A plasma thermal spraying apparatus gun

Abstract

The present application relates to the technical fields of plasma spraying, and discloses a plasma spraying gun for a plasma thermal spraying device, which comprises a gun seat, a gun tube seat, a first gun tube and a second gun tube. The second gun tube is provided with two opposite fixing positions on the side far from the first gun tube, and the first and second air supplement tubes are respectively arranged on the two fixing positions. The present application has the advantages of simple structure, easy production, high safety, no explosion risk, good spraying effect, high coating quality, and the like. Argon and hydrogen are supplied to both sides of the plasma flame to inhibit the radial spraying trend of the material, and the annular groove on the inner wall of the second gun tube generates a rotating force on the material to make the material be sprayed in a flat shape. The material is sprayed on the surface of the to-be-sprayed part to form a single-spraying long strip area, and the material is uniformly distributed in the area. Compared with the circular area formed by single spraying in the prior art, the problem of uneven material distribution and uneven coating edge is effectively solved, and the present application is especially suitable for preparing high-performance coatings.

Description

Technical Field

[0001] This invention relates to the field of plasma spraying technology, and more specifically to a spray gun for plasma thermal spraying equipment. Background Technology

[0002] Existing plasma thermal spraying equipment typically includes two conical components and an electrode. A channel must be reserved between the two conical components. The electrode is installed in the middle of one of the conical components with a gap between them. Both conical components have related structures at their bottoms. The material is fed into the gap between the electrode and the conical component by a powder-feeding gas, and then enters the electrode end, where it is ignited by the electrode to generate a plasma flame. The channel between the two conical components is used to transport a gas containing argon and hydrogen to replenish the gas consumed by the plasma flame and to increase the temperature and enthalpy of the plasma arc.

[0003] Existing spray guns have the following defects: 1. The channel between the two conical components needs to be designed with a smooth and uniform surface, which makes production difficult and the structure complex; 2. This channel is directly connected to the plasma flame generation area. If the plasma flame is unstable and air enters the channel, the pressure will rise instantly due to the hydrogen content of the gas transported in the channel being 5-15%, which can easily lead to an explosion risk. 3. The sprayed material is distributed radially, and the amount of material gradually increases from the center point to the surrounding area, resulting in uneven material distribution on the coating surface after spraying, which makes it difficult to meet the requirements for the preparation of high-performance coatings.

[0004] In view of the above-mentioned shortcomings, the present invention aims to create a spray gun for plasma thermal spraying equipment, making it more industrially valuable. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a plasma thermal spraying equipment spray gun that solves the problems of complex structure, difficult manufacturing, easy explosion risk, and uneven distribution of sprayed materials associated with traditional spray guns.

[0006] The present invention provides a spray gun for a plasma thermal spraying equipment, comprising a spray gun base, a spray gun tube base, a first spray gun tube, and a second spray gun tube; The spray gun holder, spray gun tube holder, first spray gun tube and second spray gun tube are connected in sequence. The first spray gun tube is provided with an electrode, which is installed on the spray gun tube holder. The side of the spray gun tube seat is integrally provided with a feeding position. The side of the feeding position away from the first spray gun tube is provided with a feeding connector. The inside of the spray gun tube seat is provided with a feeding channel. One end of the feeding channel is connected to the feeding connector, and the other end is connected to a plurality of feeding holes. The plurality of feeding holes are radially distributed along the axis of the electrode, and the end away from the feeding channel is connected to the inside of the first spray gun tube. The second spray gun tube has two opposing fixed positions on the side away from the first spray gun tube. The first air supply pipe and the second air supply pipe are respectively installed on the two fixed positions. The ends of the first air supply pipe and the second air supply pipe that are close to each other are inclined towards the middle of the second spray gun tube. The inner wall of the second spray gun tube is provided with an annular groove. Both the first and second air supply pipes are equipped with one-way valve assemblies, which allow gas to enter the first spray gun pipe in one direction.

[0007] Furthermore, the first gas supply pipe is used to supply argon gas, and the second gas supply pipe is used to supply hydrogen gas.

[0008] Furthermore, the first spray gun tube has a cooling chamber with an annular structure inside. The cooling chamber has a partition, and the partition has a first circulation hole and a second circulation hole on its two sides respectively. The spray gun tube seat has two circulating cooling holes on its side, and a cooling channel is provided inside the holes. The cooling channel connects the circulating cooling holes with the corresponding first and second circulation holes.

