Shut-off valve

Abstract

To provide a shut-off valve capable of reducing consumption of a metallic valve element, by restraining pressing force by high pressure gas and elastic repulsive force of a spring from simultaneously acting on the valve element when shutting off the valve.SOLUTION: A casing (2) in which a flow path (3) of a working fluid (for example, high-pressure hydrogen gas) extending in a central axis direction is formed, a valve stem (1) extending in the central axis direction, a valve body formed at a tip end portion of the valve stem, a valve seat formed in the vicinity of an end portion of the flow path (3), and an actuator (11) provided at an end portion of the casing (2) on a side opposite to the valve seat in the central axis direction and having a function of moving the valve stem (1) in the central axis direction, the elastic repulsive force eliminating device 20 has a function for eliminating the elastic repulsive force of the valve rod engaging part operating spring 4, and the valve rod operating shaft housing device 40 has a function for eliminating the elastic repulsive force of the pressure adjusting spring 44.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a shutoff valve for high-pressure fluids such as high-pressure hydrogen gas, the shutoff valve having a valve body and a valve seat made of metal. [Background technology]

[0002] In conventional shutoff valves for high-pressure fluids, such as high-pressure hydrogen gas, if the valve body is made of resin, it has good sealing performance at low pressures, but has the problem of low durability at high pressures.In contrast, if a metal valve body is used, there are no problems with strength, including durability, but there is a problem of low sealing performance at low pressures. In order to solve the problem of sealing performance under low pressure in such a metal valve body, it is effective to pre-press the metal valve body against the valve seat using a spring. However, under high pressure, the large pressing force of the high-pressure gas and the elastic repulsive force of the spring act simultaneously on the valve element, which causes the problem of wearing out the metal valve element.

[0003] As another prior art, a shutoff valve has been proposed in which the sliding properties, sealing properties, and durability of the sliding portion have been improved (see Patent Document 1). While this prior art (Patent Document 1) is useful, it is not a technology intended to solve the problem that in shutoff valves in which a metal valve disc is pressed against a valve seat by a spring, the pressing force of the high-pressure gas and the elastic repulsive force of the spring act simultaneously on the valve disc when the valve is shut off, causing it to wear out. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6972506 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been proposed in view of the problems of the prior art described above, and aims to provide a shutoff valve in which a metal valve element is pressed against a valve seat by a spring, which can reduce wear on the metal valve element by preventing the pressing force of high-pressure gas and the elastic repulsive force of the spring from acting simultaneously on the valve element when the valve is shut off. [Means for solving the problem]

[0006] The shutoff valve (100) of the present invention comprises: a casing (2) having a fluid (e.g., high-pressure air, high-pressure nitrogen gas) flow path (3) extending in the direction of the central axis; a valve stem (1: valve stem) disposed in the flow path (3) and extending in a central axis direction; A valve body (1AT) formed at the valve stem tip portion; a valve seat (3AT) formed in the casing (2) near an end of the flow path (3); a valve closing mechanism (10) that presses the valve element (1AT) against the valve seat (3AT); The valve closing mechanism (10) is composed of an actuator (11) and a valve closing force adjusting mechanism (50), The valve closing force adjustment mechanism (50) includes a pressure transmission chamber (5) and a valve stem actuation shaft accommodating device (40), The valve stem actuation shaft accommodating device (40) includes a valve stem actuation shaft (13) that engages with the valve stem (1) and is moved in the central axial direction by the actuator (11), and a pressure adjustment spring (44) that is disposed between the valve stem actuation shaft (13) and the actuator (11), The valve rod actuation shaft (13) is characterized by having a seal mechanism (30) disposed to prevent fluid from flowing into the actuator (11). In the present invention, a spring can be provided between the valve stem (1) and the valve stem actuation shaft (13) in the pressure transmission chamber (5).

