Gate valve

Abstract

To provide a gate valve that has excellent corrosion resistance and controls the flow of corrosive gas, and in particular to provide a gate valve that can suppress corrosion of the bellows. [Solution] In order to prevent the corrosive gas 20 from flowing from the valve mechanism 180 into the airtight mechanism 120 equipped with the bellows 132 through a gap formed along the outer peripheral 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 being corroded by the corrosive gas 20, a gas supply mechanism 140 is provided between the valve mechanism 180 and the airtight mechanism 120, and a non-corrosive protective gas 30 is supplied from the gas supply mechanism 140 to the gap formed along the outer peripheral surface of the rod 112, thereby preventing the corrosive gas 20 from flowing from the valve mechanism 180 into the airtight mechanism 120.

Description

[Technical Field]

[0001] The present invention relates to a gate valve suitable for controlling the flow of 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 includes control of supplying the corrosive gas to another device or stopping the supply to another device, control of changing the supply destination of the corrosive gas, control of changing the amount of the corrosive gas supplied, or control of changing the supply ratio to the supply destination when the corrosive gas is supplied to multiple destinations. [Background technology]

[0002] For example, corrosive gases are used in semiconductor manufacturing equipment when producing circuit boards. Gate valves used to control the flow of corrosive gases are required to be resistant to corrosion. For example, Patent Documents 1 and 2, which are prior art documents listed below, disclose techniques for protecting gate valves themselves from corrosion caused by corrosive gases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-346238 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-25293

[0004] Patent Document 1 discloses the provision of a sealing mechanism in a gate valve to prevent the inflow of corrosive gas from the valve portion that controls the flow of the corrosive gas into the drive mechanism that operates the valve. Patent Document 1 also points out the problem of the sealing mechanism itself, which prevents the leakage of corrosive gas, being corroded by the corrosive gas. To solve this problem, a mechanical structure is proposed to prevent the corrosive gas from flowing into the sealing mechanism. Patent Document 2 also describes the need to improve the corrosion resistance of the bellows in the sealing mechanism and proposes covering the entire bellows with a protective film made of a highly corrosion-resistant material. Summary of the Invention [Problem to be solved by the invention]

[0005] The improvements described in Patent Documents 1 and 2 are insufficient in preventing corrosion of the sealing mechanism due to corrosive gases, which results in a problem in that, for example, in semiconductor manufacturing equipment, maintenance and replacement of the sealing mechanism is required at relatively short intervals.

[0006] However, the present invention does not negate the above-mentioned improvements, for example, the improvement measures for improving the corrosion resistance of the bellows of the sealing mechanism described in Patent Document 2. In addition to the improvements of the present invention described below, it is preferable to implement the improvements described in Patent Documents 1 and 2, for example, the measure to improve the corrosion resistance of the bellows itself proposed in Patent Document 2 in addition to the present invention. However, as mentioned 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 itself.

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

[0008] [First invention] A first invention is 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 airtightness maintaining mechanism having a bellows are arranged along a major axis that is the longitudinal axis of the rod, and the airtightness maintaining mechanism is provided between the drive mechanism and the valve mechanism, thereby preventing leakage of the corrosive gas from the valve mechanism to the drive mechanism, a gas supply mechanism is further provided between the valve mechanism and the airtightness maintaining mechanism, the gas supply mechanism includes a protective gas inlet 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 is formed therein with a gas supply space for rod movement, which is a space for movably arranging the rod; the gas supply mechanism supplies the protective gas introduced from the protective gas inlet portion from the gas supply device to the rod movement gas supply space, thereby preventing the corrosive gas from moving from the valve mechanism to the airtightness maintaining mechanism. A gate valve characterized by the above.

[0009] [Second Invention] The second invention is the gate valve of the first invention, the valve mechanism has 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 through which the corrosive gas is introduced and a corrosive gas outlet for supplying the corrosive gas to another location, and further, a valve operating space for operating 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 valve operating space side of the corrosive gas outlet and a valve body provided at an end of the rod, the valve mechanism main body further includes a rod valve mechanism space that connects the valve operation space and the rod movement gas supply space of the gas supply mechanism and in which the rod is movably disposed, The cross-sectional area of ​​the rod valve mechanism space in a direction perpendicular to the long axis is larger than the cross-sectional area of ​​the rod movement gas supply space formed in the gas supply mechanism in a direction perpendicular to the long axis. Greater than A gate valve characterized by the above.

[0010] [Third Invention] A third aspect of the present invention is the gate valve of the second aspect of the present invention, the gas supply mechanism includes a gas supply mechanism body having a storage hole for storing the gas supply device, the gas supply device has a cylindrical shape, and is fixed in a state of being housed in the housing hole of the gas supply mechanism main body; a gas supply space for the rod movement in which the rod is movably disposed is formed inside the gas supply device; an outer circumferential passage for flowing the protective gas is formed between an outer circumferential surface of the gas supply device having a cylindrical shape and an inner surface of the accommodation hole of the gas supply mechanism main body; the protective gas introduced from the protective gas inlet of the gas supply mechanism is supplied over the entire circumference of the outer circumferential surface of the gas supply device through the outer circumferential passage formed along the outer circumferential surface of the gas supply device, and the protective gas is supplied from the outer circumferential surface of the gas supply device to the rod movement gas supply space; A gate valve characterized by the above.

[0011] [Fourth Invention] A fourth aspect of the present invention is the gate valve of the third aspect of the present invention, the cylindrical gas supply device that is fixed in a state of being accommodated in the accommodation hole of the gas supply mechanism main body has an outer peripheral groove that is recessed over the entire circumference of the outer peripheral surface, the gas supply device is accommodated in the accommodation hole of the gas supply mechanism main body, whereby the outer circumferential passage is formed by the outer circumferential surface of the gas supply device having a recessed shape and the inner circumferential surface of the accommodation hole of the gas supply mechanism main body; a plurality of gas supply holes connecting the rod movement gas supply space and the outer circumferential groove are formed in the gas supply device around the entire periphery of the outer circumferential groove; the protective gas introduced from the protective gas inlet of the gas supply mechanism is supplied to the outer periphery-side passage formed on the outer periphery of the gas supply device, and is further supplied from the outer periphery-side passage to the rod movement gas supply space via the multiple gas supply holes; A gate valve characterized by:

[0012] [Fifth Invention] A fifth aspect of the present invention is the gate valve of the fourth aspect of the present invention, The gate valve is characterized in that each of the multiple gas supply holes has a diameter of 0.5 mm or less.

