JP2005076862A - Safety valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized safety valve device which can attain rapid opening operation in an emergency while suppressing press force to a displacement inhibiting means which inhibits opening operation in a normal situation to be small. <P>SOLUTION: A valve body 26 displacement-driven from a closing position 42 to an opening position 43 due to melting of a fuse piece 28 receives resultant force of press force by primary pressure P1 of a gas introduced into a primary port 56 in the state where the valve body 26 is arranged in a position nearer the opening position 43 including a fluid drive starting position between the closing position 42 and the opening position 43. The valve body 26 is configured so that, in the state where the valve body 26 is arranged in a position nearer the closing position 42 than the fluid drive starting position, the resultant force of the press force by the primary pressure P1 applied to an opening direction X1 is small as compared with the state where the valve body is arranged in a position nearer the opening position 43 including the fluid drive starting position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a safety valve device provided in a pressure device such as a high-pressure gas device.

  FIG. 6 is a cross-sectional view showing a conventional safety valve 1. The safety valve 1 is provided in the pressure vessel and is used for releasing the gas in the pressure vessel in the event of an emergency in which the ambient temperature has risen, such as when a fire occurs. The safety valve 1 is configured by providing a piston 6, a pressing spring 7, and a fuse metal 8 in a housing 5 in which a valve passage 4 communicating with a primary port 2 and a secondary port 3 is formed. The piston 6 is provided at a closed position where the valve passage 4 is closed, and the fuse metal 8 prevents displacement to an open position where the valve passage 4 is opened. The piston 6 receives the gas guided to the primary port 2 and the pressing force in the opening direction by the pressing spring 7. With such a configuration, the valve passage 4 is normally closed, and in an emergency, the fuse metal 8 is melted and the piston 6 is driven to be displaced to open the valve passage 4 to discharge gas.

  FIG. 7 is a cross-sectional view showing another conventional safety valve 10. The safety valve 10 in FIG. 7 is similar to the safety valve 1 in FIG. 6, and only a different configuration will be described. The safety valve 10 in FIG. 7 is configured such that a pressure cancellation chamber 11 is formed on the opposite side of the primary port 2 with respect to the piston 6, and the primary port 2 and the pressure cancellation chamber 12 are communicated with each other through a through hole 12 formed in the piston 6. ing. In this way, the pressing force applied to the fuse metal 8 by the primary pressure p1 is cancelled. (For example, see Patent Document 1)

JP 2001-317645 A

  In the safety valve 1 shown in FIG. 6, since the pressing force by the primary pressure p1 of the gas guided to the primary port 2 is applied to the fuse metal 8, when the primary pressure p1 is high, the fuse metal 8 will creep and be deformed. . Conversely, if deformation is to be prevented, the size of the fuse metal 8 must be increased, and the safety valve 1 itself becomes larger.

  In the safety valve 10 of Patent Document 1 shown in FIG. 7, the pressing force caused by the primary pressure p <b> 1 to the fuse metal 8, which is a problem in the safety valve 1 shown in FIG. 6, can be canceled. The piston 6 must be driven only by the pressing force of the pressing spring 7 from beginning to end. Therefore, the large pressure spring 7 is required, and the safety valve device itself becomes large. In particular, when the primary pressure p1 is high, the seal structure provided in order to prevent gas leakage during normal operation provides a large sliding resistance against the piston drive in an emergency, and an extremely large pressing spring 7 is required. Further, in the configuration in which the piston 6 is driven only by the pressing spring 7, the valve passage 4 cannot be opened quickly in an emergency as in the case of using the primary pressure p1.

  An object of the present invention is to provide a small safety valve device capable of achieving a quick opening operation in an emergency while suppressing a pressing force to a displacement prevention means for preventing an opening operation in a normal time. is there.