[0007] In the present invention, The actuator (11) a shaft support member (14) that engages with the valve stem actuation shaft (13); a transmission member (15: fluid supply bottom portion 12A, spring pressing portion 16) connected to the shaft support member (14); an actuator driving fluid supply unit (12) to which an actuator driving fluid (e.g., high-pressure air, high-pressure nitrogen gas) is supplied or discharged; a shaft support member actuating spring (18) that is provided at a position opposite to the actuator driving fluid supply portion (12) and engages with the transmission member (15); It is preferable that the transmission member (15) moves in the direction of the central axis by supplying or discharging the driving fluid to the actuator driving fluid supply portion (12) and by the shaft support member operating spring (18).

[0008] In the shutoff valve (100) of the present invention, A seal mechanism (30) is provided in a flow path (3) formed in the central axis direction of the casing (2) and through which the valve stem (1) extends, and the seal mechanism (30) a C-shaped member (32: C-ring) formed by cutting out a portion of the circumference of the ring; a member (33: hollow cylinder-flange composite member) having a hollow cylindrical region (33A) and a flange (33B) extending radially outward on the valve body (1AT) side (upper side) of the region (33A) in the central axis direction (vertical direction) (of the shutoff valve 100), and the hollow cylindrical region (33A) of the member (33) having the hollow cylindrical region (33A) and the flange (33B) is inserted into the central hollow portion (32A) of the C-shaped member (32); A backup ring (34) and an O-ring (35) are placed on the flange (33B), It is preferable to provide a plurality of stages of combinations (units) each consisting of the C-shaped member (32: C-ring), a member (33) having the hollow cylindrical region (33A) and a flange (33B), and a backup ring (34) and an O-ring (35) placed on the flange (33B) of the member (33) having the hollow cylindrical region (33A) and flange (33B). Here, it is preferable that the flow path (3) through which the valve stem (1) extends has regions (31A) with large inner diameters formed intermittently at equal intervals in the axial direction, and that the C-shaped member (32: C-ring) is fitted into the regions (31A). [Effects of the Invention]

[0009] According to the present invention having the above-described configuration, the actuator (11) of the valve closing mechanism (10) can seat the valve disc (1AT) on the valve seat (3AT), and at that time, the elastic repulsive force of the spring (4) also acts in a direction to seat the valve stem (1) on the valve seat (3AT). However, the elastic repulsive force of the spring (4) can be eliminated by the elastic repulsive force elimination device (20) of the valve closing mechanism (10), and the pressure adjustment spring (44) can be eliminated by the valve stem actuation shaft accommodation device (40). Therefore, the force that seats the valve element (1AT) at the tip of the valve stem (1) on the valve seat (3AT) is only the force transmitted from the actuator (11). The spring (4) and the valve stem actuation shaft accommodation device (40) do not act on the valve element (1AT) by the amount of the elastic repulsive force of the pressure adjustment spring (44). Therefore, damage to the metal valve element (1AT) and the valve seat (3AT) is reduced. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 4 is an explanatory cross-sectional view showing a state in which the shutoff valve according to the illustrated embodiment is open. [Figure 2] FIG. 2 is a partially enlarged explanatory cross-sectional view of part A in FIG. [Figure 3] 2 is an explanatory cross-sectional view showing a state immediately after the shutoff valve shown in FIG. 1 is closed. FIG. [Figure 4] 2 is an explanatory cross-sectional view showing a state after a predetermined time has elapsed since the shutoff valve shown in FIG. 1 was closed. FIG. [Figure 5] FIG. 2 is an explanatory cross-sectional view showing a sealing mechanism in the illustrated embodiment. [Figure 6] FIG. 6 is a perspective view of a hollow cylinder-flange composite member used in the sealing mechanism of FIG. 5. [Figure 7] FIG. 6 is a perspective view of a C-ring used in the sealing mechanism of FIG. 5. [Figure 8] FIG. 10 is an explanatory cross-sectional view showing a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. First, a shutoff valve according to an embodiment of the present invention will be described with reference to FIGS. In the illustrated embodiment, high-pressure hydrogen gas is used as the fluid, and a shutoff valve used in a filling device that fills a fuel cell vehicle (FCV) with high-pressure hydrogen gas as fuel is illustrated as an example. 1 and 2 show the illustrated embodiment of the shut-off valve 100 in an open state. 1, the shutoff valve 100 has a casing 2 in which a flow path 3 for high-pressure hydrogen gas extending in the direction of the central axis (the up-down direction in FIG. 1) is formed, a valve stem 1 (valve shaft) disposed within the flow path 3 and extending in the direction of the central axis, a valve disc 1AT (tapered portion: see FIG. 2) formed at the tip of the valve stem 1 (the upper end of the valve stem 1 in FIG. 1), a valve seat 3AT (tapered portion: see FIG. 2) formed near the end of the flow path 3 within the casing 2 (the lower end of flow path 3D in FIG. 2), and a valve closing mechanism 10 that presses the valve disc 1AT against the valve seat 3AT. Details of part A in FIG. 1, including the valve disc 1AT (tapered portion) formed on the valve stem 1 and the valve seat 3AT (tapered portion) formed near the end of the flow path 3, will be described later with reference to FIG. 2.

