JPH0766872B2 - Plasma generator having modular cathodes - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma device for generating a supersonic plasma jet, and more particularly to a plasma generator having a plurality of cathodes and a common anode. It is a thing.

[Conventional technology]

As a plasma device for generating a supersonic plasma jet, “Method and Apparatus for Effecting High-Energy” of US Pat. No. 3,839,618 (issued October 1, 1974).
As seen in "Dynamic Coating of Substrates", a plasma jet is obtained by flowing an inert gas between the electrodes.
This plasma jet forms a transfer arc at an appropriate distance between the plasma generator (plasma gun) and the target object, and heats the target object or feeds the powder raw material into the gun to form a film on the target object. Used to form. Further, the gun and the object are used in a chamber whose pressure is reduced by a vacuum pump or the like, and the plasma jet becomes a supersonic flow under the reduced pressure, and various applications have been tried by this supersonic plasma generator.

Furthermore, US Pat. No. 4,328,257 (published May 4, 1982)
As shown in "System and Method for Plasma Coating", the plasma gun and the target are housed in a vacuum chamber, and a DC power source is electrically connected between the target and the target so that the plasma gun can perform various movements. Is equipped with a movement mechanism. Raw material powder such as metal is charged into a plasma gun and sprayed onto an object to form a film. Further, since these processes are performed under reduced pressure, filters, heat exchangers, vacuum pumps, etc. are attached to the vacuum chamber. However, the plasma gun in this case is composed of a pair of conventional anode and cathode.

The DC power supply connecting the plasma gun and the object described above can switch the polarity of the plasma gun and the object depending on the case.

As an example of having a common anode with two or more anodes, Japanese Patent Publication No. Sho 51
-7556 "Plasma gun" and JP-A-61-230300 "Plasma arc torch" can be seen. All of them are designed to operate in the air atmosphere, and are not designed to generate supersonic plasma under the reduced pressure as described above. Having multiple cathodes complicates the construction of the gun and makes it very difficult to optimize operating conditions.

[Problems to be Solved by the Invention]

In thermal spraying in which a raw material powder such as metal is charged using a plasma generator to form a coating, a pair of conventional anodes,
When the cathode is used, the raw material powder is structurally introduced from the side with respect to the plasma jet flow, and it is an important issue to efficiently introduce the raw material powder into the high temperature and high flow velocity part of the plasma jet center. there were. This is because there are particles that are repelled by or penetrate the plasma jet due to the particle size of the raw material powder and the difference in specific gravity.

Further, in the method in which a plurality of cathodes are provided and the raw material powder is introduced from the center of the anode in the direction of the plasma jet axis, the structure of the plasma generator becomes complicated, and it takes time to replace the cathode, anode, etc. when they are worn. Further, it has been difficult to secure a sufficient heat transfer area of the water cooling pipe for cooling the electrodes.

Furthermore, when the raw material powder is added, the anode space (arc chamber)
There is a problem that the molten powder scattered to the surface adheres, and there is a technical problem that it is difficult to optimize stable plasma operating conditions for a long time.

[Means for Solving the Problems]

In order to solve the problems described in the preceding paragraph, in the present invention, the plasma gun and the object are operated in a reduced pressure atmosphere in a vacuum chamber, and a stable operation using a supersonic plasma jet is carried out. In addition, the plurality of cathodes are divided into modules, respectively, and are individually removed so that they can be easily disassembled. Therefore, by replacing each of the modularized cathodes, the inflow angle of the plasma to the anode, the discharge distance (arc gap), and the shape of the cathode tip can be adjusted, and the degree of freedom in controlling the plasma operating conditions is improved.

Next, the anode is formed into a nozzle shape in accordance with the outlet from the central space (arc chamber) so that a stable supersonic plasma jet can be obtained under reduced pressure. Feeding of the raw material powder from above the arc chamber is performed via a sleeve-shaped component (powder feeding pipe). By changing the sleeve, the diameter of the feeding pipe is selected, and the feeding pattern of the raw material powder into the arc chamber is determined. You can control. Further, by branching the hole near the outlet of the charging pipe and directing the outlet direction of each branch hole to the direction of each cathode, the raw material powder is further charged into the high temperature part of the plasma jet. Can be easily melted to form a dense film.

As described above, the problem of adhesion of the raw material powder in the arc chamber is that the modularized cathode, powder charging tube, and anode are individually removed for easy disassembly and maintainability. Is greatly improved, and the degree of freedom in selecting these is also improved. Therefore, it is possible to select a combination and an operating condition that can avoid adhesion in the arc chamber.

Each cathode, cooling the high heat load part of the anode greatly affects the life of the device, but in the present invention, a cooling water system for cooling each cathode,
It has a separate cooling water system for cooling the anode to form a water cooling structure that ensures sufficient cooling. Especially for the anode, multiple cooling water holes penetrate between each cathode part from the bottom to the top, and at the top of the anode, the cooling water is swirled with a special clamp designed to surround the powder injection pipe, and the anode top is efficiently Has a structure for cooling. As a result, compared with the conventional plasma generator, each cathode and anode can independently control the output, and the total output can be easily increased, which is a plasma generator capable of stable and high output.

〔Example〕

The features of the present invention will be specifically described with reference to examples in FIGS. 1 to 33.

FIG. 1 shows a plasma system according to the present invention.
The plasma system includes a vacuum chamber 10 which is sealed to maintain a vacuum and serves as a pressure-resistant insulating container. This vacuum chamber 10 is constructed by a cylindrical main body portion 12 and an upper lid 13 connected to it. A cylindrical portion 12 which is a part of the vacuum chamber 10 is a lower collector which is guided to and connected to a device for treating gas and particles in the vacuum chamber 10 and maintaining an arbitrary atmospheric pressure. It includes a conical lid 14.

The downward plasma spray is formed by a plasma gun 16 mounted inside the upper lid 13, and the position of the plasma gun 16 is controlled by a plasma gun operating mechanism 18. Each of the vacuum chambers 10 is configured as a double-walled cooling structure, and the upper lid 13 has a structure that can be removed to handle the internal operating device. The plasma gun operating mechanism 18 supports and controls the plasma gun 16 through bearings and connections sealed within the wall of the top lid 13.

The powder supply mechanism, which is also connected to the upper lid 13, has a function of controlling and introducing heated powder into the plasma spray through a flexible tube connected to the plasma gun 16.

The downward plasma stream impinges on a processing component 24 which is supported by an internally cooled conductor processing component holder 25. Further, the processing component holder 25 is aligned and moved during operation by a shaft that extends through the vacuum chamber 10 to an external processing component operating mechanism 26. A dummy processing component or dummy sting 28 is disposed in the vicinity of one end of the processing component 24 and separately from the processing component 24. The dummy sting 28 is also internally water-cooled and the dummy sting operation mechanism is passed through the side wall of the vacuum chamber 10. 30
Are linked to. The processing part holder 25 and the dummy swing 28 can be adjusted to the insertion position with respect to the central axis of the vacuum chamber 10, and since they are composed of an electric conductor, they are selected for the transition arc generation in various operating conditions. Can be kept on electricity.

Processing part 24 and lower collector cone lid 14 for dummy swing
Is connected to a baffle filter module 32 for introducing overspray (non-adhered particles and gases), which baffle filter module 32 is used for cooling the overspray and most of the particles introduced. Equipped with a filter to remove. The fluid passing through the baffle filter module 32 passes through a heat exchanger 36 equipped with a cooling device and a vacuum equipped with an overspray recovery filter 40 which removes substantially all particles remaining in the fluid. It flows into the manifold 38. The vacuum manifold 38 is connected to a vacuum pump 42 having sufficient capacity to maintain the atmospheric pressure in the vacuum chamber 10 at a predetermined pressure. Usually, the atmospheric pressure is 0.6 atm to 0.001 atm. The baffle filter module 32 and the heat exchanger 36 preferably have a double wall cooling structure like the filter for recovering the overspray, but those of the type used in a normal plasma apparatus can also be used. The whole system is easy to operate and can be installed on rollers and moved on rails so that a system with one part can be used. The insulated field through plate, which makes the electrical connection with the normal sight glass and the water cooled operating door, is not shown. Processing component retention and motion control devices are mounted on the vacuum chamber 10 and hinged door 43.