[0009] Furthermore, the one-way valve assembly includes a rotating plate, a rotating shaft, and a baffle. The first and second air supply pipes are both cylindrical structures. The rotating plate is a cylindrical structure, with its central part rotatably connected to the inner wall of the corresponding air supply pipe via the rotating shaft. The baffle is fixedly connected to the upper inner wall of the air supply pipe and movably fits against the side of the rotating plate near the outlet of the air supply pipe.

[0010] Furthermore, the powder gas transported by the feeding channel is argon gas, and the powder gas carries the spraying material into the feeding hole.

[0011] Furthermore, the spray gun holder is made of insulating material, the spray gun tube holder is installed at the end of the spray gun holder, the first spray gun tube is installed on the side of the spray gun tube holder away from the spray gun holder, and the second spray gun tube is installed on the side of the first spray gun tube away from the spray gun tube holder. Both the first spray gun tube and the second spray gun tube have a circular structure.

[0012] Furthermore, the side of the spray gun tube seat away from the spray gun seat is provided with an annular protrusion, which is engaged with the first spray gun tube, and the two are connected by a second threaded ring through a threaded engagement. The first spray gun tube and the second spray gun tube are engaged with each other, and the two are connected by a first threaded ring through a threaded engagement.

[0013] Furthermore, the spray gun nozzle seat has two electrical connection holes on its side, and a wiring channel is provided inside the wiring channel. A high-temperature resistant wire is installed in the wiring channel and is connected to the electrode. A conductive contact is provided at the bottom of the electrical connection hole and is electrically connected to the high-temperature resistant wire.

[0014] Furthermore, the argon gas can be replaced with nitrogen or helium.

[0015] Furthermore, the coolant is selected from propylene glycol-based dielectric coolant, high-purity deionized water, fluorinated liquid, or ultra-low conductivity ethylene glycol / propylene glycol liquid.

[0016] By means of the above-described solution, the present invention has at least the following advantages: 1. Simple structure and easy to manufacture: By setting a detachable first gas supply pipe and a second gas supply pipe on the outside of the second spray gun tube, argon and hydrogen gas required for plasma flame consumption are supplied respectively, which replaces the method of setting a channel between two conical parts to transport gas in the existing technology. There is no need to process a smooth and uniform channel, which reduces the difficulty of production and the complexity of structure. 2. High safety and no explosion risk: Argon and hydrogen are directly supplied to both sides of the plasma flame and are connected to the atmospheric environment. There is no need for combustion in a confined space, which avoids the explosion hazard caused by air entering a narrow channel and mixing with hydrogen-containing gas, as is the case in existing technologies. At the same time, the one-way valve assembly installed in the first and second gas supply pipes can prevent the backflow of plasma flame and air, further eliminating the risk of explosion. Moreover, the one-way valve assembly does not require the use of heat-sensitive components such as springs, making it suitable for the high-temperature working environment of the spray gun. It also does not require an additional increase in the diameter of the gas supply pipe, avoiding the problem of increased explosion power caused by increasing the pipe diameter. 3. Excellent spraying effect and high coating quality: Argon and hydrogen are supplied to both sides of the plasma flame, which can suppress the radial spraying tendency of the material. Combined with the annular groove on the inner wall of the second spray gun tube, the material generates a rotational force, causing the material to be sprayed in a flat shape. The sprayed material forms a single-spray strip area on the surface of the part to be coated. The material is evenly distributed in this area. Compared with the circular area formed by single spraying in the prior art, it effectively solves the problems of uneven material distribution and uneven coating edges, and is especially suitable for preparing high-performance coatings.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show a certain embodiment of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the spray gun structure in existing plasma thermal spraying equipment. Figure 2 This is a schematic diagram of the spray gun for the plasma thermal spraying equipment of the present invention from one perspective. Figure 3 This is a schematic diagram of the spray gun for the plasma thermal spraying equipment of the present invention from another perspective. Figure 4 This is a cross-sectional view of the spray gun used in the plasma thermal spraying equipment of the present invention; Figure 5 This is a schematic diagram of the internal structure of the spray gun holder of the present invention; Figure 6 This is the invention Figure 5 Enlarged schematic diagram of the structure at point A in the middle; Figure 7 This is a radial sectional view of the first spray gun tube of the present invention; Figure 8 This is a schematic diagram of the radial material spraying zone formed when a plasma thermal spraying equipment uses a spray gun for spraying in the existing technology. Figure 9 This is a schematic diagram of the material jet spiral trajectory formed by the spray gun of the plasma thermal spraying equipment of the present invention during spraying; Figure 10 This is a schematic diagram of the flat material spraying zone formed during the spraying of the plasma thermal spraying equipment of the present invention; Figure 11 This is a schematic diagram of a single circular area formed by spraying plasma thermal spraying equipment using a spray gun on a workpiece to be coated in the prior art. Figure 12 This is a schematic diagram of a single-pass sprayed strip area formed on the workpiece by spraying with a spray gun of the plasma thermal spraying equipment of the present invention; Figure 13 This is a schematic diagram of the simulated spraying movement trajectory in existing technology; Figure 14 This is a schematic diagram of the simulated spraying movement trajectory of the spray gun used in the plasma thermal spraying equipment of the present invention; Figure 15 This is a schematic diagram of the final sprayed coating layer formed after simulated spraying in existing technology; Figure 16 This is a schematic diagram of the final sprayed layer formed after simulated spraying using a spray gun in the plasma thermal spraying equipment of the present invention.