The present invention includes a housing in which a valve passage communicating from a primary port to a secondary port is formed;
A valve body that is disposed in a closed position that closes the valve passage and is displaceable in an opening direction toward an open position that opens the valve passage, and is close to the open position including the fluid drive start position between the closed position and the open position. In the state arranged at the position, the resultant force of the primary pressure of the fluid guided to the primary port is received in the opening direction, and in the state arranged closer to the closed position than the fluid drive start position, the fluid drive start position A valve body provided so that the resultant force of the pressing force due to the primary pressure received in the opening direction is smaller than the state of being arranged at a position closer to the opening position including
Pressing means for pressing the valve body in the opening direction;
Displacement preventing means that is made of a material that melts at a predetermined melting temperature or higher, is provided in a space that is opened to the external space, and supports a valve element that is disposed in the closed position to prevent displacement in the opening direction. It is a safety valve device characterized by including.

  According to the present invention, normally, the valve body that can be displaced from the closed position to the open position is supported by the displacement prevention means in a state of being disposed at the closed position and is prevented from being displaced in the open direction, and the valve passage is The fluid is blocked from flowing from the primary port to the secondary port. In an emergency such as a fire, when the ambient temperature rises above the melting temperature of the displacement prevention means, the displacement prevention means melts and the valve body is pressed by the pressing means and displaced in the opening direction. This opens the valve passage and allows fluid to flow from the primary port to the secondary port.

  Thus, the valve body that is driven to be displaced in an emergency has a small pressing force due to the primary pressure when placed in the closed position, and is received by the primary pressure when displaced from the closed position to the fluid drive start position in the opening direction. It is comprised so that a pressing force may become large. As a result, normally, the pressing force applied to the displacement preventing means via the valve body can be reduced to prevent deformation of the displacement preventing means. In an emergency, when the pressure is pressed and displaced to the fluid drive start position by the pressing means, the valve body is displaced and driven in the opening direction with a large pressing force obtained by adding the pressing force by the primary pressure to the pressing force by the pressing means. be able to.

  Further, the present invention is characterized in that the resultant force of the pressing force received by the primary pressure by the valve body is zero in a state where the valve body is disposed closer to the closed position than the fluid drive start position.

  According to the present invention, in a state where the valve body is disposed closer to the closed position than the fluid drive start position, the pressing force received by the valve body by the primary pressure is balanced. As a result, it is possible to prevent the pressing force due to the primary pressure from being applied to the displacement prevention means via the valve body at normal times.

Further, according to the present invention, the valve body is cut off from the primary port in a state where the valve body is disposed at a position close to the open position including the fluid drive start position by the valve body and the housing, and the valve body is opened from the fluid drive start position. A pressure chamber connected to the primary port is formed in a state of being arranged at a close position,
The valve body receives a pressing force in the opening direction from the fluid in the pressure chamber,
The housing is formed with a pressure adjusting passage that communicates the pressure chamber with the external space,
A check valve means is provided interposed in the pressure adjusting passage, and the check valve means allows the flow of fluid from the external space to the pressure chamber and prevents the flow of fluid from the pressure chamber to the external space. Features.

  According to the present invention, the valve body is shut off from the primary port in a state where the valve body is disposed at a position closer to the open position including the fluid drive start position, and the valve body is disposed at a position closer to the open position than the fluid drive start position. In this state, a pressure chamber connected to the primary port is formed. The pressure chamber communicates with the external space via the pressure adjustment passage. A check valve means is interposed in the pressure adjustment passage to allow the fluid to flow from the external space toward the pressure chamber. The flow of the fluid toward the outside space is prevented. As a result, when the valve body is displaced from the open position to the fluid drive start position, the fluid is allowed to flow from the external space through the pressure adjusting passage to prevent the pressure chamber from becoming negative pressure, and the valve body can be smoothly displaced. Can be achieved. When the valve body is displaced to the fluid drive start position and the primary pressure is guided to the pressure chamber, the fluid is prevented from flowing out from the pressure chamber to the external space via the pressure adjusting passage, and the valve is pressed by the primary pressure. The body can be pressed.