Electrical energy is supplied to the operating part of the device through a fixed bus bar 44 attached to the top of the top lid 13. Flexible water cooling cable, external plasma power 46
And a high frequency power source 48 are connected to a plasma gun 16 for generating a plasma jet through a bus bar 44. The external plasma power supply 46 produces the required potential difference between the electrodes of the plasma gun 16 and between the plasma gun 16 and the processing component 24. High frequency power 48
As is well known, is used to perform initial ignition of a transfer type plasma arc by superposing a high frequency voltage on a DC voltage of a plasma power source. The variable polarity transfer arc power supply 50 is connected to the plasma gun 16, the processing component holder 25 and the dummy sting 28 through the bus bar 44. Muehlberger et al. U.S. Pat. No. 4, mentioned at the beginning
The variable polarity transfer arc power supply 50 can also generate a reverse polarity transfer plasma arc between the plasma gun 16 and the processing component 24, as described in 328257.

For the operation of the plasma gun 16, a cooling water booster pump 52 for creating a proper flow of cooling water flowing inside the plasma gun 16 as described later is used. The plasma gas source 54 supplies a suitable ionized gas for generating a plasma jet. The plasma gas used here is argon alone or argon gas containing helium or hydrogen, but other gases known to those skilled in the art can also be used.

A series of controls for the system of FIG. 1 and the speed and amplitude of various operating mechanisms are coordinated by a system control console 56.
The plasma gun 16 is operated separately under the control of the plasma control console 58. The functions performed by these consoles and the circuits contained therein are easily understood and are not shown here and will not be described in detail. The transition arc control circuit 60 controls to switch the polarity of the transition arc.

With the exception of the plasma gun 16 which uses a split cathode, the remainder of FIG. 1 is essentially the same as the plasma system described in US Pat. No. 4,328,257 to Muehlberger et al.

FIG. 2 shows the plasma gun 16 of FIG. The plasma gun 16 has an anode equipped with a powder charging device as will be described later and a cooling device built-in.
Contains 70. The powder or other material to be sprayed is introduced into the plasma gun 16 through a powder introduction tube 72 that passes through an anode stop plate 74 on top of the gun body 70.

The cooling water booster pump 52 is connected to the gun body 70 of the plasma gun 16 and supplies cooling water to the anode cooling system in the gun body 70.

The water-cooled booster pump 52 is connected to the plasma gun 16 by two pipes out of a plurality of pipes that emerge from the upper part thereof. These two tubes are connectors 76,7 attached to the anode stop plate 74.
Supply cooling water by 8. The cooling water that has passed through the anode cooling system is returned to the cooling water booster pump 52 by two pipes out of a plurality of return views coming out from the lower portion of the cooling water booster pump 52. These two return pipes are connected to connectors 80, 82 mounted on the anode stop plate 74. The anode and its cooling system will be described in detail below in FIG. Plasma gun
Attached to 16 are three separate cathode assemblies, which are described in detail below in FIGS. Individual cathode assembly
84,86,88 are usually cylindrical in shape, and the axis 90 of the cathode assembly is inclined about 45 ° with respect to the central axis 92 of the gun body 70 and is mounted so as to penetrate the outer wall of the gun body 70. To be These three cathode assemblies 84,86,88 are typically evenly concentrically arranged about the gun body 70 about every 120 °. The cathode assembly 81 receives the cooling water from the cooling water booster pump 52 of FIG. 1 through the supply pipe 93 which is one of the cooling water supply pipes 75. Similarly, the cathode assemblies 86 and 88 are supplied with cooling water by supply tubes 94 and 95, respectively. The cooling water supplied to the cathode assemblies 84, 86, 88 by the supply pipes 93, 94, 95 passes through the internal cooling system of the cathode assembly described in detail in FIG. It is ejected from the cathode assembly by the connector 96.

Each cooling water connector 96 is connected to the cooling water booster pump 52 via any one of the cooling water return pipes 79. Another connector 96 attached to each side of the cathode assemblies 84, 86, 88 is connected to the plasma gas source 54 in FIG. 1 by a pipe (not shown) to connect the plasma gas to the cathode assembly. Supply. The plasma gun 16 is shown in FIG. 2 as being composed of three cathode assemblies 84,86,88, which will be described below for ease of understanding of the drawings and, of course, the present invention. In principle, it is possible to have more than three cathode assemblies, and the angle of the cathode assembly axis 90 with respect to the central axis 92 of the gun body 70 may be other than 45 °.

As shown in FIG. 2, the external plasma power supply 46 is composed of three separate plasma power supplies 99A, 99B, 99C, which are connected to cathode assemblies 84, 86, 88, respectively. Each of the plasma power supplies 99A, 99B, and 99C has its own DC power supply, the anode terminal of which is connected to the anode inside the gun body 70, and the cathode terminals of which are corresponding cathode assemblies.
Connected to 84,86,88. Plasma power supplies 99A, 99B, 99C can be independently power regulated, thus cathode assembly 84,8
The power supplied to 6,88 can be changed independently. As shown in FIG. 2, a variable polarity transfer arc power supply 50 is connected between the anode in the gun body 70 and the processing component 24. Although not shown in FIG. 2, a high frequency power supply 48 is connected to the cathode assemblies 84,86,88, preferably one to each cathode assembly 84,86,88, to provide a plasma power supply 99A, 99B, A plasma transfer arc is initially generated by superimposing a high-frequency potential on 99C.

FIG. 3 is a partial cross-sectional view of the gun body 70, also showing a portion of the cathode assembly 84 of the plasma gun 16. The cathode assemblies 86,88 have been omitted for simplicity of illustration.

As shown in FIG. 3, the gun body 70 has a substantially cylindrical shape, and at the center thereof, there is a cylindrical inner hole 100, which penetrates from the top surface 102 to the bottom surface 104 of the gun body 70. The anode assembly 106 is attached to the lower portion of the inner hole 100. The anode assembly 106 is fixed to the lower end of the inner hole 100 by an anode holder 108 attached to the bottom surface 104 of the gun body 70. The anode holder 108 is described in detail below in FIG.

The anode connection plug 110 constitutes a part of the powder supply component attached to the upper portion of the inner hole 100. Anode connection plug 110
Extends upwardly from the top surface of the anode assembly 106,
It is fitted into a hole 112 formed in the center of the anode connecting plate on the upper surface 102 of the gun body 70. A flange 114 is provided at the lower end of the anode connecting plug 110, and this flange 114 also has an inner hole 10.
It extends to the inner surface 116 of 0. The anode connecting plug 110 has a substantially cylindrical hole 118, and the powder supply pipe holder 120 is mounted in this hole. The powder supply tube holder 120 is threaded at the top and is fixed by the screw at the upper end of the anode connection plug 110. Also, powder supply pipe holder
120 is provided with a cylindrical hole 122 therein,
A powder introduction tube 72 is attached to the hole. As described above, the powder introduction pipe 72 plays a role of guiding the metal powder and other thermal spray material from the powder supply device 20 shown in FIG. 1 to the plasma jet. Metal powder or other thermal spray material is delivered under pressure through the powder inlet tube 72 into the plasma gun 16. As shown in FIG. 3, powder introduction tube
The tip of 72 is connected to the powder introduction port 124, and is arranged inside the cylindrical hole 118 provided in the anode connection plug 110. The clamp 126, which is inserted into the top 128 of the anode assembly 106, is described in detail below in FIGS.
Reference numeral 32 denotes a hollow, substantially cylindrical shape, which is attached to a lower portion of a cylindrical hole 118 provided in the anode connection plug 110 adjacent to the powder introduction port 124. The lower side of the clamp 126 has a hollow and substantially cylindrical shape, and the top 128 of the anode assembly 106.
Located in.

