Compression waveguide plasma torch

Abstract

The application provides a compressed waveguide plasma torch, which comprises a compressed waveguide, a quartz glass tube, a first resonant cavity and a second resonant cavity, and a rectangular waveguide and a tapered waveguide. The compressed waveguide comprises a first circular opening and a second circular opening, the center of the first circular opening and the center of the second circular opening are on the same axis, the first circular opening is arranged on the upper surface of the compressed waveguide, and the second circular opening is arranged on the lower surface of the compressed waveguide. The quartz glass tube is arranged above the compressed waveguide and abuts against the inner wall of the lower side of the compressed waveguide through the first circular opening. The first resonant cavity is sleeved on the outer surface of the quartz glass tube and is arranged above the compressed waveguide. The second resonant cavity is arranged below the compressed waveguide and is connected with the compressed waveguide through the second circular opening. The rectangular waveguide is connected with the tapered waveguide through the beginning end of the rectangular waveguide, and the end of the tapered waveguide is connected with the beginning end of the compressed waveguide.

Description

Technical Field

[0001] This invention relates to the field of microwave plasma technology, and more particularly to a compressed waveguide plasma torch. Background Technology

[0002] The principle of microwave plasma generation is as follows: microwave energy is injected into gas molecules using a waveguide device, inducing a series of reactions such as excitation and ionization, thereby generating highly reactive plasma. The "void structure" characteristic of the microwave electromagnetic field can confine the plasma generated by excitation and ionization within a specific space, while simultaneously enabling plasma transmission. Compared with other methods, the method of generating plasma using a microwave plasma torch has many advantages, such as high ionization degree, wide adaptability to pressure range, high electron density, and easy control of microwave and plasma characteristics. These characteristics make microwave plasma technology research more valuable for practical applications.

[0003] Under standard atmospheric pressure, the breakdown field strength of air is 3 × 10⁻⁶. 6 V / m. In order to generate a high electric field strength and thus break down the air to produce plasma, the most common method used in traditional microwave plasma torches is a compressed waveguide structure. This structure increases the electric field strength by concentrating the electric field, which can reduce the volume of the resonant cavity. Another method is to use a resonant cavity structure with multiple input ports to provide greater microwave power, but the isolation between multiple ports is more difficult.

[0004] Traditional compressed waveguide resonant cavity plasma torches produce plasma with small volume, short processing distance, and require high power input, and usually require an external mechanical ignition device for triggering. Summary of the Invention

[0005] In view of this, the present invention provides a compressed waveguide plasma torch, which, compared with the traditional compressed waveguide resonant cavity plasma torch, generates a larger plasma volume, has a longer processing distance, and does not require a mechanical ignition device for triggering.

[0006] Specifically, the compressed waveguide plasma torch includes:

[0007] A compressed waveguide includes a first circular opening on the upper surface of the compressed waveguide and a second circular opening on the lower surface of the compressed waveguide, the centers of the first and second circular openings being on the same axis, which is perpendicular to the upper and lower surfaces of the compressed waveguide; a quartz glass tube disposed above the compressed waveguide and abutting against the lower inner wall of the compressed waveguide through the first circular opening; a first resonant cavity sleeved on the outer surface of the quartz glass tube and located above the compressed waveguide; and a second resonant cavity disposed below the compressed waveguide and connected to the compressed waveguide through the second circular opening.

[0008] Furthermore, the compressed waveguide plasma torch also includes:

[0009] A rectangular waveguide through which microwaves are input; a tapered waveguide through which the beginning of the tapered waveguide is connected to the end of the rectangular waveguide, and the end of the tapered waveguide is connected to the beginning of the compressed waveguide.

[0010] Furthermore, the axis of the center of the two circular openings passes through the point where the electric field strength is strongest within the compressed waveguide.

[0011] According to an embodiment of the present invention, the axis of the quartz glass tube coincides with the axis of the center of the two circular openings.

[0012] According to an embodiment of the present invention, the rightmost side of the compressed waveguide is the short surface.

[0013] Furthermore, the upper end of the second resonant cavity is open-circuited, and the lower end of the second resonant cavity is short-circuited; the upper end is flush with the lower inner wall of the compressed waveguide, and the axis of the second resonant cavity coincides with the axis of the center of the two circular openings mentioned above.