  According to the present invention, it is possible to reduce the pressing force that is normally applied to the displacement prevention means, and it is possible to prevent deformation without increasing the size of the displacement prevention means. In an emergency, after the valve body is displaced to the fluid drive start position, the valve body can be driven to be displaced with a large pressing force obtained by adding a pressing force due to the primary pressure, and the valve body can be quickly displaced. A quick opening operation in a short time can be achieved. Further, since the pressing force by the primary pressure can also be used for driving the valve body, the pressing means only needs to obtain a pressing force that can displace the valve body to the fluid drive start position. Can be. As described above, it is possible to realize a small safety valve device that can suppress the pressing force to the displacement preventing means that prevents the opening operation in the normal time, and can achieve the quick opening operation in an emergency.

  In addition, according to the present invention, it is possible to prevent the pressing force due to the primary pressure from being applied to the displacement prevention means via the valve body at normal times, and to reliably prevent deformation of the displacement prevention means.

  Further, according to the present invention, when a pressure chamber communicating with the external space is formed in the pressure adjusting passage provided with the check valve means, and the valve body is displaced to the fluid drive start position, the primary pressure is guided to the pressure chamber, The valve body is displaced and driven by the pressing force by the primary pressure. Thus, it is possible to realize a safety valve device that can change the pressing force that the valve body receives from the primary pressure between the state until the valve body is displaced to the fluid drive start position and the state that the valve body has reached the reference position. it can.

  FIG. 1 is a cross-sectional view showing a safety valve 20 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a specific use state in which the safety valve 20 is mounted on the high-pressure gas tank 21. In FIG. 1, the shape of the housing 25 is shown in a simplified manner, but in FIG.

  The safety valve 20 is a safety valve device provided in a pressure device that handles a gas that is a fluid. The pressure device is, for example, a pressure vessel, more specifically, a high-pressure gas tank (hereinafter simply referred to as “tank”) 21. In particular, a safety valve 20 is provided in a tank 21 for storing combustible gas such as a fuel tank for a natural gas vehicle. Are preferably used. This safety valve 20 is normally connected from a space (hereinafter referred to as “tank space”) 22 in the high pressure tank 21 to a space (hereinafter referred to as “tank space”) 23 outside the tank 21 having a lower pressure than the tank internal space 22. In the event of an emergency when the atmospheric temperature has risen, such as during a fire, the discharge of gas from the tank inner space 22 to the tank outer space 23 is allowed for safety. being called.

  The safety valve 20 includes a housing 25, a valve body 26 that is a valve body, a spring member 27 that is a pressing means, and a fuse piece 28 that is a displacement prevention means. The housing 25 is configured by attaching a lid body 32 to a main body 31, and forms a valve chamber space 33 extending along a predetermined reference axis L20. In the valve chamber space 33, a piston valve body 26, a spring member 27, and The fuse piece 28 is accommodated to constitute the safety valve 20.

  In the housing 25, a melt discharge passage 34 is provided in an end portion (hereinafter referred to as "one end portion") 38 on one X1 side of a direction X1 and X2 (hereinafter referred to as "axial direction") parallel to the reference axis L20. , X2 is formed. In the housing 25, a primary passage 35, a secondary passage 36, and a pressure adjustment passage 37 are formed extending in a direction intersecting the reference axis L20.

  The primary passage 35, the secondary passage 36, and the pressure adjustment passage 37 are end portions on the other X2 side in the axial directions X1 and X2 with respect to the axial direction X1 and X2 (hereinafter referred to as “other end portions”). 39, and is formed so that the secondary passage 36, the primary passage 35, and the pressure adjustment passage 37 are arranged in this order from the one end 38 side to the other end 39 side, and with respect to the circumferential direction around the reference axis L20. , May coincide with each other or may deviate from each other.

  The valve chamber space 33 communicates with the external space of the housing 25 by the passages 34 to 37 formed in the housing 25. Specifically, the valve chamber space 33 is communicated with the tank inner space 22 by the primary passage 35, and is communicated with the tank outer space 23 by the melt discharge passage 34, the secondary passage 36 and the pressure adjusting passage 37.