The powder dosing tube holding part 136, which will be described in detail later with reference to FIG. 15, is connected to the upper portion of the clamp 126 to receive the powder introduction port 124. On the other hand, the lower part of the powder charging pipe holding part 136 extends into the anode assembly 106, and the tip thereof is connected to the cylindrical powder charging pipe 138. The powder introduction pipe 72 has a hole 140 formed therein, and is connected to a central hole 142 provided in the powder introduction port 124 to feed the powder. Further, the center hole 142 is connected to a center hole 144 provided in the powder feeding pipe holding component 136 to feed the powder. As will be described later in detail, the center hole 144 provided in the powder feeding pipe holding component 136 is
The powder is fed to one or more powder feeding ports provided in the powder feeding pipe 138. In FIG. 3, the powder feeding pipe 138 has one
An individual powder charging port 146 is provided, and this powder charging port 146 is connected to a gas mixing chamber 148 formed in the main body 150 of the anode assembly 106.

Gas mixing chamber provided in the body 150 of the anode assembly 106
148 is connected to the nozzle portion 152 and is opened to the outside of the plasma gun 16 at the bottom portion 130 of the anode assembly 106.
The gas mixing chamber 148 is further connected to three arc chambers 154 corresponding to the anode assemblies 84, 86 and 88, respectively. These arc chambers 154 are now the body of the anode assembly 106.
It was made in 150.

FIG. 3 shows the arc chamber 154 corresponding to the anode assembly 84.
One of is drawn.

The gun body 70 is provided with a substantially cylindrical space 156 in which the cathode assembly 84 is fitted. This cylindrical space is shown by the broken line in FIG.
It is 154. Normally, the end of the cylindrical space 156 is connected to the cylindrical hole 158, which further extends into the gun body 70. This hole 158 is shown by a broken line and a solid line in FIG. And further this hole 158
Insulator 160 is fitted into. Insulator 160 has cathode tip 162 mounted therein and is one of the components of cathode assembly 84. The insulator 160 is
It stops in the arc chamber 154, and the cathode tip 162 extends into the arc chamber 154. Although not shown in FIG. 3, cathode assemblies 86 and 88 are similarly attached to plasma gun 16. As will be described later, the cathode assembly 84
Is an inner wall 166 of a cylindrical hole 168 provided in the insulator 160.
It functions as a spiral flow of the inert gas along the gas flow path 164 created by the annular space between the cathode tip part 162 and the cathode tip part 162. Plasma power supply 99A shown in FIG.
Is connected between the cathode tip 162 of the cathode assembly 84 and the body 150 of the anode assembly 106 to apply the required potential difference therebetween. This potential application and further cathode tip parts
By flowing an inert gas around 162, a plasma arc is formed in the arc chamber 154, and as a result, a plasma flow flows through the gas mixing chamber 148 and the nozzle portion 152 and is ejected from the plasma gun 16.

The velocity of the inert gas in the arc chamber 154 is in the subsonic region. As the gas enters the central gas mixing chamber 148, the gas mixes with the powder introduced through the powder dosing tube 138. The gas mixing chamber defines a region in which the velocity of the plasma flow becomes sonic. The mixture of gas and powder is accelerated in the nozzle section 152 which defines the supersonic region of the plasma flow. The plasma flow exiting the nozzle portion 152 is processed by the processing component 24.
1 and the collector cone 14 at the bottom of the vacuum chamber 10 at supersonic speed in accordance with the operation of the vacuum pump 42 shown in FIG.
Get out of. A transition arc is generated between the processing component 24 and the anode assembly 106 by a switchable transition arc power supply 50 shown in FIGS.

Although not shown in FIG. 3, the cathode assemblies 86 and 88 are corresponding arc chambers 15 in the body 150 of the anode assembly 106.
It operates in a similar manner in relation to 4, and the nozzle part 152
A plasma stream may be generated through which the gas flows from the gas mixing chamber 148 and out of the plasma gun.

FIG. 3 shows the anode assembly housed in the gun body 70.
The part 84 is shown by a solid line and a broken line. On the other hand, Fig. 4 shows the gun body.
The portion of the cathode assembly 84 that is external to 70 is shown, and FIG. 5 is a cross-sectional view of the entire cathode assembly 84.

As can be seen in FIG. 4, the cathode assembly 84 is modular and includes a cylindrical body 170 as an extension of the axis 90 of the cathode assembly 84. The split construction of the cathode assembly provides pressure isolation within the cathode assembly and allows the cathode assembly 84 to be removed from the body of the plasma gun 16 as a unitary structure. Cathode assembly
84 is removably mounted in the gun body 70 such that the body 170 of the cathode assembly 84 fits into and is housed in the cylindrical space 156 shown in phantom in FIG. This is the insulation member 160 of the cathode assembly 84.
Is seated in the gun body 70 in a small cylindrical hole 158 so that the cathode tip 162 is set in the correct position in the arc chamber.

As shown in FIG. 4, the body 170 of the cathode assembly 84 protruding outside the gun body 70 has a cooling water connector 96 and a gas connector 98. A supply pipe 96 supplied from the cooling water booster pump 52 shown in FIGS. 1 and 2 extends through an insulating nut 172 fixed to the outer end of the main body 170. Supply pipe 93
Enters the cathode assembly 84 through and the cathode assembly 84
The cooling water flowing through the internal cooling system exits the assembly to the cooling water booster pump 52 through a cooling water connector 96 which is coupled to one of the cooling water return lines 79 as described in connection with FIG. Go. Further, as described above, the inert gas from the plasma gas source 54 shown in FIG. 1 is guided to the gas connector 98.

In the cross-sectional view of cathode assembly 84 shown in FIG.
Insulation nuts screwed into the ends of the cable insulation 174 through screws 176 at the ends of the cable insulation 174 are not shown. Also not shown is the supply tube 93 coupled to the connector 178 located in the cylindrical bore of the cable insulation. The cooling water from the cooling water booster pump 52 is connected to the connector 17 by the supply pipe 93.
8 and its cooling water flow is indicated by arrow 182 in FIG.

The cable insulation 174 forms a part of the body 170 of the cathode assembly 84 with the chamber insulation 160, the cathode connecting piece 184, which is usually made of a cylindrical insulation material, and the annular insulation holder 186. The cathode connecting part 184 made of an insulating material has a threaded portion 188 at the end of the same and is connected to the cable insulator 174 by a screw part. The ring-shaped insulator holder 186 is fixed by the bolt 193 while fixing the chamber insulating material 160 to the ring-shaped space 194 in the cathode connecting part 184 at the other end 192 of the cathode connecting part 184.

The cathode connecting part 184 has a cylindrical shape and has a cylindrical space 196 in which a hollow gas connecting pipe 198 is seated. The gas connector 198 extends from the chamber insulator 160 along a portion of the cylindrical space 196. The remaining portion of the cylindrical bore forms the cathode connecting tube 200. The cathode connecting tube 200 is generally cylindrical, has a stepped profile, and has a longitudinal axis that matches the axis 90 of the cathode assembly 84. The cathode connecting tube extends from the region located at one end 190 of the cathode connecting piece 184 for attaching the cathode tip 162 to the end of the region located at the outer end of the chamber insulator 160. Cathode connecting tube 200 is gas connecting tube 1
The outer diameter is further reduced in a part of 98, the outer diameter is further reduced again in the chamber insulator 160, and a circular space is formed between the inner wall 204 of the gas connecting pipe 198 and the inner wall of the chamber insulator 160. Form. Such an annular space extends along a major portion of the gas connecting tube 198 with a first portion 208 of uniform outer diameter and a first portion 208 extending along most of the length of the chamber insulation 160. The second portion 210 having a uniform outer diameter smaller than the outer diameter of the gas passage forms a gas passage. The cathode connecting tube 200 has an annular edge that extends into the gas passage 206 located at the junction of the first and second portions 208 and 210 of the gas passage 206.

