JPS6353086B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supply device and a supply method for supplying a mixture of gas and powder.

For example, in a plasma processing furnace, a plasma jet generator mixes powder of materials such as metals and ceramics with a plasma gas such as helium or argon, or a gas that is to be reacted with the powder such as oxygen gas or nitrogen gas. However, these are sometimes supplied into the plasma as a carrier gas. In this case, it is necessary to maintain the gas at a constant amount and adjust the supply amount of the powder to a predetermined amount, or to mix the powder and the gas at a constant ratio.
In order to supply a mixture of powder and gas, it is necessary to vibrate the slope on which the powder is loaded so that the speed at which the powder moves on the slope is constant, or to stockpile the powder using a plunger or screw. There was one in which a fixed amount of powder was supplied to a flowing gas by extruding a fixed amount from a tank or by smoothing the powder supplied to a belt conveyor to a fixed thickness with a knife or the like. In such conventional methods, the amount of powder supplied is largely dependent on the amount of gas flow, and the amount of powder supplied is substantially determined by the amount of gas flow. Moreover, since the supply of powder to the gas is performed intermittently, it is difficult to maintain a constant mixing ratio. However, when supplying a mixture of gas and powder to a plasma jet generator, the amount of plasma gas supplied must be within the range necessary to maintain stable plasma, and the amount of powder supplied must be within the range required to maintain stable plasma. The mixture ratio of the gas and powder to be reacted with the powder can be adjusted and maintained constant at the predetermined ratio required for chemical reaction, and at the same time, the mixture of gas and powder can be maintained constant. It is also necessary to adjust the supply amount to a predetermined amount. In this way, in order to simultaneously adjust the mixing ratio and supply amount to a predetermined ratio and amount and maintain them constant, in the conventional method described above, the powder supply amount is largely dependent on the gas flow rate, as described above. Therefore, it has been nearly impossible to arbitrarily select the amount of gas flow, set the required amount of powder, and maintain it constant.

The present invention improves the above-mentioned conventional drawbacks and makes it possible to easily obtain a predetermined mixing ratio and supply amount of powder for any gas flow rate when supplying a mixture of gas and powder. The object of the present invention is to provide a tank body, a gas supply means equipped with a flow control valve connected to the tank body, a powder supply means equipped with a flow rate control device, a means for extracting powder and gas, and a tank body. The main idea is to use a supply device consisting of a pair of outlet pipes that communicate with each other, and a communication pipe that has a filter and a compressor in between and communicates between the pair of outlet pipes. be.

The present invention will be explained with reference to an embodiment shown in the drawings.

The tank body 1 has a funnel-shaped lower half, a gas supply pipe 2 having a flow rate control valve 2A communicates with the middle part, a powder supply hopper 3 communicates with the upper part, and a communication port 3A.
A rotary feeder 4 capable of adjusting the amount of powder supplied is interposed between the rotary feeder 4 and a take-out pipe 5 having a stop valve 5A communicating therebetween. Outlet pipes 6 and 7 having on-off valves 6A and 7A communicate with the tank body 1 above the communication position of the gas supply pipe 2 and the extraction pipe 5, respectively, and above the on-off valves 6A and 7A of the outlet pipes 6 and 7, The return pipes 8 and 9 connected to the vicinity of the communication port 3A of the powder supply hopper 3 are branched, and the return pipes 8 and 9
The tip portions 8A and 9A are formed into a nozzle shape. Filters 10, 11 are stretched over the outlet pipes 6, 7, and the outlet pipes 6, 7 are interconnected at their upper ends by a connecting pipe 12. Connecting pipe 12
A switching valve 13 and a compressor 14 are interposed therein. Further, a light emitter 15 is disposed in the middle of the tank body 1, and a light receiver 16 is disposed at a position facing the light emitter 15.