  The piston valve body (hereinafter simply referred to as “valve body”) 26 includes a rod-shaped rod 40 and a piston 41 that is integrally provided at one end of the rod 40 and has an outer diameter larger than that of the rod 40. The valve body 26 is provided in the valve chamber space 33 such that its axis line coincides with the reference axis line L20, and the piston 41 is disposed on the X1 side in the axial direction.

  The valve element 26 is displaceable at least in the opening direction X1 from the closed position 42 toward the open position 43 over a closed position 42 indicated by a solid line in FIG. 1 and an open position 43 indicated by a virtual line in FIG. In the present embodiment, the valve body 26 can also be displaced in the closing direction X2 from the open position 43 toward the closed position 42. Since the opening direction is the same as one of the axial directions and the closing direction is the same as the other of the axial directions, the reference numerals are shared.

  The housing 25 has a piston guide portion 45 on the X1 side of the secondary passage 36 in the axial directions X1 and X2, and the piston 41 of the valve body 26 is provided in a state of being fitted into the piston guide portion 45. . The inner diameter of the piston guide portion 45 is uniform with respect to the axial directions X1 and X2, and the outer periphery of the piston 41 regardless of whether the valve body 26 is in the closed position 42, the open position 43, or a transition position therebetween. The portion is in close contact with the inner peripheral portion of the piston guide portion 45. As a result, the primary passage 35, the secondary passage 36, and the pressure adjusting passage 37 are closely separated from the melt discharge passage 34 and are blocked.

  The rod 40 of the valve body 26 is formed with first and second opening / closing control units 47 and 48 with an interval in the axial direction X1 and X2, and a rod-side retracting unit is provided between the opening / closing control units 47 and 48. 49 is formed. The first opening / closing control unit 47 is formed closer to the piston 41 than the second opening / closing control unit 48. The open / close control units 47 and 48 have the same outer diameter, and the rod-side retracting unit 49 has an outer diameter smaller than that of the open / close control units 47 and 48.

  A first rod guide portion 51 is formed in the housing 25 between the primary passage 35 and the secondary passage 36 in the axial directions X1 and X2, and the second rod guide portion 51 is provided between the primary passage 35 and the pressure adjustment passage 37. A rod guide 52 is formed. The rod guide portions 51 and 52 are identical to each other and have a uniform inner diameter with respect to the axial directions X1 and X2.

  Between the first and second rod guide portions 51 and 52 of the housing 25, a housing side retracting portion 50 having an inner diameter larger than that of the first and second rod guide portions 51 and 52 is formed. The housing side retracting portion 50 opens into the valve chamber space 33. Further, the first rod guide 51 is retracted between the first rod guide 51 and the piston guide 45 of the housing 25 so that the inner diameter of the first guide 25 is larger.

  In a state where the first opening / closing controller 47 of the valve body 26 is fitted into the first rod guide 51 of the housing 25, the outer periphery of the first opening / closing controller 47 is tightly connected to the inner periphery of the first rod guide 51. Abut. As a result, the valve chamber space 33 is tightly partitioned and closed between the primary passage 35 and the secondary passage 36. In a state where the first opening / closing control unit 47 has escaped from the first rod guide unit 51, the valve chamber space 33 is opened between the primary passage 35 and the secondary passage 36.

  In a state where the second opening / closing control portion 48 of the valve body 26 is fitted into the second rod guide portion 52 of the housing 25, the outer peripheral portion of the second opening / closing control portion 48 is connected to the inner peripheral portion of the second rod guide portion 52. It is in close contact. As a result, the valve chamber space 33 is tightly partitioned and closed between the primary passage 35 and the pressure adjustment passage 37. Further, the portion of the rod 40 on the other X2 side in the axial direction from the second opening / closing control unit 48 is configured such that a gap is formed even when fitted to the second rod guide 52, and the second opening / closing control unit 48 In a state of escape from the two-rod guide portion 52, the valve chamber space 33 is opened between the primary passage 35 and the pressure adjustment passage 37.