[0012] In Fig. 1, the valve closing mechanism 10 includes an actuator 11 and a valve closing force adjustment mechanism 50. The actuator 11 is provided near the end of the flow path 3 on the opposite side from the valve seat 1AT in the central axial direction (lower in Fig. 1), and has the function of moving the valve stem 1 in the central axial direction. The valve closing adjustment mechanism 50 includes an elastic repulsive force disappearance device 20, a valve stem actuation shaft accommodating device 40, and a seal mechanism 30. The actuator 11 includes an actuator driving fluid supply unit 12 to which an actuator driving fluid (such as high-pressure air or high-pressure nitrogen gas) is supplied or discharged, a transmission member 15, and 、 The transmission member 15 has a shaft support member actuation spring 18. The transmission member 15 has a fluid supply section bottom 12A and a spring pressing section 16, and has the function of transmitting the supply or discharge of actuator drive fluid to the actuator drive fluid supply section 12 to the shaft support member 14 (of the valve stem actuation shaft accommodating device 40) and converting it into movement in the central axial direction of the shaft support member 14. The shaft support member actuation spring 18 is arranged below the transmission member 15 so as to surround the shaft 14A of the shaft support member 14, and the shaft 14A is connected to the spring pressing section 16 via a connecting section 16A. The spring 18 urges the shaft support member 14 upward in the central axial direction via the transmission member 15 and shaft 14A by its elastic repulsive force, thereby urging the valve stem actuation shaft 13 and the valve stem 1 upward in the central axial direction. In Figure 1, the actuator driving fluid supply section 12 is supplied with driving fluid by a supply means (not shown), and the size of the actuator driving fluid supply section 12 in the direction of the central axis (vertical direction) is shown to be larger (compared to Figures 3 and 4). In the state shown in Figures 3 and 4 (described later), the driving fluid is discharged from the actuator driving fluid supply section 12 by a discharge means (not shown), and the size of the actuator driving fluid supply section 12 in the direction of the central axis (vertical direction) is smaller (compared to Figure 1). Reference numeral 2-3 denotes an actuator-side casing.

[0013] A shaft 14A of a shaft support member 14 is disposed in the actuator-side casing 2-3. The shaft support member 14 has a larger diameter than the shaft 14A and supports a valve stem actuation shaft 13. The valve stem actuation shaft 13 extends in the direction of the central axis and is connected to the valve stem 1. 1 is opened, the lower end of shaft 14A abuts against stopper 17 at the lower end of actuator 11. On the other hand, when shutoff valve 100 is closed as shown in FIGS. 3 and 4, the lower end of shaft 14A moves away from stopper 17. The valve stem actuation shaft accommodating device 40, which is provided at a position intermediate between the actuator 11 and the elastic recoil force dissipating device 20, has an upper part of the shaft support member 14, a lower part of the valve stem actuation shaft 13, a valve stem actuation shaft engaging part 42 that engages with the valve stem actuation shaft 13, and a pressure adjustment spring 44 disposed in a hollow accommodating part 46. The base part 13A of the valve stem actuation shaft 13 is accommodated in a shaft support member recess 14B formed in the upper part of the shaft support member 14, thereby connecting the shaft support member 14 and the valve stem actuation shaft 13. The pressure adjustment spring 44 surrounds the shaft support member 14 and the base 13A of the valve stem actuation shaft 13. The lower part of the pressure adjustment spring 44 abuts against the bottom part of the hollow accommodating part 46, and the upper part of the pressure adjustment spring 44 abuts against the valve stem actuation shaft engaging part 42.

[0014] The elastic recoil force dissipation device 20 has a pressure transmission chamber 5, a spring 4, and a spring support member 7. The pressure transmission chamber 5 accommodates the end of the valve stem 1 opposite the valve disc 1AT (the lower end of the valve stem 1) and the end of the valve stem actuation shaft 13 on the valve stem 1 side (the upper end of the valve stem actuation shaft 13). The pressure transmission chamber 5 is provided with a valve stem engagement portion 6 that engages with the valve stem 1, and one end (upper end) of the spring 4 is attached to the valve stem engagement portion 6. The pressure transmission chamber 5 also houses a spring support member 7 that engages with the valve stem actuation shaft 13, and the spring support member 7 has a flange 7A (spring support member flange) that can come into contact with the other end (lower end) of the spring 4. The spring support member 7 accommodates the end (upper end) of the valve stem actuation shaft 13 on the valve stem 1 side, and the valve stem actuation shaft 13 and the valve stem 1 are connected via the spring support member 7 and the valve stem engagement portion 6.

[0015] High-pressure hydrogen gas from a filling device (not shown) flows into the pressure transmission chamber 5 through the intake port 2A of the casing 2, the intake port-side flow path 3A (see FIG. 2), and the valve actuation flow path 3C (see FIG. 2). Therefore, the pressure of the high-pressure hydrogen gas acts inside the pressure transmission chamber 5. When the pressure inside the pressure transmission chamber 5 rises above a predetermined value (set on a case-by-case basis by the elastic repulsive force of the pressure adjustment spring 44), the valve stem actuation shaft 13 moves in a direction (downward) away from the spring 4 due to the pressure difference between the pressure transmission chamber 5 and the hollow accommodating portion 46.

[0016] 1, high-pressure hydrogen gas flows into shutoff valve 100 from intake port 2A and is discharged from outlet 2B toward equipment on the downstream side (FCV side). Details of high-pressure hydrogen gas flow path 3 that communicates from intake port 2A to outlet 2B are shown in FIG. 2, which is a partially enlarged view of part A in FIG. 1. In FIG. 2, the metal casing 2 has a main body casing 2-1 and a discharge side casing 2-2, and the main body casing 2-1 and the discharge side casing 2-2 are joined by a casing screw portion 22. The main body casing 2-1 is formed with an inlet 2A for high-pressure hydrogen gas, and the inlet 2A is connected to a valve actuation flow path 3C via an inlet-side flow path 3A and a flow path space 3B. The flow path space 3B is connected to a discharge port-side flow path 3D formed in the main body casing 2-1 and a discharge port-side flow path 3E formed in the discharge casing 2-2, and is connected to a discharge port 2B for high-pressure hydrogen gas. A metal valve stem 1 is arranged in the hollow portion of the valve actuation flow path 3C and flow path space 3B of the main body side casing 2-1, and the tip (upper end in Figure 2) of the valve stem 1 forms a valve body 1AT with a tapered surface. A tapered surface is formed at the end of the discharge port-side flow path 3D on the side of the flow path space 3B, and this tapered surface constitutes a valve seat 3AT. The valve seat 3AT and the valve element 1AT at the tip of the valve stem 1 constitute a shutoff valve. Reference numeral 23 denotes an O-ring.