[0020] In the diagram: 1. Spray gun holder; 2. Spray gun tube holder; 3. First spray gun tube; 4. Second spray gun tube; 5. Fixed position; 6. First air supply pipe; 7. Second air supply pipe; 8. Feeding position; 9. Feeding connector; 10. Electrical connection hole; 11. Circulating cooling hole; 12. Electrode; 13. Feeding hole; 14. First threaded ring; 15. Second threaded ring; 16. Cooling chamber; 17. Ring groove; 18. Feeding channel; 19. Rotating plate; 20. Rotating shaft; 21. 21. Baffle; 22. Partition; 23. First circulation hole; 24. Second circulation hole; 25. Part to be coated; 201. Radial material spraying area; 202. Material spraying spiral trajectory; 203. Flat material spraying area; 204. Single-spray circular area; 205. Single-spray strip area; 301. Spray gun housing; 302. Spray gun inner housing; 303. Material supply area; 304. Gas supply area; 305. Mixed gas; 306. Spray nozzle. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] See Figures 1 to 16 A preferred embodiment of the present invention provides a spray gun for a plasma thermal spraying device, comprising a spray gun base 1, a spray gun tube base 2, a first spray gun tube 3, and a second spray gun tube 4.

[0023] The spray gun holder 1 is made of insulating material to prevent electric leakage.

[0024] The spray gun tube seat 2 is installed at the end of the spray gun seat 1. The spray gun tube seat 2 is a rectangular block structure. The first spray gun tube 3 is installed on the side of the spray gun tube seat 2 away from the spray gun seat 1. The second spray gun tube 4 is installed on the side of the first spray gun tube 3 away from the spray gun tube seat 2. Both the first spray gun tube 3 and the second spray gun tube 4 are annular structures. The side of the spray gun tube seat 2 away from the spray gun seat 1 is provided with an annular protrusion. The annular protrusion is engaged with the first spray gun tube 3. The first spray gun tube 3 and the second spray gun tube 4 are engaged with each other. The annular protrusion and the first spray gun tube 3 are also connected by a second threaded ring 15 through a threaded engagement. The first spray gun tube 3 and the second spray gun tube 4 are connected by a first threaded ring 14 through a threaded engagement, realizing convenient disassembly and assembly between different components.

[0025] In this invention, an electrode 12 is provided inside the first spray gun tube 3. The electrode 12 is mounted on the spray gun tube seat 2. Two power connection holes 10 are provided on the side of the spray gun tube seat 2. A wiring channel is provided inside the spray gun tube seat 2. A high-temperature resistant wire is installed in the wiring channel and connected to the electrode 12. A conductive contact is provided at the bottom of the power connection hole 10. The conductive contact is electrically connected to the high-temperature resistant wire. When the electrode 12 is energized, the positive and negative terminals are installed in the corresponding power connection hole 10 by means of threaded connection to achieve the purpose of energizing.

[0026] A feeding position 8 is integrally provided on the side of the spray gun tube seat 2. A feeding connector 9 is provided on the side of the feeding position 8 away from the first spray gun tube 3. A feeding channel 18 is provided inside the spray gun tube seat 2, and the feeding channel 18 is connected to the feeding connector 9. A feeding hole 13 is provided at the end of the feeding channel 18 away from the feeding connector 9. Multiple feeding holes 13 are provided, and the multiple feeding holes 13 are radially distributed along the axis of the electrode 12. The end of the feeding hole 13 away from the feeding channel 18 is connected to the first spray gun tube. The internal connection of 3 allows the feeding mechanism to be connected to the feeding connector 9. The feeding mechanism can feed powder into the feeding connector 9. The powder is carried by powder gas, which is argon gas. After the powder gas and powder enter multiple feeding holes 13 from the feeding channel 18, they are sprayed out and dispersed more evenly. The electrode 12 is energized and ignites an electric arc with the argon gas. When the argon gas transports the powder into the first spray gun tube 3, the powder enters the plasma flame core area through the transport action of the argon gas. The powder is fully melted and accelerated to obtain a dense coating.

[0027] Furthermore, in this invention, two fixing positions 5 are provided on the side of the second spray gun tube 4 away from the first spray gun tube 3. The two fixing positions 5 are distributed opposite each other, and a first gas supply pipe 6 and a second gas supply pipe 7 are respectively installed on the two fixing positions 5. The ends of the first gas supply pipe 6 and the second gas supply pipe 7 that are close to each other are inclined towards the middle of the second spray gun tube 4. In the prior art, the material sprayed from the second spray gun tube 4 is radial and forms a radial material spray area 201. However, in this invention, the first gas supply pipe 6 and the second gas supply pipe 7 are respectively connected to mechanisms for supplying argon and hydrogen. A ring is provided on the inner wall of the second spray gun tube 4. In groove 17, when the material is sprayed through the annular groove 17, a rotational force is generated. As the material is sprayed from the second spray gun tube 4, the material will preferentially be transferred along the material spray spiral trajectory 202. Then, under the effect of the argon and hydrogen sprayed from the first gas supply pipe 6 and the second gas supply pipe 7 reducing the outward diffusion tendency of the material, a flat material spray area 203 will be formed during the process of the material being sprayed onto the surface of the part to be coated 25. The sprayed area forms a single spray strip area 205 on the surface of the part to be coated 25. Compared with the single spray circular area 204 formed on the surface of the part to be coated 25 in the prior art, the material distribution is more uniform.

[0028] The specific dimensions of the annular groove 17 can be designed according to actual needs. For example, the depth of the annular groove 17 can be designed to be 0.8-2.5mm, and the width can be designed to be 1.5-4mm. The central axis of the annular groove 17 is arranged coaxially with the central axis of the second spray gun tube 4, and the axial distance between the annular groove 17 and the outlet end face of the second spray gun tube 4 is 1 / 5-1 / 3 of the total length of the second spray gun tube 4. The annular groove 17 is a circumferentially continuous groove, which breaks the smooth constraint of the inner wall of the second spray gun tube 4. When the material and powder pass through the annular groove 17, a local low-pressure vortex zone is formed in the groove. The airflow continuously circulates along the circumference of the groove, applying a circumferential rotational torque to the material and generating sufficient swirling intensity; ensuring that the sprayed material obtains sufficient rotational force.

[0029] refer to Figure 11 As shown, when the material is sprayed radially onto the surface of the part to be coated 25 in the prior art, the amount of material distributed in the single-spray circular area 204 gradually increases from the center of the single-spray circular area 204 to the outer circle, and the amount is uneven.

[0030] refer to Figure 12 As shown in the figure, in this invention, the radial material spraying area 201 in the prior art is restricted to a flat material spraying area 203, and the single spraying strip area 205 sprayed on the surface of the workpiece 25 is square and the material is evenly distributed.

[0031] refer to Figure 13 and Figure 14 As shown, Figure 13 This is a schematic diagram showing the material covering the surface of the workpiece 25 after being sprayed a certain length by a spray gun in a plasma thermal spraying device in the prior art (used in this invention). Figure 11 The single-spray circular area 204 formed in the middle is copied and moved to the right, which can fully reflect the final amount of material on the surface of the part to be sprayed 25). Figure 14 This is a schematic diagram showing the material covering the surface of the workpiece 25 after being sprayed a certain length by the spray gun of the plasma thermal spraying equipment of the present invention (used in the present invention). Figure 12 The single-spray strip area 205 formed in the process is copied and moved to the right, which can fully reflect the final amount of material on the surface of the part to be sprayed 25.