  With the valve body 26 provided in the housing 25, the housing 25 and the valve body 26 cooperate to form the valve passage 55, the fuse piece chamber 60, the drive pressure chamber 61, and the spring chamber 62. More specifically, when the valve chamber space 33 is partitioned by the piston 41, the fuse piece chamber 60 is configured by a portion of the valve chamber space 33 on the one X1 side in the axial direction from the piston 41. Of the portion of the valve chamber space 33 closer to the other X2 side in the axial direction than the piston 41, the portion surrounded by the second rod guide portion 52 and the portion closer to the other X2 side in the axial direction than that are configured as the driving pressure chamber 61. The driving pressure chamber 61 faces an end 58 on the other X2 side in the axial direction of the rod 40.

  Of the portion of the valve chamber space 33 on the other side in the axial direction X2 from the piston 41, the remaining portion excluding the drive pressure chamber 61 constitutes a passage portion, and this passage portion, the primary passage 35 and the secondary passage 36, Thus, the valve passage 55 is configured. The opening at the end of the primary passage 35 opposite to the valve chamber space 33 becomes the primary port 56, and the opening at the end of the secondary passage 36 opposite to the valve chamber space 33 becomes the secondary port 57. A spring chamber 62 is formed by a portion of the valve chamber space 33 that forms the valve passage 55 and between the piston 41 and the second rod guide 51 in the axial directions X1 and X2. That is, the valve passage 55 includes the spring chamber 62.

  In a state in which the valve body 26 is disposed at the closed position 42, the first opening / closing controller 47 is fitted into the first rod guide 51, and the second opening / closing controller 48 is fitted into the second rod guide 52. In this state, the valve chamber space 33 is closed between the primary passage 35 and the secondary passage 36. That is, the valve passage 55 is closed and the primary port 56 and the secondary port 57 are blocked. The valve chamber space 33 is closed between the primary passage 35 and the pressure adjustment passage 37, and the drive pressure chamber 61 is blocked from the primary port 56.

  In a state where the valve body 26 is disposed at the open position 43, the first opening / closing controller 47 escapes from the first rod guide 51, and the second opening / closing controller 48 escapes from the second rod guide 52. In this state, the valve chamber space 33 is opened between the primary passage 35 and the secondary passage 36. That is, the valve passage 55 is opened, and the primary port 56 and the secondary port 57 are connected. The valve chamber space 33 is opened between the primary passage 35 and the pressure adjustment passage 37, and the driving pressure chamber 61 is connected to the primary port 56.

  Transient positions between the closed position 42 and the open position 43 include a fluid drive start position and an opening start position. The opening start position is closer to the opening position than the fluid drive starting position.

  The fluid drive start position is such that when the valve body 26 is displaced from the closed position 42 toward the open position 43, the drive pressure chamber 61 and the primary port 56 are separated from the state where the drive pressure chamber 61 and the primary port 56 are blocked. Is a position to switch to the state of connecting. In a state in which the valve body 26 is disposed at a position closer to the closed position than the fluid drive start position, the drive pressure chamber 61 and the primary port 56 are blocked and disposed at a position from the open position including the fluid drive start position. In this state, the driving pressure chamber 61 and the primary port 56 are connected.

  The opening start position is such that when the valve body 26 is displaced from the closed position 42 toward the open position 43, the primary port 56 and the secondary port 57 are disconnected from the primary port 56 and the secondary port 57. Is a position to switch to the state of connecting. In a state where the valve body 26 is disposed at a position closer to the closed position than the opening start position, the primary port 56 and the secondary port 57 are blocked, and the valve body 26 is disposed at a position from the open position including the opening start position. Then, the primary port 56 and the secondary port 57 are connected.

  The spring member 27 is a compression coil spring, and is provided in the spring chamber 62 in a state of being fitted on the rod 40 of the valve body 26. One end of the spring member 27 is supported by a portion on the X1 side in the axial direction of the second rod guide portion 51 of the housing 25, and the other end is supported by the piston 41 of the valve body 26. A spring force is applied and elastically pressed in the opening direction X1, which is one of the axial directions.

