Gate valve

Abstract

To provide a gate valve with excellent corrosion resistance for controlling the flow of corrosive gases. In particular, to provide a gate valve that can suppress the corrosion of bellows. [Solution] To prevent corrosive gas 20 from flowing from the valve mechanism 180 to the airtight sealing mechanism 120 equipped with bellows 132 through a gap formed along the outer circumferential surface of the rod 112 that opens and closes the on / off valve 198 of the valve mechanism 180, and to prevent the bellows 132 from corroding due to the corrosive gas 20, a gas supply mechanism 140 is provided between the valve mechanism 180 and the airtight sealing mechanism 120. A non-corrosive protective gas 30 is supplied from the gas supply mechanism 140 to the gap formed along the outer circumferential surface of the rod 112, thereby suppressing the flow of corrosive gas 20 from the valve mechanism 180 to the airtight sealing mechanism 120.

Description

Technical Field

[0004]

[0001] The present invention relates to a gate valve suitable for controlling the flow of a gas, and particularly to a gate valve suitable for controlling the flow of a corrosive gas (hereinafter referred to as a corrosive gas). In this specification, controlling the flow of a corrosive gas means controlling the supply of a corrosive gas to other equipment or stopping the supply to other equipment, or controlling the change of the supply destination of a corrosive gas, or controlling the change of the supply amount of a corrosive gas, or controlling the change of the supply ratio to the supply destination in the state of supplying a corrosive gas to a plurality of supply destinations, etc.

Background Art

[0002] For example, in a semiconductor manufacturing apparatus or the like, when producing a circuit board, a corrosive gas is used. The gate valve used to control the flow of a corrosive gas is required to be resistant to corrosion. For example, in the prior art documents described below, Patent Document 1 and Patent Document 2 disclose techniques for protecting the gate valve itself from corrosion by a corrosive gas.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

[0005] The improvement measures described in Patent Documents 1 and 2 are insufficient in preventing corrosion of the sealing mechanism by corrosive gases. Therefore, for example, in semiconductor manufacturing equipment, there is a problem requiring maintenance and replacement of the sealing mechanism in a relatively short period of time.

[0006] However, the present invention does not negate the above-mentioned improvement measures, for example, the measures to improve the corrosion resistance of the bellows of the sealing mechanism described in Patent Document 2. In addition to the improvement measures of the present invention described below, it is preferable to implement the improvement measures described in Patent Document 1 and Patent Document 2, for example, the measures to improve the corrosion resistance of the bellows themselves as proposed in Patent Document 2 in addition to the present invention. However, as stated above, it is difficult to obtain a gate valve with excellent corrosion prevention by simply taking measures to improve the corrosion resistance of the bellows themselves.

[0007] The objective of this invention is to significantly improve the corrosion resistance of gate valves. [Means for solving the problem]

[0008] [First Invention] The first invention relates to a gate valve in which a drive mechanism for moving a rod, a valve mechanism for controlling the flow of a corrosive gas based on the movement of the rod, and an airtight sealing mechanism having a bellows are arranged along the long axis which is the longitudinal axis of the rod, and the airtight sealing mechanism is provided between the drive mechanism and the valve mechanism so that the airtight sealing mechanism prevents the corrosive gas from leaking from the valve mechanism to the drive mechanism. A gas supply mechanism is further provided between the valve mechanism and the airtight sealing mechanism. The gas supply mechanism comprises a protective gas introduction section into which a protective gas for preventing corrosion is introduced, and a gas supply device for supplying the introduced protective gas. The gas supply device of the gas supply mechanism has a rod-moving gas supply space formed inside, which is a space for movably arranging the rod. The gas supply mechanism supplies the protective gas introduced from the protective gas introduction section to the rod movement gas supply space from the gas supply device, thereby preventing the movement of the corrosive gas from the valve mechanism to the airtight sealing mechanism. This is a gate valve characterized by the following features.

[0009] [Second Invention] The second invention relates to the gate valve of the first invention, The valve mechanism comprises a valve mechanism body and an on / off valve for controlling the flow of the corrosive gas. The valve mechanism body is provided with a corrosive gas inlet into which the corrosive gas is introduced and a corrosive gas outlet for supplying the corrosive gas to another location, and a valve operating space for the operation of the on / off valve is formed between the corrosive gas inlet and the corrosive gas outlet. The on-off valve has a valve seat provided on the side of the valve operating space of the corrosive gas outlet and a valve body provided at the end of the rod, The valve mechanism body further includes a rod valve mechanism space that connects the valve operating space and the rod movement gas supply space of the gas supply mechanism, and also provides a space for movably positioning the rod. The cross-sectional area of ​​the rod valve mechanism space in the direction perpendicular to the long axis is greater than the cross-sectional area of ​​the rod movement gas supply space formed in the gas supply mechanism perpendicular to the long axis. This is a gate valve characterized by the following features.

[0010] [The third invention] The third invention is the gate valve of the second invention, The gas supply mechanism comprises a gas supply mechanism body having a storage hole for housing the gas supply device, The gas supply device has a cylindrical shape, and the gas supply device is fixed in a state where it is housed in the storage hole of the gas supply mechanism body. Inside the gas supply device, a gas supply space for rod movement is formed to allow the rod to be moved. An outer peripheral passage for flowing the protective gas is formed between the outer peripheral surface of the cylindrical gas supply device and the inner surface of the storage hole of the gas supply mechanism body. The protective gas introduced from the protective gas introduction section of the gas supply mechanism is supplied over the entire circumference of the outer surface of the gas supply device via the outer peripheral passage formed along the outer surface of the gas supply device, and the protective gas is supplied from the outer surface of the gas supply device to the rod movement gas supply space. This is a gate valve characterized by the following features.

[0011] [Fourth Invention] The fourth invention is the gate valve of the third invention, The cylindrical gas supply device, which is fixed in the storage hole of the gas supply mechanism body, has a recessed outer groove formed around its entire circumference on its outer surface. As the gas supply device is housed in the storage hole of the gas supply mechanism body, the outer peripheral passage is formed by the recessed outer peripheral surface of the gas supply device and the inner peripheral surface of the storage hole of the gas supply mechanism body. In the gas supply device, a number of gas supply holes connecting the rod movement gas supply space and the outer peripheral groove are formed over the entire circumference of the outer peripheral groove. The protective gas introduced from the protective gas introduction part of the gas supply mechanism is supplied to the outer peripheral side passage formed on the outer peripheral side of the gas supply device, and further supplied from the outer peripheral side passage to the rod movement gas supply space through a number of the gas supply holes. A gate valve characterized by the above.

[0012] 〔Fifth Invention〕 The fifth invention is the gate valve of the fourth invention, wherein each of the number of gas supply holes has a diameter of 0.5 mm or less, a gate valve characterized by this.