The cathode connecting component 184 has a cylindrical bore 196 and an annular recess that forms an annular gas introduction chamber 216. The annular gas introduction chamber 216 surrounds a portion of the gas connection pipe 198 that is exposed to the outside, and is connected to the gas connection pipe 198 through a plurality of small holes 218.
The other end of 198 is connected to the inlet portion of the gas passage 206. The plurality of small holes 218 are provided in the gas introducing chamber 216 having an annular shape and are connected to the gas connecting pipe 19
One of the plurality of small holes 218 is shown in FIG.

The gas connector 98 attached to the outside of the body 170 of the cathode assembly 84 shown in FIG. 4 connects the pressurized inert gas with the small hole 218 of the gas connector 198 and the annular gas introduction chamber 216. It is used to feed the inlet portion of the gas passage 206. The gas connector 98 not shown in FIG. 5 is an annular gas introduction chamber formed by the gas passage 220 of the cathode connecting part 184.
It is connected to 216. The passage 220 is shown in phantom in FIG. 5 and the gas flow is shown by the dashed arrow 222. Passage 2
The gas flowing through 20 fills an annular gas introduction chamber 216, from which it flows through a small hole 218 into the first portion 208 of the gas passage 206. The gas in the first portion 208 flows to the annular edge 212 of the cathode connecting tube 200, where it is forced in the second portion 210 of the gas passage 206 by the placement of a plurality of perforations 218 in the annular edge 212. A spiral flow pattern is formed.

Details of the toroidal edge 212 are shown in FIGS. 6 and 7 along with FIG. 7, which is a partial cross-sectional view of FIG. As shown in FIG. 6, the ring-shaped edge is a small hole of floating number, which is arranged in a ring shape at an appropriate distance just outside the cathode connecting tube 200.
Has 224. As described above, the connecting tube 200 has a longitudinal axis that coincides with the longitudinal axis of the cathode assembly 84. The plurality of small holes 224 are arranged obliquely with respect to the longitudinal axis 90, which can be seen in FIG. 7 which shows one cross section of the plurality of small holes 224. This small hole provided obliquely to the longitudinal axis 90
Reference numeral 224 denotes a gas passage 20 as a gas passage passing through the annular edge 212.
The gas is forced into a swirl pattern along the second portion 210 of 6.

A swirling flow of inert gas is maintained through the cathode tip 162 and into the arc chamber 154. Such a swirling flow contributes to stabilizing the plasma arc formed in the arc chamber 154.

As shown in FIG. 5, the cathode tip part 162 is arranged at the tip of the cathode connecting tube 200 near the tip of the chamber insulating material 160. The cathode tip part 162 is made of tungsten, copper, or the like, and can be joined to the tip of the cathode connecting tube 200 by a method such as gold brazing, but it is preferably a screw in consideration of easy removal and replacement. It is better to attach by cutting. FIG. 5 shows a cathode connecting tube 200 having a threaded portion 228 to which the cathode tip component 162 can be attached. As described above, the cooling water is supplied from the cooling water booster pump 52 via the supply pipe 93 to the cathode assembly.
Performed at 84. Supply pipe 93 is a threaded piece 17 made of insulating material
2. It passes through the cable insulation 174 and is connected by a connecting part 178. The connecting piece 178 is arranged in the cathode assembly 84 at the end 230 of a generally cylindrical connecting tube 232. The connecting tube 232 is disposed inside the cathode connecting part 184 made of an insulating material, extends into the space 236 inside the cathode connecting tube 200, and is cut at the end of the cathode connecting part 184 made of an insulating material. It is fixed by screws 234. The cathode connecting pipe 232 is connected to a water pipe 238 at the tip portion thereof, whereby cooling water can be supplied to the vicinity 240 of the back surface of the cathode tip component 162.

The cooling water is taken into the inside of the connecting pipe 232 via the supply pipe 93 and the connecting part 178, passes through the inside 244 of the water pipe 238 at the tip of the connecting pipe 232, and the cathode tip in the space inside the cathode connecting pipe 200. Inverted near the back of the component 162, the water pipe 238, the connection pipe 232
Flowing outside. In the figure, the flow of water is indicated by arrow 246. The cooling water flowing outside the connection pipe 232 is guided to the annular space 250 inside the cathode connection pipe 200, and further provided in the drainage space 252 around the cathode connection pipe 200 with an appropriate interval. It flows in via a plurality of small holes 254 provided. One of the stoma 254 is shown in FIG. The drainage space 252 is connected to the cooling water connector 96 shown in FIG. 4, the path 256 to the cooling water connector 96 is shown in broken lines in FIG. 5, and the flow of water is likewise shown in broken arrows 258. ing.

The gas path 220 and the water path 256 used for the cathode connecting part 184 made of an insulating material are shown by broken lines in FIG. 5, but in actuality, the arrangement position is shifted in consideration of maintainability. The gas connector 98 and the cooling water connector 96 are easy to handle.

As described in the description of FIG. 3, the modularized anode assembly 106 has the main body 150, and as shown in FIG. 8, the main body 150 has the central axis 260. When the anode body 150 is attached to the anode assembly 106, the central axis 260 of the body 150 is the anode assembly 106 and also the plasma gun 16 (FIG. 2).
Coincides with the central axis 92 of.

The upper end portion 128 of the anode assembly 106 has a cylindrical space 262, and the inside has a threaded portion 264. Threaded part 2
64 accommodates the insert type clamp 126 shown in FIG. 3 and FIGS. 29 to 31 described later. Below the threaded portion 264, the cylindrical space 262 tapers conically into a circular chamber 266,
The circular chamber 266 has a structure for receiving the lower end portion of the raw material powder feeding pipe holding component 136 shown in FIGS. 3 and 5. Further, the cylindrical small space 268 is the gas mixing chamber 1 of the anode.
The structure extends to the upper end of 48 and fixes the raw material powder feeding pipe 138 shown in FIGS. 3 and 15. The lower end of the anode gas mixing chamber 148 is continuous with the anode nozzle portion 152.

As described above, in this embodiment, the anode assembly 106 has three arc chambers 154, which are equally spaced around the central axis 70 of the gun body. FIG. 8 shows one of the arc chambers. The arc chamber 154 continues to the bottom of an opening 274 in the side of the body 150 of the anode assembly. The opening 174 coincides with the lower end of the cathode insulation 160 when the cathode assembly 84 is incorporated into the body 70 of the plasma gun 16. By doing this the cathode assembly 84
The cathode tip 162 within will be placed in the proper operating position inside the arc chamber 154.

The arc chamber 154 extends along the center line 276 to the gas mixing chamber 148, and has a substantially cylindrical space and a conical space 2 extending to the opening 274.
Formed with 80. The main body 150 of the anode assembly 106 has an annular cutout 282, and is shaped like being surrounded by the bottom 130 of the lower portion of the main body 150.

The cooling water in the anode cooling system flows upward through a plurality of small holes (284 and 286 in FIG. 8) provided between the arc chambers 154 of the main body 150 while being forcibly swirled in the annular notch. Reach space 262.

FIG. 9 is an external view of the anode assembly 106 as viewed from the left side of FIG. 8 because the opening 274 is shown in the center. FIG. 10 is a top view of the anode assembly 106, which is partially cut away so that the opening 274 and the arc chamber 154 that follows it can be seen.
In fact, the anode assembly 106 has two more similar openings.
One is provided for mounting the cathode assemblies 86, 88, but is not shown in FIGS. There is an annular protruding rim 288 at the bottom of the main body 150, and the rim 288 is the main body 15
When mounting the 0 on the gun body 70, the cylindrical inner hole 1 inside the gun body 1
It can be seated in the recess 290 at the lower end of 00 to prevent accurate positioning and upward displacement of the anode body.
The anode holder 108 constitutes the bottom of the gun body 70, and the annular flange 109 attached to the anode holder 108 is in contact with the lower end of the rim 288 as shown in FIG. 3 and holds the anode assembly 106.

