JP7742991B1 - Gate valve - Google Patents

Abstract

To provide a gate valve that has excellent corrosion resistance and that controls the flow of corrosive gases, 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 which 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.
[Selected figure] Figure 5

Description

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 corrosive gas (hereinafter referred to as corrosive gas). In this specification, controlling the flow of corrosive gas includes control of supplying or stopping the supply of corrosive gas to other equipment, control of changing the supply destination of corrosive gas, control of changing the amount of corrosive gas supplied, or control of changing the supply ratio to a destination when corrosive gas is supplied to multiple destinations.

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, the prior art documents listed below, Patent Documents 1 and 2, disclose techniques for protecting gate valves themselves from corrosion caused by corrosive gases.

Japanese Patent Application Laid-Open No. 2000-346238 JP 2018-25293 A

Patent Document 1 discloses the provision of a sealing mechanism in a gate valve to prevent corrosive gas from flowing 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, which prevents the leakage of corrosive gas, itself 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 states 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.

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

However, the present invention does not negate the above-mentioned improvements, such as the improvement to the corrosion resistance of the bellows in the sealing mechanism described in Patent Document 2. It is preferable to implement the improvements described in Patent Documents 1 and 2 in addition to the improvements of the present invention described below, such as the improvement to the corrosion resistance of the bellows themselves 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 simply by taking measures to improve the corrosion resistance of the bellows themselves.

The purpose of this invention is to significantly improve the corrosion resistance of gate valves.

[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.

[Second Invention]
A second aspect of the present invention is the gate valve of the first aspect, wherein
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,
a cross-sectional area of the rod valve mechanism space in a direction perpendicular to the long axis is larger than a cross-sectional area of the rod movement gas supply space formed in the gas supply mechanism in a direction perpendicular to the long axis;
A gate valve characterized by the above.

[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.

[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:

[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 large number of gas supply holes has a diameter of 0.5 mm or less.

[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 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, which is the longitudinal axis of the rod, is smaller than a cross-sectional area of the bellows accommodating space perpendicular to the long axis;
A gate valve characterized by the above.

The present invention provides a gate valve for controlling the flow of corrosive gases that has excellent corrosion resistance and can significantly reduce the corrosive effects of the corrosive gases.

1 is an explanatory diagram showing the front external shape of an embodiment of a gate valve to which the present invention is applied. FIG. 2 is an explanatory diagram showing the planar appearance of the gate valve shown in FIG. 1 . FIG. 2 is an explanatory diagram showing a cross section of the gate valve shown in FIG. 1 . FIG. 3 is an explanatory diagram showing a cross section of the gate valve shown in FIG. 2 . FIG. 4 is a partially enlarged view of the gate valve shown in FIG. 3 . FIG. 2 is an explanatory diagram showing a state in which a valve mechanism body of the gate valve is removed. FIG. 2 is an enlarged view of a gas supply mechanism and an airtightness maintaining mechanism 120 of the gate valve. 3 is an explanatory diagram for explaining a gas supply mechanism of the gate valve. FIG. FIG. 9 is a cross-sectional view of the gas supply mechanism shown in FIG. 8 taken along line AA. 3 is an explanatory diagram for explaining a gas supply device of the gas supply mechanism. FIG.

In the embodiment of the gate valve 50 for implementing the invention described below, components designated by the same reference numerals have essentially the same structure, perform the same functions, 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 an embodiment of a gate valve having the function of controlling whether or not to supply corrosive gas 20 to another location. However, gate valves to which the present invention is applicable are not limited to gate valves that control whether or not to supply 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 corrosive gas 20, changing the amount of corrosive gas supplied, or changing the supply ratio to a destination when corrosive gas is supplied to multiple destinations. The configuration and effects of the airtightness mechanism 120, which is an important component of the present invention, allow it 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 with the above control function, the following describes an example in which a gate valve 50 is used that has the function of controlling whether or not to supply corrosive gas 20 to another location.