[0013] [Sixth Invention] A sixth aspect of the present invention is the gate valve of the fourth aspect of the present invention, The airtightness maintaining mechanism has a mechanism for movably arranging the rod on the side of the gas supply mechanism. Airtight mechanism rod placement space a protective gas supply mechanism side end formed thereon; The airtightness maintaining mechanism includes: the airtightness maintaining mechanism rod arrangement space a bellows storage space for storing the rod and the bellows arranged on the outer periphery of the rod is formed closer to the drive mechanism than the A longitudinal axis of the rod is perpendicular to the longitudinal axis. the airtightness maintaining mechanism rod arrangement space The cross-sectional area of ​​the bellows storage space perpendicular to the major axis is smaller than the cross-sectional area of ​​the bellows storage space perpendicular to the major axis. A gate valve characterized by the above. [Effects of the Invention]

[0014] According to the present invention, in a gate valve for controlling the flow of a corrosive gas, it is possible to obtain a gate valve having excellent corrosion resistance that can significantly suppress the influence of the corrosive action of the corrosive gas. [Brief explanation of the drawings]

[0015] [Figure 1]1 is an explanatory diagram showing the front external shape of an embodiment of a gate valve to which the present invention is applied. [Figure 2] FIG. 2 is an explanatory diagram showing the external shape of the gate valve shown in FIG. 1 in plan view. [Figure 3] FIG. 2 is an explanatory diagram showing a cross section of the gate valve shown in FIG. [Figure 4] FIG. 3 is an explanatory diagram showing a cross section of the gate valve shown in FIG. 2. [Figure 5] FIG. 4 is a partially enlarged view of the gate valve shown in FIG. 3. [Figure 6] FIG. 2 is an explanatory diagram showing a state in which a valve mechanism body of the gate valve is removed. [Figure 7] FIG. 2 is an enlarged view of the gas supply mechanism and airtightness maintaining mechanism 120 of the gate valve. [Figure 8] 3 is an explanatory diagram for explaining a gas supply mechanism of the gate valve. FIG. [Figure 9] 9 is a cross-sectional view of the gas supply mechanism shown in FIG. 8 taken along line AA. [Figure 10] 3 is an explanatory diagram for explaining a gas supply device of the gas supply mechanism. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] In the embodiment of the gate valve 50 for carrying out the invention described below, components designated by the same reference numerals have essentially the same structure, perform the same function, and achieve substantially the same effects. To avoid repetition, descriptions of components designated by the same reference numerals may be omitted. The embodiment described below is a gate valve having a function of controlling whether or not to supply the corrosive gas 20 to another location. However, the gate valve to which the present invention is applicable is not limited to gate valves that control whether or not to supply the corrosive gas 20 to another location. In addition to gate valves that perform this control, the present invention can also be applied to gate valves that have the function of changing the supply destination of the corrosive gas 20, changing the amount of corrosive gas supplied, or changing the supply ratio to a destination when the corrosive gas is supplied to multiple destinations. The configuration and effects of the airtightness maintaining mechanism 120, which is an important component of the present invention, enable the present invention to be applied even if the structure and function of the gas supply mechanism 140 are different. As a typical example of a gate valve having the above control function, an example in which a gate valve 50 having a function of controlling whether or not the corrosive gas 20 is supplied to another location will be described below.

[0017] 1. Description of the overall configuration of a gate valve 50 according to an embodiment of the present invention (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 shown as one embodiment is used to control the supply of corrosive gas 20 to semiconductor manufacturing equipment 26. The corrosive gas 20 to be controlled is, for example, a gas that has a strong corrosive effect and is used in the manufacture of semiconductor chips.

[0018] Gate valve 50 includes drive mechanism 60, airtightness maintaining mechanism 120, gas supply mechanism 140, and valve mechanism 180, which are arranged from one side to the other along major axis 115, which indicates the longitudinal direction of rod 112 provided inside gate valve 50. Valve mechanism 180 has an on-off valve 198 for controlling the supply of corrosive gas 20 to semiconductor manufacturing equipment 26 based on the movement of rod 112, and drive mechanism 60 controls the movement of rod 112, and the supply of corrosive gas 20 to semiconductor manufacturing equipment 26, which is another device, is controlled based on the movement of rod 112.

[0019] The airtightness mechanism 120 has a bellows 132 therein, which prevents the 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 airtightness mechanism 120 and the valve mechanism 180 to prevent the bellows 132 from being corroded by the corrosive gas 20. The gas supply mechanism 140 supplies a non-corrosive or low-corrosive protective gas 30 to a space formed around the outer periphery of the rod 112 disposed therein, thereby preventing the corrosive gas 20 from flowing from the valve mechanism 180 into the airtightness mechanism 120. This action allows the gas supply mechanism 140 to prevent the bellows 132 provided in the airtightness mechanism 120 from being corroded by the corrosive gas 20. For example, nitrogen gas is used as the protective gas 30. The corrosive gas 20 may be any of a variety of 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 semiconductor manufacturing equipment 26, the gate valve 50 is fixed and maintained in a fixed position relative to the semiconductor manufacturing equipment 26. The corrosive gas 20 is supplied to a corrosive gas inlet 172 of a valve mechanism 180 of the gate valve 50 from a corrosive gas 20 supply source (not shown) via piping 22, and is then supplied to the semiconductor manufacturing equipment 26 from a corrosive gas outlet 174 of the valve mechanism 180 via piping 24. The gate valve 50 is provided with an airtightness mechanism 120 having an internal bellows 132 to prevent the corrosive gas 20 from flowing from the valve mechanism 180 into the drive mechanism 60. However, if the corrosive gas 20 flows into the airtightness mechanism 120, the bellows 132 itself may be corroded by the corrosive gas 20. Furthermore, corrosion may occur not only in the bellows 132 but also in various other components of the airtightness mechanism 120. The gate valve 50 includes a gas supply mechanism 140, which acts to prevent the corrosive gas 20 from flowing from the valve mechanism 180 into the airtightness mechanism 120. This significantly reduces the problem of the bellows 132 itself being corroded by the corrosive gas 20. The gas supply mechanism 140 receives a protective gas 30 via a supply pipe 32 and supplies the protective gas 30 to a gas supply rod outer circumferential space 161 (shown in FIG. 5 ) formed on the outer periphery of the rod 112 located inside the gas supply mechanism 140. This configuration prevents the corrosive gas 20 from flowing from the valve mechanism 180 into the airtightness mechanism 120, thereby preventing corrosion of the bellows 132. As a result, the mass production efficiency of the semiconductor manufacturing apparatus 26 can be significantly improved.

