3-way powder protection valve with cylindrical heating element

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 device, and more particularly to a three-way valve for protecting against powder that can effectively suppress the 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 device, and the periphery of the rotating ball installed inside. [Background technology]

[0002] Generally, the manufacturing process of semiconductors and flat panel displays is broadly divided into a front-end process (fabrication process) and a back-end process (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. The back-end process refers to the process of separating the chips manufactured in the front-end process into individual pieces, combining them with lead frames, and assembling them into finished products.

[0003] At this time, the process of depositing a thin film on the wafer or 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 process, 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 semiconductor and flat panel display production lines, vacuum pumps and scrubbers, which are gas treatment devices, are used to carry out the processes, and the line connecting the vacuum pump and scrubber is called the exhaust line. In this exhaust line, three-way valves, as shown in Figures 1 and 2, are widely used to control the direction of reaction by-product gases and improve the efficiency of the scrubber.

[0005] The three-way valve includes a casing 10 having an inlet pipe 13 through which reaction by-product gas flows in and a plurality of outlet pipes 11 and 12 through which 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 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, reaction by-product gases or powder contained in the reaction by-product gases permeate and accumulate in the gap A1 between the rotating ball 20 and the ball seat 14 that supports the rotating ball 20, causing a problem of difficulty in operating the rotating ball 20. In particular, because the inlet hole of the rotating ball 20 faces the inlet pipe 13 of the valve casing 10, reaction by-product gases tend to permeate the gap between the rotating ball 20 and the ball seat 14 and solidify into powder.

[0007] Furthermore, there is a problem in that powder deposits 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 installed inside. Therefore, a solution to this problem was needed, but no suitable solution had yet been found. 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 area around the rotating ball installed inside, in 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 dust protection valve according to the technical concept of the present invention is a three-way dust protection valve installed in a semiconductor or flat panel display manufacturing line to control the flow of a reaction by-product gas, and comprising: 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 outlet holes selectively communicating with the plurality of outlet pipes of the valve casing, and controlling the 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, wherein the heating element is a cylindrical heating element and is installed in plurality so as to be deeply inserted from near 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.

[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 detachable state.

[0011] The storage pocket may be formed in a direction perpendicular to the inlet pipe of the valve casing, pass above and below the vicinity of the inlet pipe, and pass 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 further include a nozzle-forming member provided to surround the outer peripheral surface of the rear end of the inlet pipe, and the inner peripheral surface of the nozzle-forming member may be formed with a chamber-forming groove that forms an annular nitrogen gas chamber between the nozzle-forming member and the outer peripheral 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 peripheral 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 peripheral 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 circular tubular 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 supplied to the chamber forming groove of the valve casing from the outside may be connected to one of the storage pockets, and the nitrogen gas supplied from the outside may be heated by passing through the one storage pocket and coming into contact with the outer surface of a cylindrical heating element.

[0014] The valve casing may also be characterized in that it is provided inside 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 connected so as to cross the front end of the one storage pocket near the entrance, 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.

[0015] Another feature of the present invention is that a spiral wire is provided along the outer surface of the cylindrical heating element stored in one of the storage pockets, and the nitrogen gas passing through the one of the storage pockets moves spirally along the spiral wire, thereby increasing 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, pass above and below the vicinity of the inlet pipe, and pass above and below the vicinity of an outlet pipe among the plurality of 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 that 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 elements stored in the storage pockets from falling out, and that have wire withdrawal holes that allow wires to be drawn out from the cylindrical heating elements.

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

[0020] The three-way valve for protecting against powder according to the present invention effectively heats a wide area from the rotating ball to the inlet and outlet pipes using cylindrical heating elements arranged around the rotating ball, thereby effectively suppressing the deposition and penetration of powder from reaction by-product gases.

[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 sprayed 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 makes it possible to easily insert and install the cylindrical heating element, and if necessary, to easily remove and separate the cylindrical heating element from the storage pocket, which is an advantage in terms of maintenance.

[0023] In addition, 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, eliminating the need for a separate device for heating the nitrogen gas externally or a separate device for insulating the high-temperature nitrogen gas during transport. [Brief explanation of the drawings]

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

[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. Because 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 herein. However, this is not intended to limit the present invention to the specific disclosed form, but should be understood to include all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. In the description of each drawing, similar components are designated by similar reference numerals. In the accompanying drawings, the dimensions of structures are shown exaggerated or reduced to clarify the present invention or to understand the schematic configuration.