1. Description of the Overall Configuration of a Gate Valve 50 as an Example to Which the Present Invention is Applied (1) Description of the Basic Configuration of the Gate Valve 50 One example of a gate valve to which the present invention is applied is shown in Figures 1 and 2. The gate valve 50 described as this example 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.

The gate valve 50 comprises a drive mechanism 60, an airtightness mechanism 120, a gas supply mechanism 140, and a valve mechanism 180, which are arranged from one side to the other along a major axis 115 indicating the longitudinal direction of a rod 112 provided inside the gate valve 50. The valve mechanism 180 has an on-off valve 198 for controlling the supply of corrosive gas 20 to the semiconductor manufacturing equipment 26 based on the movement of the rod 112. The movement of the rod 112 is controlled by the drive mechanism 60, and the supply of corrosive gas 20 to another device, the semiconductor manufacturing equipment 26, is controlled based on the movement of the rod 112.

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. Nitrogen gas, for example, is used as the protective gas 30. The corrosive gas 20 may be any of a variety of gases, such as chlorine (Cl ₂ ), fluorine (F ₂ ), hydrogen chloride (HCl), and ammonia (NH ₃ ).

(2) Description of Basic Operation and Effects of 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 the valve mechanism 180 of the gate valve 50 from a corrosive gas 20 supply source (not shown) via piping 22 to a corrosive gas inlet 172 of the valve mechanism 180, 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 maintaining 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 maintaining 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 devices constituting the airtightness mechanism 120. The gate valve 50 includes a gas supply mechanism 140, which acts to prevent the corrosive gas 20 from flowing into the airtightness mechanism 120 from the valve mechanism 180. This significantly reduces the problem of the bellows 132 itself being corroded by the corrosive gas 20. The gas supply mechanism 140 receives protective gas 30 via a supply pipe 32 and supplies the protective gas 30 to a protective gas inlet 142 of the gas supply mechanism 140. The protective gas 30 is then supplied 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 into the airtightness mechanism 120 from the valve mechanism 180, thereby suppressing corrosion of the bellows 132. As a result, the mass production efficiency of the semiconductor manufacturing apparatus 26 can be significantly improved.

The drive mechanism 60, airtightness retention mechanism 120, and gas supply mechanism 140 are each fixed together by 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. Releasing the fixation by the fixing screws 182 and 183 allows the drive mechanism 60, rod movement gas supply space 160, and gas supply mechanism 140 to 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, protective gas supply mechanism side end 130, and gas supply mechanism 140 (see Figure 6). This improves the efficiency of gate valve 50 maintenance.

2. Specific Description 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 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 airtightness maintaining mechanism 120, gas supply mechanism 140, and valve mechanism 180 in Figure 3. The valve mechanism 180 includes a valve mechanism main body 190 for forming a corrosive gas inlet 172 and a corrosive gas outlet 174. Formed inside the valve mechanism main body 190 are 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 with the rod movement gas supply space 160 of the gas supply mechanism 140.

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 more than 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 axis 181 is provided on the valve operating space 199 side 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 axis 181, and an O-ring 194 provided on the valve element 192 is also circular. The valve seat 196 and 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 the 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. When the valve element 192 faces the valve seat 196, the movement of the rod 112 along the longitudinal axis 115 stops. The drive mechanism 60 tilts the rod 112 slightly relative to the longitudinal axis 115 in the direction of arrow B, which is toward the corrosive gas outlet 174. The O-ring 194 attached to the valve element 192 tightly contacts the valve seat 196, resulting in a closed valve state and stopping the supply of corrosive gas 20 to the semiconductor manufacturing equipment 26. When the valve is open, 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, so that the valve element 192 is housed within the rod valve mechanism space 200.

The valve mechanism main body 190 not only contains the valve operating space 199, but also contains 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 along the axis 181 is length L4, which is slightly longer than the cross-sectional length L5 of the rod 112. As shown in Figure 4, the length perpendicular to the axis 181 and 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 along the major axis 115, is longer than length L8 of the valve body 192 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 element 192 fixed to the other end 195 can all move from the valve operating space 199 and be completely housed inside the rod valve mechanism space 200.

