3-way valve with cylindrical heating element for powder protection

Abstract

The present invention relates to a three-way valve for protecting against powder, which is provided with a cylindrical heating element so as to effectively suppress deposition and penetration of powder over a wide area including an inlet pipe, an outlet pipe, and a rotating ball provided therein, in an exhaust line of a semiconductor or flat panel display manufacturing device. The present invention relates to a three-way valve for protecting against powder, which is provided with a cylindrical heating element so as to effectively suppress deposition and penetration of powder over a wide area including an inlet pipe, an outlet pipe, and a rotating ball provided therein. The three-way valve includes a valve casing having an inlet pipe for receiving a reaction by-product gas, and a plurality of outlet pipes for discharging the inlet reaction by-product gas in different directions, a rotating ball rotatably provided inside the valve casing for controlling a flow direction of the reaction by-product gas, and a heating element provided in the valve casing for heating the inside of the valve casing. The heating element is provided as a cylindrical heating element, and a plurality of heating elements are provided so as to be deeply inserted from near each corner of one side of the valve casing toward the other side, and the inside of the valve casing can be heated while being arranged at a plurality of points around the rotating ball.

Description

[Technical field]

[0001] The present invention relates to a semiconductor or flat panel display manufacturing apparatus, and more particularly to a three-way valve for protecting against powder, which can effectively suppress deposition and penetration of powder over a wide area including the inlet and outlet pipes in the exhaust line of the semiconductor or flat panel display manufacturing apparatus, and the periphery of the rotating ball installed therein. [Background technology]

[0002] Generally, the manufacturing process of semiconductors and flat panel displays is largely composed of a front-end fabrication process and a back-end assembly process. The front-end process refers to the process of manufacturing so-called semiconductor chips by repeatedly depositing a thin film on a wafer in various process chambers and selectively etching the deposited thin film to process a specific pattern, and the back-end process refers to the process of separating the chips manufactured in the front-end process into individual pieces and combining them with lead frames to assemble them into finished products.

[0003] At this time, the process of depositing a thin film on the wafer and etching the thin film deposited on the wafer is performed at high temperatures in a process chamber using harmful gases such as silane, arsine, and boron chloride, and process gases such as hydrogen. During the above processes, a large amount of reaction by-product gases containing various flammable gases, corrosive foreign matter, and toxic components are generated inside the process chamber.

[0004] In such semiconductor and flat panel display production lines, a vacuum pump and a scrubber, which is a gas treatment device, are used to carry out the process, and the line connecting the vacuum pump and the scrubber is called an exhaust line. In this exhaust line, a three-way valve as shown in Figures 1 and 2 is widely used to control the direction of the reaction by-product gas and improve the efficiency of the scrubber.

[0005] The three-way valve includes a casing 10 having an inlet pipe 13 through which the reaction by-product gas flows in and a plurality of outlet pipes 11, 12 through which the reaction by-product gas flows out, and a rotating ball 20 inside the casing 10 that rotates with the rotation of a rotating shaft 25 to control the flow of the reaction by-product gas.

[0006] However, in the case of a three-way valve used in an exhaust line where a large amount of powder is generated, after a certain period of use, the reaction by-product gas or the powder contained in the reaction by-product gas permeates and accumulates in the gap A1 between the rotating ball 20 and the ball seat 14 that supports the rotating ball 20, making it difficult to operate the rotating ball 20. In particular, since the inlet hole of the rotating ball 20 faces the inlet pipe 13 of the valve casing 10, the reaction by-product gas has a strong tendency to permeate the gap between the rotating ball 20 and the ball seat 14 and solidify into powder.

[0007] In addition, there is a problem in that powder is deposited not only in the gap between the rotating ball 20 and the ball seat 14, but also throughout the entire area through which the reaction by-product gas flows, including the inlet pipe 13 and outlet pipes 11 and 12 of the valve casing 10 and even around the rotating ball 20 provided inside. Therefore, a solution to this problem was needed, but no suitable solution existed. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present invention has been proposed to solve the above-mentioned conventional problems, and an object of the present invention is to provide a three-way valve for protecting against powder, which can effectively suppress the deposition and penetration of powder over a wide area including the inlet and outlet pipes and the periphery of the rotating ball installed inside the exhaust line of semiconductor and flat panel display manufacturing equipment. [Means for solving the problem]

