CN115315055A - Microwave cold plasma jet device - Google Patents
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- CN115315055A CN115315055A CN202210842203.XA CN202210842203A CN115315055A CN 115315055 A CN115315055 A CN 115315055A CN 202210842203 A CN202210842203 A CN 202210842203A CN 115315055 A CN115315055 A CN 115315055A
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- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/30—Plasma torches using applied electromagnetic fields, e.g. high frequency or microwave energy
Abstract
The invention discloses a microwave cold plasma jet device, which comprises a cavity part, a microwave coupling part, a tuning part and an electric field modulation part, wherein the cavity part is provided with a cavity; the cavity part is of a double-resonant cavity structure with one open end, and the microwave transmission mode is a TEM mode; the microwave coupling part can couple microwave energy to the cavity part in a conductive coupling, capacitive coupling, magnetic coupling and other modes; the electric field modulation is achieved in part by an inner electrode wrapped by an insulating layer to which nanosecond pulses (or DC voltages) are applied. The invention provides a microwave cold plasma jet method based on the characteristics of small ozone generation amount, higher plasma concentration, richer excited particles and easier formation of long direct cold plasma by nanosecond pulse (or DC).
Description
Technical Field
The invention belongs to the fields of material treatment, material detection, plasma biomedicine, clinical medicine and the like, and particularly relates to a microwave cold plasma jet device with an auxiliary electric field, which can obtain stable normal-pressure long-straight microwave cold plasma jet.
Background
The plasma consists of electrons, ions, neutral particles, etc., and is called cold plasma when the temperature of the heavy particles is much lower than the temperature of the electrons. At present, the atmospheric pressure cold plasma is widely applied to the fields of waste gas treatment, auxiliary combustion, surface modification, medical sterilization, clinical medicine and the like. The atmospheric pressure cold plasma jet is generated in an open space, the separation of a discharge area and a working area is realized while active substances and charged particles are conveyed, and the safety is higher, so that the atmospheric pressure cold plasma jet has a better application prospect in the fields of biology, clinical medicine and the like. In practical applications, the jet length is the key parameter of primary consideration, which greatly affects and restricts the application of the atmospheric cold plasma jet. Meanwhile, the plasma composition is also a key factor to be considered, which limits the application scenarios of the plasma jet.
The cold plasma can be generated by driving a corresponding device through high pressure, microwave, radio frequency and the like, and the driving mode and the device structure have important influence on the jet length and the components. The microwave cold plasma jet has the advantages of high electron density, high ionization degree, strong controllability, small ozone generation amount and the like, and can be efficiently applied to various scenes such as germ inactivation, wound treatment, human body operation and the like.
The cold plasma jet is generated in an open space, and the jet length is short due to the influx of air, so that the jet length is prolonged by three ways at present to solve the problem.
One is that large-flow inert gas (helium, argon, neon, etc.) is used as working gas, so that the jet flow nozzle is in an inert gas environment with relatively low breakdown field intensity threshold value, which is favorable for plasma formation, and meanwhile, high-flow gas can pull the plasma to be sprayed outwards; (such as helium plasma jet of 11cm length produced by sinusoidal high voltage driving a central electrode wrapped in a quartz tube as proposed by Luxinpeh group in 2008)
The plasma jet length is obviously increased under extremely high and fast energy input through high-voltage nanosecond pulse driving;
the three parts are used for regulating and controlling the shape of plasma jet flow in a mode of matching a double resonant cavity with double airflow constraint through a composite coaxial double-wire structure (corresponding to the patent number CN 201910658894.6).