FIG. 11 shows an arc chamber 154, a gas mixing chamber 148 of the main body 150,
FIG. 6 is a cross-sectional view showing the positional relationship of nozzle portions 152. As described above, the arc chamber 154 is composed of the conical space 280 that encloses the cathode tip portion 162 and the cylindrical space 278 that is connected to the gas mixing chamber 148. Inert gas is swirling and cathode tip 16
2 around and through the arc chamber 154 the gas mixing chamber
It flows into 148. The arc chamber 154 is the body 15 of the anode assembly.
A discharge space for generating a plasma arc is formed between 0 and the cathode tip 162. The shape of the plasma arc changes depending on the pressure and amount of the swirling flow passing through the arc chamber 154, but the plasma arc passes through the arc chamber 154 from the cathode tip 162 and becomes a gas mixing chamber.
It reaches up to the vicinity of 148. The temperature of the plasma gas in the gas mixing chamber 148 changes depending on the arc reaching point. Further, the swirling flow of the inert gas causes the arc to flow into the cylindrical space 2 of the arc chamber 154.
78, or the effect of not concentrating on one point on the wall of the gas mixing chamber 148 increases the stability of the plasma arc.

Since the anode assembly 106 is modular, it can be easily removed from the plasma gun 16. For this reason, the anode assembly 106 having a different diameter and shape of the arc chamber 154 is used.
By preparing the above, it becomes possible to easily select and replace according to the conditions of the plasma system to be used.

When operating the plasma gun 16, the cathode assembly 8
It is also possible to change the angle of 4,86,88 with respect to the central axis 260 of the anode assembly 106 to some extent. In the example
As shown in FIG. 11, the central axis 276 of the cathode assembly is tilted about 45 ° from the central axis 260 of the anode assembly 106. In the present invention, this angle can be varied from 30 ° to 105 °, but in practice it exceeds 45 °, for example 90 °.
It was confirmed that the raw material powder charged to the inner wall of the gas mixing chamber 148 adheres to the inner wall of the gas mixing chamber 148 at a temperature of about °.

FIG. 11 also shows four different arrangements of the arc chamber 154. Of these, the one shown by the solid line has the widest application range in the embodiment, but other arrangement examples are also effective in another application example.

The arrangement of the cylindrical space portion 278 of the arc chamber 154 as the next embodiment, but as shown in FIG. 11, the position where the conical space portion 280 starts is broken line on the gas mixing chamber side as compared to the previous embodiment. 296,
They are close to each other as indicated by a chain line 302. Along with this, the cathode tip portion 162 is also arranged as shown by a broken line 298 and a chain line 304 in the figure. Further, in the case of the alternate long and short dash line 302, there is also an example in which the shape of the cathode tip portion 162 is thin as shown by the broken line 306.

The gas mixing chamber 148 of the present invention plays a role of introducing the raw material powder from the powder charging port 146 to a state where the plasma gas is below the sonic velocity before being accelerated to supersonic velocity by the nozzle portion 152.
Since the raw material powders having different physical properties have different melting points, it is desirable to change the length of the gas mixing chamber 148 in order to put the plasma gas in an appropriate temperature range. When the gas mixing chamber 148 having an appropriate length is selected, it is possible to prevent unmelted particles and powder from adhering to the gas mixing chamber 148 or the inner wall of the nozzle portion 152. Since the anode assembly 106 is modularized and can be easily replaced, it can be appropriately selected if several kinds of gas mixing chambers 148 having different lengths are held.

The shape of the gas mixing chamber 148 also affects the spray pattern of the charged raw material powder. Usually, the spray pattern has a triangular shape corresponding to the positions of the three anodes.

12, 13 and 14 show the shapes of three different types of gas mixing chambers 148 and the nozzle portion 152 that follows them. Figure 12 shows
It is almost the same as that shown in Fig. 3,8,11 etc.
In FIG. 13, the length of the gas mixing chamber 148 is longer than that in FIG. 12, and the nozzle portion is relatively short. In FIG. 14, the length of the gas mixing chamber 148 is midway between FIGS. 12 and 13, and the nozzle portion 152 is divided into two parts 308 and 310. The upper part 308 of the nozzle spreads at a constant angle from the lower end 272 of the gas mixing chamber to the upper end 312 of the lower part 310 of the nozzle, and the lower part 310 of the nozzle is larger than the upper part 308 of the nozzle at a constant angle to a position matching the lower end of the bottom 130 of the plasma gun. Spread at an angle of.

The powder dosing tube holding part 136 is also shown in FIG. 3, but is shown together with the powder dosing tube 138 in FIG. As shown in FIG. 3, the powder charging tube holding member 136 is the anode assembly 1
Clamp attached to the top of 06 to guide the flow of water
It penetrates through the middle of 126 to the circular chamber 266 of the body 150 of the anode assembly shown in FIG. As shown in FIG. 15, the powder feeding pipe holding part 136 has an annular groove 314 in the upper part, and although it is not shown in the figure, it has a structure for inserting an O-ring and has an upper part of the clamp 126. 132 and seal the cooling water. Similarly, the lower groove 316 also uses an O-ring to seal the cooling water with the circular chamber 266 of the body 150. As shown in FIG. 15, the powder feeding pipe 138 has a threaded portion 318 on the outer periphery of the upper end and is structured to be screwed into the lower end of the holding component 136.

The raw material powder introduced through the powder introduction pipe 72 and the powder introduction port 124 is introduced into the gas mixing chamber 148 of the anode assembly 106 via the center hole of the powder introduction pipe holding part 136. The powder feeding tube 138 can be selected from various shapes as shown in FIGS. 16 to 25.

A major feature of the present invention is that a plurality of cathode assemblies and anode assemblies are modularized as described above,
Although it is easy to remove, the powder feeding pipe 138 is also easy to replace and has a high degree of freedom in shape selection. Therefore, by changing the powder feeding pipe, the powder feeding position into the gas mixing chamber 148 can be changed.

The shape and diameter of the powder charging port can be changed like the material of the powder charging pipe 138. According to the present invention, as will be described later, a powder supply port is provided in each of the three different arc chambers 154. Powder dosing tube with multiple powder dosing ports of various shapes
138 will be described with reference to FIGS. The important point of having a separate replaceable powder dosing tube 138 is:
The angle of the various powder inlets within each arc chamber can be modified to optimize.

16 and 17 show the combination of the powder feeding pipes 138. Here, the case where one powder supply port is provided is shown. As shown in FIG. 16, the powder dosing tube 138 has an upper end 324 on the threading side.
Has a central hole 322 extending along the length of the powder feeding tube 138 from the opposite side to the lower end 320. The central hole 322 extends from the end surface 324 on the threaded side along the length direction of the powder feeding pipe 138 to the intermediate portion 326. Further, one powder charging port 328 is formed from the portion 326 to the lower end surface 320 along the length direction of the powder charging pipe 138. The end of the powder charging port 328 is made up of a conical shaped portion 330. Powder charging port 3
28, including the conical portion 330, is provided coaxially with the central axis 332 of the powder feeding pipe 138. When the powder charging tube 138 shown in FIGS. 16 and 17 is mounted inside the anode assembly 106 as in the central hole 322, the central axis 332 coincides with the central axis 260 of the main body 150 and the central axis 92 of the main body 70 of the plasma gun 16. To do. Powder input tube 13
Since the lower end surface 320 of 8 continues to the first end surface 270 of the gas mixing chamber 148, the powder fed to the central hole 322 of the powder feeding pipe 138 is gas along the central axis of the gas mixing chamber 148. Mixing chamber 1
It is thrown into 48. As best shown in FIG. 17, the lower end 320 of the powder dosing tube 138 has rounded recessed grooves 334 equally spaced around it.