[0013] 〔Sixth Invention〕 The sixth invention is the gate valve of the fourth invention, The airtight holding mechanism has a protective gas supply mechanism side end portion in which an airtight holding mechanism rod arrangement space for arranging the rod movably on the side of the gas supply mechanism is formed, In the airtight holding mechanism, a bellows storage space for storing the rod and the bellows arranged on the outer periphery of the rod is formed on the side of the drive mechanism rather than the airtight holding mechanism rod arrangement space, The cross-sectional area of the airtight holding mechanism rod arrangement space perpendicular to the long axis, which is the longitudinal axis of the rod, is smaller than the cross-sectional area of the bellows storage space perpendicular to the long axis. A gate valve characterized by this.

Advantages of the Invention

[0014] According to the present invention, in a gate valve that controls the flow of a corrosive gas, a gate valve excellent in corrosion resistance that can greatly suppress the influence of the corrosive action of the corrosive gas can be obtained.

Brief Description of the Drawings

[0015] [Figure 1]This is an explanatory diagram showing the front external shape of one embodiment of a gate valve to which the present invention is applied. [Figure 2] Figure 1 is an explanatory diagram showing the planar external shape of the gate valve. [Figure 3] Figure 1 is an explanatory diagram showing a cross-section of the gate valve. [Figure 4] Figure 2 is an explanatory diagram showing a cross-section of the gate valve. [Figure 5] Figure 3 is a partially enlarged view of the gate valve shown. [Figure 6] This is an explanatory diagram showing the gate valve with the valve mechanism body removed. [Figure 7] This is an enlarged view of the gas supply mechanism and airtightness maintenance mechanism 120 of the gate valve described above. [Figure 8] This is an explanatory diagram illustrating the gas supply mechanism of the gate valve described above. [Figure 9] Figure 8 is a cross-sectional view AA of the gas supply mechanism. [Figure 10] This is an explanatory diagram illustrating the gas supply device of the gas supply mechanism described above. [Modes for carrying out the invention]

[0016] In one embodiment of the gate valve 50 for carrying out the invention described below, components with the same reference numerals have basically the same structure, perform the same function, and produce almost the same effect. To avoid redundant explanations, explanations of components with the same reference numerals may be omitted. Furthermore, the embodiment described below is an embodiment of a gate valve that has the function of controlling whether or not to supply corrosive gas 20 to another. However, the gate valve to which the present invention can be applied is not limited to a gate valve that controls whether or not to supply corrosive gas 20 to another. In addition to gate valves that perform this control, the present invention can also be applied to gate valves that have the function of controlling the destination of the supply of corrosive gas 20, controlling the amount of corrosive gas supplied, or controlling the supply ratio to destinations when corrosive gas is supplied to multiple destinations. With regard to the present invention, due to the structure and effect of the airtight sealing mechanism 120, which is an important component, it can be applied even if the structure and function of the gas supply mechanism 140 are different. As a representative example of a gate valve with the above-mentioned control function, the following describes an example using a gate valve 50 that has the function of controlling whether or not to supply corrosive gas 20 to another source.

[0017] 1. Description of the overall configuration of a gate valve 50, which is one embodiment to which the present invention is applied. (1) Explanation of the basic configuration of the gate valve 50 An embodiment of a gate valve to which the present invention is applied is shown in Figures 1 and 2. The gate valve 50 described as an embodiment is used to control the supply of corrosive gas 20 to a semiconductor manufacturing apparatus 26. The corrosive gas 20 to be controlled is, for example, a highly corrosive gas used in the manufacture of semiconductor chips.

[0018] The gate valve 50 comprises a drive mechanism 60, an airtightness maintenance mechanism 120, a gas supply mechanism 140, and a valve mechanism 180, all arranged from one side to the other along a major axis 115 indicating the longitudinal direction of a rod 112 located inside it. The valve mechanism 180 has an on / off valve 198 for controlling the supply of corrosive gas 20 to the semiconductor manufacturing apparatus 26 based on the movement of the rod 112. The drive mechanism 60 controls the movement of the rod 112, and the supply of corrosive gas 20 to the semiconductor manufacturing apparatus 26, which is another piece of equipment, is controlled based on the movement of the rod 112.

[0019] The airtight sealing mechanism 120 has a bellows 132 inside, which prevents corrosive gas 20 from flowing from the valve mechanism 180 into the drive mechanism 60. Furthermore, in this embodiment, a gas supply mechanism 140 is provided between the airtight sealing mechanism 120 and the valve mechanism 180 to prevent the bellows 132 from corroding due to the corrosive gas 20. The gas supply mechanism 140 supplies a protective gas 30 that is non-corrosive or has low corrosivity into a space formed on the outer circumference of a rod 112 located inside, thereby suppressing the flow of corrosive gas 20 from the valve mechanism 180 into the airtight sealing mechanism 120. Through this action, the gas supply mechanism 140 can suppress the corrosion of the bellows 132 provided in the airtight sealing mechanism 120 due to the corrosive gas 20. Nitrogen gas is used as the protective gas 30, for example. Corrosive gases 20 can include various gases, such as chlorine (Cl2), fluorine (F2), hydrogen chloride (HCl), and ammonia (NH3).

[0020] (2) Explanation of the basic operation and effects of the gate valve 50 When the gate valve 50 is used to control the supply of corrosive gas 20 to the semiconductor manufacturing apparatus 26, the gate valve 50 is fixed and held in a certain position relative to the semiconductor manufacturing apparatus 26. The valve mechanism 180 of the gate valve 50 receives the corrosive gas 20 from a source of corrosive gas 20 (not shown) via piping 22 to the corrosive gas inlet 172 of the valve mechanism 180, and then supplies it to the semiconductor manufacturing apparatus 26 via piping 24 from the corrosive gas outlet 174 of the valve mechanism 180. The gate valve 50 is equipped with an airtight sealing mechanism 120 that includes a bellows 132 inside to prevent the corrosive gas 20 from flowing from the valve mechanism 180 into the drive mechanism 60. However, when the corrosive gas 20 flows into the airtight sealing mechanism 120, there is a problem that the bellows 132 itself will be corroded by the corrosive gas 20. Furthermore, not only the bellows 132 but also various other components of the airtight sealing mechanism 120 will corrode. The gate valve 50 is equipped with a gas supply mechanism 140, which suppresses the flow of corrosive gas 20 from the valve mechanism 180 into the airtight sealing mechanism 120. This significantly improves the problem of the bellows 132 itself being corroded by the corrosive gas 20. Protective gas 30 is supplied to the gas supply mechanism 140 via a supply pipe 32 to the protective gas introduction section 142 of the gas supply mechanism 140, and the protective gas 30 is supplied to the gas supply rod outer peripheral space 161 (shown in Figure 5) formed on the outer circumference of the rod 112 located inside the gas supply mechanism 140. With this configuration, the flow of corrosive gas 20 from the valve mechanism 180 into the airtight sealing mechanism 120 is suppressed, and corrosion of the bellows 132 is suppressed. As a result, the mass production efficiency of the semiconductor manufacturing equipment 26 can be significantly improved.

[0021] The drive mechanism 60, the airtight sealing mechanism 120, and the gas supply mechanism 140 are each integrally fixed by fixing means, and the gas supply mechanism 140 is integrally fixed to the valve mechanism 180 by fixing screws 182 and 183, which are fixing means. When the fixing by fixing screws 182 and 183 is released, the drive mechanism 60, the gas supply space for rod movement 160, and the gas supply mechanism 140 can be removed from the valve mechanism 180. In this case, the rod 112 located inside the valve mechanism 180 and the valve body 192 fixed to the end of the rod 112 can be removed from the valve mechanism 180 in an integral state with the drive mechanism 60, the protective gas supply mechanism side end 130, and the gas supply mechanism 140 (shown in Figure 6). This improves the efficiency of maintenance of the gate valve 50.

[0022] 2. Specific explanation of each mechanism constituting the gate valve 50 2.1 Description of Valve Mechanism 180 (1) Description of the valve mechanism 180 Figure 3 is a cross-sectional view of Figure 1, Figure 4 is a cross-sectional view of Figure 2, and Figure 5 is an enlarged view of the airtight sealing mechanism 120, gas supply mechanism 140, and valve mechanism 180 in Figure 3. The valve mechanism 180 includes a valve mechanism body 190 for forming a corrosive gas inlet 172 and a corrosive gas outlet 174. Inside the valve mechanism body 190, there is a valve operating space 199 that houses an on / off valve 198, and a rod valve mechanism space 200 for connecting the valve operating space 199 and the rod movement gas supply space 160 of the gas supply mechanism 140.

[0023] The shaft 181 is the shaft connecting the center of the corrosive gas inlet 172 and the center of the corrosive gas outlet 174. The diameter L2 of the opening of the corrosive gas inlet 172 is at least twice the diameter L3 of the opening of the corrosive gas outlet 174. A valve seat 196, which is circular in the plane perpendicular to the shaft 181, is provided on the valve operating space 199 side of the corrosive gas outlet 174, and a valve body 192 is fixed to the other end 195 of the rod 112. The valve body 192 is circular in shape when folded in the plane perpendicular to the shaft 181, and the O-ring 194 provided on the valve body 192 is also circular. The valve seat 196 and the valve body 192 constitute an on-off valve 198. In the valve operating space 199 of the valve mechanism body 190, when the on-off valve 198 is in the closed state, the rod 112 moves along the long axis 115 to the other side, which is the valve mechanism 180 side, by the drive mechanism 60. When the valve body 192 is in a position facing the valve seat 196, the movement of the rod 112 along the long axis 115 stops, and the rod 112 is tilted by the drive mechanism 60 slightly in the direction of arrow B, which is in the direction of the corrosive gas outlet 174, relative to the long axis 115. The O-ring 194 provided on the valve body 192 is in close contact with the valve seat 196, resulting in a closed state, and the supply of corrosive gas 20 to the semiconductor manufacturing apparatus 26 is stopped. When the valve is opened, first the valve body 192 moves in the direction of arrow A, and then the rod 112 moves along the long axis 115 towards the drive mechanism 60, which is one side, and the valve body 192 is housed inside the rod valve mechanism space 200.

[0024] Inside the valve mechanism body 190, there is not only a valve operating space 199, but also a rod valve mechanism space 200 that connects the valve operating space 199 to the rod movement gas supply space 160 formed inside the gas supply mechanism body 148. The length of the rod valve mechanism space 200 in the direction along the axis 181 is L4, which is slightly longer than the cross-sectional length L5 of the rod 112. Also, as shown in Figure 4, the length in the direction perpendicular to the axis 181 and further perpendicular to the major axis 115 is L9, which is longer than the length L8 of the valve body 192. The length from the opening end on the gas supply mechanism 140 side, which is one of the opening ends of the corrosive gas inlet 172 of the rod valve mechanism space 200, to the rod movement gas supply space 160 of the gas supply mechanism 140, i.e., the length L1 in the direction along the major axis 115, is longer than the length L8 of the valve body 192 in the direction along the major axis 115. Due to this relationship, when the on-off valve 198 is in the open position, the other end 195 of the rod 112 and the valve body 192 fixed to the other end 195 can both be moved out of the valve operating space 199 and completely housed inside the rod valve mechanism space 200.

[0025] (2) Explanation of the effects related to the valve mechanism 180 The diameter L2 of the opening of the corrosive gas inlet 172 is greater than twice the diameter L3 of the opening of the corrosive gas outlet 174. By making the diameter L3 of the corrosive gas outlet 174 smaller than the opening of the corrosive gas outlet 174, fluctuations in the corrosive gas 20 supplied to the semiconductor manufacturing apparatus 26 due to the opening and closing operation of the on-off valve 198 can be reduced. For example, the diameter L2 is approximately 40 mm, while the diameter L3 is 20 mm or less. Furthermore, in this embodiment, since the valve body 192 is completely housed inside the rod valve mechanism space 200, the flow of the corrosive gas 20 becomes smoother, and fluctuations in the corrosive gas 20 supplied from the corrosive gas outlet 174 to other locations can be suppressed.

[0026] The rod valve mechanism space 200 has a circular cross-section perpendicular to the long axis 115, with a diameter L4 greater than the diameter L5 of the rod 112's cross-section, and the difference between lengths L4 and L5 is in the range of 3 mm to 5 mm. Because this difference is small, turbulence in the flow from the valve operating space 199 to the rod movement gas supply space 160 can be suppressed, improving the effect of the protective gas 30 in the gas supply mechanism 140 in blocking the flow of corrosive gas 20 and further stabilizing it.

[0027] 2.2 Description of the drive mechanism 60 Figure 3 is a cross-sectional view of Figure 1, and Figure 4 is a cross-sectional view of Figure 2. Note that in Figure 3, some details of the connection between the drive mechanism 60 and the airtightness holding mechanism 120 are omitted. The drive mechanism 60 has a cylinder 62 and a piston 64. The piston 64, which supplies driving fluid to the valve closing supply unit 72, moves to the other side and closes the on-off valve 198 of the valve mechanism body 190. Conversely, when driving fluid is supplied to the valve opening supply unit 74, the fluid supplied from the valve closing supply unit 72 is gradually discharged by a mechanism (not shown), and the fluid from the valve opening supply unit 74 moves the piston 64 to one side in the opposite direction from the valve mechanism body 190, and the valve body 192 fixed to the other end 195 of the rod 112 is housed in the rod valve mechanism space 200 shown in Figure 3, and the on-off valve 198 is in the open state.

[0028] The relationship between the operation of the drive mechanism 60 and the opening and closing operation of the on-off valve 198 of the valve mechanism 180 will be explained. In the open valve state, the piston 64 is located on one side inside the cylinder 62, in other words, on the side opposite to the valve mechanism 180. An on-off cam 66 is fixed to the cylinder 62, and the on-off cam 66 is located on one side in the open valve state compared to its position in the closed valve state. An on-off hole 67 is formed in the on-off cam 66 as shown in Figure 3, and the on-off hole 67 is also located on one side compared to the closed valve state of the on-off valve 198.

[0029] When the on-off valve 198 is in the open state, the roller 68 provided at one end of the rod 112 is moved to one side by the other end of the on-off hole 67. Therefore, compared to when the valve is closed, the roller 68 is positioned to one side when the valve is open. The roller 68 moves the rod 112 to its most advanced position on one side, and the valve body 192 provided at the other end 195 of the rod 112 is completely housed inside the rod valve mechanism space 200 formed inside the valve mechanism body 190. Since the valve body 192 is not present in the valve operating space 199 of the valve mechanism body 190, the corrosive gas 20 introduced from the corrosive gas inlet 172 of the valve mechanism body 190 is smoothly discharged from the corrosive gas outlet 174 and supplied to the semiconductor manufacturing apparatus 26.

[0030] When closing the on-off valve 198 inside the valve mechanism 180, fluid is supplied to the valve closing supply unit 72 shown in Figure 4, and the piston 64 moves to the other side of the cylinder 62, i.e., to the valve mechanism 180 side. As the piston 64 moves, the pressing end 65 and the on-off cam 66 provided on the piston 64 move to the other side. A spring 80 is provided between the pressing end 65 fixed to the piston 64 and the fixed plate 114 fixed to the rod 112. As the pressing end 65 moves to the other side together with the piston 64, the fixed plate 114 fixed to the rod 112 moves to the other side via the spring 80, and the rod 112 having the valve body 192 moves to the other side. A position control roller 137 is fixed to the fixed plate 114, and the position control roller 137 moves to the other side along the position control groove 136 together with the rod 112. When the valve body 192, which was housed inside the rod valve mechanism space 200, moves to the other side and reaches a position facing the valve seat 196, the position control roller 137 fixed to the fixing plate 114 reaches the other end of the position control groove 136, preventing the position control roller 137 and the fixing plate 114 from moving to the other side, and thus preventing the movement of the rod 112.

[0031] However, as the fluid supply from the valve closing supply unit 72 continues, the opening / closing cam 66 moves to the other side, and the roller 68 moves perpendicular to the long axis 115 along the inside of the opening / closing hole 67 shown in Figure 3. In this state, the position control roller 137, which is integrated with the rod 112, acts as a fulcrum in the lever principle at the other end of the position control groove 136. The point of force is the roller 68 constrained to the opening / closing hole 67, and the point of action is the valve body 192 fixed to the other end 195 of the rod 112. The change in distance between the piston 64 and the rod 112 after the position control roller 137 fixed to the rod 112 reaches the other end of the position control groove 136 is absorbed by the contraction of the spring 80. As the rod 112 tilts with respect to the long axis 115 with the position control roller 137 as the fulcrum, the O-ring 194 of the valve body 192 comes into close contact with the valve seat 196, and the opening / closing valve 198 closes.

[0032] Conversely, when opening the on-off valve 198 from a closed state, fluid is supplied to the valve opening supply unit 74. In the initial state, the piston 64 moves slightly to one side, which reduces the inclination of the roller 68 fixed to the rod 112 along the opening / closing hole 67 with respect to the long axis 115, causing it to change to a horizontal direction. As a result, a gap is created between the valve body 192 fixed to the rod 112 and the valve seat 196. In this state, the spring 80 presses the fixing plate 114 to the other side against the pressing end 65, so the position control roller 137 is in contact with the other end of the position control groove 136, and the valve body 192 hardly moves in the direction along the long axis 115. Furthermore, when fluid is supplied to the cylinder 62 from the valve opening supply unit 74 and the piston 64 moves to one side, the roller 68 moves to one side due to the other end of the opening / closing hole 67, and the rod 112 and the valve body 192 provided on the rod 112 move to one side along the long axis 115. As a result, the valve body 192 is ultimately housed in the rod valve mechanism space 200 formed in the valve mechanism body 190 of the valve mechanism 180. Once the valve mechanism 180 is housed in the rod valve mechanism space 200, the position control roller 137 provided on the fixing plate 114 reaches one end of the position control groove 136, stopping the movement of the rod 112 along its long axis 115, and completing the opening operation of the on-off valve 198.

[0033] 2.3 Description of the airtight sealing mechanism 120 In Figures 3 to 5, an airtight sealing mechanism 120 and a gas supply mechanism 140 are provided between the drive mechanism 60 and the valve mechanism 180. In order to allow the rod 112 to move within the gas control device 100, a rod valve mechanism space 200 is formed in the valve mechanism 180, a rod movement gas supply space 160 is formed in the gas supply mechanism 140, and a rod airtight sealing mechanism space 124 is formed in the airtight sealing mechanism 120. As a result, there is a risk that corrosive gas 20 may flow into the drive mechanism 60 through the space on the outer circumference of the long axis 115. To prevent corrosive gas 20 from flowing into the drive mechanism 60, an airtight sealing mechanism 120 having a cylindrical bellows 132 is provided between the gas supply mechanism 140 and the drive mechanism 60.

[0034] The fixing plate 114 of the airtight sealing mechanism 120 is securely fixed to the rod 112, and the protective gas supply mechanism side end 130 provided on the airtight sealing mechanism body 122 is securely fixed to the airtight sealing mechanism body 122, which constitutes the entire outer circumference of the airtight sealing mechanism 120. A bellows storage space 134 is formed inside the airtight sealing mechanism body 122, and a cylindrical bellows 132 is housed in the bellows storage space 134. One end of the bellows 132 is securely fixed to the fixing plate 114, and the other end of the bellows 132 is securely fixed to the protective gas supply mechanism side end 130.

[0035] A rod 112 with a circular cross-section is located in the center of a cylindrical bellows 132. The bellows 132 expands and contracts in the direction of its long axis 115, blocking the movement of fluid between the inside and outside of the bellows 132. By providing the bellows 132, corrosive gas 20 is prevented from flowing from the airtight sealing mechanism 120 into the drive mechanism 60. However, the bellows 132 itself corrodes due to the corrosive gas 20, necessitating its replacement in a relatively short period of time. Furthermore, corrosion of the internal components of the airtight sealing mechanism 120 also occurred. Therefore, it is desirable to suppress the flow of corrosive gas 20 into the airtight sealing mechanism 120 as much as possible.

[0036] 2.4 Description of the airtight sealing mechanism 120 and the gas supply mechanism 140 Figures 1 to 5 illustrate the structural relationship between the gas supply mechanism 140 and other equipment. Figures 7 to 10 show the detailed structure of the gas supply mechanism 140. The gas supply mechanism 140 is provided between the airtight sealing mechanism 120 and the valve mechanism 180 to prevent corrosive gas 20 from flowing from the valve operating space 199 of the valve mechanism body 190 into the bellows housing space 134 of the airtight sealing mechanism 120. Between the rod valve mechanism space 200 formed in the valve mechanism 180 and the rod airtight mechanism space 124 formed in the airtight mechanism 120, a rod movement gas supply space 160 is provided inside the gas supply mechanism 140. The gas supply mechanism 140 supplies a protective gas 30, which is non-corrosive or has low corrosivity, to the rod movement gas supply space 160, thereby suppressing the flow of corrosive gas 20 from the valve operating space 199 through the rod valve mechanism space 200 into the bellows housing space 134. For example, nitrogen gas (N2) can be used as the protective gas 30. Since nitrogen gas is non-corrosive, there is no risk of it corroding the equipment. In addition, nitrogen gas is relatively easy to obtain and has a high safety effect in handling. Furthermore, even if it is mixed with corrosive gas 20 and sent to the semiconductor manufacturing equipment 26, problems are unlikely to occur.

[0037] The gas supply mechanism 140 is fixed to the airtight sealing mechanism body 122 of the airtight sealing mechanism 120. As shown in Figures 7 and 8, the gas supply mechanism 140 has a gas supply mechanism body 148, and a protective gas introduction section 142 having a protective gas inlet 144 for taking in protective gas 30 is fixed to the gas supply mechanism body 148 by a support section 146. The protective gas introduction section 142, the support section 146, and the gas supply mechanism body 148 are provided with a gas supply passage 150 for guiding the protective gas 30 taken in from the protective gas inlet 144 to a gas supply device 153 housed and fixed in the body. In this embodiment, the gas supply passage 150 is formed inside the protective gas introduction section 142, the support section 146, and the gas supply mechanism body 148. The main body 148 of the gas supply mechanism houses and fixes the gas supply device 153, and the gas supply device 153 has a cylindrical rod movement gas supply space 160 formed in its center for which the rod 112 is movably positioned.

[0038] The gas supply mechanism body 148 has a cylindrical storage hole 162 that extends along the long axis 115. A storage hole bottom 164 is formed on the other side of the storage hole 162 in the direction along the long axis 115, and a rod storage hole bottom space 165 for movably arranging a rod 112 is formed in the center of the surface perpendicular to the long axis 115 of the storage hole bottom 164. The gas supply device 153 is inserted into the storage hole 162 and fixed in place with the other side of the gas supply device 153 in close contact with the storage hole bottom 164 of the storage hole 162. In this embodiment, the storage hole 162 is open on one side 166, which is the side of the gas supply mechanism body 148 on the side of the airtightness maintenance mechanism 120, and closed on the other side, which is in the direction of the valve mechanism 180 along the long axis 115 from the side of the one side 166. This structure allows the gas supply device 153 to be inserted into the storage hole 162 from the side of the airtight sealing mechanism 120, which is one side 166, and then fixed in place. Since the storage hole 162 that houses the gas supply device 153 does not open to the other side 167, as shown in Figure 6, when the fixing screws 182 and 183 are removed and the gas supply mechanism body 148 is detached from the valve mechanism body 190 of the valve mechanism 180, the gas supply device 153 is not exposed to the other side 167. As a result, when performing operations such as moving the valve mechanism 180 and gas supply mechanism 140 from a fixed state to a detached state, or vice versa, it is less likely that the fixing state between the gas supply mechanism body 148 and the gas supply device 153 will change. Maintenance work on the on-off valve 198 is actually performed relatively frequently. If the storage hole 162 opens to the other side 167 of the gas supply device 153, the gas supply device 153 will be exposed to the outside when the gas supply mechanism 140 is removed from the valve mechanism 180. As a result, the fixing state between the storage hole 162 of the gas supply mechanism body 148 and the gas supply device 153 is likely to change. In other words, during maintenance work, adverse effects such as subtle changes in the fixing state between the gas supply mechanism body 148 of the gas supply mechanism 140 and the gas supply device 153 are more likely to occur.

[0039] In the diagrams relating to the gas supply mechanism body 148 and gas supply device 153 shown in Figures 8 to 10, an outer groove 154 is formed around the entire circumference of the outer surface 156 of the gas supply device 153. By inserting and fixing the gas supply device 153 into the storage hole 162 of the gas supply mechanism body 148, an outer peripheral passage 152 is formed around the entire circumference of the outer surface 156 of the gas supply device 153 due to the shape of the inner surface of the storage hole 162 and the outer groove 154 of the gas supply device 153. The inner end of the gas supply passage 150 opens into the outer peripheral passage 152, and the protective gas 30 introduced from the protective gas inlet 144 of the protective gas introduction section 142 flows into the outer peripheral passage 152 formed by the outer groove 154 of the gas supply device 153 via the outer peripheral passage 152, filling the entire outer peripheral passage 152 with protective gas 30.

[0040] Figure 10 is an enlarged view of the protective gas supply holes 158 formed in the gas supply device 153. Numerous gas supply holes 158 connecting the outer peripheral groove 154 formed on the outer circumference of the gas supply device 153 and the rod movement gas supply space 160 formed on the inside of the gas supply device 153 are formed around the entire circumference 155 of the gas supply device 153 at angular intervals of a predetermined angle θ. In Figure 8, gas supply holes 158 with a diameter of Φ1 are formed closer to the gas supply passage 150, and gas supply holes 159 with a larger diameter of Φ2 are formed on the opposite side of the gas supply passage 150. This configuration provides a correction for uniformity to prevent a decrease in the supply amount of protective gas 30 on the side farther from the gas supply passage 150. However, sufficient effect can also be obtained by providing protective gas supply holes 158 with the same diameter Φ1 around the entire circumference of the outer peripheral groove 154 of the gas supply device 153. Furthermore, the angle θ at which the protective gas supply holes 158 are formed may be made smaller in the direction opposite to the gas supply passage 150 to make the supply amount of protective gas 30 more uniform, but a good effect can be obtained even with the same angular spacing.

[0041] The following explanation assumes that protective gas supply holes 158 of the same diameter φ1 are formed at the same angle θ intervals along the entire circumference of the outer peripheral passage 152 formed on the outer circumference of the gas supply device 153. The protective gas 30 guided into the outer peripheral passage 152 is supplied to the rod movement gas supply space 160 via the numerous gas supply holes 158 formed along the entire circumference of the gas supply device 153. The supply of protective gas 30 from the numerous gas supply holes 158 in the gas supply mechanism 140 suppresses the flow of corrosive gas 20 that would otherwise flow from the valve operating space 199 of the valve mechanism 180 into the airtight sealing mechanism 120, and further fills the bellows storage space 134 of the airtight sealing mechanism 120, the airtight sealing mechanism rod arrangement space 126, and the rod valve mechanism space 200 of the valve mechanism body 190 with protective gas 30. This configuration prevents the corrosive gas 20 from coming into contact with the bellows 132, thus protecting the bellows 132 from the effects of the corrosive gas 20.

[0042] When the on-off valve 198 is opened, the fixing plate 114 that secures one end of the bellows 132 moves to one side, and the volume of the inner diameter space of the bellows 132 within the bellows housing space 134 increases rapidly. As a result, corrosive gas 20 present in the valve operating space 199 is more easily drawn into the airtight sealing mechanism 120. What is important here is to prevent the flow of corrosive gas 20 from the valve operating space 199 into the bellows housing space 134 by supplying protective gas 30 from the gas supply device 153. To achieve this, the gas flow in the rod movement gas supply space 160 must be stabilized so that it is close to laminar flow with minimal turbulence. For example, if a large vortex is generated, it becomes difficult to completely prevent the flow of corrosive gas 20 into the bellows housing space 134 by supplying protective gas 30.

[0043] In the rod movement gas supply space 160 that supplies the protective gas 30, the inner surface of the gas supply device 153 and the surface of the bottom of the storage hole 164 facing the rod 112 are made to protrude inward by a length L8 from other components, so as to bring them closer to the outer surface of the rod 112, in order to reduce the distance between the rod 112 and the inner surface of the gas supply device 153. By narrowing the gas supply rod outer peripheral space 161, which is the distance between each of the above inner surfaces and the outer circumference of the rod 112, the movement of gas inside the rod movement gas supply space 160 is stabilized as much as possible, in other words, large vortices are prevented from forming. With this structure, even if a pumping action occurs that enlarges the bellows storage space 134, the inflow of corrosive gas 20 can be stably suppressed by supplying the protective gas 30 with the drive mechanism 60. Furthermore, the cross-sectional area perpendicular to the long axis 115 in the rod movement gas supply space 160 is significantly smaller than the cross-sectional area perpendicular to the long axis 115 in the rod valve mechanism space 200. As a result, changes in gas movement in the rod movement gas supply space 160 are greatly suppressed, and gas movement in the movement gas supply space 160 is stabilized. This makes it easier to suppress the inflow of corrosive gas 20 from the valve operating space 199, resulting in a stabilized corrosion suppression effect.

[0044] It is desirable to equalize and stabilize the supply of protective gas 30 from the outer circumferential groove 154 of the protective gas 30 to the rod movement gas supply space 160. As shown in Figures 9 and 10, a number of protective gas supply holes 158 are formed radially in the gas supply device 153, and protective gas 30 is supplied from these protective gas supply holes 158. In this embodiment, holes are formed and the protective gas 30 is supplied from these holes. The holes have high processing accuracy, stabilize their characteristics, and can stabilize the supply characteristics over the entire circumference of the cylindrical gas supply device 153. Furthermore, changes in characteristics during assembly can be reduced. Also, changes over time are very small. For these reasons, a very stable effect can be obtained over a long period of time. Since protective gas 30 is a gas and is hardly affected by surface tension, the diameter of the protective gas supply holes 158 can be made small. For example, the diameter Φ1 of the gas supply holes 158 can be 0.5 mm or less, preferably 0.2 mm or less. By setting the diameter Φ1 of the protective gas supply hole 158 to such a value, it is possible to make it less susceptible to the effects of pressure changes and pressure unevenness in the outer groove 154. Furthermore, as shown in Figure 10, it is preferable to keep the angle θ constant and provide 25 or more, preferably 40 or more, protective gas supply holes 158 at a constant angle θ around the entire circumference of the gas supply device 153. By setting these conditions, it is possible to prevent corrosive gas 20 from flowing into the airtight sealing mechanism 120 through the rod movement gas supply space 160 during the opening and closing operations of the on / off valve 198.

[0045] In Figure 5, the length L1 is set to 45 mm or more, and more preferably 50 mm or more, in order to suppress the influence of fluctuations in the corrosive gas 20 within the valve operating space 199 on the gas supply mechanism 140. The diameter L2 of the circular opening of the corrosive gas inlet 172 is greater than twice the diameter L3 of the circular opening of the corrosive gas outlet 174. By reducing the diameter L3 of the corrosive gas outlet 174, fluctuations in the corrosive gas 20 supplied to the semiconductor manufacturing apparatus 26 due to the opening and closing operation of the on-off valve 198 can be reduced. For example, the diameter L2 is approximately 40 mm, while the diameter L3 is 20 mm or less.

[0046] 3. Description of the invention applied to the examples 3.1 Description of the First Invention [First Invention] The first invention relates to a gate valve 50 in which a drive mechanism 60 for moving a rod 112, a valve mechanism 180 for controlling the flow of a corrosive gas 20 based on the movement of the rod 112, and an airtight sealing mechanism 120 having a bellows 132 are arranged along the long axis 115, which is the longitudinal axis of the rod 112, and the airtight sealing mechanism 120 is provided between the drive mechanism 60 and the valve mechanism 180 so that the airtight sealing mechanism 120 prevents leakage of the corrosive gas 20 from the valve mechanism 180 to the drive mechanism 60, A gas supply mechanism 140 is further provided between the valve mechanism 180 and the airtightness maintenance mechanism 120. The gas supply mechanism 140 includes a protective gas introduction section 142 into which a protective gas 30 for preventing corrosion is introduced, and a gas supply device 153 for supplying the introduced protective gas 30. The gas supply device 153 of the gas supply mechanism 140 has a rod movement gas supply space 160 formed inside, which is a space for movably arranging the rod 112. The gas supply mechanism 140 supplies protective gas 30 introduced from the protective gas introduction section 142 to the rod movement gas supply space 160 via the gas supply device 153, thereby preventing the movement of corrosive gas 20 from the valve mechanism 180 to the airtightness maintenance mechanism 120. The gate valve 50 is characterized by the following features.

[0047] According to the first invention, a protective gas 30, which is non-corrosive or has low corrosiveness, is supplied from a gas supply mechanism 140 provided between the valve mechanism 180 and the airtightness maintenance mechanism 120 to a rod movement gas supply space 160 formed inside the gas supply mechanism 140 where the rod 112 is located. By supplying the protective gas 30, it is possible to suppress the flow of corrosive gas 20 into the airtightness maintenance mechanism 120. As a result, it is possible to suppress corrosion of various devices of the airtightness maintenance mechanism 120, including the bellows 132, by the corrosive gas 20.

[0048] 3.2 Description of the Second Invention [Second Invention] The second invention relates to the gate valve 50 of the first invention, The valve mechanism 180 includes a valve mechanism body 190 and an on / off valve 198 for controlling the flow of corrosive gas 20. The valve mechanism body 190 is provided with a corrosive gas inlet 172 into which corrosive gas 20 is introduced and a corrosive gas outlet 174 for supplying corrosive gas 20 elsewhere. Furthermore, a valve operating space 199 for the operation of the on / off valve 198 is formed between the corrosive gas inlet 172 and the corrosive gas outlet 174. The on / off valve 198 has a valve seat 196 provided on the side of the valve operating space 199 of the corrosive gas outlet 174 and a valve body 192 provided at the end of the rod 112. The valve mechanism body 190 further has a valve mechanism space 200 for a rod that connects the valve operating space 199 and the gas supply space 160 for rod movement of the gas supply mechanism 140, and also allows the rod 112 to be moved. The cross-sectional area of ​​the rod valve mechanism space 200 perpendicular to the long axis 115 is larger than the cross-sectional area of ​​the rod movement gas supply space 160 formed in the gas supply mechanism 140 perpendicular to the long axis 115. The gate valve 50 is characterized by the following features.

[0049] In the second invention, fluctuations in the corrosive gas 20 generated in the valve operating space 199 of the valve mechanism 180 can be suppressed from being transmitted to the rod movement gas supply space 160. As a result, the inflow of corrosive gas 20 into the airtight sealing mechanism 120 can be stably prevented. Increasing the supply of protective gas 30 to the rod movement gas supply space 160 has various effects, but even with a relatively small amount of protective gas 30 supplied, the inflow of corrosive gas 20 into the airtight sealing mechanism 120 can be stably suppressed.

[0050] 3.3 Description of the Third Invention [The third invention] The third invention is the gate valve 50 of the second invention, The gas supply mechanism 140 includes a gas supply mechanism body 148 having a storage hole 162 for housing the gas supply device 153. The gas supply device 153 has a cylindrical shape and is fixed in a state where it is housed in the storage hole 162 of the gas supply mechanism body 148. Inside the gas supply device 153, a rod movement gas supply space 160 is formed for movably positioning the rod 112. An outer peripheral passage 152 for flowing protective gas 30 is formed between the outer peripheral surface 156 of the cylindrical gas supply device 153 and the inner surface of the storage hole 162 of the gas supply mechanism body 148. The protective gas 30 introduced from the protective gas introduction section 142 of the gas supply mechanism 140 is supplied over the entire circumference of the outer circumferential surface 156 of the gas supply device 153 via the outer circumferential passage 152 formed along the outer circumferential surface 156 of the gas supply device 153, and the protective gas 30 is supplied from the outer circumferential surface 156 of the gas supply device 153 to the rod movement gas supply space 160. The gate valve 50 is characterized by the following features.

[0051] The structure, which involves forming a storage hole 162 in the main body 148 of the gas supply mechanism and housing the gas supply device 153 in the storage hole 162, thereby forming an outer peripheral passage 152 for flowing protective gas 30 on the outer peripheral surface 156 of the gas supply device 153, has the advantage of being manufactured with high precision. Furthermore, this configuration exhibits little change over time, providing stable performance over a long period. It also has the advantage of easily ensuring airtightness against temperature changes.

[0052] 3.4 Description of the Fourth Invention [Fourth Invention] The fourth invention is the gate valve 50 of the third invention, The cylindrical gas supply device 153, which is fixed in a state where it is housed in the storage hole 162 of the gas supply mechanism body 148, has a recessed outer circumferential groove 154 formed around its entire circumference on the outer circumferential surface 156. As the gas supply device 153 is housed in the storage hole 162 of the gas supply mechanism body 148, the outer peripheral passage 152 is formed by the outer peripheral surface 156 of the gas supply device 153, which has a recessed shape, and the inner peripheral surface of the storage hole 162 of the gas supply mechanism body 148. The gas supply device 153 has numerous gas supply holes 158 that connect the rod movement gas supply space 160 and the outer periphery groove 154, formed around the entire circumference of the outer periphery groove 154. The protective gas 30 introduced from the protective gas introduction section 142 of the gas supply mechanism 140 is supplied to the outer peripheral passage 152 formed on the outer periphery of the gas supply device 153, and further supplied from the outer peripheral passage 152 to the rod movement gas supply space 160 via a number of gas supply holes 158. The gate valve 50 is characterized by the following features.

[0053] The structure is designed to supply protective gas 30, guided into the outer peripheral passage 152, to the rod movement gas supply space 160 via a number of gas supply holes 158. As a method of supplying protective gas 30, guided into the outer peripheral passage 152, to the rod movement gas supply space 160, a gap perpendicular to the long axis 115 may be formed at the contact point between the gas supply device 153 and the storage hole 162 formed in the gas supply mechanism body 148, and the gas may be supplied through this gap perpendicular to the long axis 115. However, in the fourth invention, instead of forming a gap perpendicular to the long axis 115 at the contact point between the gas supply device 153 and the storage hole 162 formed in the gas supply mechanism body 148, a number of holes, which are gas supply holes 158, are formed in the gas supply device 153, and the protective gas 30 is supplied from the outer peripheral passage 152 to the rod movement gas supply space 160 via these gas supply holes 158. By using a structure that utilizes gas supply holes 158 in this manner, the amount of protective gas 30 supplied from the outer peripheral passage 152 to the rod movement gas supply space 160 can be stabilized. Furthermore, instability in characteristics, such as changes in the amount of protective gas 30 supplied to the rod movement gas supply space 160 due to slight manufacturing errors when inserting the gas supply device 153 into the storage hole 162 of the gas supply mechanism body 148, can be suppressed. This structure also has the effect of being less susceptible to changes over time. In addition, by using protective gas supply holes 158, the processing accuracy can be increased, and the diameter of the protective gas supply holes 158 can be reduced. By providing many protective gas supply holes 158 with a small diameter, the uniformity of the supply of protective gas 30 to the rod movement gas supply space 160 can be increased, thereby enhancing and stabilizing the effect of preventing the inflow of protective gas 30.

[0054] 3.5 Description of the Fifth Invention [The fifth invention] The fifth invention is the gate valve 50 of the fourth invention, The gate valve 50 is characterized in that each of the numerous gas supply holes 158 has a diameter of 0.5 mm or less.

[0055] It is desirable that the supply of protective gas 30 from the outer peripheral passage 152 to the rod movement gas supply space 160 be uniform. If there are inconsistencies in the supply amount of protective gas 30 in the circumferential direction 155 in Figure 9, there is a risk that the effect of preventing corrosive gas 20 from flowing into the airtight sealing mechanism 120 will be inconsistent. To make the supply of protective gas 30 from the outer peripheral passage 152 to the rod movement gas supply space 160 more uniform, it is desirable that the diameter of each gas supply hole 158 is small. The diameter of the gas supply hole 158 should be 0.5 mm or less. A diameter of 0.2 mm or less would be even more effective.

[0056] 3.6 Description of the sixth invention [The sixth invention] The sixth invention is the gate valve 50 of the second invention, The airtight sealing mechanism 120 has a protective gas supply mechanism side end 130 in which an airtight sealing mechanism rod arrangement space 126 is formed for movably arranging the rod 112 on the side of the gas supply mechanism 140, The airtight sealing mechanism 120 has a bellows storage space 134 for housing the rod 112 and the bellows 132 arranged on the outer circumference of the rod 112, on the side of the drive mechanism 60 rather than the airtight sealing mechanism rod arrangement space 126. The cross-sectional area of ​​the rod arrangement space 126 of the airtight mechanism, which is perpendicular to the long axis 115, which is the longitudinal axis of the rod 112, is smaller than the cross-sectional area of ​​the bellows storage space 134, which is perpendicular to the long axis 115. The gate valve 50 is characterized by the following features.

[0057] As mentioned above, when the on-off valve 198 is opened, the bellows 132 expands along the long axis 115, increasing the volume of the bellows storage space 134. Conversely, when the valve is closed, the bellows 132 contracts along the long axis 115, reducing the volume of the bellows storage space 134. When turbulence occurs in the gas flow due to such changes, the effect of suppressing the inflow of corrosive gas 20 by supplying protective gas 30 from the rod movement gas supply space 160 is reduced, making it difficult to suppress the flow of corrosive gas 20. There are also limits to how much the supply amount of protective gas 30 can be increased. In this embodiment, the protective gas supply mechanism side end 130 of the airtightness holding mechanism body 122 is made to protrude toward the rod 112 in the vertical plane of the long axis 115 between the bellows storage space 134 and the rod movement gas supply space 160, forming an airtightness holding mechanism rod arrangement space 126 inside the protective gas supply mechanism side end 130. By reducing the cross-section perpendicular to the long axis 115 of the airtightness mechanism rod arrangement space 126, turbulence of the gas during the opening and closing operations of the bellows storage space 134 is suppressed, and the gas flow in the rod movement gas supply space 160 is stabilized. As a result, the inflow of corrosive gas 20 into the airtightness mechanism 120 can be stably suppressed with a relatively small supply of protective gas 30. [Explanation of symbols]

[0058] 20: Corrosive gas, 22: Piping, 24: Piping, 26: Semiconductor manufacturing equipment, 30: Protective gas, 50: Gate valve, 60: Drive mechanism, 62: Cylinder, 64: Piston, 65: Pressing end, Opening / closing cam, 66, 67: Opening / closing hole, 68: Roller, 72: Closing valve supply unit, Opening valve supply unit, 74: Opening valve supply unit, 80: Spring, 112: Rod, 113: Drive side space, 114: Fixing plate, 115: Long shaft, 118: Main body side Fixed part, 120: airtight sealing mechanism, 121: fixing screw, 122: airtight sealing mechanism body, 123: cylindrical support, 124: airtight sealing mechanism space for rod, 125: cylindrical projection, 126: airtight sealing mechanism rod arrangement space, 127: guide groove, 128: guide end, 130: protective gas supply mechanism side end, 132: bellows, 134: bellows storage space, 140: gas supply mechanism, 142: protective gas introduction part, 1 43: Fixing screw, 144: Protective gas inlet, 146: Support part, 148: Gas supply mechanism body, 150: Gas supply passage, 151: Gas supply part, 152: Outer peripheral passage, 153: Gas supply device, 154: Outer peripheral groove, 155: Circumferential direction, 156: Outer peripheral surface, 158: Gas supply hole, 159: Gas supply hole, 160: Gas supply space for rod movement, 161: Outer peripheral space for gas supply rod, 162: Storage hole, 164 : Bottom of storage hole, 165: Bottom space of storage hole for rod, 166: One side, 167: Other side, 172: Corrosive gas inlet, 174: Corrosive gas outlet, 180: Valve mechanism, 182: Fixing screw, 183: Fixing screw, 190: Valve mechanism body, 192: Valve body, 194: O-ring, 196: Valve seat, 198: On / off valve, 199: Valve operating space, 200: Valve mechanism space for rod, 202: Outer circumference space of valve mechanism rod.

Claims

1. In a gate valve in which a drive mechanism for moving a rod, a valve mechanism for controlling the flow of a corrosive gas based on the movement of the rod, and an airtight sealing mechanism having a bellows are arranged along the long axis which is the longitudinal axis of the rod, and the airtight sealing mechanism is provided between the drive mechanism and the valve mechanism, the airtight sealing mechanism prevents the corrosive gas from leaking from the valve mechanism to the drive mechanism, A gas supply mechanism is further provided between the valve mechanism and the airtight sealing mechanism. The gas supply mechanism comprises a protective gas introduction section into which a protective gas for preventing corrosion is introduced, and a gas supply device for supplying the introduced protective gas. The gas supply device of the gas supply mechanism has a rod-moving gas supply space formed inside, which is a space for movably arranging the rod. The gas supply mechanism supplies the protective gas introduced from the protective gas introduction section to the rod movement gas supply space from the gas supply device, thereby preventing the movement of the corrosive gas from the valve mechanism to the airtight sealing mechanism. A gate valve characterized by the following features.

2. In the gate valve according to claim 1, The valve mechanism comprises a valve mechanism body and an on / off valve for controlling the flow of the corrosive gas. The valve mechanism body is provided with a corrosive gas inlet into which the corrosive gas is introduced and a corrosive gas outlet for supplying the corrosive gas to another location, and a valve operating space for the operation of the on / off valve is formed between the corrosive gas inlet and the corrosive gas outlet. The on-off valve has a valve seat provided on the side of the valve operating space of the corrosive gas outlet and a valve body provided at the end of the rod, The valve mechanism body further includes a rod valve mechanism space that connects the valve operating space and the rod movement gas supply space of the gas supply mechanism, and also provides a space for movably positioning the rod. The cross-sectional area of ​​the rod valve mechanism space in the direction perpendicular to the long axis is greater than the cross-sectional area of ​​the rod movement gas supply space formed in the gas supply mechanism perpendicular to the long axis. A gate valve characterized by the following features.

3. In the gate valve according to claim 2, The gas supply mechanism comprises a gas supply mechanism body having a storage hole for housing the gas supply device, The gas supply device has a cylindrical shape, and the gas supply device is fixed in a state where it is housed in the storage hole of the gas supply mechanism body. Inside the gas supply device, a gas supply space for rod movement is formed to allow the rod to be moved. An outer peripheral passage for flowing the protective gas is formed between the outer peripheral surface of the cylindrical gas supply device and the inner surface of the storage hole of the gas supply mechanism body. The protective gas introduced from the protective gas introduction section of the gas supply mechanism is supplied over the entire circumference of the outer surface of the gas supply device via the outer peripheral passage formed along the outer surface of the gas supply device, and the protective gas is supplied from the outer surface of the gas supply device to the rod movement gas supply space. A gate valve characterized by the following features.

4. In the gate valve according to claim 3, The cylindrical gas supply device, which is fixed in the storage hole of the gas supply mechanism body, has a recessed outer groove formed around its entire circumference on its outer surface. As the gas supply device is housed in the storage hole of the gas supply mechanism body, the outer peripheral passage is formed by the recessed outer peripheral surface of the gas supply device and the inner peripheral surface of the storage hole of the gas supply mechanism body. The gas supply device has numerous gas supply holes connecting the rod movement gas supply space and the outer periphery groove, formed around the entire circumference of the outer periphery groove. The protective gas introduced from the protective gas introduction section of the gas supply mechanism is supplied to the outer peripheral passage formed on the outer periphery of the gas supply device, and further supplied from the outer peripheral passage to the rod movement gas supply space via a number of gas supply holes. A gate valve characterized by the following features.

5. In the gate valve according to claim 4, A gate valve characterized in that each of the numerous gas supply holes has a diameter of 0.5 mm or less.

6. In the gate valve according to claim 2, The airtight sealing mechanism has a protective gas supply mechanism side end formed with an airtight sealing mechanism rod arrangement space for movably arranging the rod on the side of the gas supply mechanism, The airtight sealing mechanism has a bellows storage space for housing the rod and the bellows arranged around the outer circumference of the rod, on the side of the drive mechanism rather than the airtight sealing mechanism rod arrangement space. The cross-sectional area of ​​the space for arranging the rod of the airtight mechanism, perpendicular to the long axis which is the longitudinal axis of the rod, is smaller than the cross-sectional area of ​​the bellows storage space, perpendicular to the long axis. A gate valve characterized by the following features.

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