[0032] refer to Figure 15 and Figure 16 As shown, Figure 13 and Figure 14 The schematic diagram shows the final sprayed layer after the outlines of the single-spray circular area 204 and the single-spray elongated area 205 are removed. The density of the dots in this sprayed layer is positively correlated with the amount of material. Figure 15 As can be seen, the coating layer formed by the spray gun in the existing plasma thermal spraying equipment is difficult to maintain a smooth edge, and the material distribution is uneven, with a significantly higher material content in the central area of ​​the coating layer; while... Figure 16As can be seen, the coating layer formed by the plasma thermal spraying equipment of this invention maintains a smooth edge and has a uniform material distribution; it is particularly suitable for preparing high-performance coatings and can meet the needs of various industries for strengthening, repairing, or performing special functions on substrate surfaces, such as: 1. Applied in the aerospace field, it is used for components such as engine blades, turbine disks, and combustion chambers to prepare thermal barrier coatings, wear-resistant coatings, and anti-corrosion coatings, thereby improving the high temperature resistance, wear resistance, and resistance to gas corrosion of the components and extending their service life; 2. In the field of mechanical manufacturing and processing, it is used to adapt to machine tool spindles, cutting tools, molds, gears, bearings, etc., to spray wear-resistant, friction-reducing, and anti-galling coatings, reduce component wear, improve processing accuracy and equipment service life, and can also be used for the repair of waste parts, such as crankshafts and cylinder blocks; 3. In the petrochemical industry, it is used in equipment such as pipelines, valves, pumps, and heat exchangers to prepare anti-corrosion, wear-resistant, and anti-scaling coatings, resisting the erosion of acid, alkali, high temperature and high pressure media, reducing equipment wear, and ensuring production safety; 4. In the metallurgical field, it is used for spraying high-temperature resistant, wear-resistant, and impact-resistant coatings on rolling mill rolls, blast furnace tuyeres, steelmaking converter linings, etc., to improve the wear resistance of metallurgical equipment and reduce the frequency of downtime maintenance. 5. In the power sector, it is used to prepare anti-corrosion, wear-resistant, and high-temperature resistant coatings for boiler water-cooled walls, turbine blades, and transmission line fittings, to cope with the erosion of high-temperature flue gas and humid environments, and to ensure the stable operation of power equipment; 6. In the automotive industry, it is used to spray wear-resistant, heat-resistant, and friction-reducing coatings on engine pistons, cylinder walls, brake discs, and other parts to improve the performance of the parts and reduce energy consumption and wear; 7. In the medical field, it is used for artificial joints, orthopedic implants, etc., to spray biocompatible coatings (such as hydroxyapatite coatings) to improve the integration of implants with human tissues and reduce rejection reactions; 8. In other fields, it can also be applied to mold repair, hardware tool strengthening, ceramic product surface modification, nuclear industry equipment protection and other scenarios.

[0033] It should be noted that the materials used for spraying need to be compatible with the heating characteristics of high-temperature plasma (around 20,000K) to deposit into a coating in a molten or semi-molten state. Different materials are selected mainly based on actual needs, such as: metals and alloys (using copper, aluminum, zinc, nickel, chromium, nickel-based alloys, cobalt-based alloys, and iron-based alloys, etc., for wear resistance, corrosion resistance, and conductivity); ceramics (using oxide ceramics, carbide ceramics, and nitride ceramics, etc., for making high-temperature resistant, heat-insulating, wear-resistant, and insulating layers); cermets (using metal and ceramic composites to combine the toughness of metals and the wear resistance of ceramics) or other special materials (such as carbon fiber reinforced ceramics, metal matrix composites, used for high-end aerospace components to improve the overall performance of the coating; hydroxyapatite, bioglass, etc., used for biocompatible coatings for medical implants; graphite-based composites, used for sealing components of aero-engines to improve sealing performance).

[0034] refer to Figure 1 As shown, a spray gun used in a plasma thermal spraying device in the prior art generally includes a spray gun housing 301, a spray gun inner housing 302, and an electrode 12. Both the spray gun housing 301 and the spray gun inner housing 302 have a conical structure. An air supply area 304 needs to be reserved between the spray gun housing 301 and the spray gun inner housing 302. The electrode 12 is installed in the middle of the spray gun inner housing 302. A material supply area 303 is reserved between the electrode 12 and the spray gun inner housing 302. Each nozzle 306 is located at its bottom. Material is fed into the feeding zone 303 using powder-feeding gas and then enters the end of the electrode 12, where it is ignited by the electrode 12 to generate a plasma flame. The gas supply zone 304 is used to transport a mixed gas 305, which includes argon and hydrogen. This mixed gas 305 is supplied to the area where the plasma flame is generated, replenishing the consumed argon and hydrogen and increasing the temperature and enthalpy of the plasma arc. However, the shortcomings of existing plasma thermal spraying equipment spray guns are: First: The interior of the spray gun housing 301 needs to be equipped with a smooth and uniform air supply zone 304, which is difficult to produce and has a complex structure. Second: Since the gas supply zone 304 is directly connected to the area where the plasma flame is generated, if the unstable plasma flame brings air into the gas supply zone 304, the hydrogen content in the mixed gas 305 is between 5-15%, and the combustion pressure in the small space increases instantaneously, which can easily lead to an explosion risk. Third: The sprayed material is distributed radially, with the amount of material gradually increasing from the center point outwards, resulting in uneven material distribution on the coating surface after spraying.

[0035] As an advantage of the present invention, it effectively solves the defects of spray guns used in plasma thermal spraying equipment in the prior art: First: In this invention, a detachable first gas supply pipe 6 and a second gas supply pipe 7 are provided outside the second spray gun pipe 4. The first gas supply pipe 6 and the second gas supply pipe 7 respectively supply argon and hydrogen required for plasma flame consumption, which replaces the method of setting up a gas supply zone 304 to transport argon and hydrogen in the prior art. The structure is simple and easy to produce. Second: Argon and hydrogen are directly supplied to both sides of the plasma flame and connected to the atmospheric environment, eliminating the need for combustion in a small space and thus eliminating the risk of explosion; Third: Argon and hydrogen are supplied to both sides of the plasma flame, which suppresses the tendency of radial spraying and makes the material spray in a flat shape. The material sprayed on the surface of the part to be coated 25 forms a single spray strip area 205, and the material is evenly distributed in the single spray strip area 205.

[0036] In this invention, the total operating current range of electrode 12 is 250-750A, the argon flow rate range is 25 to 100L / min (57-228SCFH), the hydrogen flow rate range is 0-19L / min (0-44SCFH), the total gas flow rate (argon + hydrogen) shall not be less than 35L / min (80SCFH), and when the argon flow rate is less than 35L / min (80SCFH), the arc current shall be limited to 600A, and the ratio of hydrogen to argon shall not exceed 1:3.

[0037] Similarly, argon can be replaced with nitrogen or helium; the appropriate gas can be selected based on the actual needs. Coolant requirements: Inlet temperature (minimum 10°C - maximum 25°C), outlet temperature (maximum 50°C); Inlet pressure (minimum 11-maximum 15 bar), pressure loss (11 L / min); Water flow rate (minimum 10-maximum 15 L / min).

[0038] refer to Figure 2 , Figure 4 , Figure 5 and Figure 7 As shown, as a further improvement of the present invention, a cooling chamber 16 is provided inside the first spray gun tube 3. The cooling chamber 16 has an annular chamber structure. A partition 22 is provided in the cooling chamber 16. A first circulation hole 23 and a second circulation hole 24 are respectively provided on both sides of the partition 22. Two circulation cooling holes 11 are provided on the side of the spray gun tube seat 2. A cooling channel is provided inside the spray gun tube seat 2. The cooling channel connects the circulation cooling holes 11 with the corresponding first circulation holes 23 and second circulation holes 24. When a cooling mechanism is connected to the two circulation cooling holes 11, coolant can be introduced into the cooling chamber 16 to achieve the cooling purpose and maintain the nozzle life and arc column stability.

[0039] It should be noted that the cooling mechanism is connected to a cooling box that cools the coolant via a pressure pump, pipes, a tank for storing coolant, and a cooling system. Typically, the pressure pump is connected between one of the circulating cooling holes 11 and the tank for storing coolant, and the other circulating cooling hole 11 is connected to the cooling box. The outlet of the cooling box is connected to the tank for storing coolant. All components are connected by pipes. When the cooling mechanism is started, the pressure pump delivers the coolant from the tank into the cooling chamber 16 through the circulating cooling hole 11, the cooling channel, and the first circulating hole 23. The coolant in the cooling chamber 16 absorbs heat through the inner wall of the first spray gun pipe 3, controlling the temperature of the spray gun used in the plasma thermal spraying equipment to prevent it from getting too high. After absorbing heat, the coolant is delivered to the cooling box through the second circulating hole 24, the cooling channel, and the other circulating cooling hole 11. After being cooled by the cooling box, the coolant is then supplied to the tank for circulation.

[0040] The coolant used is propylene glycol-based dielectric coolant, high-purity deionized water, fluorinated liquid, or ultra-low conductivity ethylene glycol / propylene glycol liquid, which is suitable for cooling plasma spray nozzles.

[0041] refer to Figure 5 and Figure 6 As shown, furthermore, a one-way valve assembly is provided in both the first gas supply pipe 6 and the second gas supply pipe 7. This one-way valve assembly can provide a one-way flow channel for argon and hydrogen, preventing the plasma flame and air from being transmitted into the first gas supply pipe 6 and the second gas supply pipe 7 and causing an explosion in the confined space.

[0042] In this invention, the one-way valve assembly includes a rotating plate 19, a rotating shaft 20, and a baffle 21. The first air supply pipe 6 and the second air supply pipe 7 are both cylindrical structures, the rotating plate 19 is a cylindrical plate structure, and the middle part of the rotating plate 19 is rotatably connected to the inner wall of the corresponding first air supply pipe 6 and second air supply pipe 7 through the rotating shaft 20. The baffle 21 is fixedly connected to the upper inner wall of the first air supply pipe 6 and the second air supply pipe 7, and the baffle 21 is movably attached to the side of the rotating plate 19 near the outlet of the first air supply pipe 6 and the second air supply pipe 7.

[0043] During operation, when the first gas supply pipe 6 supplies argon gas into the second spray gun pipe 4, the gas pushes the rotating plate 19. Because the upper end of the rotating plate 19 is blocked by the baffle 21, the lower end of the rotating plate 19 can only open outwards around the rotating shaft 20, allowing the gas to escape smoothly. However, when plasma flame and air enter the first gas supply pipe 6 in the opposite direction, they push the side of the rotating plate 19 closer to the baffle 21. Because the upper end of the rotating plate 19 is blocked by the baffle 21, the force-bearing area of ​​the upper half of the rotating plate 19 is smaller than that of the lower half, causing the upper end of the rotating plate 19 to tend to rotate outwards. However, after being blocked by the baffle 21, the upper end of the rotating plate 19 cannot rotate outwards, thus achieving the self-closing of the first gas supply pipe 6. The dynamic seal prevents the backflow of plasma flame and air. Compared with the one-way valve assembly in the prior art, the one-way valve assembly in this invention, through the combination of baffle 21 and rotating plate 19, can effectively maintain sufficient gas flow space without changing the pipe diameter. It does not require an additional increase in the diameter of the first gas supply pipe 6 due to matching the one-way valve assembly in the prior art. When the one-way valve assembly fails, plasma flame and air are not easy to enter or enter the small space in a limited way, avoiding the risk of explosion or reducing the power of the explosion. It replaces the traditional technology that requires an additional increase in the diameter of the first gas supply pipe 6 to match the one-way valve assembly, which results in a relatively large explosion power due to the mixing of plasma flame and air in a larger space.

[0044] Furthermore, the one-way valve assembly in this invention does not require the use of components that are not easily heated, such as springs, making it particularly suitable for use in spray guns for plasma thermal spraying equipment.

[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A spray gun for a plasma thermal spraying device, characterized in that: It includes a spray gun holder (1), a spray gun tube holder (2), a first spray gun tube (3), and a second spray gun tube (4); The spray gun holder (1), spray gun tube holder (2), first spray gun tube (3) and second spray gun tube (4) are connected in sequence. The first spray gun tube (3) is provided with an electrode (12), which is installed on the spray gun tube holder (2). The spray gun tube seat (2) is integrally provided with a feeding position (8) on its side. The feeding position (8) is provided with a feeding connector (9) on the side away from the first spray gun tube (3). The spray gun tube seat (2) is provided with a feeding channel (18) inside. One end of the feeding channel (18) is connected to the feeding connector (9), and the other end is connected to a plurality of feeding holes (13). The plurality of feeding holes (13) are radially distributed along the axis of the electrode (12), and the end away from the feeding channel (18) is connected to the interior of the first spray gun tube (3). The second spray gun tube (4) has two opposing fixed positions (5) on the side away from the first spray gun tube (3). The first air supply tube (6) and the second air supply tube (7) are respectively installed on the two fixed positions (5). The ends of the first air supply tube (6) and the second air supply tube (7) that are close to each other are inclined towards the middle of the second spray gun tube (4). The inner wall of the second spray gun tube (4) is provided with an annular groove (17). The first air supply pipe (6) and the second air supply pipe (7) are each equipped with a one-way valve assembly, which allows gas to enter the first spray gun pipe (3) in one direction. The one-way valve assembly includes a rotating plate (19), a rotating shaft (20), and a baffle (21). The first air supply pipe (6) and the second air supply pipe (7) are both cylindrical structures. The rotating plate (19) is a cylindrical plate structure, and its middle part is rotatably connected to the inner wall of the corresponding air supply pipe through the rotating shaft (20). The baffle (21) is fixedly connected to the upper inner wall of the air supply pipe and is movably attached to the side of the rotating plate (19) near the outlet of the air supply pipe.

2. The spray gun for a plasma thermal spraying equipment according to claim 1, characterized in that: The first gas supply pipe (6) is used to supply argon gas, and the second gas supply pipe (7) is used to supply hydrogen gas.

3. The spray gun for a plasma thermal spraying equipment according to claim 1, characterized in that: The first spray gun tube (3) has a cooling chamber (16) with an annular chamber structure inside. Coolant is introduced into the cooling chamber (16). A partition (22) is provided inside the cooling chamber (16). A first circulation hole (23) and a second circulation hole (24) are provided on both sides of the partition (22). Two circulating cooling holes (11) are provided on the side of the spray gun tube seat (2). A cooling channel is provided inside the hole. The cooling channel connects the circulating cooling hole (11) with the corresponding first circulation hole (23) and second circulation hole (24).

4. The spray gun for a plasma thermal spraying equipment according to claim 1, characterized in that: The powder gas transported by the feeding channel (18) is argon gas, and the powder gas carries the spraying material into the feeding hole (13).

5. The spray gun for a plasma thermal spraying equipment according to claim 1, characterized in that: The spray gun holder (1) is made of insulating material. The spray gun tube holder (2) is installed at the end of the spray gun holder (1). The first spray gun tube (3) is installed on the side of the spray gun tube holder (2) away from the spray gun holder (1). The second spray gun tube (4) is installed on the side of the first spray gun tube (3) away from the spray gun tube holder (2). Both the first spray gun tube (3) and the second spray gun tube (4) are in the form of a ring.

6. The spray gun for a plasma thermal spraying equipment according to claim 1, characterized in that: The spray gun tube seat (2) has an annular protrusion on the side away from the spray gun seat (1). The annular protrusion is engaged with the first spray gun tube (3), and the two are connected by a second threaded ring (15) through a threaded connection. The first spray gun tube (3) is engaged with the second spray gun tube (4), and the two are connected by a first threaded ring (14) through a threaded connection.

7. The spray gun for a plasma thermal spraying equipment according to claim 1, characterized in that: The spray gun tube seat (2) has two electrical connection holes (10) on its side, and a wiring channel is provided inside. A high-temperature resistant wire is installed in the wiring channel and is connected to the electrode (12). A conductive contact is provided at the bottom of the electrical connection hole (10) and is electrically connected to the high-temperature resistant wire.

8. The spray gun for a plasma thermal spraying equipment according to claim 2, characterized in that: The argon gas is replaced with nitrogen or helium.

9. A spray gun for a plasma thermal spraying equipment according to claim 3, characterized in that: The coolant is selected from one of propylene glycol-based dielectric coolant, high-purity deionized water, or fluorinated liquid.

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