In the above supply device, gases such as helium, argon, nitrogen, hydrogen,
Oxygen, carbon dioxide, air, or a mixture thereof is supplied from the gas supply pipe 2 into the tank 1, and the amount of supply is regulated by the flow rate control valve 2A of the gas supply pipe 2. The powder 17 is stored in the powder supply hopper 3 and is supplied into the tank 1 from the communication port 3A of the powder supply hopper 3, and the amount of powder supplied is adjusted by the rotary feeder 4. When the powder is used for plasma, for example, metals such as titanium, tantalum, niobium, palladium, platinum, molybdenum, tungsten, silicon, aluminum, magnesium, calcium, cadmium, copper, nickel, chromium, and boron, and borides of the above metals are used. , carbides, nitrides, oxides, chlorides, other alloys such as stainless steel, Inconel, and brass, and ceramics. The gas supplied into the tank body 1 is passed through the outlet pipe 6.
Close the on-off valve 6A of the outlet pipe 7, open the on-off valve 7A of the outlet pipe 7 to take out the powder, and pass the entrained powder 17 through the filter 11.
After removing it separately at the outlet pipe 6 via the connecting pipe 12
The powder is guided to the return pipe 8 and is injected from the tip 8A of the return pipe 8, mixed with the powder 17 near the communication port 3A of the powder supply hopper 3, and stirred to be constant. Thus, a gas circulation means is formed by the outlet pipe 7 → the communication pipe 12 → the outlet pipe 6 → the return pipe 8, and the direction of this circulation is indicated by arrow B.
The above-mentioned circulation of the gas is performed by the compressor 14 via the switching valve 13, and in the direction of arrow B, the communication pipe 12 is connected to the B side of the switching valve 13. That is, in this case, the outlet pipe 6 is connected to the discharge side of the compressor 14, and the outlet pipe 7 is connected to the compressor 14.
Connect to the suction side of the The mixing ratio of gas and powder is determined by the amount of powder 17 supplied from the rotary feeder 4 and the amount of gas supplied from the gas supply pipe 2. The concentration of the powder is determined by measuring the density of the powder using the light receiver 16 based on the degree of diffuse reflection of the emitted light by the powder 17. The gas-powder mixture thus stirred by the circulating gas and mixed at a constant ratio is taken out from the take-out pipe 5. At this time, the amount taken out from the extraction pipe 5 is balanced with the amount supplied from the gas supply pipe 2.

As described above, the mixing ratio of gas and powder can be adjusted arbitrarily by the powder supply amount and gas supply amount, and the powder supply amount and gas supply amount are independent of each other. Thus, the amount of the gas-powder mixture taken out can also be adjusted in relation to the amount of gas fed, completely independent of the amount of powder fed. Further, by closing the on-off valve 7A of the outlet pipe 7, opening the on-off valve 6A of the outlet pipe 6, and connecting the communication pipe 12 to the A side of the switching valve 13, the outlet pipe 6 will be connected to the suction side of the compressor 14, and the outlet pipe 7 will be connected to the suction side of the compressor 14. is connected to the discharge side of the compressor 14, and the gas circulation direction is the direction shown by arrow A. At this time, the powder accumulated in the filter 11 is backwashed and removed when the gas passes through the filter 11. Therefore, the clogging of the filter 11 is eliminated. filter 10,
If the gas circulation direction is switched as described above before the filters 10 and 11 become clogged and the passage of gas is impaired, the filters 10 and 11 can be regenerated without having to be removed. The gas-powder mixture thus mixed is supplied from the take-out pipe 5 to a plasma jet generator as shown in FIG. 2, for example. In the plasma jet generator shown in FIG. 2, the extraction pipe 5 is electrically insulated and connected to the inner nozzle pipe 18, and the inner nozzle pipe 18 is coaxially inserted into the outer nozzle pipe 19. Tube 18 and outer nozzle tube 1
A cylindrical cathode 20 is disposed coaxially between the electrodes 9 . Spaces 20A, 2 inside and outside the cathode 20
A gas supply port 21 is provided for supplying an inert gas such as helium or argon through 0B. The outer nozzle pipe 19 has a double wall to form a cooling chamber 19A. Inner nozzle pipe 18 and cathode 20 as required
Cool in water in the same way. In this way, negative electricity is applied to the cathode 20 and positive electricity is applied to the outer nozzle pipe 19 or the counter electrode 24, inert gas is injected from the gas supply port 21, and a high frequency discharge or the like is generated between the outer nozzle pipe 19 and the cathode 20. When ignition is performed in a known manner, a discharge of the inert gas occurs at the outlet of the inner nozzle tube 18 and a plasma of the inert gas is generated.

When the mixture is then injected from the inner nozzle pipe 18, the mixture is also heated and becomes a plasma state.
A water supply port 19 is provided in the cooling chamber 19A of the outer nozzle pipe 19.
Pass cooling water through B. In order to stably generate plasma, it is necessary to maintain a constant supply amount of plasma gas as described above, and the amount of gas supplied from the gas supply port 21 and the inner nozzle pipe 1 must be maintained constant.
It is necessary that the amount of gas injected from step 8 is constant, but according to the supply device of the present invention, the amount of gas and powder supplied in the mixture can be accurately kept constant at a desired value. The amount of gas injected from the inner nozzle pipe 18 is constant at a desired value, and plasma is generated stably.

The present invention is not limited to the above-mentioned embodiments; for example, the gas circulation direction may not be alternately reversed. In addition, the present invention does not apply to plasma processing furnaces.
Needless to say, it can also be applied to thermal spraying, electrostatic coating, fluidized dipping, etc.

Since the present invention has the above configuration, the gas supplied from the gas supply means into the tank body is circulated to the circulation means by the compressor while the powder is removed by the filter, and the gas is circulated by the compressor to the circulation means. A constant mixing ratio is achieved by uniformly stirring the powder and gas supplied in predetermined amounts to the tank body from the powder supply means equipped with a flow rate adjustment device and the gas supply means equipped with a flow rate adjustment valve, respectively. becomes. The mixing ratio is adjusted by adjusting the powder supply amount and the gas supply amount, but since the powder supply amount and gas supply amount can be adjusted independently, the The mixing ratio and the amount taken out can be easily adjusted accurately over a wide range without the need for any particular control device. Further, on-off valves are interposed on both of the pair of outlet pipes or on the discharge side, and a return pipe is inserted from at least the discharge side of the circulation means, and the tip of the return pipe is connected to the communication port of the powder supply means. When connected diagonally downward to the vicinity, by closing the on-off valve of the outlet pipe on the discharge side, the gas discharged by the compressor via the connecting pipe will be guided to the return pipe, and the powder will be supplied from the return pipe. Since the powder is injected obliquely downward near the communication port of the powder supply means, the powder falling from the communication port of the powder supply means is scattered by the injected gas, and the gas and powder are mixed more uniformly. . Furthermore, if a switching valve is provided in the connecting pipe to switch between the suction side and the discharge side of the compressor, the filter can be backwashed by switching between the suction side and the discharge side of the compressor, and the filter can be removed. You can eliminate clogging of the filter by removing it.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a supply device, and FIG. 2 is a longitudinal sectional view of a plasma jet generator. In the figure 1... Tank body, 2... Gas supply pipe, 3... Powder supply hopper, 5... Takeout pipe, 6, 7... Outlet pipe,
8, 9... Return pipe, 10, 11... Filter, 12
...Communication pipe.

Claims (1)

[Scope of Claims] 1. A tank body, a gas supply means equipped with a flow control valve communicating with the tank body, a powder supply means equipped with a flow rate control device, a powder and gas extraction means, and a tank body A supply device comprising a circulation means constituted by a pair of outlet pipes that communicate with each other, and a communication pipe that has a filter and a compressor in between and communicates between the pair of outlet pipes. 2. A tank body, a gas supply means equipped with a flow control valve that communicates with the tank body, a powder supply means equipped with a flow rate control device, a means for extracting powder and gas, and a pair of outlets that respectively communicate with the tank body. In a supply device comprising a circulation means constituted by a pipe and a communication pipe having a filter and a compressor in the middle and communicating between the pair of outlet pipes, at least the discharge of the pair of outlet pipes of the circulation means is provided. An on-off valve is interposed on the side,
Furthermore, a supply device characterized in that a return pipe is extended from at least the discharge side of the circulation means, and the tip of the return pipe is connected diagonally downward to the vicinity of the communication port of the powder supply means. 3. A tank body, a gas supply means equipped with a flow control valve that communicates with the tank body, a powder supply means equipped with a flow rate control device, a means for extracting powder and gas, and a pair of outlets that respectively communicate with the tank body. In a supply device comprising a circulation means constituted by a pipe and a communication pipe having a filter and a compressor in the middle and communicating between the pair of outlet pipes, each of the pair of outlet pipes of the circulation means has an opening/closing mechanism. A supply device characterized in that a valve is interposed, and a switching valve for switching between a suction side and a discharge side of a compressor is interposed in a connecting pipe.