[0014] Furthermore, the second resonant cavity also includes:

[0015] The inner conductor, which is cylindrical, is disposed in the second resonant cavity and is coaxial with the second resonant cavity. The second resonant cavity and the inner conductor together constitute the ignition assembly.

[0016] According to an embodiment of the present invention, the top shape of the inner conductor includes: a plane, a hemisphere, a cone, or a frustum.

[0017] Furthermore, the compressed waveguide also includes: at least one coupling port, which is opened on the upper surface of the compressed waveguide; and a coupling interface with the same shape, size and number as the above-mentioned at least one coupling port is also opened at the corresponding position on the bottom surface of the first resonant cavity.

[0018] Furthermore, the compressed waveguide plasma torch also includes:

[0019] At least one coupling element corresponds to the shape, size, and number of the at least one coupling port mentioned above; the first resonant cavity is coupled to the upper surface of the compressed waveguide through the at least one coupling element.

[0020] Furthermore, after the ignition assembly ignites a plasma flame inside the quartz glass tube, the first resonant cavity and the plasma inside the quartz glass tube form a coaxial resonant cavity.

[0021] Furthermore, the compressed waveguide also includes:

[0022] At least one air inlet is disposed on the lower surface of the compression waveguide;

[0023] Furthermore, the air intake direction of the air inlet is obliquely upward toward the inner cavity of the quartz glass tube, and the projection of this air intake direction onto the lower inner wall of the compression waveguide forms an angle θ with the radial direction of the quartz glass tube, where 0° < θ ≤ 90°.

[0024] Furthermore, if there are multiple air intakes, each air intake is centrally symmetrically distributed along the center of the second circular opening.

[0025] Furthermore, the compressed waveguide also includes:

[0026] A short-circuit piston is disposed at the end of the compression waveguide, and a piston rod is connected to the right side of the short-circuit piston; under the action of the piston rod, the short-circuit piston has a lateral stroke within the compression waveguide.

[0027] Based on this, compared with traditional compressed waveguide resonant cavity plasma torches, the compressed waveguide plasma torch provided by the present invention has at least the following beneficial effects:

[0028] Under the same environment and input power, the volume of plasma produced is larger.

[0029] Under the same environment and input power, the generated plasma flame can handle a longer and adjustable distance.

[0030] Under the same environment and input power, there is no need to set up an additional mechanical ignition device to ignite the plasma flame.

[0031] The input power required to generate and maintain a plasma flame of the same size and length is smaller.

[0032] It can be more widely used in waste exhaust gas treatment, material surface treatment, biomedicine and other applications. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a traditional compressed waveguide resonant cavity plasma torch;

[0034] Figure 2 This is an exploded structural diagram of a compressed waveguide plasma torch according to a preferred embodiment of the present invention;

[0035] Figure 3 This is a top view of a compressed waveguide plasma torch according to a preferred embodiment of the present invention;

[0036] Figure 4 yes Figure 3 The cross-sectional view of the compressed waveguide plasma torch along line AA is shown.

[0037] Figure 5This is a schematic diagram illustrating a first resonant cavity coupled to the upper surface of a compressed waveguide via a coupling element, according to a preferred embodiment of the present invention; and,

[0038] Figure 6 This is a schematic diagram illustrating an air inlet on a compressed waveguide according to a preferred embodiment of the present invention.

[0039] [Explanation of Labels in the Attached Image]

[0040] 1-Rectangular waveguide; 2-Graduated waveguide; 3-Compressed waveguide; 31-Axis; 32-First circular opening; 33-Second circular opening; 34-Upper surface; 35-Lower surface; 36-Coupled port; 37-Air inlet; 38-Short-circuit piston; 39-Piston rod; 4-First resonant cavity; 5-Quartz glass tube; 6-Second resonant cavity; 61-Inner conductor; 62-Upper end; 63-Lower end; 7-Coupled element. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Those skilled in the art should understand that the various embodiments of the invention listed below are merely illustrative examples to make the objectives, technical solutions, and advantages of the invention clearer, and are not intended to limit the content and scope of protection of the invention. In the embodiments listed below, the same reference numerals will represent the same or similar elements or components.

[0042] It should be noted that in this specification, when a component is described as "comprising", "having", or "containing" an element, it means that the component may include one or more elements, and the component may include other elements at the same time, and does not mean that the component has only one element, unless otherwise stated.