[0017] 1 and 2, which show the shutoff valve in an open state, the tapered surface that is formed at the end of the discharge port-side flow path 3D on the flow path space 3B side and that forms the valve seat 3AT is separated from the tapered surface at the tip of the valve stem 1 that forms the valve element 1AT. On the other hand, in Figures 3 and 4, which show the shutoff valve in a closed state, the tapered surface of the valve element 1AT is seated on the tapered surface that forms the valve seat 3AT. 2, when the shutoff valve is open, high-pressure hydrogen gas (arrow A1) supplied from suction port 2A flows into flow path space 3B via suction port-side flow path 3A. The high-pressure hydrogen gas that has flowed into flow path space 3B passes through discharge port-side flow path 3D and discharge port-side flow path 3E formed in discharge port-side casing 2-2, and is discharged from discharge port 2B downstream (FCV-side equipment: not shown) (arrow A2).

[0018] For example, when the shut-off valve 100 shown in Figures 3 and 4 is changed from a closed state to an open state, the actuator driving fluid is supplied to the actuator driving fluid supply section 12 (by a supply means not shown). When driving fluid is supplied to the actuator driving fluid supply section 12, the fluid pressure increases the dimension of the actuator driving fluid supply section 12 in the central axis direction (up and down direction), and the fluid supply section bottom 12A and spring pressing section 16 (transmission member 15) descend in the direction of arrow D against the elastic repulsive force of the shaft support member operating spring 18.

[0019] Because the spring pressing portion 16 is connected to the shaft 14A of the shaft support member at the connecting portion 16A, when the spring pressing portion 16 descends, the shaft support member 14 descends in the direction of arrow D. When the shaft support member 14 descends in the direction of arrow D, the valve stem actuation shaft 13, which is connected to the shaft support member 14 via the shaft support member recess 14B, also descends in the direction of arrow D. As the valve stem actuation shaft 13 descends in the direction of arrow D, the valve stem 1 also descends in the direction of arrow D via the spring support member 7. When the valve stem 1 descends, the valve element 1AT (tapered surface, FIG. 2) at the tip of the valve stem 1 moves away from the valve seat 3AT (tapered surface, FIG. 2) formed in the discharge port side flow path 3D, and the shutoff valve 100 opens.

[0020] 3 shows a state in which the shutoff valve 100 is closed after being opened to allow high-pressure hydrogen gas to flow (FIG. 1). When changing from the state shown in FIG. 1 to the state shown in FIG. 3, the actuator driving fluid is discharged from the actuator driving fluid supply unit 12. When the driving fluid is discharged and the pressure inside the actuator driving fluid supply part 12 drops, the dimension of the actuator driving fluid supply part 12 in the central axis direction (vertical direction) decreases due to the elastic repulsive force of the shaft support member actuating spring 18. As a result, the fluid supply part bottom part 12A and the spring pressing part 16 rise in the direction of the arrow U.

[0021] Because the spring pressing portion 16 is connected to the shaft 14A at the connecting portion 16A, when the spring pressing portion 16 rises, the shaft support member 14 rises in the direction of the arrow U. When the shaft support member 14 rises in the direction of the arrow U, the elastic repulsive force of the pressure adjustment spring 44 acts on the valve stem actuation shaft engaging portion 42, causing the valve stem actuation shaft 13 to rise in the direction of the arrow U. As the valve stem actuation shaft 13 rises in the direction of the arrow U, the spring support member 7 presses the spring 4 and the valve stem engaging portion 6, causing the valve stem 1 to rise. As the valve stem 1 rises, the valve disc 1AT (tapered surface, Figure 2) at the tip of the valve stem 1 sits on the valve seat 3AT (tapered surface) formed in the discharge port-side flow path 3D, and the shutoff valve 100 closes.