1) When the inert gas is used as the working gas, a large gas cylinder is required to be arranged, so that the device is inconvenient to carry and is not suitable for working environments such as outdoors, grounded material taking and the like, and the plasma jet is not suitable for being applied to some special environments (such as lung treatment and the like);
2) In common working gas, air has wider application prospect due to the advantages of no need of a gas cylinder, portability, easy operation and the like, but also has the problems that the breakdown field intensity threshold is far greater than that of inert gas, a large amount of ozone is generated when discharge is excited by using high-voltage driving dielectric barrier discharge and other modes, and the like, and is not beneficial to the health of a treated object when applied to clinical medicine;
3) When the plasma jet is drawn by the airflow to be sprayed out, medical objects such as treated pathogens and the like can be separated from the positions under the disturbance of the airflow, and the potential problem of biochemical pollution is caused;
4) When the microwave cold plasma jet is generated in a combined type coaxial double-line and double-airflow mode, because the opening end of the microwave cold plasma jet is of a straight pipe structure, the electric field intensity is not further enhanced, and the excitation field intensity of the air microwave cold plasma is difficult to achieve, so that the application of the microwave cold plasma jet in the air which is working gas is restricted.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a microwave cold plasma jet device.
The invention can be realized by the following technical scheme:
a microwave cold plasma jet device comprises a cavity part, a microwave coupling part, a tuning part and an electric field modulation part;
the cavity part is an outer tube with one open end, a middle tube with two open ends and an inner electrode coaxial resonant cavity structure, the outer tube is provided with a microwave feed-in port and a tangential flow shielding gas inlet, and the middle tube is provided with a gas inlet;
the microwave coupling portion includes a coupling loop to couple microwave energy to the cavity portion;
the tuning part is a structure that the tuning end adjusts the length of the resonant cavity so as to adjust the field intensity of the opening end, and the upper end of the tuning end is a reflecting end surface; the depth of the cavity part adjusted by the tuning end is Y lambda/4, wherein lambda is the wavelength under the microwave frequency, and Y is a positive odd number;
the electric field modulation part is connected with an inner electrode by applying nanosecond pulse/DC voltage, and the inner electrode is wrapped by a coaxial insulating layer.
Furthermore, the outer tube, the middle tube and the inner electrode are all made of metal materials, and the microwave transmission modes between the outer tube and the middle tube and between the middle tube and the inner electrode are both TEM modes.
Further, the axial length of the outer tube is N lambda/4, wherein lambda is the wavelength at the microwave frequency, and N is a positive odd number.
Furthermore, the upper ports of the outer tube and the middle tube are gradually-changed closing-in structures, the closing-in of the outer tube is 0-60 degrees, and the closing-in of the middle tube is 0-30 degrees.
Furthermore, a porous coaxial gasket with a metal upper surface is arranged between the middle pipe and the coaxial insulating layer, and the distance range from the upper surface of the porous coaxial gasket to the opening end of the cavity part is within
Wherein λ is the wavelength at said microwave frequency and M is a positive odd number.
Furthermore, the inner electrode is inserted into the cavity of the coaxial insulating layer, and the inner layer of the coaxial insulating layer is coated on the outer side of the inner electrode.
Furthermore, the upper end of the middle pipe is not higher than the outer pipe, and the upper ends of the inner electrode and the coaxial insulating layer can be higher/lower than the middle pipe.
Further, the outer tube and the middle tube introduce gas through a shielding gas inlet or a gas inlet.
Further, the shielding gas is introduced at the shielding gas inlet in a tangential flow manner; the gas flow rate of the shielding gas inlet and the gas inlet is controlled to be 0-20L/min.
Furthermore, the distance between the coupling ring and the upper port of the outer pipe is adjustable; the microwave plasma jet device is suitable for the electromagnetic wave frequency range of several MHz to several GHz.
Furthermore, the output pulse width of the nanosecond pulse power supply is 10-900 ns, the rising edge is 1-200 ns, the amplitude is 3-220 kV, the frequency is 1-20 kHz, and the duty ratio is 1-99%; the output voltage of the DC power supply is 0-60 kV or 0-60 kV.