In the plasma gun having the cathode divided into the above modules, good results are obtained when the powders are separately supplied to the individual arc chambers 154 by the plurality of powder charging ports.
18 and 19 show the structure of the powder feeding pipe 138 having the powder feeding ports 336, 338 and 340 divided into three parts. These three powder input ports 3
36,338,340 are shown in FIG. Only the powder supply port 338 drawn below is shown in cross section in FIG. The three powder charging ports 336, 338, 340 are positioned at the end positions 326 of the central hole 332 so that they have a relatively small acute angle with respect to the central axis 332.
Linearly extends to the lower end 320. Powder inlet 336,3
38 and 340 respectively connect to the hanging part 342 and end at the lower end part 320.
When the powder dosing tube 138 shown in FIGS. 18 and 19 is installed in the anode assembly 106, the powder dosing ports 336,338,340.
Are connected to arc chambers corresponding to the vicinity of a portion where the gas mixing chamber 148 and the arc chamber 154 are in contact with each other.

It has been found that when multiple powder inlets are applied to a plasma gun having a modular cathode, the gun performance varies with the angle and size of the powder inlet. Since the powder feeding pipe 138 has a feature that it can be easily converted, there is an advantage that the powder feeding pipe 138 having various shapes can be selected when applied to various thermal spraying.

The arrangement shown in FIGS. 20 and 21 is the same as the arrangement shown in FIGS. 18 and 19 in that the central hole 322 continues from the threaded portion 324 to the portion 344 at the center in the lengthwise direction of the powder charging port 138. Is.
Before the central portion 344, the central hole 322 has a conical shape 34
It continues to the middle of 6. Usually three different powder inlets 348,35 evenly spaced around the central axis 332.
0,352 continues from the conical portion 346 to the lower end surface 320 of the powder feeding pipe 138. In the arrangement shown in FIGS. 20 and 21, most of the lower end 320 has three relatively large cutouts 354, 356, 3
Have 58. Powder inlets 348,350,352 are cutouts 354,3
56 and 358 continue to a portion of the powder charging pipe 138 that contacts the cylindrical side surface 360. The end of the powder inlet 348,350,352 is the 16th,
The conical portion 330 in the case of FIG. 17 is the conical portion 342 in the case of FIGS.
It doesn't end with a shape like. Also powder inlet 348,35
0,352 is the powder feeding port 33 with respect to the central axis 332 of FIGS.
A sharp angle greater than the 6,338,340 angle is taken with respect to the central axis 332.

For the powder dosing tube 138 shown in FIGS. 22 and 23, the central hole 322 is shorter than that shown in FIGS. The end of the central hole 322 is a portion 362. 3 different powder inlets 3
64,366,368 are evenly spaced around the central axis 332.
From the end of the central hole 322 in the portion 362 to the lower end 320. Lower end 320 has three different cutouts 370,372,3
It consists of 74, and the powder inlets 364, 366 and 368 are the cutting parts 3 respectively.
It continues to the middle of 70,372,374. The angles with respect to the central axis 332 of the powder charging ports 364, 366, 368 shown in FIGS.
The angle is approximately the same as the angle of the powder charging ports 336, 338, 340 with respect to the central axis 332. In the case of Fig. 22 and 23, powder charging port 364,3
66,368 are the powder inlets 336,338,340 shown in FIGS.
It has a relatively larger diameter than the powder inlets 348, 350, 352 shown in Figs. As in FIGS. 20 and 21,
The powder inlets 364, 366, 368 shown in FIG. 23 do not spread at the ends and continue to the cutouts 370, 372, 374.

In the case of the powder dosing tube 138 shown in FIGS. 24 and 25, the central hole 322 continues from the threaded end surface 324 to the part 376 along the length direction of the powder dosing tube 138. 3 different powder inlets 37
8,380,382 are arranged parallel to the center axis 332 and at equal intervals, and three cutouts 384,386,38 in the lower end 320 of the powder feeding pipe 138 from the end of the central hole 322 near the site 376.
Followed by 8, respectively. Powder inlet 378,380,382 is the second
It has a relatively large diameter as in the case of the powder inlets 364, 366, 368 shown in Figs.

The greatest advantage of a multi-split electrode plasma gun, such as plasma gas 16 with modular cathodes, is a greater power level improvement than a single cathode plasma gun. This increase in power level is possible by observing and adjusting the presence of the multi-split electrodes and the factors described thus far such as optimizing the plasma system with the multi-split electrodes. However, increased power levels require greater cooling. This tendency is particularly remarkable for the anode assembly, which is a common component of the entire plasma gun 16. The cathode assemblies 84,86,88 are cooled by individual independent cooling systems as previously described in FIGS.

As shown in FIG. 2, the cooling water booster pump 52 has a cooling water supply pipe 75.
It can be seen that the cooling water is supplied to the connectors 76 and 78 mounted on the anode stop plate 74 of the plasma gun 16 by using two of the pipes. The cooling water circulates in the anode cooling system described later and is then discharged by the connectors 80 and 82, and the cooling water return pipe 79
Two of them are returned to the cooling water booster pump 52.

FIG. 26 shows the bottom surface of the anode stop plate 74, and the positions of the connectors 76, 78, 80, 82 attached to the other surface are indicated by broken lines. The connectors 76 and 78 are attached at symmetrical positions with respect to the central axis 92, and are connected to the bottom surface side of the anode stop plate 74 through the openings 390 and 392, respectively. Connector 80, 82 has central axis 9
2 are installed symmetrically with respect to 2, and the distance from the central axis 92 is smaller than those of the connectors 76 and 78 installed at an angle of 90 ° with them, and the openings 394 and 396, respectively.
And is connected to the bottom surface of the anode stop plate 74 via. Openings 390 and 392
Is located in an annular portion 398 sandwiched by two grooves 400, 402 provided on a concentric circle provided on the bottom surface of the anode stop plate 74. Seals 404 and 406 are placed in the grooves 400 and 402, respectively, as shown in FIG. Attach the anode stop plate 74 to the gun body 70.
The seeks 404, 406 seal from the bottom surface of the anode stop plate 74 outside the groove 400 of the annular ring 398, and from the annular portion 408 between the groove 402 and the central hole 112 when attached to the upper surface 102 of the. The openings 394 and 396 connected to the connectors 80 and 82 are installed in the annular portion 408. FIG. 27 is a top view of the gun body 70 when the anode stop plate 74 is removed. Here is the body 70
It can be seen that the upper surface 102 has a cylindrical inner hole 100 penetrating the main body 70. Screw holes 410, 412, 414 are provided on the upper surface 102 of the main body 70, and these screw holes correspond to the holes 416, 418, 420 provided on the outer peripheral portion of the anode stop plate 74, respectively. When you install the 74, it is perfectly aligned. Insert bolts into the through holes 416, 418, 420 provided in the anode stop plate and screw holes 410, 412, 414.
Then, the anode stop plate 74 is fixed to the upper surface 102 of the main body 70. One such bolt 422 is shown in FIG.

Referring again to FIG. 27, an annular portion 424 is provided on the upper surface 102 of the gun body 70. The annular portion 424 is connected to the bottom surface 104 of the main body 70 by three through hole groups 426, 428, 430 each of which includes three through holes. One of the through holes forming the through hole group 426 Through hole 432
Is shown in FIG. When the anode stop plate 74 is attached to the upper surface 102 of the main body 70, the annular portion 414 becomes the annular portion 3 on the bottom surface of the anode stop plate 74.
It perfectly matches 98. The cooling water that has entered the gun body 70 through the connectors 76 and 78 passes through the through holes 390 and 392 and has an annular portion 424.
Flow into. Further, the cooling water from the annular portion 424 has a through hole group 4
It flows through 26,428,430 to the bottom surface 104 of the gun body 70. The flow of cooling water in the through hole 432 and other paths is
This is indicated by an arrow in the figure.

FIG. 28 is a top view of the anode holder 108. Anode holder 108
Is provided with three holes 426, 438, 440 on the outer periphery. The anode holder 108 is attached to the bottom surface 104 of the gun body 70 by passing a bolt through the through holes 436, 438, 440 and tightening the bolt in a screw hole provided in the bottom surface 104 of the gun body 70. FIG. 3 shows a state in which the bolt 442 is tightened in the screw hole 444 through the through hole 436 provided in the anode holder 108. When the anode holder 108 is fixed to the bottom surface 104 of the gun body 70, the seal 446 attached to the annular groove 448 provided on the top surface of the anode holder 108, as shown in FIG. The annular portion 450 provided on the anode holder is closely attached to the bottom surface 104 of the anode holder and the anode holder portion outside thereof is sealed. The annular portion 450 occupies between the annular flange 292 and the annular wall 452, is arranged concentrically with the annular groove 448, and is connected to the through hole groups 426, 428, 430 in the gun body 70. The cooling water flowing downward through the groups of through holes 426, 428, 430 flows into the annular portion 450 and surrounds the annular flange 292. The annular flange 292 is angled and grooved 454 as shown in FIG. Since the groove 454 is cut at an angle around the annular flange 292, when the cooling water is extruded from the annular portion 450 through the groove 454, the water flow is extruded as a swirl flow. As described above with reference to FIG. 8, the anode assembly 106 has an annular space 282 surrounding the bottom portion 130, and the annular space 282 has an inner side of the annular flange 292 as shown in FIG. The cooling water in a swirling flow is supplied. In this way, the cooling water swirls and the circular notch groove 282
And maximizes heat exchange in the wall of the anode assembly 106 between the nozzle portions 152.

The spiral cooling water in the annular notch groove 282 passes upward from the annular notch groove 282 through the water passages 284 and 286 shown in FIG. 3 or FIGS. 8 and 10 in the main body 150 of the anode assembly 106. Flows to. By extending this water passage between the arc chambers 154, the portion of the anode assembly 106 is further cooled.

When the cooling water reaches the uppermost end portion of the void including the water passages 284 and 286, the cooling water usually flows into the lower portion 134 of the insertable clamp 126. FIG. 30 shows the insert type clamp 12 shown in FIG. 29.
FIG. 6 is a cross-sectional view of 6 showing that the lower clamp portion 134 has multiple angled notches therein. Here, the cooling water is directly guided to the outside of the powder feeding pipe holding component 136, and the water flow is swirled again so that the powder feeding pipe holding component 136 is sufficiently cooled there. Such a water flow generated in the inner side 460 of the hollow structure of the insertable clamp 126 and the annular passage 458 formed on the outer surface of the powder feeding pipe holding part 136 is very important. This is because the powder charging port holding component 136 can function as a heat sink. A large amount of heat generated in the gas mixing chamber 148 is transferred upward through a powder charging pipe holding member 136 functioning as a heat sink through a powder charging pipe 138 made of a material such as tungsten, and an annular passage. The swirl flow in 458 gives the powder inlet holding part 136 as much cooling effect as necessary.

As the cooling water continues to flow upward in the annular passage 458,
Above the insertable clamp 126 through multiple passageways 462 132
Be led to. Irrespective of the central axis of such insertable clamp 126, an upwardly angled eyelet 462 is provided at the 31st position.
Shown in the partial cross-section of the figure. The cooling water flowing through the small hole 462 flows into the annular deep groove 464 located below the flange 114 of the anode connection plug 110 at the upper portion 132 of the insertable clamp 126.

FIG. 32 is a bottom view of the anode connection plug 110, showing the bottom surface of the flange 114. As shown in FIG. 32, the flange 114 has eight narrow grooves 466 arranged around the flange at substantially equal intervals. The cooling water in the annular deep groove 464 flows into the annular passage 468 formed by the outer surface 470 of the anode connection plug 110 and the cylindrical hole 100 of the gun body 70 by the narrow groove 466.

The cooling water flowing through the annular passage 468 is directed upwards to the gun body 7
It flows into an annular space 472 on the upper surface 102 of 0.

An annular space 472 surrounding the cylindrical inner hole 100 is arranged adjacent to the annular passage 408 on the lower surface of the anode connecting plate 74. As a result, the cooling water in cut 472 flows through holes 80 and 82 to connectors 80 and 82. From the connectors 80 and 82, the cooling water returns through the two cooling water return pipes 79 of the cooling water booster pump 52.

As shown in FIGS. 2 and 26, the connector 76 is approximately 90 ° away from the connector 82 with respect to the central axis 92. However, for convenience of drawing, the connector 76 is shown in FIG. 3 to face the connector 82 on a straight line passing through the central axis 92.

The plasma gun 16 has been described above in connection with the supply of powdered thermal spray material. The introduction of powder-sprayed metals and other materials into the plasma stream is a well known technique. Relatively long due to powdering of the thermal spray material. Also,
Sometimes it will be possible to feed to a suitable place in a plasma gun with a tortuous feed path. For example, a plasma gun having one cathode located coaxially above the anode has a troublesome structure in which powder is supplied from the side surface of the plasma gun.

Although powdery metals and other substances are relatively easy to handle and are suitable for feeding into the plasma gun through a long and winding feed path, the need to feed such materials in powdered form is a disadvantage. There are also some points. For one, materials such as metals are difficult and expensive to manufacture in powder form. Also, after manufacture, such powdery materials require special handling to minimize oxidation and the like. For this reason, it would be advantageous if the thermal spray material could be introduced in liquid or molten form. Such an attempt is readily accomplished with a plasma gun having a modular cathode, with material fed through the center of the gun at the top of the anode assembly. This allows the use of relatively short, direct material feed equipment and minimizes the risk of solidification of the molten material in the feed path or the occurrence thereof.

FIG. 33 is an example of an apparatus that may be used in connection with the invention to spray metal or other material in the molten state. First
The apparatus shown in FIG. 33 includes a metal melt feeder 474. The melter 474 is designed to be installed in the plasma gun 16 at a place to replace the powder introduction pipe 72, the powder pipe holder 120, the powder introduction port 124, the powder feeding pipe holding component 136, and the powder feeding pipe 138. The metal melt feeder shown in FIG. 33 has a feed pipe support 476 of similar shape to the powder feed pipe clamp 126 shown in FIG. The filler tube support 476 has a threaded upper portion 478 that matches the threaded portion of the anode connection plug 110 when the support 476 is installed on the plasma gun 16. Feed pipe support 4
When the 76 is installed in the anode connection plug 110, the feed pipe support 4
The lower end 480 of the hollow feed pipe 482 mounted on the hollow cylindrical insulator 484 inside 76 extends downward from the lower end 486 of the feed pipe support 476. The lower end 480 of the hollow feed tube 482 is the anode assembly 10
The first end 2 of the gas mixing chamber 148 is passed through the cylindrical squeezing portion 268 of 6.
Reaching 70.

The upper end 488 of the hollow feed tube 482 terminates in a cylindrical feed tube connector 490 having a crucible 492 therein. A hollow, cylindrical crucible 492 is located in the feed pipe connector 490 and has an annular passage with the inner wall 496 of the feed connector 490.
Forming 494. The lower end 498 of the annular passage 494 is a hollow feed pipe 4
Continue to the upper edge 488 of 82. The pipe port 500 partially extends from the lower end 502 of the hollow supply pipe 504 to the hollow inside of the crucible 492.
The pipe port 500 sits on the upper end of the supply pipe connector 490.

Hollow supply tube 504 terminates at its upper end 506 so as to receive plug 508 therein. Gas connector 510
Is connected to the plug 508. The plug 508 with the gas connector 510 can be removed from the upper end of the hollow feed tube 504 to feed material into the hollow tube 504. Upper end 506 of hollow tube 504
From the above, with the plug 508 removed, the inside of the hollow supply pipe 504 is filled with a solid metal or other material sprayed. The plug 508 is then replaced on the top of the donor tube and the tube 504
Electric power is applied to heat the metal inside. The power is boosted by a DC power source connected to electrodes 514 and 516. Electrode 516 is connected to a hollow feed tube 482 between the top of feed tube support 476 and the bottom of feed connector 490.

The electrodes 514 and 516 are shown in an exaggerated and large form in FIG. 33, but are actually much smaller so that a metal melt feeder 476 can be installed in the plasma gun 16. The same is true for electrode 518. Electrode 518, hollow tube 50
4 is connected to the lower end 502. The DC power supply 522 is connected between the electrode 518 and the body 150 of the anode assembly.

A DC power source 512 is connected to electrodes 514 and 516 to generate sufficient heat in hollow tube 504 to melt the solid pieces of metal. When the DC power source is connected to the power source 518 and the main body 150, the molten metal is supplied from the hollow tube 504 through the crucible 492 and the hollow feed tube 482 to the gas mixing chamber 148 in the anode assembly 106. Provide sufficient heat to prevent freezing.

The solid metal piece in hollow tube 504 melts when powered by DC power supply 512, and the molten metal passes through mouth tube 500 into crucible 4
Flows down into 92. Although the crucible 492 is filled with molten metal, the molten metal overflows the crucible 492 by the action of the gas pressure transmitted from the gas mixing chamber 148 of the anode assembly 106 and does not flow into the annular passage 494.

As previously mentioned, gas pressure is created in the gas mixing chamber 148 by introducing an inert gas into the cathode assemblies 84, 86 and 88 to form the plasma and arc streams. This gas pressure is transmitted to the upper end of the crucible 492 through the feed pipe 482 and the annular passage 494, and prevents molten metal from overflowing from the crucible there. As a result, the molten metal remains the anode metal until it is desired to be fed into the gas mixing chamber 148 of the anode assembly 106.

When the molten metal is fed from the crucible 492 into the gas mixing chamber 148 of the anode assembly 106, gas pressure is applied to the upper end of the hollow tube 504. Although not shown in FIG. 33, a gas delivery line connects a gas connector 510 at the upper end of plug 508 to a source of an inert gas such as argon. Hollow tube with argon gas
By supplying to the inside of 504 and the upper end 506, the gas mixing chamber 14
Negative effect of pressure from 8, resulting in crucible 492
The molten metal in the inside overflows, and the feed pipe 482 passes through the annular passage 494.
Flows through the inner bottom edge 498 of the. Molten metal flows through hollow feed tube 482 to gas mixing chamber 148 in anode assembly 106 where it mixes with the plasma stream. The DC power supply 522 supplies enough power to prevent unwanted solidification while the spray metal flows through the path.

If it is desired to limit the delivery of molten metal to the gas mixing chamber 148 in the anode assembly 106, the supply of argon gas to the gas connector 510 is limited. This again causes the molten metal to be forced out of the top of the crucible 492 by the gas pressure in the gas mixing chamber 148, creating an equilibrium condition.

〔The invention's effect〕

As described above, according to the present invention, compared with the conventional plasma generator, since the raw material powder can be charged to the center of the anode in the flow direction of the plasma jet without the adhesion of the powder, the yield of film formation on the object is high, Moreover, since it is easy to increase the output due to the effective water cooling structure, etc., a highly produced plasma generator will be supplied. Moreover, the selection range of the raw material powder can be greatly expanded by branching the tip of the powder feeding pipe.

[Brief description of drawings]

FIG. 1 shows a block diagram of the entire plasma system including a plasma generator of the present invention and a perspective view of a vacuum chamber. FIG. 2 shows an assembled external view of the plasma generator of the present invention. FIG. 3 is a sectional view of the plasma generator shown in FIG. 2, showing the structure of a modularized anode, cathode, powder charging tube, and the like. FIG. 4 shows an external view of a modularized cathode. FIG. 5 shows a sectional view of the cathode of FIG. FIG. 6 is a side view from the cathode tip direction in FIG. 5, and a swirl flow is formed around the cathode by the small holes arranged on the concentric circles for introducing the inert gas. FIG. 7 shows a cross-sectional view of the component 212 of FIG. 6 with the oblique small holes for generating the swirling flow. FIG. 8 shows a sectional view of an anode having notches such as a module cathode, a powder charging pipe, and a cooling water passage. FIG. 9 shows a front view of the anode shown in FIG. FIG. 10 shows a top view of the anode shown in FIG. FIG. 11 shows the positional relationship between the anode and the cathode, showing four different cathode arrangements. FIGS. 12, 13 and 14 show cross sections of anodes having different nozzle shapes, in which three different arc chambers and nozzle shapes are shown. Figure 15 shows a powder dosing tube holder with a removable powder dosing tube, which is attached to the top of the anode. 16 and 17 show a first embodiment of the cross-sectional view of the powder feeding pipe shown in FIG. 15 and the side view from the end face direction. Similarly, FIGS. 18 and 19 show a second embodiment of the powder charging pipe shown in FIG. 20 and 21 similarly show a third embodiment of the powder charging pipe shown in FIG. Similarly, FIGS. 22 and 23 show a fourth embodiment of the powder feeding pipe shown in FIG. Similarly, FIGS. 24 and 25 show a fifth embodiment of the powder charging pipe shown in FIG. FIG. 16 shows a bottom view of an anode stop plate 74 for incorporating the anode shown in FIGS. 2 and 3. FIG. 27 is a top view of a gun body 70 incorporating the cathode, anode, powder charging tube and the like shown in FIGS. 2 and 3. FIG. 28 shows a top view of an anode holder 108 for incorporating the anode shown in FIGS. 2 and 3. FIG. 29 shows a sectional view of the clamp 126 for forming swirling cooling water, which is arranged on the upper portion of the anode shown in FIGS. 2 and 3. FIG. 30 shows a sectional view of the clamp shown in FIG. 29, taken along line 30-30 in the same figure. The cooling water forms a swirl flow due to the small holes penetrating diagonally. FIG. 31 shows a top view of the clamp shown in FIG. FIG. 32 shows the plug 110 for connecting the anode shown in FIGS. 2 and 3.
The bottom view of is shown. FIG. 33 shows the entire surface (partial cross-sectional view) of an embodiment of an apparatus for charging a molten raw material (molten metal or the like) from the upper part of the anode instead of the powder charging tube. 10 …… Vacuum chamber, 13 …… Upper lid, 14 …… Lower lid, 16 …… Plasma gun, 24 …… Processing parts, 70 …… Gun body, 72 …… Powder supply tube, 74 …… Anode stop plate, 84 , 86,88 …… Cathode assembly, 106 …… Anode assembly, 108 …… Anode holder, 120 …… Powder supply tube holder, 124 …… Powder inlet, 126 …… Clamp, 136 …… Powder input tube holder Parts, 138 ... Powder injection pipe, 148 ... Gas mixing chamber, 154 ... Arc chamber.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Eric Mühlberger USA, California 92672 San Clemente, Calé Balanda 509 (72) Inventor Albert Sikinger USA, CA 92714 Irvine, Dusk Street 14911 (72) Inventor Steven Eric Mühlberger -California, USA 92672 San Clemente, North Ola Vista 250 (72) Inventor Don Everett Bailey USA, California 92388 Moreno Valley, Perthley Avenue 25849 (56) Reference JP-A-61-230300 (JP, A) Japanese Patent Publication 51-7556 (JP, B2)

Claims (3)

[Claims] 1. A plasma system that operates in a reduced-pressure atmosphere at atmospheric pressure or lower, comprising a common cathode and a plurality of cathodes arranged so as to surround the anode, and an anode surrounded by the plurality of cathodes. A small hole for charging the sprayed raw material is provided above the center of the space, and the small hole is made into a sleeve shape that can be easily replaced. By changing the sleeve, the raw material can be charged with any small hole diameter. A plasma generator characterized by being capable of 2. The plasma generator according to claim 1, wherein the tip of the small hole portion of the raw material charging sleeve is branched into a plurality of pieces.
A plasma spraying device characterized in that the raw material can be charged to any position in the central space of the anode by changing the branching angle. 3. A plasma system which operates in a reduced-pressure atmosphere at atmospheric pressure or below, is composed of a common anode and a plurality of cathodes arranged so as to surround the anode, and an anode surrounded by the plurality of cathodes. A small hole for charging the sprayed raw material is provided above the center of the space, and a crucible or the like is provided above the center of the space of the anode. The raw material is melted in the crucible or the like and is passed through the small hole. The plasma spraying device is characterized in that it is charged into the space of the anode.