[0022] In the shutoff valve 100 according to the illustrated embodiment, when a predetermined time has passed since the state in Fig. 3, the pressing force from the pressure adjustment spring 44 is reduced and the elastic repulsive force of the spring 44 disappears. The mechanism behind this will be explained with reference to Fig. 4. As shown in Figure 3, even when the tapered surface 1AT (Figure 2) at the tip of the valve stem 1 is seated on the tapered surface 3AT (valve seat: Figure 2) and the shutoff valve 100 is closed, high-pressure hydrogen gas flowing in from the suction port 2A flows through the suction port-side flow path 3A, the flow path space 3B, and the valve actuation flow path 3C. In Figure 4, which shows the state a predetermined time has elapsed since the shutoff valve 100 was closed, the high-pressure hydrogen gas that has flowed through the valve actuation flow path 3C flows into the pressure transmission chamber 5. The pressure of the inflowing high-pressure hydrogen gas moves the valve stem actuation shaft 13 toward the hollow accommodation portion 46, which is not under pressure. At the same time, the spring support member 7 engaged with the valve stem actuation shaft 13 also descends in the direction of arrow D (the direction in which the valve disc 1AT of the valve stem 1 moves away from the valve disc 1AT).

[0023] When the flange 7A of the spring support member 7 descends in the direction of arrow D by a predetermined amount or more, the spring 4 moves from a state in which it abuts the flange 7A (the state shown in Figure 3) to a state in which it is separated from the flange 7A, as shown in Figure 4. In other words, the spring 4, which was compressed by the raised flange 7A, moves away as the flange 7A descends, and the compressed state is released, and the spring 4 moves into an extended state. As a result, the elastic repulsive force of the spring 4 pressing the valve stem engagement portion 6 in the direction of arrow U disappears.

[0024] As a result, the force to close the valve is reduced by the elastic repulsive force of the spring 4, and only the pressure of the high-pressure hydrogen gas remains. In this way, by adjusting the force pressing the valve stem 1 according to the pressure of the acting fluid, the pressing force can be reduced by the amount of the applied fluid pressure. Therefore, it is possible to prevent the application of force greater than that required to close the valve, thereby reducing damage to the valve disc 1AT and valve seat 3AT.

[0025] Here, the position of the valve stem actuation shaft 13 in the central axial direction moves due to the up and down movement of the flange 7A of the spring support member 7, but because the valve stem 1 is connected to the valve stem engagement portion 6, the up and down movement of the flange 7A of the spring support member 7 and the up and down movement of the valve stem 1 are not synchronized. Therefore, the position of the valve stem 1 in Figures 3 and 4 is the same, and the tapered surface of the valve disc 1AT (Figure 2) at the tip of the valve stem remains seated on the valve seat 3AT (Figure 2). Although not shown, instead of using fluid pressure to open and close the shutoff valve, it is also possible to open and close the shutoff valve using an electric motor.

[0026] Next, with reference to FIGS. 5 to 7, the sealing mechanism of the shutoff valve shown in FIGS. 1 to 4 will be described. In order to prevent high-pressure hydrogen from leaking from the part where the valve stem slides, multiple stages of seals are required, and for this reason, a seal mechanism is provided in the shutoff valves shown in Figures 1 to 4. In Figures 1, 3, and 4, a seal mechanism 30 is provided at the position where the valve stem actuation shaft 13 slides. In FIG. 5, the sealing mechanism 30 has a structure in which units each combining an O-ring 35, a backup ring 34, a hollow cylinder-flange composite member 33, and a C-ring 32 are stacked in multiple stages. In the flow path 3 formed in the central axis direction (vertical direction) of the casing 2 (Figures 1 to 4) and having the valve stem actuation shaft 13 extending therein, the hollow portion 31 in which the valve stem actuation shaft 13 slides has multiple regions 31A with a large inner diameter (expanded diameter portions) formed intermittently and at equal intervals in the central axis direction (two locations in the example of Figure 5).

[0027] The C-ring 32 in the seal mechanism 30 installed in the hollow portion 31 in which the valve stem actuation shaft 13 slides has a circular shape with a part cut out in the circumferential direction, and fits into the expanded diameter portion 31A of the hollow portion 31. A hollow cylinder / flange composite member 33 is disposed above the C-ring 32. The hollow cylinder / flange composite member 33 has a hollow cylindrical region 33A (main body) extending in the central axis direction (up and down direction), and the hollow cylinder / flange composite member 33 is inserted into the hollow portion 32A at the radial center of the C-ring 32. A flange 33B extending radially outward is formed on the main body 33A of the hollow cylinder-flange composite member 33, and a backup ring 34 and an O-ring 35 are placed on the flange 33B. Another backup ring 34 is provided above the O-ring 35, so that the O-ring 35 is sandwiched between the two backups 34, 34. The sealing mechanism 30 is constructed by stacking multiple units (combinations C32-35) each consisting of an O-ring 35, two backup rings 34, 34, a hollow cylinder-flange composite member 33, and a C-ring 32. Figure 5 shows two layers of combinations C32-35 stacked together.

