiation and sustain voltage desired in the present invention cannot be lowered, and the density is high. This is because a high plasma is not obtained stably, and the plasma is not suppressed from being converted into an arc.

The conductor electrode 5 shown serves to maintain the width a and the height b of the discharge gap.

Second Embodiment

2 is a cross-sectional view showing the electrode structure of the apparatus for generating a low temperature plasma at atmospheric pressure according to a second embodiment of the present invention.

The second embodiment shows an example that can generate a low-temperature plasma at atmospheric pressure through the electrode of the tubular structure.

According to FIG. 2, an electrode 1 ′ is formed on an outer surface of the tubular body, and a dielectric 3 ′ is attached to an inner circumference thereof, and the tubular body is spaced apart from the electrode 1 ′ and the dielectric 3 ′. In the center of the electrode 2 'is disposed along its longitudinal direction.

Although not shown, both ends of the tubular body are supported and fixed with both ends of each electrode 1 'and 2' appropriately insulated.

Another dielectric 4 'is fixed to the outer periphery of the electrode 2' disposed at the center of the tubular body, and the dielectric 4 'has a discharge gap 7 and is spaced apart at regular intervals. .

The thicknesses of the dielectrics 3 'and 4' are the same as in the first embodiment described above.

The width a and the height b of the discharge gap 7 are the same as in the first embodiment described above, and the width a of the discharge gap 7 is formed at the outer periphery of the electrode 2 'of the discharge gap 7. ) And the conductor electrode 5 for maintaining the height b is provided as described above.

The electrode 1 'disposed outside of the tubular body is grounded, and the electrode 2' disposed inside thereof is connected to the power supply device 6.

The installation position, the shape, and the arrangement relationship of the electrodes 1 ', 2' and the dielectrics 3 ', 4' may be modified in various ways as in the above-described first embodiment.

The pulsed DC or AC power of 50 Hz to 10 GHz frequency band is supplied to the device having the electrode structures of the first and second embodiments through the power supply means 6 at an electric field strength of 1 to 100 KV / cm. At this time, the discharge is generated in the discharge gap 7 to generate a plasma.

The apparatus of the present invention makes it possible to stably generate a large area of uniform plasma.

Through the plasma of the reaction gas, the activity of various materials including metal, rubber, fiber, paper, and synthetic resin such as polymer, plastic, nylon, epoxy, etc. can be increased to bond, polish, clean, thin film deposition, dyeing, printing, etc. It can facilitate and greatly improve its characteristics.

It is also possible to remove poisons or purify contaminated air via direct plasma.

In addition, ozone can be produced and sterilized and disinfected, and purification of tap water, waste water purification, automobile exhaust gases such as SO _x and NO _x, and the like can be utilized for complete combustion of an automobile engine.

In addition, it is possible to manufacture a very bright lamp and can be used in various surface treatment processes, including semiconductor manufacturing process using a photochemical reaction.

For example, air, water vapor (H ₂ O), oxygen (O ₂ ), nitrogen (N) between the electrodes (1, 2, 1 ', 2') to which the dielectrics (3, 4, 3 ', 4') are attached. ₂ ), hydrogen (H ₂ ), argon (Ar), helium (He), methane (CH ₄ ), ammonia (NH ₃ ), carbon tetrafluoride (CF ₄ ), acetylene (C ₂ H ₂ ), propane (C ₃ After supplying various reaction gases such as H ₈ ) alone or mixed, power is applied to generate plasma at atmospheric pressure, and the generated plasma is bonded, polished, cleaned, thin film deposition, sterilization, disinfection, ozone manufacturing, dyeing and printing. It can be useful for etching, tapping, water and waste water purification, purification of air and automobile exhaust gas, complete combustion of automobile engine, and manufacturing of high brightness lamps.

Experimental Example

In the experimental example of the present invention, as in the first embodiment, the two electrodes 1 and 2 face each other so that the alumina dielectrics 3 and 4 are provided on opposite surfaces of the electrodes 1 and 2. In the dielectric 3, a width (a) of 100 μm and a height (b) of 3 mm were formed to form a penetrated gap.

The distance between the two electrodes 1, 2 was 7 mm, and air was supplied therebetween, and a DC bipolar pulsed power source in the range of 40 to 80 KHz was applied to discharge at atmospheric pressure.

As a result, the discharge start voltage of 8-12KV and the sustain voltage of 6-8KV were shown, and it was possible to stably generate a high density plasma without generating an arc.

At atmospheric pressure, the discharge start voltage of air is 30 KV / cm, and when the distance between electrodes is 7 mm, about 23 KV is required, but the present invention is greatly reduced by about 50%.

As described in detail above, the apparatus for generating a glow discharge plasma at atmospheric pressure according to the present invention provides the following effects.

First, the atmospheric pressure plasma generator having a structure having a dielectric having a discharge gap for inducing capillary discharge can suppress the transition of the plasma to the arc between the two electrodes, and to stabilize the plasma with low temperature and high density. You can get it. In addition, discharge start and sustain voltages are very low, wide frequency can be used, power consumption is low, and manufacturing cost of power supply and electrode becomes low.

Second, it forms radicals with high plasma density and high energy state at atmospheric pressure to bond, polish, clean, thin film deposition, sterilization, disinfection, ozone production, printing, dyeing, etching, water and wastewater purification, air and automobile exhaust gas. It can be utilized for purification, complete combustion, high brightness lamp manufacturing, etc. In this case, a large number of effects can be obtained, such as greatly improving characteristics and greatly reducing processing time.

Claims (2)

One side is connected to the power supply means 6 and the other side is grounded, and a pair of electrodes 1, 2, 1 ′, 2 ′ are spaced apart from each other; Dielectrics 3, 4, 3 ', 4' having a predetermined thickness are disposed opposite to each other on the surface where the electrodes 1, 2, 1 ', 2' face each other, and any one of the dielectrics has a thickness thereof. Has at least one discharge gap 7 penetrating vertically; The discharge gap 7 is provided with a conductor electrode 5 for maintaining the width a and the height b of the discharge gap 7; Low temperature plasma at atmospheric pressure, characterized in that by applying a pulsed direct current or alternating current power through the power supply means 6 between the electrodes (1, 2, 1 '. 2') and supplying the reaction gas between the electrodes. Device for generating the. The method of claim 1, wherein the electrodes (1, 2, 1 ', 2', 5) are formed of a conductive metal; The dielectrics 3,4.3 'and 4' include alumina (Al ₂ O ₃ ), boron nitride (BN), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), quartz (SiO ₂ ), and the like having excellent insulating properties. Apparatus for generating a low temperature plasma at atmospheric pressure, characterized in that formed by any one selected from MgO.