  The fuse piece 28 is a short cylindrical member having a through hole, and is provided in the fuse piece chamber 60. The fuse piece 28 is provided with its axis line aligned with the reference axis line L <b> 20, and one end part is in contact with the piston 41 of the valve body 26, and the other end part is in contact with one end part in the axial direction of the housing 25. Therefore, the fuse piece 28 supports the valve body 26 arranged at the closed position 42 from the downstream side in the opening direction X1 to prevent displacement in the opening direction X.

  The fuse piece 28 is made of a material having a temperature characteristic that melts at a melting temperature lower than a temperature expected to reach the ambient temperature of the safety valve 20 in an emergency such as a fire, for example, a low melting point alloy that is a lead alloy. Become. When the fuse piece 28 is made of a low melting point alloy, it is called a fuse metal or the like.

  The fuse piece chamber 60 is opened to a tank outer space 23 that is an outer space of the housing 25 by a melt discharge passage 34 in which a filter 63 for reducing the flow velocity is interposed. The fuse piece 28 melts when the ambient temperature becomes equal to or higher than the melting temperature. The melt produced by melting the fuse piece 28 can be discharged to the outside through the melt discharge passage 34. A filter 63 for reducing the flow velocity is interposed in the melt discharge passage 34, and the melt can be prevented from being discharged at a high speed. Since the fuse piece 28 is cylindrical and the through hole faces the melt discharge passage 34, the melt is smoothly discharged.

  A check valve means 65 is interposed in the pressure adjusting passage 37. This check valve means 65 allows the flow of the fluid from the tank outer space 23, which is an external space, to the driving pressure chamber 61, here the atmospheric gas in the tank outer space 23, and moves from the driving pressure chamber to the tank outer space 23. The flow of the fluid, here, the gas in the driving pressure chamber 61 is prevented.

  FIG. 3 is a cross-sectional view for explaining the operating state of the safety valve 20. 3 (1) shows a state in which the valve body 26 is in the closed position 42, FIG. 3 (2) shows a state in which the valve body 26 is in the fluid drive start position, and FIG. Is in the open position 43.

  In the initial state in which the safety valve 20 is attached to the tank 21, as shown in FIGS. 1 and 3 (1), the valve body 26 is at the closed position 42, and the fuse piece 28 moves the valve body 26 in the opening direction X. Displacement is blocked. In this state, the valve passage 55 is closed, the primary port 56 and the secondary port 57 are blocked, and the drive pressure chamber 61 and the primary port 56 are blocked. Therefore, the gas in the tank inner space 22 is stopped from being discharged to the tank outer space 23.

  The valve body 26 faces the primary passage 35 between the first and second opening / closing control units 47 and 48, and the primary pressure P <b> 1 that is the gas pressure in the tank internal space 22 led to the primary port 56 is changed to the first pressure P <b> 1. Received by the first and second opening / closing control units 47 and 48. In the first opening / closing control unit 47, the pressing force received based on the primary pressure P1 is a pressing force toward the opening direction X1, and in the second opening / closing control unit 48, the pressing force received based on the primary pressure P1 is the closing direction. This is the pressing force toward X2.

  The outer diameters of the first and second opening / closing control units 47 and 48 are formed to be the same, and the sectional area A1 of the first opening / closing control unit 47 and the sectional area A2 of the second opening / closing control unit 48 are the same, The pressure receiving area that the valve body 26 receives the primary pressure P1 in the opening direction X1 is the same as the pressure receiving area that receives the primary pressure P1 in the closing direction X1. Therefore, the pressing force applied to the valve body 26 by the primary pressure P1 is balanced between the pressing force in the opening direction X1 and the pressing force in the closing direction X2, and the resultant force of the pressing force received by the valve body 26 by the primary pressure P1 is zero (0). It becomes.

  In such a safety valve 20, in an initial state in which the valve body 26 is in the open position 42, the pressing force that contributes to the driving force for displacing the valve body 26 in the opening direction 42 is only the pressing force due to the spring force of the spring member 27. The pressing force applied to the fuse piece 28 via the valve body 26 is only the pressing force by the spring member 27. Such an initial state is maintained in the remaining normal times except for an emergency in which a fire or the like has occurred.