(2) Description of Actions and 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 body 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 other locations from the corrosive gas outlet 174 can be suppressed.

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 cross-sectional diameter L5 of the rod 112, 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 and further stabilizing the effectiveness of the protective gas 30 in the gas supply mechanism 140 in blocking the flow of corrosive gas 20.

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 Figure 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. 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. 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 Figure 3, and the on-off valve 198 is in an open state.

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 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. The on-off cam 66 has an on-off hole 67 formed therein, 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 its closed valve state.

When the on-off valve 198 is open, the roller 68 attached to 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 in the open state. The roller 68 moves the rod 112 to the farthest position to one side, and the valve element 192 attached to the other end 195 of the rod 112 is completely housed within 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 through 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.

To close the on-off valve 198 inside the valve mechanism 180, fluid is supplied to the valve-closing supply unit 72 shown in Figure 4, moving 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 opening/closing cam 66 attached to 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 carrying 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 disc 192 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 fixed plate 114 reaches the other end of the position control groove 136, preventing the position control roller 137 and fixed plate 114 from moving to the other side, and preventing the rod 112 from moving.

However, as fluid continues to be supplied from the valve-closing supply unit 72, 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 Figure 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 enters a closed state.

Conversely, when the on-off valve 198 is opened from a closed state, fluid is supplied to the valve-opening supply unit 74. Initially, the piston 64 moves slightly to one side, reducing the inclination of the roller 68, fixed to the rod 112 along the opening/closing hole 67, relative to the longitudinal axis 115 and shifting it horizontally. This creates a gap 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 barely moves in the direction along the longitudinal 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 longitudinal axis 115. As a result, the valve disc 192 is finally completely 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 has been 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, 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.

3 to 5 , the airtightness maintaining mechanism 120 and the gas supply mechanism 140 are provided between the drive mechanism 60 and the valve mechanism 180. To movably position the rod 112 within 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 rod airtightness maintaining mechanism space 124. This raises the risk of corrosive gas 20 flowing into the drive mechanism 60 through the space on the outer periphery of the longitudinal axis 115. To prevent the corrosive gas 20 from flowing into the drive mechanism 60, the airtightness maintaining mechanism 120 has a cylindrical bellows 132 and is provided between the gas supply mechanism 140 and the drive mechanism 60.

The fixed plate 114 of the airtightness mechanism 120 is airtightly fixed to the rod 112, and the protective gas supply mechanism side end 130 provided on the airtightness mechanism main body 122 is airtightly fixed to the airtightness mechanism main body 122 which constitutes the entire outer periphery of the airtightness mechanism 120. A bellows accommodating space 134 is formed inside the airtightness mechanism main body 122, and a cylindrical bellows 132 is accommodated in the bellows accommodating space 134. One end of the bellows 132 is hermetically fixed to the fixed plate 114, and the other end of the bellows 132 is hermetically fixed to the protective gas supply mechanism side end 130.

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 the 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 airtight 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 the problem of corrosion of the internal components of the airtight mechanism 120. For this reason, it is desirable to prevent the corrosive gas 20 from flowing into the airtight mechanism 120 as much as possible.

2.4 Description of the Airtightness Mechanism 120 and the Gas Supply Mechanism 140 Figures 1 to 5 show the structural relationship between the gas supply mechanism 140 and other devices. Figures 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 housing space 134 of the airtightness mechanism 120. The rod movement gas supply space 160 formed inside the gas supply mechanism 140 is provided between the rod valve mechanism space 200 formed in the valve mechanism 180 and the rod airtightness holding mechanism space 124 formed in the airtightness holding mechanism 120. The gas supply mechanism 140 supplies the rod movement gas supply space 160 with a protective gas 30, which is a non-corrosive or low-corrosive gas, and prevents the corrosive gas 20 from flowing from the valve operation space 199 into the bellows accommodating space 134 via the rod valve mechanism space 200. Nitrogen gas (N2), for example, can be used as the protective gas 30. Because nitrogen gas is non-corrosive, it does not corrode equipment. Nitrogen gas is also relatively easy to obtain and has the advantage of being highly safe to handle. Furthermore, problems are unlikely to occur even if the protective gas 30 is mixed with the corrosive gas 20 and sent to the semiconductor manufacturing equipment 26.