[0028] By adopting this configuration, it is possible to form an expanded diameter portion 31A into which the C-ring 32 fits without increasing the inner diameter of the portion (hollow portion) where the valve stem actuation shaft 13 slides, thereby easily arranging multiple stages of seals and reliably preventing leakage of high-pressure hydrogen gas. The sealing mechanism 30 can be disposed at any position where the shaft (including the valve stem 1) slides, other than the position where the valve stem actuation shaft 13 slides. Although not shown, a cup seal can be used instead of the O-ring 35. In that case, it is preferable to arrange the cup seal so that the upward direction in Figures 1, 3, and 4 is the open direction of the cup seal.

[0029] The hollow cylinder-flange composite member 33 and the C-ring 32 are shown in FIGS. 6 and 7, respectively. The backup ring 34 is made of resin and is provided to prevent a part of the O-ring 35 from extending due to high pressure and getting into the gap with the inner wall (so-called "O-ring protrusion"), which could cause the O-ring 35 to rupture at the part that has gotten in.

[0030] The hollow cylinder-flange composite member 33 shown in Figure 6 is made of metal and has a hollow cylindrical main body 33A extending in the central axis direction (up and down direction), and a flange 33B (flange 33B at the upper edge of main body 33A) located above main body 33A and extending radially outward. When installing the seal mechanism 30, the hollow cylindrical portion of the main body 33A is inserted into and fitted into the hollow portion 32A of the C-ring 32. This prevents the C-ring 32 from shrinking radially inward. When the sealing mechanism 30 is installed, a backup ring 34 and an O-ring 35 are placed on the flange 33B that extends outward in the radial direction.

[0031] The C-ring 32 shown in Fig. 7 is made of metal and is formed in a C-shape with a portion of the ring cut out in the circumferential direction, with multiple (four in the illustrated embodiment) slits 32B formed at approximately equal intervals in the circumferential direction. The formation of the slits 32B makes it easier for the C-ring 32 to expand radially outward, making it easier to insert the main body 33A of the hollow cylinder-flange composite member 33 into the hollow portion 32A in the radial center of the C-ring 32. Note that the number of slits 32B may be less than three or may be five or more (for example, two to six). The dimension TS of the C ring 32 in the central axis direction (the vertical direction in Figs. 1, 3, and 4) is set to be thicker than the dimension TR in the radial direction. The ratio of the radial dimension TR to the dimension TS in the central axis direction of the C ring 32 is set in the range of 1:1 to 1:10. This is because if the axial dimension TS of the C ring 32 is thick, the C ring 32 will be less likely to contract in the radial direction. The dimension TS of the C-ring 32 in the central axis direction is set to a value that allows it to resist the shear force acting in the central axis direction. The radial thickness of the C-ring 32 is thinner at the slit 32B. As described above, the main body 33A of the hollow cylinder / flange composite member 33 is inserted into the hollow portion 32A of the C-ring 32, and the flange 33B of the hollow cylinder / flange composite member 33, which is arranged adjacent to and above the C-ring 32, covers the C-ring 32. Therefore, even if the radial thickness is thinner at the slit, there is no risk of the function of the sealing mechanism 30 being impaired.