[0026] Furthermore, terms such as "first" and "second" may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be designated a "second component," and similarly, a second component may be designated a "first component" without departing from the scope of the present invention. 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 pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with 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 protecting against powder according to an embodiment of the present invention, Figure 4 is an exploded oblique view of a three-way valve for protecting 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 the valve casing in a three-way valve for protecting against powder according to an embodiment of the present invention, and Figure 6 is a vertical cross-sectional view for explaining the nitrogen gas injection structure in a three-way valve for protecting against powder according to an embodiment of the present invention.

[0028] As shown in the figure, the three-way powder protection valve according to the 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 multiple cylindrical heating elements 120 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 this effectively prevents the deposition of powder generated from reaction by-product gases. Also, by spraying 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 penetration of reaction by-product gases between the rotating ball 150 and the ball seat 117 of the valve casing 110, which would otherwise cause the deposition of powder.

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

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

[0032] A plurality of circular, elongated storage pockets 113 for storing cylindrical heating elements 120 are formed on one side of the valve casing 110, on which the inlet pipe 111 and the outlet pipes 112a and 112b are not provided. The storage pockets 113 are formed long and extend to the vicinity of the other side of the valve casing 110. This allows the cylindrical heating elements 120 to be easily stored in the storage pockets 113, and when inspection or replacement of the heating elements 120 is required, the heating elements 120 can be easily removed from the storage pockets 113 and separated. 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 inlet pipe 111 and above and below the outlet pipe 112a, which is one of the plurality of outlet pipes 112a and 112b and is provided in a straight line with the inlet pipe 111.

[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 is provided on its inner circumferential surface with a chamber forming groove 116a that forms an annular nitrogen gas chamber C1 between the nozzle forming member 116 and the outer circumferential surface of the inlet pipe 111 to be filled with nitrogen gas supplied from the outside, and a nozzle forming groove 116b that forms an annular injection nozzle C2 at 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 toward 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 and is injected from injection nozzle C2, which has a narrower cross section than nitrogen gas chamber C1, it is injected more strongly due to the ejection effect. As shown in the enlarged view of FIG. 6, the nitrogen gas injected from injection nozzle C2 forms a cylindrical air curtain along the outer periphery of inlet pipe 111, thereby effectively blocking the reaction by-product gas from penetrating into gap A between periphery 150a of inlet hole 151 of rotating ball 150 and ball seat 117. This solves the fatal problem of reaction by-product gas penetrating gap A between periphery 150a of inlet hole 151 of rotating ball 150 and ball seat 117, causing powder deposition and imposing a high driving load on rotating ball 150. In addition, the high-temperature nitrogen gas injected strongly in the flow direction of the reaction by-product gas from injection nozzle C2 also improves the flow of reaction by-product gas passing through the powder protection three-way valve.

[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 said one storage pocket 113 and comes into contact with the outer surface of the cylindrical heating element 120 provided inside it, whereby the nitrogen gas is heated and then injected from the injection nozzle C2 in a high temperature state. With 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 for insulating it.

[0035] 4 and 5, in order to maximize the heating effect of the nitrogen gas as described above, a spiral wire 125 is provided along the outer circumferential surface of the cylindrical heating element 120 stored in the one storage pocket 113. As a result, the nitrogen gas passing through the one storage pocket 113 moves spirally along the spiral wire 125, thereby increasing the contact time with the cylindrical heating element 120 and providing more effective heating.

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

[0037] The nozzle forming member 116 is provided with a temperature sensor 140, which can measure the temperature of the nitrogen gas immediately after it has passed through the storage pocket 113. This makes it possible to measure the temperature of the high-temperature nitrogen gas that is sprayed from inside the powder protection three-way valve 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 housed in the housing pockets 113 from falling out. The pocket covers 121 are provided on a flat panel with wire outlet holes 121a for allowing the wires 120a of the cylindrical heating elements 120 to be drawn out, and are provided to cover the entrances of the housing 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 that covers the entire one side of the valve casing 110 to hide the pocket covers 121 therein. This allows the plurality of housing pockets 113 provided on one side of the valve casing 110, the plurality of cylindrical heating elements 120 housed in the housing pockets 113, and major components such as the pocket covers 121 to be completely concealed and protected.