The gas supply mechanism 140 is fixed to the airtightness retention mechanism main body 122 of the airtightness retention 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 section 142 having a protective gas inlet 144 for taking in protective gas 30 is fixed by a support section 146. The protective gas introduction section 142, the support section 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 section 142, the support section 146, and the gas supply mechanism main body 148. The gas supply mechanism main body 148 houses and fixes a gas supply device 153, and a cylindrical rod movement gas supply space 160 is formed in the center of the gas supply device 153, allowing the rod 112 to be movably positioned.

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 positioning 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 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 main body 148 facing the airtightness retention mechanism 120, and is closed on the other side, which is along the long axis 115 from the one side 166 toward the valve mechanism 180. 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. Therefore, as shown in FIG. 6 , 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, 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 not likely to be affected. In reality, maintenance of 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 more likely to occur.

8 to 10, which illustrate the gas supply mechanism main body 148 and gas supply device 153, an outer circumferential groove 154 is formed around the entire outer circumferential surface 156 of the gas supply device 153. By inserting and securing the gas supply device 153 into the storage hole 162 of the gas supply mechanism main body 148, the shape of the inner circumferential surface of the storage hole 162 and the outer circumferential groove 154 of the gas supply device 153 forms an outer circumferential passage 152 around the entire outer circumferential surface 156 of the gas supply device 153. The inner circumferential 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 introduction 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, filling the entire outer circumferential passage 152 with protective gas 30.

Figure 10 is an enlarged view of the protective gas supply holes 158 formed in the gas supply device 153. A large number of gas supply holes 158 connecting the peripheral groove 154 formed on the outer periphery of the gas supply device 153 and 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 Figure 8, a gas supply hole 158 with a diameter Φ1 is formed closer to the gas supply passage 150, and a gas supply hole 159 with a larger diameter Φ2 is formed on the opposite side of the gas supply passage 150. This configuration compensates for uniformity so that the supply amount of protective gas 30 on the side farther from the gas supply passage 150 does not decrease. However, sufficient effect can be achieved 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 forming the protective gas supply holes 158 may be made smaller in the opposite direction of the gas supply passage 150 to make the supply of protective gas 30 more uniform, but good results can be obtained even if the angle interval is the same.

The following description will be given assuming 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 an 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 numerous gas supply holes 158 formed around 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 attempts to flow from the valve operation space 199 of the valve mechanism 180 into the airtightness holding mechanism 120, and further allows the bellows accommodating space 134 of the airtightness holding mechanism 120, the airtightness holding mechanism rod arrangement space 126, and the rod valve mechanism space 200 of the valve mechanism main body 190 to be filled with 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 .

When the on-off valve 198 is opened, the fixing plate 114 that secures one end of the bellows 132 moves to one side, causing a sudden increase in the volume of the space inside the bellows 132 within the bellows storage space 134. As a result, the corrosive gas 20 present in the valve operating space 199 is more likely to be sucked into the airtightness mechanism 120. What is important here is to prevent the flow of corrosive gas 20 from the valve operating space 199 into the bellows storage 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 and has little turbulence. For example, if a large vortex occurs, it becomes difficult to completely prevent the flow of corrosive gas 20 into the bellows storage space 134 by supplying protective gas 30.