[0021] The drive mechanism 60, the airtightness maintaining mechanism 120, and the gas supply mechanism 140 are fixed together by respective fixing means, and the gas supply mechanism 140 is fixed together with the valve mechanism 180 by fixing means such as fixing screws 182 and 183. When the fixing by the fixing screws 182 and 183 is released, the drive mechanism 60, the gas supply space 160 for rod movement, 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 element 192 fixed to the end of the rod 112 can be removed from the valve mechanism 180 together with the drive mechanism 60, the protective gas supply mechanism side end 130, and the gas supply mechanism 140 (as shown in FIG. 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 the valve mechanism 180 (1) Description of the configuration of the valve mechanism 180 Fig. 3 is a cross-sectional view of Fig. 1, Fig. 4 is a cross-sectional view of Fig. 2, and Fig. 5 is an enlarged view of the airtightness maintaining mechanism 120, the gas supply mechanism 140, and the valve mechanism 180 in Fig. 3. The valve mechanism 180 is provided with a valve mechanism main body 190 for forming the corrosive gas inlet 172 and the corrosive gas outlet 174. Inside the valve mechanism main body 190, there are formed a valve operating space 199 incorporating 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 axis 181 connects 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 having a circular shape in a plane perpendicular to the axis 181 is provided on the side of the valve operating space 199 of the corrosive gas outlet 174, and a valve element 192 is fixed to the other end 195 of the rod 112. The valve element 192 has a circular shape in a plane perpendicular to the axis 181, and an O-ring 194 provided on the valve element 192 is also circular. The valve seat 196 and the valve element 192 constitute an on-off valve 198. In the valve operating space 199 of the valve mechanism main body 190, when the on-off valve 198 is in a closed state, the rod 112 is moved along the longitudinal axis 115 by the drive mechanism 60 toward the other side, that is, the valve mechanism 180 side, and when the valve element 192 is positioned facing the valve seat 196, the movement of the rod 112 along the longitudinal axis 115 stops, and the rod 112 is tilted slightly by the drive mechanism 60 relative to the longitudinal axis 115 in the direction of arrow B, which is the direction toward the corrosive gas outlet 174, so that the O-ring 194 provided on the valve element 192 comes into close contact with the valve seat 196, resulting in a closed valve state and stopping the supply of the corrosive gas 20 to the semiconductor manufacturing equipment 26. When the valve is opened, the valve element 192 first moves in the direction of arrow A, and then the rod 112 moves along the longitudinal axis 115 toward the drive mechanism 60, that is, one side, and the valve element 192 is housed inside the rod valve mechanism space 200.

[0024] The valve mechanism main body 190 is provided with not only a valve operating space 199 but also a rod valve mechanism space 200 that connects the valve operating space 199 with the rod movement gas supply space 160 formed inside the gas supply mechanism main body 148. The length of the rod valve mechanism space 200 in the direction along the axis 181 is length L4, which is slightly longer than the cross-sectional length L5 of the rod 112. Furthermore, as shown in FIG. 4 , the length in a direction perpendicular to the axis 181 and also perpendicular to the major axis 115 is length L9, which is longer than the length L8 of the valve body 192. The length from the opening end of the rod valve mechanism space 200 on the gas supply mechanism 140 side, which is the opening end on one side of the corrosive gas inlet 172, to the rod movement gas supply space 160 of the gas supply mechanism 140, i.e., length L1 in the direction along the major axis 115, is longer than 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 state, the other end 195 of the rod 112 and the valve body 192 fixed to the other end 195 can all move from the valve operating space 199 and be completely stored 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 equipment 26 due to the opening and closing operation of the on-off valve 198 can be reduced. Note that, for example, the diameter L2 is approximately 40 mm, while the diameter L3 is 20 mm or less. Furthermore, in this embodiment, the valve element 192 is completely housed inside the rod valve mechanism space 200, so the flow of the corrosive gas 20 is smooth, and fluctuations in the corrosive gas 20 supplied to others from the corrosive gas outlet 174 can be suppressed.

[0026] The rod valve mechanism space 200 has a circular cross section perpendicular to the major axis 115, a diameter L4 that is larger than the diameter L5 of the cross section of the rod 112, and the difference between the lengths L4 and L5 is in the range of 3 mm to 5 mm. Because this difference is small, it is possible to suppress turbulence in the flow from the valve operating space 199 to the rod movement gas supply space 160, and the effect of blocking the flow of the corrosive gas 20 by the protective gas 30 in the gas supply mechanism 140 is improved and further stabilized.

[0027] 2.2 Description of the Drive Mechanism 60 Fig. 3 is a cross-sectional view of Fig. 1, and Fig. 4 is a cross-sectional view of Fig. 2. Note that Fig. 3 omits the illustration of part of the connection between the drive mechanism 60 and the airtightness maintaining mechanism 120. The drive mechanism 60 has a cylinder 62 and a piston 64, and the piston 64, which supplies drive fluid to the closing valve supply part 72, moves to the other side and closes the on-off valve 198 of the valve mechanism main body 190. Conversely, when drive fluid is supplied to the opening valve supply part 74, the fluid supplied from the closing valve supply part 72 is gradually discharged by a mechanism not shown, and the piston 64 is moved to one side, in the direction opposite to the valve mechanism main body 190, by the fluid from the opening valve supply part 74, and the valve element 192 fixed to the other end part 195 of the rod 112 is accommodated in the rod valve mechanism space 200 shown in Fig. 3, and the on-off valve 198 is in an 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 now be described. In the open valve state, the piston 64 is located on one side inside the cylinder 62, in other words, on the opposite side from the valve mechanism 180. An on-off cam 66 is fixed to the cylinder 62, and in the open valve state, the on-off cam 66 is located on one side compared to its position in the closed valve state, and 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 on-off valve 198 in the closed valve state.

[0029] When the on-off valve 198 is in an 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, so that in the open state the roller 68 is positioned to one side compared to when the valve is closed. The roller 68 causes the rod 112 to move furthest to one side, and the valve element 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 main body 190. Because the valve element 192 is not present in the valve operating space 199 of the valve mechanism main body 190, the corrosive gas 20 introduced from the corrosive gas inlet 172 of the valve mechanism main body 190 is smoothly discharged from the corrosive gas outlet 174 and supplied to the semiconductor manufacturing equipment 26.

[0030] When closing the on-off valve 198 inside the valve mechanism 180, fluid is supplied to the closing valve supply unit 72 shown in FIG. 4 to move the piston 64 to the other side of the cylinder 62, i.e., toward the valve mechanism 180. As the piston 64 moves, the pressing end 65 and the opening / closing 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. When 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 stored 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 fixed plate 114 reaches the other end of the position control groove 136, preventing the position control roller 137 and the fixed plate 114 from moving to the other side, and preventing the movement of the rod 112.

[0031] However, as the supply of fluid 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 longitudinal axis 115 along the inside of the opening / closing hole 67 shown in FIG. 3. In this state, the position control roller 137 integrated with the rod 112 acts as a fulcrum at the other end of the position control groove 136 based on the principle of a lever. The point of force is the roller 68 constrained by the opening / closing hole 67, and the point of action is the valve disc 192 fixed to the other end 195 of the rod 112. Any change in the 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 relative to the longitudinal axis 115 using the position control roller 137 as a fulcrum, the O-ring 194 of the valve disc 192 comes into close contact with the valve seat 196, and the opening / closing valve 198 is in a closed state.

[0032] Conversely, when the on-off valve 198 is opened 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, which is fixed to the rod 112 along the opening / closing hole 67, with respect to the major axis 115 and causes it to move horizontally. As a result, a gap is formed between the valve element 192 fixed to the rod 112 and the valve seat 196. In this state, the spring 80 presses the fixed plate 114 toward 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 element 192 hardly moves in the direction along the major axis 115. Furthermore, when fluid is supplied from the valve-opening supply unit 74 to the cylinder 62 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 element 192 attached to the rod 112 move to one side along the major axis 115. As a result, the valve element 192 is finally completely housed in the rod valve mechanism space 200 formed in the valve mechanism body 190 of the valve mechanism 180. When the valve mechanism 180 has been completely housed in the rod valve mechanism space 200, the position control roller 137 provided on the fixed plate 114 reaches one end of the position control groove 136, the movement of the rod 112 in the direction along the long axis 115 stops, and the opening operation of the on-off valve 198 is completed.

[0033] 2.3 Description of the airtightness mechanism 120 3 to 5, an airtightness maintaining mechanism 120 and a gas supply mechanism 140 are provided between the drive mechanism 60 and the valve mechanism 180. In order to movably dispose the rod 112 in the gas control device 100, the valve mechanism 180 has a rod valve mechanism space 200, the gas supply mechanism 140 has a rod movement gas supply space 160, and the airtightness maintaining mechanism 120 has a Airtight mechanism space for rod 124 are formed, respectively. For this reason, there is a risk that corrosive gas 20 may flow into drive mechanism 60 through the space on the outer periphery of long axis 115. In order to prevent corrosive gas 20 from flowing into drive mechanism 60, airtightness maintaining mechanism 120 having cylindrical bellows 132 is provided between gas supply mechanism 140 and drive mechanism 60.

[0034] The fixed plate 114 of the airtight mechanism 120 is fixed to the rod 112 in an airtight state The protective gas supply mechanism side end 130 fixed to the airtightness mechanism main body 122 is in contact with the airtightness mechanism main body 122 which constitutes the entire outer periphery of the airtightness mechanism 120. In an airtight state A bellows storage space 134 is formed inside the airtightness keeping mechanism main body 122, a cylindrical bellows 132 is stored in the bellows storage space 134, one end of the bellows 132 is fixed in a sealed state to the fixing plate 114, and the other end of the bellows 132 is fixed in a sealed state to the end portion 130 on the protective gas supply mechanism side.

[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 a long axis 115, blocking the movement of fluid between the inside and outside of the bellows 132. The provision of the bellows 132 prevents the corrosive gas 20 from flowing from the airtightness mechanism 120 into the drive mechanism 60. However, there is a problem in that the bellows 132 itself is corroded by the corrosive gas 20, necessitating replacement of the bellows 132 in a relatively short period of time. Furthermore, there is also a problem in that the internal components of the airtightness mechanism 120 are corroded. For this reason, it is desirable to prevent the corrosive gas 20 from flowing into the airtightness mechanism 120 as much as possible.

[0036] 2.4 Description of the airtightness maintaining mechanism 120 and the gas supply mechanism 140 1 to 5 show the structural relationship between the gas supply mechanism 140 and other devices. In addition, FIGS. 7 to 10 show the detailed structure of the gas supply mechanism 140. The gas supply mechanism 140 is provided between the airtightness mechanism 120 and the valve mechanism 180 to prevent the corrosive gas 20 from flowing from the valve operating space 199 of the valve mechanism main body 190 into the bellows storage space 134 of the airtightness mechanism 120. Airtight mechanism space for rod 124 By providing a rod movement gas supply space 160 formed inside the gas supply mechanism 140 between the rod movement gas supply space 160 and the rod valve mechanism space 200, the gas supply mechanism 140 supplies a protective gas 30, which is a non-corrosive or low-corrosive gas, to the rod movement gas supply space 160, thereby preventing the corrosive gas 20 from flowing from the valve operation space 199 into the bellows storage space 134 via the rod valve mechanism space 200. Nitrogen gas (N2), for example, can be used as the protective gas 30. Since nitrogen gas is non-corrosive, there is no risk of it corroding equipment. Nitrogen gas is also relatively easy to obtain and has the advantage of being highly safe to handle. Furthermore, even if nitrogen gas is mixed with the 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 airtightness holding mechanism main body 122 of the airtightness holding mechanism 120. As shown in Figures 7 and 8, the gas supply mechanism 140 has a gas supply mechanism main body 148, to which a protective gas introduction part 142 having a protective gas inlet 144 for taking in protective gas 30 is fixed by a support part 146. The protective gas introduction part 142, the support part 146, and the gas supply mechanism main 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 main body. In this embodiment, the gas supply passage 150 is formed inside the protective gas introduction part 142, the support part 146, and the gas supply mechanism main body 148. A gas supply device 153 is housed and fixed in the gas supply mechanism main body 148, and a cylindrical gas supply space 160 for rod movement is formed in the center of the gas supply device 153 so that the rod 112 can be movably positioned.

[0038] A cylindrical storage hole 162 extending along the long axis 115 is formed in the gas supply mechanism main body 148. 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 the rod 112 is formed in the center of the surface of the storage hole bottom 164 perpendicular to the long axis 115. The gas supply device 153 is inserted into the storage hole 162, and the gas supply device 153 is fixed in a state where the other side surface of the gas supply device 153 is in close contact with the storage hole bottom 164 of the storage hole 162. In this embodiment, the storage hole 162 is open at one side surface 166, which is the side surface of the gas supply mechanism main body 148 facing the airtightness maintaining mechanism 120, and is closed at the other side, which is the direction of the valve mechanism 180 along the long axis 115 from the side of the one side surface 166. With this structure, the gas supply device 153 is inserted into and fixed in the storage hole 162 from one side surface 166, which is the surface on the side of the airtightness holding mechanism 120. The storage hole 162 that stores the gas supply device 153 does not open to the other side surface 167, so that when the fixing screws 182 and 183 are removed and the gas supply mechanism main body 148 is detached from the valve mechanism main body 190 of the valve mechanism 180, as shown in FIG. 6 , the gas supply device 153 is not exposed to the other side surface 167. As a result, when the valve mechanism 180 and the gas supply mechanism 140 are changed from a fixed state to a detached state, or vice versa, the fixed state between the gas supply mechanism main body 148 and the gas supply device 153 is unlikely to be affected, such as by a change in the fixed state between the gas supply mechanism main body 148 and the gas supply device 153. In reality, the maintenance work for the on-off valve 198 is relatively frequent. If the storage hole 162 were open to the other side surface 167 of the gas supply device 153, the gas supply device 153 would be exposed to the outside when the gas supply mechanism 140 was removed from the valve mechanism 180. As a result, there is a high possibility that the fixed state between the storage hole 162 of the gas supply mechanism main body 148 and the gas supply device 153 will change. In other words, during maintenance work, etc., adverse effects such as subtle changes in the fixed state between the gas supply mechanism main body 148 of the gas supply mechanism 140 and the gas supply device 153 are likely to occur.

[0039] 8 to 10 , which illustrate the gas supply mechanism main body 148 and the gas supply device 153, an outer circumferential groove 154 is formed around the entire circumference of the outer circumferential surface 156 of the gas supply device 153. By inserting and fixing the gas supply device 153 into the accommodation hole 162 of the gas supply mechanism main body 148, an outer circumferential passage 152 is formed around the entire circumference of the outer circumferential surface 156 of the gas supply device 153 due to the shapes of the inner circumferential surface of the accommodation hole 162 and the outer circumferential groove 154 of the gas supply device 153. The inner end of the gas supply passage 150 opens into the outer circumferential passage 152, and the protective gas 30 introduced from the protective gas inlet 144 of the protective gas introducing part 142 flows through the outer circumferential passage 152 into the outer circumferential passage 152 formed by the outer circumferential groove 154 of the gas supply device 153, and the entire outer circumferential passage 152 is filled with the protective gas 30.

[0040] FIG. 10 is an enlarged view of protective gas supply holes 158 formed in the gas supply device 153. A large number of gas supply holes 158, which connect the peripheral groove 154 formed on the outer periphery of the gas supply device 153 to the rod movement gas supply space 160 formed inside the gas supply device 153, are formed at angular intervals of a predetermined angle θ around the entire circumference in the circumferential direction 155 of the gas supply device 153. In FIG. 8, gas supply holes 158 with a diameter Φ1 are formed closer to the gas supply passage 150, and gas supply holes 159 with a larger diameter Φ2 are formed on the opposite side of the gas supply passage 150. This configuration compensates for a uniform supply of protective gas 30 so that the amount of supply of protective gas 30 on the side farther from the gas supply passage 150 does not decrease. However, sufficient effect can be obtained by providing protective gas supply holes 158 with the same diameter Φ1 around the entire circumference of the peripheral groove 154 of the gas supply device 153. The angle θ of the protective gas supply holes 158 may be made smaller in the opposite direction of the gas supply passage 150 to make the supply amount of the protective gas 30 more uniform, but good results can be obtained even if the angle interval is the same.

[0041] The following description will be given on the assumption that protective gas supply holes 158 of the same diameter φ1 are formed at equal intervals of the same angle θ around the entire circumference of the outer periphery-side passage 152 formed on the outer periphery of the gas supply device 153. The protective gas 30 introduced into the outer periphery-side passage 152 is supplied to the rod movement gas supply space 160 via the many gas supply holes 158 formed around the entire circumference of the gas supply device 153. The supply of protective gas 30 from the many gas supply holes 158 in the gas supply mechanism 140 suppresses the flow of corrosive gas 20 that attempts to flow from the valve operating space 199 of the valve mechanism 180 into the airtightness holding mechanism 120, and further prevents the flow of corrosive gas 20 from the bellows storage space 134 of the airtightness holding mechanism 120. Airtightness mechanism rod arrangement space 126, The rod valve mechanism space 200 of the valve mechanism body 190 can be filled with the protective gas 30. This configuration prevents the corrosive gas 20 from coming into contact with the bellows 132, and the bellows 132 is not affected by the corrosive gas 20.

[0042] When the on-off valve 198 is opened, the fixing plate 114 that fixes one end of the bellows 132 moves to one side, and the volume of the space inside the bellows 132 within the bellows accommodating space 134 on the inner diameter side is rapidly increased. As a result, the corrosive gas 20 present in the valve operating space 199 is easily sucked into the airtightness maintaining mechanism 120. What is important here is to prevent the flow of the corrosive gas 20 from the valve operating space 199 into the bellows accommodating space 134 by supplying the 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 in a state with little turbulence, similar to laminar flow. For example, if a large vortex occurs, it becomes difficult to completely prevent the flow of the corrosive gas 20 into the bellows accommodating space 134 by supplying the protective gas 30.

[0043] In the rod movement gas supply space 160, which supplies the protective gas 30, the inner surface of the gas supply device 153 and the surface of the storage hole bottom 164 facing the rod 112 protrude inward by a length L8 from other components so as to approach the outer periphery of the rod 112, thereby narrowing the gap between the rod 112 and the inner surface of the gas supply device 153. By narrowing the gas supply rod outer periphery space 161, which is the gap between each inner surface and the outer periphery of the rod 112, the movement of gas within the rod movement gas supply space 160 is stabilized as much as possible, in other words, the generation of large vortices is prevented. With this structure, even if a large pumping action occurs in the bellows storage space 134, the supply of the protective gas 30 to the drive mechanism 60 can stably suppress the inflow of corrosive gas 20. Furthermore, the cross-sectional area perpendicular to the major axis 115 of the rod movement gas supply space 160 is much smaller than the cross-sectional area perpendicular to the major axis 115 of the rod valve mechanism space 200. As a result, changes in gas movement in the rod movement gas supply space 160 are greatly suppressed, stabilizing the gas movement in the movement gas supply space 160. This makes it easier to suppress the inflow of corrosive gas 20 from the valve operation space 199, resulting in an effect of stabilizing the corrosion inhibition action.

[0044] It is desirable to uniformly and stably supply the protective gas 30 from the outer peripheral groove 154 to the rod movement gas supply space 160. As shown in FIGS. 9 and 10 , multiple protective gas supply holes 158 are formed radially in the gas supply device 153, and the protective gas 30 is supplied through these protective gas supply holes 158. In this embodiment, holes are formed and the protective gas 30 is supplied through the holes. The holes are machined with high precision, stabilizing the characteristics and ensuring stable supply characteristics throughout the entire circumference of the cylindrical gas supply device 153. Furthermore, changes in characteristics during assembly are reduced. Changes over time are also very small. Therefore, a very stable effect can be achieved over a long period of time. Because the protective gas 30 is a gas and is hardly affected by surface tension, the diameter of the protective gas supply holes 158 can be 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. Setting the diameter Φ1 of the protective gas supply holes 158 to this value makes it possible to reduce the influence of pressure changes and pressure unevenness in the outer circumferential groove 154. Furthermore, as shown in Fig. 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 such conditions, it is possible to prevent the corrosive gas 20 from flowing into the airtightness holding mechanism 120 through the rod movement gas supply space 160, even when the on-off valve 198 is opened or closed.

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

[0046] 3. Description of the invention as applied in 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 airtightness maintaining mechanism (120) having a bellows (132) are arranged along a major axis (115) that is the longitudinal axis of the rod (112), and the airtightness maintaining mechanism (120) is provided between the drive mechanism (60) and the valve mechanism (180), thereby preventing 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 maintaining 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 therein, which is a space for movably arranging the rod 112, The gas supply mechanism 140 supplies the protective gas 30 introduced from the protective gas introduction part 142 to the rod movement gas supply space 160 from the gas supply device 153, thereby preventing the corrosive gas 20 from moving from the valve mechanism 180 to the airtightness maintaining mechanism 120. The gate valve 50 is characterized by the above.

[0047] According to the first invention, a structure is provided in which protective gas 30, which is a non-corrosive or low-corrosive gas, is supplied from gas supply mechanism 140 provided between valve mechanism 180 and airtightness holding mechanism 120 to rod movement gas supply space 160 formed inside gas supply mechanism 140 in which rod 112 is disposed. Supply of protective gas 30 can prevent corrosive gas 20 from flowing into airtightness holding mechanism 120. As a result, an effect is achieved in which corrosion of various devices, including bellows 132 of airtightness holding mechanism 120, by corrosive gas 20 can be prevented.

[0048] 3.2 Description of the second invention [Second Invention] The second invention is the gate valve 50 of the first invention, The valve mechanism 180 has a valve mechanism body 190 and an on-off valve 198 for controlling the flow of the corrosive gas 20. The valve mechanism body 190 is provided with a corrosive gas inlet 172 through which the corrosive gas 20 is introduced and a corrosive gas outlet 174 for supplying the corrosive gas 20 to another location, and further, a valve operating space 199 for operating an 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 a 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 main body 190 further includes a rod valve mechanism space 200 that connects the valve operating space 199 and the rod movement gas supply space 160 of the gas supply mechanism 140 and in which the rod 112 is movably disposed, The cross-sectional area of ​​the rod valve mechanism space 200 in a direction 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 in a direction perpendicular to the long axis 115. The gate valve 50 is characterized by the above.

[0049] In the second invention, it is possible to suppress the fluctuations in the corrosive gas 20 generated in the valve operating space 199 of the valve mechanism 180 from being transmitted to the rod movement gas supply space 160. As a result, it is possible to stably prevent the corrosive gas 20 from flowing into the airtightness holding mechanism 120. Although increasing the supply of the protective gas 30 to the rod movement gas supply space 160 causes various effects, even supplying a relatively small amount of protective gas 30 has the effect of stably suppressing the corrosive gas 20 from flowing into the airtightness holding mechanism 120.

[0050] 3.3 Description of the third invention [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 storing a gas supply device 153, The gas supply device 153 has a cylindrical shape, and is fixed in a state where it is housed in a housing hole 162 of the gas supply mechanism main body 148. Inside the gas supply device 153, a gas supply space 160 for rod movement is formed in which the rod 112 is movably arranged. An outer circumferential passage 152 for flowing the protective gas 30 is formed between the outer circumferential surface 156 of the cylindrical gas supply device 153 and the inner surface of the accommodation hole 162 of the gas supply mechanism main body 148, The protective gas 30 introduced from the protective gas inlet 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 through an 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 above.

[0051] The gas supply mechanism main body 148 is provided with a storage hole 162, and the gas supply device 153 is stored in the storage hole 162. This structure forms an outer circumferential passage 152 for flowing the protective gas 30 on the outer circumferential surface 156 of the gas supply device 153, which has the advantage of being able to be manufactured with high precision. Furthermore, this structure is less susceptible to change over time, and a stable effect can be obtained over a long period of time. In addition, it is also suitable for temperature changes. Airtightness The effect is easy to ensure.

[0052] 3.4 Description of the fourth invention [Fourth Invention] A fourth aspect of the present invention is the gate valve 50 of the third aspect of the present invention, wherein The cylindrical gas supply device 153, which is fixed in a state housed in the housing hole 162 of the gas supply mechanism main body 148, has a recessed outer circumferential groove 154 formed around the entire periphery of its outer circumferential surface 156. When the gas supply device 153 is stored in the storage hole 162 of the gas supply mechanism main body 148, an outer peripheral passage 152 is formed by the outer peripheral surface 156 of the gas supply device 153 having a recessed shape and the inner peripheral surface of the storage hole 162 of the gas supply mechanism main body 148, In the gas supply device 153, a large number of gas supply holes 158 are formed around the entire circumference of the outer circumferential groove 154, connecting the rod movement gas supply space 160 and the outer circumferential groove 154, The protective gas 30 introduced from the protective gas introduction part 142 of the gas supply mechanism 140 is supplied to an outer periphery side passage 152 formed on the outer periphery side of the gas supply device 153, and is further supplied from the outer periphery side passage 152 to a rod movement gas supply space 160 via a number of gas supply holes 158. The gate valve 50 is characterized by the above.

[0053] The structure is such that the protective gas 30 introduced into the outer periphery-side passage 152 is supplied to the rod movement gas supply space 160 via a large number of gas supply holes 158. As a method for supplying the protective gas 30 introduced into the outer periphery-side passage 152 to the rod movement gas supply space 160, a structure may be adopted in which a gap is formed perpendicular to the long axis 115 at the contact portion between the gas supply device 153 and the storage hole 162 formed in the gas supply mechanism main body 148, and the protective gas is supplied via this gap perpendicular to the long axis 115. However, the fourth invention does not adopt the method of forming a gap perpendicular to the long axis 115 at the contact portion between the gas supply device 153 and the storage hole 162 formed in the gas supply mechanism main body 148, but rather adopts a structure in which a large number of gas supply holes 158 are formed in the gas supply device 153, and the protective gas 30 is supplied from the outer periphery-side passage 152 to the rod movement gas supply space 160 via the gas supply holes 158. By using the gas supply holes 158 in this manner, the amount of protective gas 30 supplied from the outer periphery-side passage 152 to the rod movement gas supply space 160 can be stabilized. Furthermore, it is possible to prevent instability of 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 housing hole 162 of the gas supply mechanism main body 148. This structure is also less susceptible to changes over time. Furthermore, the use of the protective gas supply holes 158 allows for improved processing accuracy, and the diameter of the protective gas supply holes 158 can be reduced. Providing many small-diameter protective gas supply holes 158 improves the uniformity of the supply of protective gas 30 to the rod movement gas supply space 160, thereby enhancing and stabilizing the effect of preventing the inflow of protective gas 30.

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

[0055] It is desirable that the supply of the protective gas 30 from the outer periphery-side passage 152 to the rod movement gas supply space 160 flow uniformly. If the supply amount of the protective gas 30 varies in the circumferential direction 155 in FIG. 9, this may result in variations in the effect of preventing the corrosive gas 20 from flowing into the airtightness retention mechanism 120. To ensure a more uniform supply of the protective gas 30 from the outer periphery-side passage 152 to the rod movement gas supply space 160, the smaller the diameter of each of the multiple gas supply holes 158, the greater the uniformity. The diameter of the gas supply hole 158 is desirably 0.5 mm or less. A diameter of 0.2 mm or less provides even greater effectiveness.

[0056] 3.6 Description of the sixth invention [Sixth Invention] A sixth aspect of the present invention is the gate valve 50 of the second aspect of the present invention, The airtightness maintaining mechanism 120 is a mechanism for movably arranging the rod 112 on the side of the gas supply mechanism 140. Airtight mechanism rod placement space 126 a protective gas supply mechanism side end 130 formed with The airtightness maintaining mechanism 120 includes: Airtight mechanism rod placement space 126 A bellows storage space 134 for storing the rod 112 and the bellows 132 disposed around the outer periphery of the rod 112 is formed closer to the drive mechanism 60 than the rod 112. A longitudinal axis 115 of the rod 112 is perpendicular to the longitudinal axis 115. Airtight mechanism rod placement space 126 The cross-sectional area of ​​the bellows storage space 134 perpendicular to the major axis 115 is smaller than the cross-sectional area of ​​the bellows storage space 134. The gate valve 50 is characterized by the above.