[0039] The rotating ball 150 is rotatably mounted within 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 constantly connected to the inlet pipe 111 of the valve casing 110, and a plurality of outlet holes 152 that correspond to the plurality of outlet pipes 112a, 112b provided in the valve casing 110 and selectively communicate with one of the outlet pipes 112a, 112b depending on the direction of rotation. The rotating ball 150 is connected to the rotating shaft 119 of the actuator 130 and rotates, selectively blocking or opening one of the outlet pipes 112a, 112b provided in the valve casing 110 depending on the angle of rotation, thereby controlling the flow direction of the reaction by-product gas. The rotating ball 150 is very similar to 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 that flows into the inside of the valve casing 110 and is sprayed through the spray nozzle C2 forms a cylindrical air curtain, which effectively blocks the reaction by-product gas from penetrating into the gap A between the periphery of the inlet hole 151 of the rotating ball 150 and the ball seat 117.

[0040] The cylindrical heating elements 120 are housed in the housing pockets 113 of the valve casing 110 and serve to heat the rotating ball 150 and the interior of the valve casing 110. As shown in the figure, the cylindrical heating elements 120 housed in the housing pockets 113 are deeply inserted from the corners of one side of the valve casing 110 toward the other side, and are therefore arranged at multiple points surrounding the rotating ball 150, thereby heating the interior of the valve casing 110. This allows the rotating ball 150 to be heated three-dimensionally from all sides, and by heating a wide area extending from the inlet pipe 111 to the outlet pipes 112a and 112b, the deposition and penetration of powder generated from reaction by-product gases 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 rotation shaft 119. The actuator 130 is provided as a pneumatic actuator 130 that generates a driving force for rotating the rotating ball 150 by air pressure. To this end, the actuator 130 has an air inlet 132a through which 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 embodiments of the present invention have been described above, the present invention is susceptible to various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Therefore, the above description should not be construed as limiting the scope of the present invention, which is defined by the scope 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 installed in a semiconductor or flat panel display manufacturing line and controls the flow of reaction by-product gas, 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 outlet holes selectively communicating with a plurality of outlet pipes of the valve casing, and controlling the flow direction of the 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 plurality 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, 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 manner; a nozzle-forming member provided on an inner peripheral surface of the nozzle-forming member, the nozzle-forming member having a chamber-forming groove defining an annular nitrogen gas chamber between the nozzle-forming member and the outer peripheral surface of the inlet pipe and filled with nitrogen gas supplied from outside; and a nozzle-forming groove defining an annular injection nozzle between the nozzle-forming member and the outer peripheral 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 peripheral surface of the rear end of the inlet pipe toward the inside of the inlet hole of the rotating ball. The nitrogen gas injected from the injection nozzle forms a circular tubular 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.

2. 2. The three-way valve for protecting against powder according to claim 1, wherein 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 one of the plurality of outlet pipes that is provided in a straight line with the inlet pipe.

3. 2. The three-way valve for protecting against powder according to claim 1, wherein 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 the nitrogen gas supplied from the outside is heated by passing through the one storage pocket and coming into contact with the outer surface of the cylindrical heating element.

4. 4. The three-way valve for protecting against powder according to claim 3, wherein the valve casing is formed with a nitrogen gas inlet hole at one end connected to the nitrogen gas transfer hose via a connecting end and at the other end communicating with the front end of the one storage pocket in the vicinity of the inlet so as to cross over it, and a nitrogen gas transfer hole connecting the rear end of the one storage pocket to the nitrogen gas chamber and transferring nitrogen heated by a cylindrical heating element in the one storage pocket to the nitrogen gas chamber.

5. 4. A three-way valve for protection against powder as described in claim 3, characterized in that a spiral wire is provided along the outer 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.

6. 6. The three-way valve for protection against powder according to claim 5, wherein the nozzle forming member is provided with a temperature sensor so that the temperature of the nitrogen gas immediately after passing through the storage pocket can be measured.

7. 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, 6. The three-way valve for protection against powder according to claim 5, 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.

8. A three-way valve for powder protection that is installed in a semiconductor or flat panel display manufacturing equipment line and controls the flow of reaction by-product gas, 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 outlet holes selectively communicating with a plurality of outlet pipes of the valve casing, and controlling the flow direction of the 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 plurality 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, 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 manner; a plurality of pocket covers bolted to one side of the valve casing, covering the entrances of the storage pockets one-to-one to prevent the cylindrical heating elements stored in the storage pockets from falling out, and having wire withdrawal holes for allowing wires to be drawn out from the cylindrical heating elements.

9. The three-way valve for protecting against powder according to claim 8, wherein the valve casing further includes a side cover member that covers an entire side of the valve casing to conceal the pocket cover therein.

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