In the rod movement gas supply space 160, which supplies 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 to approach the outer periphery of the rod 112, 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. This structure makes it possible to stably suppress the inflow of corrosive gas 20 by supplying protective gas 30 to the drive mechanism 60, even when a pumping action occurs that increases the bellows storage space 134. Furthermore, the cross-sectional area perpendicular to the major axis 115 of the rod movement gas supply space 160 is significantly 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 gas movement in the movement gas supply space 160. This makes it easier to suppress the inflow of corrosive gas 20 from the valve operating space 199, which has the effect of stabilizing corrosion inhibition.

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 Figures 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 their 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. As a result, 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 factors such as 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 them less susceptible to pressure changes and pressure unevenness within the peripheral 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 achieving these conditions, even when the on-off valve 198 is opened or closed, it is possible to prevent the corrosive gas 20 from flowing into the airtightness retention mechanism 120 through the rod movement gas supply space 160.

In Figure 5, 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 caused by 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.

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 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 inlet 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.

According to the first invention, a protective gas 30, which is a non-corrosive or low-corrosive gas, is supplied from the gas supply mechanism 140 provided between the valve mechanism 180 and the airtightness mechanism 120 to the rod movement gas supply space 160 formed inside the gas supply mechanism 140 in which the rod 112 is disposed. The supply of the protective gas 30 prevents the corrosive gas 20 from flowing into the airtightness mechanism 120. This has the effect of preventing corrosion of various devices, including the bellows 132 of the airtightness mechanism 120, caused by the corrosive gas 20.

3.2 Description of the Second Invention [Second Invention]
A second aspect of the present invention is the gate valve 50 of the first aspect of the present 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 that movably disposes the rod 112 therein.
The cross-sectional area of the rod valve mechanism space 200 in a direction perpendicular to the major 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 major axis 115.
The gate valve 50 is characterized by the above.

In the second invention, fluctuations in the corrosive gas 20 generated in the valve operating space 199 of the valve mechanism 180 can be prevented from being transmitted to the rod movement gas supply space 160. As a result, the flow of the corrosive gas 20 into the airtightness retention mechanism 120 can be stably prevented. Increasing the supply of protective gas 30 to the rod movement gas supply space 160 will have various effects, but even supplying a relatively small amount of protective gas 30 has the effect of stably suppressing the flow of the corrosive gas 20 into the airtightness retention mechanism 120.

3.3 Description of the Third Invention [Third Invention]
A third aspect of the present invention is the gate valve 50 of the second aspect of the present 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.
A rod movement gas supply space 160 for movably arranging the rod 112 is formed inside the gas supply device 153,
An outer circumferential passage 152 for flowing the protective gas 30 is formed between an 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.

The structure in which the housing hole 162 is formed in the gas supply mechanism main body 148 and the gas supply device 153 is housed in the housing hole 162, thereby forming the outer circumferential passage 152 for flowing the protective gas 30 on the outer circumferential surface 156 of the gas supply device 153, has the advantage of being able to be manufactured with high precision. Furthermore, this configuration is less susceptible to change over time, and stable effects can be obtained over a long period of time. Another advantage is that it is easy to ensure airtightness even with temperature changes.

3.4 Explanation 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 is fixed in a state of being housed in the housing hole 162 of the gas supply mechanism main body 148. The cylindrical gas supply device 153 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 accommodated in the accommodation hole 162 of the gas supply mechanism main body 148, an outer circumferential passage 152 is formed by the outer circumferential surface 156 of the gas supply device 153 having a recessed shape and the inner circumferential surface of the accommodation hole 162 of the gas supply mechanism main body 148,
The gas supply device 153 has a number of gas supply holes 158 formed around the entire circumference of the outer circumferential groove 154, which connect the rod movement gas supply space 160 and the outer circumferential groove 154.
The protective gas 30 introduced from the protective gas inlet 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.