[0043] Furthermore, in this specification, ordinal numbers such as "first" or "second" are used only to distinguish multiple elements with the same name and do not imply an inherent hierarchy, rank, execution order, or manufacturing order between the elements, unless otherwise stated. The element numbers in the specification may differ from those in the claims. For example, an element referred to as "second" in the specification may be an element referred to as "first" in the claims.

[0044] In this specification, unless otherwise stated, "or" for feature A and "and / or" for feature B means the existence of only feature A, the existence of only feature B, or the existence of both feature A and feature B. "and" for feature A means the existence of both feature A and feature B.

[0045] Furthermore, in this specification, terms such as "top," "upper," "bottom," "front," "back," or "middle," as well as terms such as "above," "on top," "on the surface," "below," "below," or "between," are used to describe the relative positions between multiple elements. These directional terms are referenced to the directions shown in the accompanying drawings, and the described relative positions can be interpreted as including their translation, rotation, or reflection.

[0046] Furthermore, terms used in the specification and claims, such as “above,” “over,” “on top,” “below,” or “under,” are intended to allow an element to contact not only directly but also indirectly.

[0047] Furthermore, terms used in the specification and claims, such as "connection," mean that an element can be directly connected to other elements as well as indirectly connected to other elements. On the other hand, terms such as "electrical connection" and "coupled" used in the specification and claims mean that an element can be directly electrically connected to other elements as well as indirectly connected to other elements; the present invention does not limit the connection methods between the various elements.

[0048] Furthermore, the dimensions of each component in the accompanying drawings are only schematically shown. The fact that two components in the drawings are similar in size does not mean that they are similar in size in the actual product. The fitting clearance and surface quality parameters of the components are not shown in the accompanying drawings.

[0049] In this specification, unless otherwise stated, the terms used herein (including technical and scientific terms) have the meanings commonly known to those skilled in the art. It should be noted that, unless otherwise stated in the embodiments of the invention, these terms (e.g., terms defined in a general dictionary) should have the same meaning as those skilled in the art, the background of the invention, or the context of this specification, and should not be read in an idealized or excessive manner.

[0050] Under standard atmospheric pressure, in order to generate a breakdown field strength exceeding that of air (3 × 10⁻⁶), 6 A high electric field intensity of V / m can break down air to generate plasma. Traditional compressed waveguide resonant cavity plasma torches, such as... Figure 1 As shown, a commonly used structure is the compressed waveguide, which increases the electric field strength by concentrating the electric field. Its working principle is roughly as follows:

[0051] First, microwaves are input into rectangular waveguide 1, and under the directional guidance of rectangular waveguide 1, the microwaves enter tapered waveguide 2. The structure of tapered waveguide 2 is characterized by a linear reduction in its longitudinal dimensions from the beginning to the end. Based on this, the electric field can be concentrated, generating a high field strength region at its end. The microwaves are then transmitted to compressed waveguide 3, with the rightmost side of compressed waveguide 3 being a short path. Quartz glass tube 5 is inserted vertically into compressed waveguide 3 and passes through the region with the strongest electric field strength within compressed waveguide 3. Air enters quartz glass tube 5 from bottom to top, and when the air passes through the region with the highest field strength, it is ionized, generating microwave plasma.

[0052] However, such conventional plasma torches typically require high power input to generate a high electric field strength exceeding the breakdown field strength of air, or an additional mechanical ignition device for triggering; furthermore, the plasma generated by such conventional plasma torches is small in volume and has a short processing distance.

[0053] In view of this, the present invention provides a compressed waveguide plasma torch, which, compared with the traditional compressed waveguide resonant cavity plasma torch, generates a larger plasma volume, a longer processing distance, requires less power, and does not require a mechanical ignition device for triggering.

[0054] According to an embodiment of the present invention, please refer to Figures 2-6 The compressed waveguide plasma torch includes:

[0055] The compressed waveguide 3 includes a first circular opening 32 on the upper surface 34 and a second circular opening 33 on the lower surface 35; a quartz glass tube 5 is disposed above the compressed waveguide 3 and abuts against the lower inner wall of the compressed waveguide 3 through the first circular opening 32; a first resonant cavity 4 is sleeved on the outer surface of the quartz glass tube 5 and is located above the compressed waveguide 3; and a second resonant cavity 6 is disposed below the compressed waveguide 3 and is connected to the compressed waveguide 3 through the second circular opening 33.

[0056] Furthermore, the compressed waveguide plasma torch also includes: a rectangular waveguide 1, through which microwaves are input; and a tapered waveguide 2, the beginning of which is connected to the end of the rectangular waveguide 1, and the end of the tapered waveguide 2 is connected to the beginning of the compressed waveguide 3. This part is prior art and will not be described in detail here.

[0057] In a preferred embodiment of the present invention, the center of the first circular opening 32 and the center of the second circular opening 33 are on the same axis 31, which is perpendicular to the upper surface 34 and the lower surface 35 of the compressed waveguide 3.

[0058] In a preferred embodiment of the present invention, axis 31 passes through the point where the electric field intensity is strongest within the compressed waveguide 3.

[0059] In a preferred embodiment of the present invention, the axis of the quartz glass tube 5 coincides with the axis 31.

[0060] In some embodiments, the rightmost side (the end of the compression waveguide 3) is a short surface.

[0061] In the preferred embodiment described above, a short-circuit piston 38 is provided at the end of the compressed waveguide 3, and a piston rod 39 is connected to the right side of the short-circuit piston 38, forming an adjustable short-circuit path. Under the action of the piston rod 39, the short-circuit piston 38 has a lateral stroke within the compressed waveguide 3. Of course, for the sake of mechanical balance, the number of piston rods 39 can also be multiple or in various forms, and the present invention does not limit them.

[0062] Therefore, even if the bottom end of the quartz glass tube 5 is not precisely located in the region of strongest electric field intensity within the compressed waveguide 3, it can be adjusted by the short-circuit piston 38. The surface of the short-circuit piston 38 acts as a short-circuit surface, and its lateral movement within the compressed waveguide 3 adjusts the electric field intensity distribution inside the compressed waveguide 3, allowing the region of strongest electric field intensity within the compressed waveguide 3 to move laterally. On the other hand, during subsequent large-volume plasma excitation and maintenance, the electric field intensity distribution may also change. The short-circuit piston 38 can also be used for timely adjustment, ensuring that the bottom end of the quartz glass tube 5 is always accurately located in the region of strongest electric field intensity within the compressed waveguide 3.

[0063] Furthermore, the upper end 62 of the second resonant cavity 6 is open-circuited, and the lower end 63 of the second resonant cavity 6 is short-circuited.

[0064] In a preferred embodiment of the present invention, the upper end 62 of the second resonant cavity 6 is flush with the lower inner wall of the compressed waveguide 3, and the axis of the second resonant cavity 6 coincides with the axis 31.

[0065] Furthermore, the second resonant cavity 6 also includes an inner conductor 61, which is cylindrical and disposed within the second resonant cavity 6, forming an ignition assembly together with the second resonant cavity 6. The top end shape of the inner conductor 61 includes: a plane, a hemisphere, a cone, or a frustum.

[0066] In a preferred embodiment of the present invention, the inner conductor 61 has a hemispherical top and is coaxial with the second resonant cavity 6. CST simulation results show that, under the same conditions, when the top of the inner conductor 61 is a hemispherical top, the electric field strength around the top of the inner conductor 61 is the strongest, which is more conducive to plasma excitation.

[0067] CST simulation experiments show that the presence of this ignition component can change the electric field distribution within the compressed waveguide 3, and enhance the electric field strength in certain regions within the compressed waveguide 3, especially around the top of the inner conductor 61, where the electric field strength is significantly enhanced.

[0068] According to a preferred embodiment of the present invention, CST simulation results show that when the input power of the compressed waveguide plasma torch is 0.5W, the electric field strength in the region near the inner conductor 61 at the lower part of the quartz glass tube 5 inside the compressed waveguide plasma torch is 1.6 × 10⁻⁶. 3 The electric field strength is V / m, while in the region near the top of the inner conductor 61, the electric field strength is 4.2 × 10⁻⁶. 4 The peak electric field intensity within this compressed waveguide plasma torch reaches 1.2 × 10⁻⁶ V / m. 5 V / m. Clearly, with a relatively low input power, the peak electric field strength around the tip of the inner conductor 61 can exceed the breakdown field strength of air, thus exciting the plasma and generating a plasma flame. Based on this, the compressed waveguide plasma torch provided by this invention can achieve plasma excitation without the need for an additional mechanical ignition device, even with low input power. Therefore, the minimum input power required for plasma excitation by the compressed waveguide plasma torch provided by this invention is lower than that of a traditional compressed waveguide resonant cavity plasma torch.