[0009] In order to achieve the above object, a three-way valve for protecting against powder according to the technical idea of ​​the present invention is a three-way valve for protecting against powder that is installed in a manufacturing line of a semiconductor or flat panel display to control a flow of a reaction by-product gas, the three-way valve including: a valve casing having an inlet pipe through which a reaction by-product gas flows and a plurality of outlet pipes through which the inlet reaction by-product gas flows out in different directions; a rotating ball rotatably installed inside the valve casing, having an inlet hole communicating with the inlet pipe of the valve casing and an outlet hole selectively communicating with the plurality of outlet pipes of the valve casing, and controlling a flow direction of the reaction by-product gas; and a heating element installed in the valve casing to heat the inside of the valve casing, the heating element being provided as a cylindrical heating element, and being installed in a plurality of positions so as to be deeply inserted from near each corner of one side of the valve casing toward the other side, the heating element being arranged at a plurality of points around the rotating ball, so that the inside of the valve casing can be heated.

[0010] Here, a circular, elongated storage pocket for storing the cylindrical heating element may be formed near each corner of one side of the valve casing, and the cylindrical heating element may be provided in a removable state.

[0011] The storage pocket may be formed in a direction perpendicular to the inlet pipe of the valve casing, passing above and below the vicinity of the inlet pipe, and passing above and below the vicinity of an outflow pipe among the plurality of outflow pipes that is provided in a straight line with the inflow pipe.

[0012] The valve casing may include a nozzle forming member provided to surround an outer circumferential surface of the rear end of the inlet pipe, and an inner circumferential surface of the nozzle forming member may be provided with a chamber forming groove that forms an annular nitrogen gas chamber between the nozzle forming member and the outer circumferential surface of the inlet pipe and that is filled with nitrogen gas supplied from outside, and an annular nozzle forming groove that forms an injection nozzle between the nozzle forming groove and the outer circumferential surface of the inlet pipe in a gap narrower than the nitrogen gas chamber so that nitrogen gas can be injected from the chamber forming groove along the outer circumferential surface of the rear end of the inlet pipe toward the inside of the inlet hole of the rotating ball, and the nitrogen gas injected from the injection nozzle forms a cylindrical air curtain, thereby blocking reaction by-product gas from penetrating into the gap between the periphery of the inlet hole of the rotating ball and the ball seat.

[0013] In addition, a nitrogen gas transfer hose that transfers nitrogen gas from the outside to be supplied to the chamber forming groove of the valve casing may be connected to one of the storage pockets, and nitrogen gas supplied from the outside may be heated by passing through the one storage pocket and coming into contact with the outer peripheral surface of a cylindrical heating element.

[0014] The valve casing may further include a nitrogen gas inlet hole having one end connected to the nitrogen gas transfer hose via a connecting end and the other end communicating so as to cross with a front end portion near the entrance of one of the storage pockets, and a nitrogen gas transfer hole which connects the rear end portion of one of the storage pockets to the nitrogen gas chamber and transfers nitrogen heated by a cylindrical heating element in one of the storage pockets to the nitrogen gas chamber.

[0015] Another feature of the present invention is that a spiral wire is provided along the outer peripheral surface of the cylindrical heating element stored in one of the storage pockets, and nitrogen gas passing through one of the storage pockets moves spirally along the spiral wire, thereby lengthening the contact time with the cylindrical heating element.

[0016] The nozzle forming member may be provided with a temperature sensor so that the temperature of the nitrogen gas immediately after it has passed through the storage pocket can be measured.

[0017] The storage pocket for the cylindrical heating element may be formed in a direction perpendicular to the inlet pipe of the valve casing, passing above and below the vicinity of the inlet pipe, and passing above and below the vicinity of an outlet pipe among the multiple outlet pipes that is provided in a straight line with the inlet pipe, and one storage pocket through which the nitrogen gas passes may be formed to pass above the vicinity of the inlet pipe.

[0018] The valve casing may further include a plurality of pocket covers which are bolted to one side of the valve casing and cover the entrances of the storage pockets one-to-one to prevent the cylindrical heating element stored in the storage pocket from falling out, and which are provided with wire withdrawal holes which allow the wires of the cylindrical heating element to be drawn out.

[0019] The valve casing may further include a side cover member that covers the entire side surface of the valve casing to hide the pocket cover therein. Effect of the Invention

[0020] The three-way valve for protection against powder according to the present invention can effectively suppress deposition and penetration of powder from reaction by-product gases by effectively heating a wide area from the rotating ball to the inlet pipe and outlet pipe using cylindrical heating elements arranged around the rotating ball to surround it.

[0021] In addition, the present invention effectively prevents the chronic problem of powder deposition caused by the penetration of reaction by-product gas into the gap between the periphery of the inlet hole of the rotating ball and the ball seat by forming a cylindrical air curtain using high-temperature nitrogen gas injected along the outer circumferential surface of the rear end of the inlet pipe.

[0022] In addition, the present invention has a configuration in which a storage pocket is formed in the valve casing, which has the advantage of making it easy to insert and install the cylindrical heating element, and if necessary, easy to remove and separate the cylindrical heating element from the storage pocket, thereby providing a maintenance advantage.

[0023] In addition, since the present invention is configured so that nitrogen gas supplied from outside is sprayed after passing through a storage pocket containing a cylindrical heating element, there is no need to separately provide a device for heating the nitrogen gas externally or a device for insulating the high-temperature nitrogen gas during transportation. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a reference diagram for explaining a three-way valve according to the prior art. [Diagram 2] FIG. 1 is a reference diagram for explaining a three-way valve according to the prior art. [Diagram 3] FIG. 1 is a perspective view of a powder protection three-way valve according to an embodiment of the present invention. [Figure 4] FIG. 1 is an exploded perspective view of a powder protection three-way valve according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a partial cross-sectional view for explaining a nitrogen gas flow path structure formed in a valve casing in the three-way valve for protection against powder according to the embodiment of the present invention. [Figure 6] FIG. 2 is a vertical cross-sectional view for explaining a nitrogen gas injection structure in a powder protection three-way valve according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] A three-way valve for powder protection according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can be modified in various ways and can have various forms, specific embodiments are shown in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, and it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. In the description of each drawing, similar components are represented by similar reference numerals. In the accompanying drawings, the dimensions of structures are shown enlarged to clarify the present invention, or reduced to understand the schematic configuration.

[0026] In addition, terms such as first and second can be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another. For example, the first component can be named the second component, and the second component can be named the first component, without departing from the scope of the present invention. Meanwhile, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0027] <Embodiment> Figure 3 is an oblique view of a three-way valve for protection against powder according to an embodiment of the present invention, Figure 4 is an exploded oblique view of a three-way valve for protection against powder according to an embodiment of the present invention, Figure 5 is a partial cross-sectional view for explaining the nitrogen gas flow path structure formed in a valve casing in a three-way valve for protection against powder according to an embodiment of the present invention, and Figure 6 is a longitudinal cross-sectional view for explaining the nitrogen gas injection structure in a three-way valve for protection against powder according to an embodiment of the present invention.

[0028] As shown in the figure, the three-way valve for powder protection according to an embodiment of the present invention comprises a valve casing 110, a rotating ball 150, and an actuator 130, and further includes, as main components, a plurality of cylindrical heating elements 120 and a temperature sensor 140 arranged to surround the periphery of the rotating ball 150.

[0029] In the present invention, by arranging a plurality of cylindrical heating elements 120 so as to surround the periphery of the rotating ball 150, it is possible to heat a wide area extending from the inlet pipe 111 and the outlet pipes 112a, 112b to the periphery of the rotating ball 150, and it is possible to effectively suppress the deposition of powder generated from the reaction by-product gas. By injecting high-temperature nitrogen gas along the outer circumferential surface of the rear end of the inlet pipe 111 to form a cylindrical air curtain, it is possible to effectively prevent the problem of the reaction by-product gas penetrating between the rotating ball 150 and the ball seat 117 of the valve casing 110 and depositing powder.

[0030] The three-way powder protection valve according to the embodiment of the present invention will be described in detail below, focusing on each of the above-mentioned components.

[0031] The valve casing 110 has an internal space for accommodating a rotating ball 150, an inlet pipe 111 through which a reaction by-product gas flows in centering on the internal space, and a plurality of outlet pipes 112a, 112b through which the reaction by-product gas flowing in through the inlet pipe 111 flows out in different directions. In addition, a front end of the inlet pipe 111 and a rear end of the outlet pipes 112a, 112b are provided with flanges for connecting to different pipes. Here, ball seats 117 for rotatably supporting the rotating ball 150 are provided on the inner side of the wall of the valve casing 110 near the rear end of the inlet pipe 111 and near the front end of the outlet pipes 112a, 112b, respectively.

[0032] A plurality of storage pockets 113 for storing cylindrical heating elements 120 are formed in a circular, elongated shape on one side of the valve casing 110 where the inlet pipe 111 and the outlet pipes 112a and 112b are not provided. The storage pockets 113 are formed long to the vicinity of the other side of the valve casing 110. As a result, the cylindrical heating elements 120 are provided in a state where they are simply stored in the storage pockets 113, and when inspection or replacement of the heating elements 120 is required, they can be easily removed and separated from the storage pockets 113. As shown in Figs. 4 and 5, the storage pockets 113 are formed near each corner of one side of the valve casing, and are formed in a direction perpendicular to the inlet pipe 111 of the valve casing 110, passing above and below the vicinity of the inlet pipe 111, and passing above and below the vicinity of the outlet pipe 112a, which is provided in a straight line with the inlet pipe 111, of the plurality of outlet pipes 112a and 112b.

[0033] The valve casing 110 includes a nozzle forming member 116 provided to surround the outer circumferential surface of the rear end of the inlet pipe 111. The nozzle forming member 116 has an inner circumferential surface formed with a chamber forming groove 116a for forming an annular nitrogen gas chamber C1 between the outer circumferential surface of the inlet pipe 111 and the nozzle forming groove 116b for forming an annular injection nozzle C2 in a gap narrower than the nitrogen gas chamber C1 between the nozzle forming groove 116a and the outer circumferential surface of the inlet pipe 111 so that nitrogen gas can be injected from the chamber forming groove 116a along the outer circumferential surface of the rear end of the inlet pipe 111 to the inside of the inlet hole 151 of the rotating ball 150 in a direction coinciding with the flow direction of the reaction by-product gas. As a result, when the nitrogen gas moves to the injection nozzle C2 having a narrower cross section than the nitrogen gas chamber C1 and is injected, it is injected more strongly due to the ejection effect, and as shown in the enlarged part of FIG. 6, the nitrogen gas injected from the injection nozzle C2 forms a cylindrical air curtain along the outer circumferential surface of the inlet pipe 111, so that the reaction by-product gas can be effectively prevented from penetrating into the gap A between the peripheral portion 150a of the inlet hole 151 of the rotating ball 150 and the ball seat 117. This solves the fatal problem of the reaction by-product gas penetrating into the gap A between the peripheral portion of the inlet hole 151 of the rotating ball 150 and the ball seat 117, causing powder to be deposited, resulting in a high driving load on the rotating ball 150. In addition, the flow of the reaction by-product gas passing through the powder protection three-way valve is improved by the high-temperature nitrogen gas injected strongly in the flow direction of the reaction by-product gas through the injection nozzle C2.

[0034] Furthermore, the nitrogen gas transfer hose that transfers the external nitrogen gas is connected to one of the multiple storage pockets 113 that is located above the inlet pipe 111, and the nitrogen gas supplied from the outside passes through the one storage pocket 113 and comes into contact with the outer circumferential surface of the cylindrical heating element 120 provided inside it, whereby the nitrogen gas is heated and then sprayed from the spray nozzle C2 in a high temperature state. According to this configuration, the protective three-way valve itself has a nitrogen gas heating function, so there is no need to provide a separate device for heating the nitrogen gas externally or a device for insulation.

[0035] In order to maximize the heating effect of the nitrogen gas as described above, as shown in Figures 4 and 5, a spiral wire 125 is provided along the outer circumferential surface of the cylindrical heating element 120 stored in the one storage pocket 113. This allows the nitrogen gas passing through the one storage pocket 113 to move in a spiral shape along the spiral wire 125, thereby lengthening the contact time with the cylindrical heating element 120 and allowing for more effective heating.

[0036] Here, in order to transfer the nitrogen gas from the nitrogen gas transfer hose to the annular nitrogen gas chamber C1, a nitrogen gas inlet hole 114a and a nitrogen gas transfer hole 114b are formed inside the valve casing 110 as shown in Fig. 5. One end of the nitrogen gas inlet hole 114a is connected to the nitrogen gas transfer hose via a connection end 114, and the other end is connected to the front end near the inlet of one storage pocket 113 so as to cross. The nitrogen gas transfer hole 114b is formed by connecting the rear end of the one storage pocket 113 and the nitrogen gas chamber C1, and transfers the nitrogen heated by the cylindrical heating element 120 in the one storage pocket 113 to the annular nitrogen gas chamber C1.

[0037] The nozzle forming member 116 is provided with a temperature sensor 140, which allows the temperature of the nitrogen gas to be measured immediately after it has passed through the storage pocket 113. This makes it possible to measure the temperature of the high-temperature nitrogen gas injected from inside the powder protection three-way valve in order to suppress powder formation, and based on this, the temperature of the cylindrical heating element 120 can be controlled to an appropriate level.

[0038] A plurality of pocket covers 121 are further provided on one side of the valve casing 110 to prevent the cylindrical heating elements 120 accommodated in the accommodation pockets 113 from coming off. The pocket cover 121 is provided on a flat panel with wire outlet holes 121a for allowing wires 120a of the cylindrical heating elements 120 to be drawn out, and is provided to cover the entrances of the accommodation pockets 113 one-to-one by fastening with bolts. In addition, as shown in FIG. 4, the valve casing 110 further includes a side cover member 110a for covering the entire one side of the valve casing 110 to hide the pocket cover 121 therein. As a result, the plurality of accommodation pockets 113 provided on one side of the valve casing 110, the plurality of cylindrical heating elements 120 accommodated in the accommodation pockets 113, and main components such as the pocket cover 121 can be completely concealed and protected.

[0039] The rotating ball 150 is rotatably installed in the inner space of the valve casing 110 and serves to control the flow direction of the reaction by-product gas. To this end, the rotating ball 150 includes one inlet hole 151 that is always connected to the inlet pipe 111 of the valve casing 110, and a plurality of outlet holes 152 that correspond to a plurality of outlet pipes 112a, 112b provided in the valve casing 110 and selectively communicate with one of the plurality of outlet pipes 112a, 112b according to the rotation direction. Thus, the rotating ball 150 is connected to the rotating shaft 119 of the actuator 130 and rotates, and serves to selectively block and open one of the plurality of outlet pipes 112a, 112b formed in the valve casing 110 according to the rotation angle, thereby controlling the flow direction of the reaction by-product gas. Such a rotating ball 150 is very similar to the known prior art, and therefore a detailed description thereof will be omitted. However, in the case of the rotating ball 150 included in the three-way valve for protecting against powder according to the embodiment of the present invention, there is almost no problem that the reaction by-product gas and the powder solidified therefrom penetrate and accumulate between the ball seat 117 of the valve casing 110, which may cause damage or inoperability. This is because the high-temperature nitrogen gas flowing into the inside of the valve casing 110 and sprayed through the spray nozzle C2 forms a cylindrical air curtain, effectively blocking the penetration of the reaction by-product gas into the gap A between the peripheral portion of the inlet hole 151 of the rotating ball 150 and the ball seat 117.

[0040] The cylindrical heating element 120 is installed in a state of being housed in the storage pocket 113 of the valve casing 110, and serves to heat the rotating ball 150 and the inside of the valve casing 110. As shown in the figure, the plurality of cylindrical heating elements 120 housed in the storage pocket 113 are deeply inserted from the vicinity of each corner of one side of the valve casing 110 toward the other side, so that the inside of the valve casing 110 can be heated while being arranged at a plurality of points surrounding the rotating ball 150. As a result, the rotating ball 150 can be heated three-dimensionally from all sides, and a wide area extending from the inlet pipe 111 to the outlet pipes 112a and 112b can be heated, so that deposition and penetration of powder generated from the reaction by-product gas can be effectively suppressed.

[0041] In the case of the cylindrical heating element 120, as described above, it is possible to heat almost the entire rotating ball 150 and valve casing 110, and it has the great advantage that it can be installed simply by storing it in the storage pocket 113, and when inspection or replacement is required, it can be easily removed from the storage pocket 113 and separated.

[0042] The actuator 130 provides a driving force for rotating the rotating ball 150, and is connected to the rotating ball 150 by a rotating shaft 119. The actuator 130 is provided as an air pressure actuator 130 that generates a driving force for rotating the rotating ball 150 by air pressure. To this end, the actuator 130 includes an air inlet 132a through which the driving air flows in, and an air outlet 132b through which the air is discharged after passing through the inside of the actuator 130, and a solenoid valve 133 is provided between them to adjust the flow rate of the driving air.

[0043] Although the preferred embodiment of the present invention has been described above, the present invention can utilize various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiment. Therefore, the above description should not be construed as limiting the scope of the present invention, which is defined by the limits of the following claims. [Explanation of symbols]

[0044] 110: Valve casing 113: Storage pocket 116: Nozzle forming member 120: Cylindrical heating element 125: Spiral wire 130: Actuator 140: Temperature sensor 150: Rotating ball

Claims

1. A three-way valve for powder protection, which is provided in a semiconductor or flat panel display manufacturing line and controls the flow of a reaction by-product gas, comprising: a valve casing including an inlet pipe through which a reaction by-product gas flows and a plurality of outlet pipes through which the inlet reaction by-product gas flows out in different directions; a rotating ball rotatably installed inside the valve casing, the rotating ball having an inlet hole communicating with the inlet pipe of the valve casing and an outlet hole selectively communicating with a plurality of outlet pipes of the valve casing, and configured to control a flow direction of a reaction by-product gas; a heating element provided in the valve casing and capable of heating the inside of the valve casing; Including, The heating element is provided as a cylindrical heating element, and is provided in a plurality of positions so as to be deeply inserted from the vicinity of each corner of one side of the valve casing toward the other side, and is arranged at a plurality of points around the rotating ball so as to heat the inside of the valve casing.

2. 2. The three-way powder protection valve according to claim 1, wherein a circular, elongated storage pocket for storing the cylindrical heating element is formed near each corner of one side of the valve casing, and the cylindrical heating element is provided in a detachable state.

3. 3. The three-way valve for protection against powder as described in claim 2, characterized in that the storage pocket is formed in a direction perpendicular to the inlet pipe of the valve casing, passes above and below the vicinity of the inlet pipe, and passes above and below the vicinity of an outflow pipe among the plurality of outflow pipes that is provided in a straight line with the inflow pipe.

4. 3. The three-way valve for protecting against powder according to claim 2, wherein the valve casing includes a nozzle forming member provided to surround an outer circumferential surface of the rear end of the inlet pipe, and an inner circumferential surface of the nozzle forming member is provided with a chamber forming groove for forming an annular nitrogen gas chamber between the nozzle forming member and the outer circumferential surface of the inlet pipe and for filling the nitrogen gas supplied from outside with the chamber forming groove, and a nozzle forming groove for forming an annular injection nozzle between the nozzle forming member and the outer circumferential surface of the inlet pipe in a gap narrower than the nitrogen gas chamber so that nitrogen gas can be injected from the chamber forming groove along the outer circumferential surface of the rear end of the inlet pipe toward the inside of the inlet hole of the rotating ball, and the nitrogen gas injected from the injection nozzle forms a cylindrical air curtain, thereby blocking the penetration of reaction by-product gas into the gap between the periphery of the inlet hole of the rotating ball and the ball seat.

5. 5. The three-way valve for protecting against powder as described in claim 4, characterized in that a nitrogen gas transfer hose for externally transferring nitrogen gas to be supplied to the chamber forming groove of the valve casing is connected to one of the storage pockets, and nitrogen gas supplied from the outside is heated by passing through the one storage pocket and coming into contact with the outer peripheral surface of a cylindrical heating element.

6. 6. The three-way valve for protecting against powder as described in claim 5, characterized in that the valve casing is formed with a nitrogen gas inlet hole, one end of which is connected to the nitrogen gas transfer hose via a connecting end and the other end of which is in communication with a front end portion near the inlet of the one storage pocket so as to cross, and a nitrogen gas transfer hole, which connects the rear end of the one storage pocket to the nitrogen gas chamber and transfers nitrogen heated by a cylindrical heating element in the one storage pocket to the nitrogen gas chamber.

7. 6. A three-way valve for protection against powder as described in claim 5, characterized in that a spiral wire is provided along the outer peripheral surface of the cylindrical heating element stored in one of the storage pockets, and nitrogen gas passing through one of the storage pockets moves spirally along the spiral wire, thereby lengthening the contact time with the cylindrical heating element.

8. 8. The three-way valve for protection against powder according to claim 7, wherein the nozzle forming member is provided with a temperature sensor so that the temperature of the nitrogen gas immediately after it has passed through the storage pocket can be measured.

9. The cylindrical heating element storage pocket is formed in a direction perpendicular to the inlet pipe of the valve casing, passes above and below the inlet pipe, and passes above and below the outlet pipe that is aligned with the inlet pipe among the plurality of outlet pipes, 8. The three-way valve for protection against powder according to claim 7, wherein one storage pocket through which the nitrogen gas passes is formed so as to pass above and in the vicinity of the inlet pipe.

10. 3. The three-way powder protective valve according to claim 2, further comprising a plurality of pocket covers which are bolted to one side of the valve casing, cover the inlets of the storage pockets one-to-one to prevent the cylindrical heating element stored in the storage pocket from falling out, and have wire withdrawal holes which allow wires of the cylindrical heating element to be withdrawn.

11. The three-way valve for protecting against powder according to claim 10, wherein the valve casing further includes a side cover member for covering an entire side surface of the valve casing to hide the pocket cover therein.

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