[0032] FIG. 8 shows a modification of the embodiment described with reference to FIGS. In the shutoff valve 100 of the embodiment shown in FIGS. 1 to 7, the spring 4 is provided in the pressure transmission chamber 5, but in the modified example shown in FIG. 8, no spring is provided. 8, the spring 4 is not provided, but when a fluid flows into the shutoff valve 100, the presence of the sealing mechanism 30 causes fluid pressure to be applied to the pressure transmission chamber 5-1. Because fluid pressure is applied to the upper part of the valve stem actuation shaft 13 that is pressing against the valve stem 1, an opposing force is applied to the pressure adjustment spring 44, reducing the pressing force on the valve stem 1. Therefore, the pressing force on the valve stem 1 does not become an excessive pressing force resulting from the pressure from the actuator 11 plus the fluid pressure, thereby preventing damage to the valve seat 3AT and valve disc 1AT. Other configurations and effects of the modified example of FIG. 8 are the same as those of the embodiment of FIGS.

[0033] It should be noted that the illustrated embodiments are merely examples and are not intended to limit the technical scope of the present invention. [Explanation of symbols]

[0034] 1. Valve stem 1AT···Valve body 2. Casing 3. Flow path 3AT...Valve seat 4. Spring 5, 5-1... Pressure transmission chamber 6. Valve stem engagement part 7. Spring support member 7A···Flange (Flange of spring support member) 10. Valve closing mechanism 11. Actuator 12. Actuator drive fluid supply unit 12A...Bottom of fluid supply section 13. Valve stem operating shaft 14. Shaft support member 15 Transmission member 16 Spring pressing part 20. Elastic repulsion force dissipation device 30. Sealing mechanism 31A: Area with large inner diameter in the flow path 32....C-shaped member (C-ring) 32A···C-ring hollow 32B···C ring gap 33. Hollow cylinder-flange composite member 33A: Hollow cylindrical area (main body) of hollow cylinder-flange composite member 33B....Hollow cylinder-flange composite member flange 34 Backup ring 35···O-ring 40... Valve stem actuation shaft accommodation device 50... Valve closing force adjustment mechanism 100 Shut-off valve

Claims

1. a casing having a fluid flow path extending in a central axis direction; a valve stem disposed within the flow passage and extending in a central axis direction; A valve body formed at the valve stem tip portion; a valve seat formed near an end of a flow path within the casing; a valve closing mechanism that presses the valve body against the valve seat; The valve closing mechanism consists of an actuator and a valve closing force adjustment mechanism. The valve closing force adjusting mechanism includes a pressure transmission chamber and a valve stem actuation shaft accommodating device. the valve stem actuation shaft accommodating device includes a valve stem actuation shaft that engages with the valve stem and is moved in the central axis direction by the actuator, and a pressure adjustment spring that is disposed between the valve stem actuation shaft and the actuator, a valve shaft for operating the valve rod, the valve shaft being provided with a seal mechanism for preventing fluid from flowing into the actuator side;

2. 2. The shutoff valve according to claim 1, wherein a spring is provided between the valve stem and the valve stem actuation shaft in the pressure transmission chamber.

3. The actuator is a shaft support member that engages with the valve stem actuation shaft; a transmission member connected to the shaft support member; an actuator driving fluid supply unit to which an actuator driving fluid is supplied or discharged; a shaft support member actuating spring that is provided at a position facing the actuator driving fluid supply portion and engaged with the transmission member, 3. The shutoff valve according to claim 1, wherein the transmission member moves in the direction of the central axis by supplying or discharging the driving fluid to the actuator driving fluid supply portion and by the shaft support member operating spring.

4. A seal mechanism is provided in a flow path formed in the central axis direction of the casing and through which the valve stem extends, and the seal mechanism a member formed in a C-shape by cutting out a portion of the circumference of the ring; a member having a hollow cylindrical region and a flange extending radially outward on the central axis direction valve body side of the region, the hollow cylindrical region of the member having the hollow cylindrical region and the flange being inserted into a central hollow portion of the C-shaped member, A backup ring and an O-ring are mounted on the flange, 3. The shutoff valve according to claim 1, wherein a plurality of stages of combinations each including the C-shaped member, the member having the hollow cylindrical region and a flange, and a backup ring and an O-ring mounted on the flange of the member having the hollow cylindrical region and the flange are provided.

Images