Advantageous effects
The invention uses a microwave source to drive a double-resonant cavity structure to generate normal-pressure microwave cold plasma jet which is low in temperature, easy to adjust and capable of being operated by hands, and introduces an auxiliary electric field formed by high voltage on the basis of the normal-pressure microwave cold plasma jet to pull charged particles with maximum density in the microwave plasma to move outwards from a nozzle, so that the jet length is prolonged. The invention uses the electric field to lead the charged particles to move, thereby effectively avoiding the biochemical pollution possibly caused by the disturbance of the airflow. Meanwhile, the high voltage can drive to generate cold plasma, and ignition can be assisted at the end opening of the torch tube, so that the formation of microwave plasma jet flow is facilitated, and the stability of the microwave plasma jet flow is improved. Because the difference between the nanosecond pulse/DC high voltage and the working frequency of the microwave is large, field decoupling can be realized between a direct current electric field and a microwave field in the plasma resonator. In addition, the microwave cold plasma generating device is based on the deformation of a Microwave Plasma Torch (MPT), and a gradually-changing closing-up structure is added at the upper ends of the outer tube and the middle tube and used for regulating and controlling an electric field at the opening end. The insulating layer outside the central electrode can prevent the sheath layer from being too high in voltage to cause charged particles to generate bombardment on the discharge electrode, so that the service life of the electrode is prolonged, the whole jet device can be in contact with the electrode, and the safety is improved.
Drawings
FIG. 1 is a schematic structural view according to the present invention;
fig. 2 is a schematic view of another structure according to the present invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification.
Detailed description of the preferred embodiment 1
The specific embodiment 1 provides the composite modulation microwave cold plasma jet device disclosed by the invention, and a typical structure schematic diagram is provided in combination with fig. 1.
The composite field modulation microwave cold plasma jet device consists of a cavity part, a microwave coupling part, a tuning part and an electric field modulation part;
referring to fig. 1, the microwave cold plasma jet device of the present invention comprises a microwave feed-in port 1, an outer tube 2, a tuning end 3, a middle tube 4, a central inner electrode 5, a coupling ring 6, a porous coaxial gasket 7, a coaxial insulating layer 8, a tangential flow shielding gas inlet 9, a nanosecond pulse/DC high-voltage input port 10, and a gas inlet 11;
the cavity part is of a coaxial resonant cavity structure with an outer tube 2 with one open end, a middle tube 4 with two open ends and a central inner electrode 5;
the outer tube 2, the middle tube 4 and the inner electrode 5 are made of metal materials, microwave transmission modes between the outer tube 2 and the middle tube 4 and between the middle tube 4 and the inner electrode 5 are TEM modes, and the inner electrode 5 is connected with an auxiliary power supply (DC or nanosecond pulse modulation source);
the axial length of the outer tube 2 is Nlambda/4 (lambda is the wavelength at the microwave frequency, and N is a positive odd number);
the upper ports of the outer tube 2 and the middle tube 4 are of gradually-changed closing-in structures, the closing-in of the outer tube 2 is 0-60 degrees, the closing-in of the middle tube 4 is 0-30 degrees, and the design is used for adjusting the electric field at the ports;
a porous coaxial gasket 7 with a metal upper surface is arranged between the middle pipe 4 and the coaxial insulating layer 8, and the distance range from the upper surface of the porous coaxial gasket 7 to the opening end of the cavity part is
(λ is the wavelength at the microwave frequency, M is a positive odd number);
the central inner electrode is inserted into the cavity of the coaxial insulating layer 8, and the inner layer of the insulating layer is coated on the outer side of the central inner electrode; the upper end of the coaxial insulating layer 8 is closed, and preferably, a quartz tube with the closed upper end is used;
the upper end of the middle tube 4 is not higher than the outer tube, the upper ends of the inner electrode 5 and the insulating layer can be higher than or lower than the middle tube, preferably, the upper end of the middle tube 4 is 0-2 mm lower than the upper end of the outer tube, and the upper end of the inner electrode 5 is-5 mm lower than the upper end of the middle tube; in FIG. 1, the upper end of the inner electrode wrapped by the insulating layer is flush with the upper port of the middle pipe 4;
the outer pipe 2 and the middle pipe 4 can introduce gas, preferably, the shielding gas is introduced at the shielding gas inlet 9 in a tangential flow mode; the gas flow rates of the shielding gas inlet 9 and the gas inlet 11 are controlled to be 0-20L/min;
the microwave coupling part can optionally couple microwave energy to the cavity part in a conductive coupling, capacitive coupling and other modes; FIG. 1 is a schematic diagram of a structure for introducing microwave energy into a resonant cavity by conductive coupling; the distance between the coupling ring 6 and the upper port of the outer pipe 2 is adjustable; the microwave plasma jet device is suitable for the electromagnetic wave frequency range of several MHz to several GHz, preferably, stable normal pressure microwave cold plasma jet with the length of 5-40 mm is generated under the frequency of 2.45GHz, and the microwave power conversion efficiency is more than 80%.
The tuning part is a structure that the tuning end 3 adjusts the length of the resonant cavity so as to adjust the field intensity of the opening end, and the upper end of the tuning end is a reflecting end surface which is made of metal; the depth of the cavity part adjusted by the tuning end is Y lambda/4 (lambda is the wavelength under the microwave frequency, and Y is a positive odd number);
the electric field modulation part is an auxiliary power supply (nanosecond pulse or DC voltage) connected with the inner electrode 5; the output pulse width of the nanosecond pulse power supply is 10-900 ns, the rising edge is 1-200 ns, the amplitude is 3-220 kV, the frequency is 1-20 kHz, and the duty ratio is 1-99%; the output voltage of the DC power supply is 0-60 kV or 0-60 kV;
the microwave plasma jet device can work by the following 18 methods:
1) The microwave is coupled into the resonant cavity through the microwave coupling part to form a TEM standing wave in the resonant cavity, the nanosecond pulse power supply is connected to a central inner electrode wrapping the coaxial insulating tube, and the plasma is formed at the axial position of an upper port of the resonant cavity and is driven by a pulse electric field to be sprayed outwards;
2) The microwaves are coupled into the resonant cavity through the microwave coupling portion to form a standing TEM wave in the resonant cavity, high voltage (positive/negative)
The power supply is connected to a central inner electrode wrapping the coaxial insulating tube, and plasma is formed at the axial position of the upper port of the resonant cavity and is driven by the high-voltage electric field to be sprayed outwards;
3) The microwave is coupled into the resonant cavity through the microwave coupling part, a TEM standing wave is formed in the resonant cavity, and plasma is formed at the axial position of the upper port of the resonant cavity and is sprayed out;
4) The nanosecond pulse power supply is connected to a central inner electrode wrapping the coaxial insulating tube, and plasma is formed at the upper end of the inner electrode and is sprayed out;
5) A DC high-voltage (positive/negative) power supply is connected to a central inner electrode wrapping the coaxial insulating tube, and plasma is formed at the upper end of the inner electrode and is sprayed out;
6) Based on the method 1), the outer tube is not connected with the ground wire, and the infinite end is used as the ground wire;
7) Based on the method 2), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
8) Based on the method 4), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
9) Based on the method 5), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
10 Based on the method 1), gas (single/mixed) is input from an inlet 9 and an inlet 11, a microwave plasma jet is driven to be sprayed out by cooperating with a pulse electric field, and the plasma components are adjusted;
11 Based on the method 2), gas (single/mixed) is input from an inlet 9 and an inlet 11, and drives microwave plasma jet to be sprayed out in cooperation with a high-voltage electric field, and the plasma components are adjusted;
12 Based on method 3), gas (single/mixed) is input from an inlet 9 and an inlet 11, microwave plasma jet is pulled to be sprayed out, and plasma components are adjusted;
13 Based on method 4), gas (single/mixed) is input from an inlet 9 and an inlet 11, the cold plasma jet driven by nanosecond pulse is pulled to be sprayed out, and the plasma components are adjusted;
14 Based on method 5), gas (single/mixed) is input from an inlet 9 and an inlet 11, cold plasma jet driven by nanosecond pulse is pulled to be sprayed out, and plasma components are adjusted;
15 Based on the method 1), the coaxial insulating layer is an insulating coating;
16 Based on method 2), the coaxial insulating layer is an insulating coating;
17 Based on method 4), the coaxial insulating layer is an insulating coating;
18 Based on method 5), the coaxial insulating layer is an insulating coating;
specific example 2
FIG. 2 is a schematic diagram of another structure supporting dual resonant cavities, an auxiliary electric field and three gas flows to cooperatively modulate the length of a microwave cold plasma jet according to the invention;
the composite field modulation microwave cold plasma jet device consists of a cavity part, a microwave coupling part, a tuning part and an electric field modulation part;
referring to fig. 2, the composite field modulation microwave cold plasma jet device of the present invention includes a microwave feed port 1, an outer tube 2, a tuning port 3, a middle tube 4, a coupling ring 6, a porous coaxial gasket 7, a tangential flow shielding gas inlet 9, a nanosecond pulse/DC high-voltage input end, a middle tube gas inlet 11, a capillary gas inlet 12, a capillary inner electrode 13, and a coaxial insulating tube 14;
the cavity part is of a coaxial resonant cavity structure with an outer tube 2, a middle tube 4 and an inner electrode 13 of a capillary tube;
the outer tube, the middle tube and the inner electrode of the capillary tube are all made of metal materials, the outer tube, the middle tube and the reflecting end form a coaxial resonant cavity 1 with one open end, the middle tube, the inner electrode of the capillary tube and the reflecting end form a coaxial resonant cavity 2 with one open end, and TEM standing wave fields are formed in the middle tube, the inner electrode of the capillary tube and the reflecting end;
the inner electrode of the capillary is connected with an auxiliary power supply (DC or nanosecond pulse modulation source);
the axial length of the outer tube is
(λ is the wavelength at the microwave frequency, N is a positive odd number);
the upper ports of the outer pipe and the middle pipe are of gradually-changed closing-in structures, the closing-in of the outer pipe is 0-60 degrees, the closing-in of the middle pipe is 0-30 degrees, and the design is used for adjusting the electric field at the ports;
a porous coaxial gasket with the upper surface made of metal is arranged between the middle pipe and the coaxial insulating pipe 14, and the distance range from the upper surface of the porous gasket to the opening end of the cavity part is
(λ is the wavelength at the microwave frequency, M is a positive odd number);
the inner surface of the coaxial insulating tube 14 is wrapped on the outer surface of the inner electrode of the capillary, the axial length of the coaxial insulating tube is consistent with that of the inner electrode of the capillary, the inner diameter of the coaxial insulating tube is consistent with that of the outer diameter of the inner electrode of the capillary, and preferably, a quartz insulating tube is used for wrapping the outer surface of the inner electrode of the capillary;
the upper end of the middle tube is not higher than the outer tube, the upper end of the electrode in the capillary tube can be higher/lower than the middle tube, preferably, the upper end of the middle tube is 0-2 mm lower than the upper end of the outer tube, and the upper end of the electrode in the capillary tube is-5 mm lower than the upper end of the middle tube; in FIG. 2, the upper port of the inner electrode of the capillary tube is flush with the upper port of the middle tube;
the outer tube, the middle tube and the inner electrode of the capillary tube can introduce gas, and preferably, the shielding gas inlet 9 is introduced in a tangential flow mode; the gas flow rate of the gas inlet 9 and the gas inlet 11 is controlled to be 0-20L/min, and the gas flow rate of the gas inlet 12 is controlled to be 0-1L/min;
the microwave coupling part can optionally couple microwave energy to the cavity part in a conductive coupling, capacitive coupling or other modes; FIG. 2 is a schematic diagram of a configuration for introducing microwave energy into a resonant cavity by conductive coupling; the distance between the coupling ring 6 and the upper port of the outer pipe is adjustable; the microwave plasma jet device is suitable for the electromagnetic wave frequency range of several MHz to several GHz, preferably, stable normal pressure microwave cold plasma jet with the length of 5-40 mm is generated under the frequency of 2.45GHz, and the microwave power conversion efficiency is more than 80%.
The tuning part is a structure that the tuning end 3 adjusts the length of the resonant cavity so as to adjust the field intensity of the opening end, and the upper end of the tuning end is a reflecting end surface which is made of metal; the depth of the cavity part adjusted by the tuning end is Y lambda/4 (lambda is the wavelength under the microwave frequency, and Y is a positive odd number);
the electric field modulation part is an auxiliary power supply (nanosecond pulse or DC voltage) connected with the electrodes 13 in the capillary; the output pulse width of the nanosecond pulse power supply is 10-900 ns, the rising edge is 1-200 ns, the amplitude is 3-220 kV, the frequency is 1-20 kHz, and the duty ratio is 1-99%; the output voltage of the DC power supply is 0-60 kV or 0-60 kV;
the microwave plasma jet device can work by the following 18 methods:
1) The microwave is coupled into the resonant cavity through the microwave coupling part, a TEM standing wave is formed in the resonant cavity, the nanosecond pulse power supply is connected to an electrode in the capillary, and plasma is formed at the axial position of an upper port of the resonant cavity and is driven by a pulse electric field to be sprayed outwards;
2) The microwave is coupled into the resonant cavity through the microwave coupling part to form a TEM standing wave in the resonant cavity, the high-voltage (positive/negative) power supply is connected to the inner electrode of the capillary tube, and the plasma is formed at the axial position of the upper port of the resonant cavity and is driven by a high-voltage electric field to be sprayed out;
3) The microwave is coupled into the resonant cavity through the microwave coupling part, a TEM standing wave is formed in the resonant cavity, and plasma is formed at the axial position of the upper port of the resonant cavity and is sprayed out;
4) The nanosecond pulse power supply is connected to the inner electrode of the capillary, and plasma is formed at the upper end of the inner electrode and is sprayed outwards;
5) A DC high-voltage (positive/negative) power supply is connected to the inner electrode of the capillary, and plasma is formed at the upper end of the inner electrode and is sprayed out;
6) Based on the method 1), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
7) Based on the method 2), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
8) Based on the method 4), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
9) Based on the method 5), the outer pipe is not connected with the ground wire, and the infinite end is taken as the ground wire;
10 Based on method 1), gas (single/mixed) is input from an inlet 9, an inlet 11 and an inlet 12, a microwave plasma jet is driven to be sprayed out by cooperating with a pulse electric field, and the plasma components are adjusted;
11 Based on method 2), gas (single/mixed) is input from an inlet 9, an inlet 11 and an inlet 12, and drives microwave plasma jet to be sprayed out in cooperation with a high-voltage electric field, and the plasma components are adjusted;
12 Based on method 3), gas (single/mixed) is input from inlet 9, inlet 11, inlet 12, microwave plasma jet is pulled to be sprayed out, and plasma components are adjusted;
13 Based on method 4), gas (single/mixed) is input from an inlet 9, an inlet 11 and an inlet 12, cold plasma jet driven by nanosecond pulse is pulled to be sprayed out, and plasma components are adjusted;
14 Based on method 5), gas (single/mixed) is input from an inlet 9, an inlet 11 and an inlet 12, cold plasma jet driven by nanosecond pulse is pulled to be sprayed out, and plasma components are adjusted;
15 Based on the method 1), the inner electrode of the capillary tube can be an annular inner electrode which is flush with the upper port of the coaxial insulating tube, the outer surface of the annular electrode is wrapped by the inner surface of the insulating tube, and the outer diameter of the annular electrode is consistent with the inner diameter of the coaxial insulating tube;
16 Based on the method 2), the inner electrode of the capillary tube can be an annular inner electrode which is flush with the upper port of the coaxial insulating tube, the outer surface of the annular electrode is wrapped by the inner surface of the insulating tube, and the outer diameter of the annular electrode is consistent with the inner diameter of the coaxial insulating tube;
17 Based on the method 4), the inner electrode of the capillary tube can be an annular inner electrode which is flush with the upper port of the coaxial insulating tube, the outer surface of the annular electrode is wrapped by the inner surface of the insulating tube, and the outer diameter of the annular electrode is consistent with the inner diameter of the coaxial insulating tube;
18 Based on the method 5), the inner electrode of the capillary tube can be an annular inner electrode which is flush with the upper port of the coaxial insulating tube, the outer surface of the annular electrode is wrapped by the inner surface of the insulating tube, and the outer diameter of the annular electrode is consistent with the inner diameter of the coaxial insulating tube;
the invention prolongs the length of the microwave cold plasma jet, can intelligently generate specific cold plasma by matching with different driving parameters and gas parameters, and improves the operability and practicability of the microwave cold plasma jet in the fields of clinical hospitals and the like.