[0057] As described above, when the on-off valve 198 is opened, the bellows 132 expands along the major axis 115, increasing the volume of the bellows accommodating space 134. On the other hand, when the valve is closed, the bellows 132 contracts along the major axis 115, reducing the volume of the bellows accommodating space 134. If this type of change causes turbulence in the gas flow, the effect of supplying the protective gas 30 from the rod movement gas supply space 160 to suppress the inflow of the corrosive gas 20 is reduced, making it difficult to suppress the flow of the corrosive gas 20. There is also a limit to significantly increasing the supply amount of the protective gas 30. In this embodiment, the protective gas supply mechanism side end 130 of the airtightness keeping mechanism main body 122 is protruded toward the rod 112 in a plane perpendicular to the major axis 115 between the bellows accommodating space 134 and the rod movement gas supply space 160, and a protective gas supply mechanism side end 130 is provided inside the protective gas supply mechanism side end 130. Airtight mechanism rod placement space 126 is formed. Airtight mechanism rod placement space 126 By reducing the cross section perpendicular to the long axis 115 of the bellows housing space 134, gas turbulence during valve opening and closing operations is suppressed, stabilizing the gas flow in the rod movement gas supply space 160. As a result, with a relatively small supply of protective gas 30, the flow of corrosive gas 20 into the airtightness maintaining mechanism 120 can be stably suppressed. [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 and closing cam 66, 67: Opening and closing hole, 68: Roller, 72: Closed valve supply part, Open valve supply part 74: Open valve supply part, 80: Spring, 112: Rod, 113: Drive side space, 114: Fixing plate, 115: Long axis, 118: Main body side fixing part, 120: Airtightness maintaining mechanism, 121: Fixing screw, 122: Airtightness maintaining mechanism main body, 123: Cylinder support, 124: Airtight mechanism space for rod , 125: Cylindrical protrusion, 126: Airtight mechanism rod placement 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, 143: fixing screw, 144: protective gas inlet, 146: support part, 148: gas supply mechanism main body, 150: gas supply passage, 151: gas supply part, 152: outer periphery side passage, 153: gas supply device, 154: outer periphery groove, 155: circumferential direction, 156: outer periphery surface, 158: gas supply hole, 159: gas supply hole, 160: Gas supply space for rod movement, 161: gas supply rod outer peripheral space, 162: storage hole, 164: storage hole bottom, 165: storage hole bottom space for rod, 166: one side surface, 167: other side surface, 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: valve mechanism rod outer peripheral space.

Claims

1. A gate valve in which a drive mechanism that moves a rod along a long axis and controls the inclination of the rod relative to the long axis, a valve mechanism that controls the flow of corrosive gas, and an airtight mechanism having a bellows are arranged along the long axis, the valve mechanism performs opening and closing operations based on the movement of the rod along the long axis and the inclination of the rod relative to the long axis, and the airtight mechanism is arranged between the drive mechanism and the valve mechanism, thereby preventing leakage of the corrosive gas from the valve mechanism to the drive mechanism, a gas supply mechanism is further provided between the valve mechanism and the airtightness maintaining mechanism, the gas supply mechanism including a protective gas inlet into which a protective gas for preventing corrosion is introduced, a gas supply device for supplying the introduced protective gas, and a gas supply mechanism main body having a cylindrical storage hole therein; the gas supply device is fixed in a state of being housed in the housing hole of the gas supply mechanism main body, the gas supply device has a rod movement gas supply space formed therein, the space being a space for movably arranging the rod; an outer circumferential passage for flowing the protective gas is formed between an outer circumferential surface of the gas supply device and an inner circumferential surface of the accommodation hole of the gas supply mechanism main body; The protective gas introduced from the protective gas inlet of the gas supply mechanism is supplied over the entire circumference of the outer circumferential surface of the gas supply device through the outer circumferential passage formed along the outer circumferential surface of the gas supply device, and the protective gas is supplied from the outer circumferential surface of the gas supply device to the rod movement gas supply space, thereby preventing the corrosive gas from moving from the valve mechanism to the airtightness maintaining mechanism. A gate valve characterized by:

2. In the gate valve according to claim 1, The gas supply device, which is fixed in a state housed in the housing hole of the gas supply mechanism main body, has a recessed outer circumferential groove formed over the entire periphery of the outer circumferential surface, the gas supply device is accommodated in the accommodation hole of the gas supply mechanism main body, whereby the outer circumferential passage is formed by the outer circumferential surface of the gas supply device having the recessed shape and the inner circumferential surface of the accommodation hole of the gas supply mechanism main body, a plurality of gas supply holes connecting the rod movement gas supply space and the outer circumferential groove are formed in the gas supply device around the entire periphery of the outer circumferential groove; the protective gas introduced from the protective gas inlet of the gas supply mechanism is supplied to the outer periphery-side passage formed on the outer periphery of the gas supply device, and is further supplied from the outer periphery-side passage to the rod movement gas supply space via the multiple gas supply holes; A gate valve characterized by:

3. In the gate valve according to claim 2, A gate valve characterized in that each of the large number of gas supply holes has a diameter of 0.5 mm or less.

4. In the gate valve according to claim 2, the storage hole formed in the gas supply mechanism main body has an opening on one side surface of the gas supply mechanism main body that is on the side of the airtightness maintaining mechanism, and has a storage hole bottom on the side of the valve mechanism that is opposite to the one side surface that is on the side of the airtightness maintaining mechanism, The gas supply device is inserted into the opening on the one side surface of the storage hole and fixed thereto. A gate valve characterized by:

5. The gate valve according to claim 2, the airtightness maintaining mechanism has a protective gas supply mechanism side end portion in which an airtightness maintaining mechanism rod arrangement space for movably arranging the rod on the gas supply mechanism side is formed, a bellows accommodating space for accommodating the rod and the bellows arranged around the outer periphery of the rod is formed in the airtightness maintaining mechanism on the drive mechanism side of the airtightness maintaining mechanism rod arrangement space, a cross-sectional area of ​​the airtightness mechanism rod arrangement space perpendicular to the long axis is smaller than a cross-sectional area of ​​the bellows accommodating space perpendicular to the long axis; A gate valve characterized by:

6. The gate valve according to claim 5, a cross-sectional area perpendicular to the long axis of the gas supply space for rod movement formed inside the gas supply device of the gas supply mechanism is smaller than a cross-sectional area of ​​the airtightness holding mechanism rod arrangement space of the airtightness holding mechanism; A gate valve characterized by:

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