[0069] In another preferred embodiment of the invention, the height of the inner conductor 61 within the second resonant cavity 6 is adjustable. Based on this, the position of the highest electric field intensity within the compressed waveguide 3, particularly its position in the height direction, can be adjusted.

[0070] Furthermore, the compressed waveguide 3 also includes: at least one coupling port 36, which is opened on the upper surface 34 of the compressed waveguide 3; the bottom surface of the first resonant cavity 4 is also opened with a coupling interface that is consistent with the shape, size and number of the above-mentioned at least one coupling port 36.

[0071] Furthermore, the compressed waveguide plasma torch also includes: at least one coupling element 7, which corresponds to the shape, size and number of the at least one coupling port 36; the first resonant cavity 4 is coupled to the upper surface 34 of the compressed waveguide 3 through the at least one coupling element 7.

[0072] In a preferred embodiment of the present invention, the axis of the first resonant cavity 4 coincides with the axis 31, and the multiple coupling ports 36 are centrally symmetrically distributed along the axis 31.

[0073] In such Figure 5 In the illustrated embodiment, two coupling ports 36 are formed on the upper surface 34 of the compressed waveguide 3. Correspondingly, two coupling interfaces of the same shape and size are also formed at corresponding positions on the bottom surface of the first resonant cavity 4. The coupling ports 36 on the compressed waveguide 3 are not directly connected to the coupling interfaces on the bottom surface of the first resonant cavity 4, but are connected through two coupling elements 7 corresponding to the shape and size of the coupling ports 36. Based on this, after the ignition assembly excites the plasma, this coupling structure can couple electromagnetic energy from the compressed waveguide 3 into the first resonant cavity 4.

[0074] Furthermore, after the ignition assembly ignites the plasma flame inside the quartz glass tube 5, the first resonant cavity 4 and the plasma inside the quartz glass tube 5 form a coaxial resonant cavity.

[0075] This invention, through a longitudinal extension of a first resonant cavity 4 above a compressed waveguide 3, allows microwaves to successfully break down the gas and generate plasma. Due to the metallic properties of the plasma, the electric field distribution within the first resonant cavity 4 changes. At this point, the first resonant cavity 4 and the plasma within the quartz glass tube 5 form a coaxial resonant cavity structure. This coaxial resonant cavity structure enhances and sustains the plasma flame. Based on this, the compressed waveguide plasma torch provided by this invention can generate and sustain a larger plasma flame with a longer processing distance. CST simulation results show that when the input power reaches 1.5kW, this compressed waveguide plasma torch can guarantee the sustained maintenance of a larger plasma flame with a longer processing distance. The minimum input power required to maintain this plasma flame is lower than that of a traditional compressed waveguide resonant cavity plasma torch.

[0076] In a preferred embodiment of the present invention, the dimensions of the coupling member 7 in the height direction can be set as needed to adjust the position of the first resonant cavity in the height direction, that is, to adjust the position of the first resonant cavity 4 and the plasma forming coaxial resonant cavity in the quartz glass tube 5 in the height direction. Based on this, it is beneficial to form a better plasma flame.

[0077] Furthermore, the compressed waveguide 3 also includes:

[0078] At least one air inlet 37 is disposed on the lower surface 35 of the compression waveguide 3. Based on this, air can be introduced into the compression waveguide 3, and the air is ionized in the high field strength region near the inner conductor 61 after entering, generating microwave plasma.

[0079] Furthermore, the air intake direction of at least one air inlet 37 is obliquely upward toward the inner cavity of the quartz glass tube 5; the projection of this air intake direction onto the lower inner wall of the compression waveguide 3 forms an angle θ with the radial direction of the quartz glass tube 5, where 0° < θ ≤ 90°. Based on this, a spiral upward airflow can be generated inside the quartz glass tube 5, which on the one hand can protect the quartz glass tube 5 from being melted by the high-temperature plasma; on the other hand, the spiral upward airflow can drive the plasma flame, making the plasma flame's processing distance longer.

[0080] Even better, there are multiple air intakes (37 in total), such as Figure 6 (Perspective) Figure 5In a preferred embodiment of the present invention shown in the bottom view of the compressed waveguide 3, there are four air inlets 37, all with the same shape and size. Each air inlet 37 is centrally symmetrically distributed along axis 31. The air inlets 37 are located on the inner wall of the quartz glass tube 5, and the angle θ between the projection of their air inlet direction onto the lower inner wall of the compressed waveguide 3 and the radial direction of the quartz glass tube 5 is 90°. Based on this, the spiraling upward airflow generated by the four air inlets 37 inside the quartz glass tube 5 will be superimposed on each other with maximum efficiency rather than canceling each other out, thus enhancing the aforementioned effect.

[0081] In another preferred embodiment of the invention, an air pressurization device is provided to provide an initial velocity to the air introduced through the air inlet 37. Based on this, the spiral upward airflow generated inside the quartz glass tube 5 through the air inlet 37 is stronger, which can enhance the above-mentioned effect, and the processing distance of the obtained plasma flame can also be adjusted by adjusting the initial velocity.

[0082] In summary, the compressed waveguide plasma torch provided by this invention can generate a larger volume of plasma under standard atmospheric pressure; the generated plasma flame can handle a longer and adjustable distance; no additional mechanical ignition device is required to ignite the plasma flame; the minimum input power required to ignite the plasma is lower; and the input power required to generate and maintain a plasma flame of the same size and length is also lower. The compressed waveguide plasma torch provided by this invention can be practically applied to waste gas treatment, material surface treatment, biomedicine, and other applications.

[0083] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compressed waveguide plasma torch, comprising: The application relates to a microwave generator, which comprises: a compression waveguide (3) comprising a first circular opening (32) formed in the upper surface (34) of the compression waveguide (3) and a second circular opening (33) formed in the lower surface (35) of the compression waveguide (3), the centers of the first circular opening (32) and the second circular opening (33) being on the same axis (31); a quartz glass tube (5) arranged above the compression waveguide (3) and abutting the inner wall of the lower side of the compression waveguide (3) through the first circular opening (32); a first resonant cavity (4) sleeved on the outer surface of the quartz glass tube (5) and located above and coupled with the compression waveguide (3); a second resonant cavity (6) arranged below the compression waveguide (3) and connected with the compression waveguide (3) through the second circular opening (33), the upper end (62) of the second resonant cavity (6) being open, the lower end (63) of the second resonant cavity (6) being short-circuited, and the second resonant cavity (6) further comprising an inner conductor (61) arranged in the second resonant cavity (6) and forming an ignition assembly together with the second resonant cavity (6).

2. The compressed waveguide plasma torch of claim 1, wherein, The application further comprises: a rectangular waveguide (1) through which microwaves are input from the beginning end; a tapered waveguide (2) connected with the end of the rectangular waveguide (1) at the beginning end and connected with the beginning end of the compression waveguide (3) at the end.

3. The compressed waveguide plasma torch of claim 1, wherein, The axis (31) passes through the position with the strongest electric field intensity in the compression waveguide (3).

4. The compressed waveguide plasma torch of claim 1, wherein, The compression waveguide (3) further comprises at least one coupling port (36) formed in the upper surface (34), and the bottom surface of the first resonant cavity (4) is provided with a coupling interface corresponding to the shape, size and number of the at least one coupling port (36).

5. The compressed waveguide plasma torch of claim 4, wherein, The application further comprises: at least one coupling member (7) corresponding to the shape, size and number of the at least one coupling port (36), and the first resonant cavity (4) is coupled with the upper surface (34) of the compression waveguide (3) through the at least one coupling member (7).

6. The compressed waveguide plasma torch of claim 5, wherein, After the plasma flame is generated in the quartz glass tube (5), the first resonant cavity (4) and the plasma in the quartz glass tube (5) form a coaxial resonant cavity.

7. The compressed waveguide plasma torch of claim 1, wherein, The compression waveguide (3) further comprises: at least one air inlet (37) formed in the lower surface (35); the air inlet direction of the at least one air inlet (37) is obliquely upward to the inner cavity of the quartz glass tube (5), and the projection of the air inlet direction on the inner wall of the lower side of the compression waveguide (3) forms an angle theta with the radial direction of the quartz glass tube (5), wherein 0 < theta <= 90.

8. The compressed waveguide plasma torch of claim 1, wherein, The compression waveguide (3) further comprises: a short-circuit piston (38) arranged at the end of the compression waveguide (3), a piston rod (39) connected with the right side of the short-circuit piston (38), and the short-circuit piston (38) having a transverse stroke in the compression waveguide (3) under the action of the piston rod (39).

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