The protective gas 30 introduced into the outer periphery-side passage 152 is supplied to the rod movement gas supply space 160 via a number of gas supply holes 158. Another method for supplying the protective gas 30 introduced into the outer periphery-side passage 152 to the rod movement gas supply space 160 is to form a gap perpendicular to the longitudinal axis 115 at the contact point between the gas supply device 153 and the storage hole 162 formed in the gas supply mechanism main body 148, and supply the protective gas via this gap perpendicular to the longitudinal axis 115. However, in the fourth invention, instead of forming a gap perpendicular to the longitudinal axis 115 at the contact point between the gas supply device 153 and the storage hole 162 formed in the gas supply mechanism main body 148, a 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 these 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 passage 152 to the rod movement gas supply space 160 can be stabilized. This structure also prevents instability of characteristics, such as changes in the amount of protective gas 30 supplied to the rod movement gas supply space 160, due to subtle 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 increased processing precision, allowing the diameter of the protective gas supply holes 158 to 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 effectiveness of preventing the inflow of protective gas 30.

3.5 Explanation 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.

It is desirable for the supply of protective gas 30 from the outer periphery passage 152 to the rod movement gas supply space 160 to flow uniformly. If the supply amount of protective gas 30 varies in the circumferential direction 155 in Figure 9, this may result in unevenness in the effect of preventing corrosive gas 20 from flowing into the airtight retention mechanism 120. To ensure a more uniform supply of protective gas 30 from the outer periphery 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 preferably 0.5 mm or less. An even greater effect is achieved if the diameter is 0.2 mm or less.

3.6 Explanation 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 has a protective gas supply mechanism side end 130 in which an airtightness maintaining mechanism rod arrangement space 126 for movably arranging the rod 112 on the gas supply mechanism 140 side is formed,
The airtightness mechanism (120) has a bellows storage space (134) formed on the drive mechanism (60) side of the airtightness mechanism rod placement space (126) for storing the rod (112) and the bellows (132) arranged around the outer periphery of the rod (112);
The cross-sectional area of the airtightness mechanism rod arrangement space 126 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 accommodating space 134 perpendicular to the long axis 115.
The gate valve 50 is characterized by the above.

As described above, when the on-off valve 198 is opened, the bellows 132 expands along the longitudinal 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 longitudinal axis 115, reducing the volume of the bellows accommodating space 134. If this change causes turbulence in the gas flow, the effect of the supply of protective gas 30 from the rod movement gas supply space 160 in suppressing the inflow of corrosive gas 20 is reduced, making it difficult to suppress the flow of corrosive gas 20. There is also a limit to significantly increasing the supply amount of protective gas 30. In this embodiment, the protective gas supply mechanism side end 130 of the airtightness mechanism main body 122 protrudes toward the rod 112 in a plane perpendicular to the longitudinal axis 115 between the bellows accommodating space 134 and the rod movement gas supply space 160, forming an airtightness 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 , gas turbulence during the valve 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, with a relatively small supply of protective gas 30, the flow of corrosive gas 20 into the airtightness mechanism 120 can be stably suppressed.

20: Corrosive gas, 22: Pipe, 24: Pipe, 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: Valve closing supply part, Valve opening supply part 74: Valve opening supply part, 80: Spring, 112: Rod, 113: Drive side space, 114: Fixing plate, 115: Long axis, 118: Main body side Fixing part, 120: airtightness mechanism, 121: fixing screw, 122: airtightness mechanism main body, 123: cylindrical support, 124: airtightness mechanism space for rod , 125: cylindrical protrusion, 126: airtightness 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 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: Outer periphery space for gas supply rod, 162: Storage hole, 164 : bottom of storage hole, 165: bottom space of storage hole 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 (6)

A gate valve comprising: a drive mechanism that moves a rod along a major axis and controls the inclination of the rod relative to the major axis; a valve mechanism that controls the flow of corrosive gas; and an airtightness maintaining mechanism having a bellows, which are arranged along the major axis; the valve mechanism performs opening and closing operations based on the movement of the rod along the major axis and the inclination of the rod relative to the major axis; and the airtightness maintaining 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. 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. 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. 3. 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: 3. 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: