UA70855A - Method and device for introduction of powder into method and device for introduction of powder into plasma flow of sprayers plasma flow of sprayers - Google Patents

Abstract

A method for introduction of powder into the plasma flow of sprayers operating on the mixtures of combustible gas with oxidizer, by preliminary mixing of powder with carrier gas and supply of gas-powder mixture into the arched channel of the nozzle of plasmotrone. In this case, a part of gas mixture from the area of arched channel near the wall containing combustible components is extracted and issupplied for combustion and preheating of gas-powder mixture. Device for realization of method contains nozzle with arched and additional cylindrical channels and fuel unit, through which the tube forintroduction of powder passes. The tube forms with side walls of fuel unit housing a circular clearance connected with arched channel of the nozzle of plasmotrone.

Description

Description of the invention

The invention relates to the field of spraying using an electric arc and can be used in 2 installations of plasma spraying of powders operating on mixtures of combustible gas with an oxidizer.

Known methods and devices for introducing powder material into the plasma jet of atomizers (see, for example, the book by V.M. Pashchenko "Equipment for gas-thermal coating" - K.: Polytechnic Polytechnic Institute, 2001. p. 287-290, fig. 9.49- 9.51). These methods and devices have significant drawbacks. One of the disadvantages is a decrease in the temperature of the plasma flow as a result of the addition of a cold carrier gas.

In part, this shortcoming is eliminated by another method, taken as a prototype, which is carried out with the help of a device for introducing powder material (see, for example, the book by V. M. Pashchenko "Equipment for gas-thermal coating" - K.: IVC "Polytechnic", 2001. p. .289, Fig. 9.50). This method makes it possible to reduce the proportion of the transporting gas in the powder mixture using a device that is installed directly in front of the nozzle of the plasma atomizer and makes it possible to cut off the necessary part of the transporting gas 72 as a result of changing the position of the adjusting screw.

A known method of introducing powder into the plasma jet of atomizers using a device taken as a prototype (see, for example, the book by V.M. Pashchenko "Equipment for gas-thermal coating" - K.: Polytechnic Institute, 2001. p. 288, fig. 9.49, b). The device consists of a plasmatron nozzle, arc and additional cylindrical channels, a fitting for introducing powder.

The disadvantage of the method and device is the lack of heating of the mixture of powder and transporting gas before introducing them into the plasma jet of the plasmatron arc channel.

The invention is based on the task of improving the method and device for introducing powder material into the plasma jet of atomizers operating on mixtures of combustible gas with an oxidant by heating the transporting gas and powder, which ensures a significant reduction in the cooling of the plasma at the point of introduction of powder 22, and therefore reduces the requirements to the fractional composition of the starting material - the size of the fused particles increases, the properties of the coating - adhesion strength, porosity along the cross section of the spraying spot - are leveled off. Productivity and quality of sprayed coatings increases.

The problem is solved by introducing the powder into the arc channel of the plasmatron by pre-mixing the powder with the carrier gas and feeding the gas mixture into the arc channel of the plasmatron. What is new is that part of the gas mixture from the wall zone of the arc channel, which contains combustible components, are selected and served for burning and heating the gas-powder mixture.

The task of improving the device for introducing powder into the plasma jet is solved by the fact that the device contains a plasmatron nozzle with arc and additional cylindrical channels, a fitting for introducing powder, the new thing is that it additionally contains a burner unit through which a fitting passes

Zo forms an annular gap with the side walls of the burner assembly body, which is connected to the arc channel - the plasmatron nozzle.

Fig. 1 shows the scheme of supplying powder material, Fig. 2 shows the general view of the burner assembly. "

The device for introducing powder into the plasma jet contains a nozzle 71 (Fig. 1) with an arc 2 (Fig. 1) and an additional 3 (Fig. 1) cylindrical channels. In the additional channel of nozzle 1 of the plasmatron, a unit with burners (Fig. 2) is installed, which is mounted using a thread. Fitting 4 passes through the burner assembly

From" (Fig. 1), which forms an annular gap 5 relative to the side walls of the housing 6 (Fig. 2) of the burner unit, which is connected to the arc channel 2 (Fig. 1) of the nozzle 1 (Fig. 1) of the plasmatron. The burner unit (Fig. 2) contains: body b; combustion chamber 7 (Fig. 2); cover 8; hole 9, which is placed in the middle of the cover 8; holes 10, which are placed on the surface of the cover 8 in a circle, at an angle of 0...207 relative to its axis, and the angle between the axes of the holes is also 0...407; holes 11, which are located in the lower part of the body b in a circle, at an angle of 30...457 relative to its axis and av | the angle between the axes of the holes is 60...907.

Let's consider the method of introducing powder into the plasma jet of atomizers using the example of the device for co-introduction of powder. Fig. 20 The plasma jet generated in the plasmatron flows through the arc channel 2 into the atmosphere. Powder, pre-mixed with the transporting gas, is fed through the fitting 4 into the arc channel 2. The static pressure sl of the gas flow in the arc channel 2 of the plasmatron is higher than the atmospheric pressure. Under the effect of the difference in static pressures, part of the gas mixture from the arc channel 2 of the plasmatron flows through the annular gap 5 of the burner assembly between the fitting 4 and the walls of the plasmatron channel into the combustion chamber 7, where the combustion of the components of this 29 mixture is organized. The torch, which burns in the hole C, heats the transporting gas and powder due to the transfer of heat to. by the walls of the fitting 4, the torches burning in the holes 10 stabilize the burning of the main torch, which flows out through the hole 9. Through the holes 11, the diameter of which can vary depending on the initial composition of the mixture, air is sucked in from the environment to adjust the ratio "combustible components - oxidizer " in the initial gas mixture. Transporting gas and powder is additionally heated due to the transfer of heat from the combustion chamber 60 to the 7 walls of the fitting 4.

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Claims (2)

The formula of the invention 1. The method of introducing powder into the plasma jet of atomizers operating on mixtures of combustible gas with an oxidant, by pre-mixing the powder with the transporting gas and supplying the gas-powder av! of the mixture into the arc channel of the plasmatron nozzle, which differs in that part of the gas mixture from the wall 39 zone of the arc channel, which contains combustible components, is selected and fed for burning and heating in the gas-powder mixture. 2. A device for introducing powder into a plasma jet, containing a nozzle with arc and additional cylindrical channels, a fitting for introducing powder, which is distinguished by the fact that it additionally contains a "burner unit" through which a fitting passes, forming with the side walls of the body of the burner unit - c 10 annular gap connected to the arc channel of the plasmatron nozzle. "» Official bulletin "Industrial property". Book 1 "Inventions, useful models, topographies of integral " . K-4 . go . GI n. . microcircuits", 2004, M 10, 15.10.2004. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. -i («c) (ee) 1 sl 60 b5