The above description is intended to be illustrative of the preferred embodiment of the present invention and should not be taken as limiting the invention, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
Claims (11)
1. A microwave cold plasma jet device is characterized by comprising a cavity part, a microwave coupling part, a tuning part and an electric field modulation part;
the cavity part is an outer tube with an open end, a middle tube with two open ends and an inner electrode coaxial resonant cavity structure, the outer tube is provided with a microwave feed-in port and a tangential flow shielding gas inlet, and the middle tube is provided with a gas inlet;
the microwave coupling portion includes a coupling loop to couple microwave energy to the cavity portion;
the tuning part is a structure that the tuning end adjusts the length of the resonant cavity so as to adjust the field intensity of the opening end, and the upper end of the tuning end is a reflecting end surface; the depth of the cavity part adjusted by the tuning end is Y lambda/4, wherein lambda is the wavelength under the microwave frequency, and Y is a positive odd number;
the electric field modulation part is connected with an inner electrode by applying nanosecond pulse/DC voltage, and the inner electrode is wrapped by a coaxial insulating layer.
2. The microwave cold plasma jet device according to claim 1, wherein the outer tube, the middle tube and the inner electrode are all made of metal materials, and the microwave transmission modes between the outer tube and the middle tube and between the middle tube and the inner electrode are both TEM modes.
3. A microwave cold plasma jet device according to claim 1, wherein the axial length of the outer tube is N λ/4, where λ is the wavelength at the microwave frequency and N is a positive odd number.
4. The microwave cold plasma jet device according to claim 1, wherein the upper ports of the outer tube and the middle tube are gradually necking structures, the necking of the outer tube is 0-60 degrees, and the necking of the middle tube is 0-30 degrees.
5. A microwave cold plasma jet device according to claim 1, wherein a porous coaxial gasket 7 with a metal upper surface is arranged between the middle tube and the coaxial insulating layer, and the distance range of the upper surface of the porous coaxial gasket 7 from the opening end of the cavity part is as follows
Wherein λ is the wavelength at said microwave frequency and M is a positive odd number.
6. A microwave cold plasma jet device according to claim 1, wherein the inner electrode is inserted into the cavity of the coaxial insulating layer, and the inner layer of the coaxial insulating layer covers the outer side of the inner electrode.
7. A microwave cold plasma jet device according to claim 1, wherein the upper end of the middle tube is not higher than the outer tube, and the upper ends of the inner electrode and the coaxial insulating layer can be higher/lower than the middle tube.
8. A microwave cold plasma jet device according to claim 1, wherein the outer tube, the middle tube, introduces gas through the shield gas inlet or the gas inlet.
9. A microwave cold plasma jet device according to claim 8, wherein said shield gas inlet is introduced in a tangential flow; the gas flow rate of the shielding gas inlet and the gas inlet is controlled to be 0-20L/min.
10. A microwave cold plasma jet device according to claim 8, wherein the coupling ring is adjustable in distance from the upper port of the outer tube; the microwave plasma jet device is suitable for the electromagnetic wave frequency range of several MHz to several GHz.
11. A microwave cold plasma jet device according to claim 8, wherein the output pulse width of the nanosecond pulse power supply is 10-900 ns, the rising edge is 1-200 ns, the amplitude is 3-220 kV, the frequency is 1-20 kHz, and the duty ratio is 1-99%; the output voltage of the DC power supply is 0-60 kV or 0-60 kV.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP7430429B1 (en) | 2023-01-11 | 2024-02-13 | 株式会社アドテックプラズマテクノロジー | Coaxial microwave plasma torch |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP7430429B1 (en) | 2023-01-11 | 2024-02-13 | 株式会社アドテックプラズマテクノロジー | Coaxial microwave plasma torch |
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Inventor after: Yu Bingwen Inventor after: Jin Wei Inventor after: Bai Yiwen Inventor after: Yu Dengjie Inventor after: Wei Haoze Inventor before: Yu Bingwen Inventor before: Jin Wei Inventor before: Bai Yiwen |