  When the ambient temperature rises due to the occurrence of a fire around the tank 21, the fuse piece 28 also rises in temperature, and the fuse piece 28 melts when the melting point temperature is exceeded. When the fuse piece 28 is melted in an emergency such as the occurrence of a fire, the valve body 26 cannot be prevented from being displaced by the fuse piece 28. As a result, the melted material of the fuse piece 28 is discharged so as to be pushed out from the melt discharge passage 34, and the valve body 26 is pressed by the pressing force of the spring member 27 and is driven to move in the opening direction X1.

  At this time, until the valve body 26 is displaced to the fluid drive start position shown in FIG. 3B, the resultant force of the pressing force received by the primary pressure P1 is zero as in the initial state. . Further, the driving pressure chamber 61 is communicated with the tank outer space 23 by the pressure adjusting passage 37 in which the check valve means 65 is interposed, and the gas in the tank outer space 23 can be sucked, so that the driving pressure chamber 61 is closed. The negative pressure as in the space is prevented, and the valve body 26 can be smoothly displaced.

  When the valve body 26 is displaced to the fluid drive start position, the primary port 56 and the drive pressure chamber 61 are connected, and the valve body 26 receives the primary pressure P1 even at the portion facing the drive pressure chamber 61. The resultant force of the pressing force received by the primary pressure P1 is the pressing force in the opening direction X1. In such a state, the valve body 26 is pressed not only by the pressing force by the spring member 27 but also by the pressing force by the primary pressure P1, and is pressed by a large pressing force, and is driven only by the pressing force of the spring member 27. Compared to the case, it is accelerated and driven to move at a high speed.

  When the valve body 26 is displaced and driven to the opening start position in this way, the valve passage 55 is opened, the primary port 55 and the secondary port 56 are connected, and the gas in the tank inner space 22 is transferred to the tank. It is discharged into the outer space 23. Finally, the valve body 26 is displaced to the open position 43 shown in FIG. 3 (3), the valve passage 55 is opened with as much opening as possible, and the gas in the tank inner space 22 smoothly flows into the tank outer space 23. Discharged.

  According to the safety valve 20 of the present embodiment, normally, the valve body 26 that can be displaced from the closed position 42 to the open position 43 is supported by the fuse piece 28 in a state of being disposed at the closed position 42 and is opened in the opening direction X1. And the valve passage 55 is blocked to prevent the gas from flowing from the primary port 56 to the secondary port 57. In an emergency such as a fire, when the ambient temperature rises above the melting temperature of the fuse piece 28, the fuse piece 28 is melted and the valve element 26 is pressed by the spring force applied from the spring member 27 and displaced in the opening direction X <b> 1. To do. As a result, the valve passage 55 is opened and fluid flow from the primary port 56 to the secondary port 57 is allowed.

  Thus, the valve body 26 that is displaced and driven in the event of an emergency is disposed in a position near the open position 43 including the fluid drive start position between the closed position 42 and the open position 43, so that the gas guided to the primary port 56 In a state in which the resultant force of the pressing force by the primary pressure P1 is received in the opening direction X1 and is disposed at a position closer to the closed position 42 than the fluid drive start position, it is disposed at a position closer to the open position 43 including the fluid drive start position. Compared to the state, the resultant force of the pressing force by the primary pressure P1 received in the opening direction X1 is reduced. In other words, in the state of being disposed at the closed position 42, the pressing force received by the primary pressure P1 is small and is zero in the present embodiment, and when displaced from the closed position 42 to the fluid drive start position in the opening direction X1, The pressing force received by the primary pressure P1 is configured to increase.

  As a result, normally, the pressing force applied to the fuse piece 28 via the valve body 26 can be reduced to prevent deformation of the fuse piece 28. In the present embodiment, it is possible to prevent the pressing force due to the primary pressure P <b> 1 from being applied to the fuse piece 26 via the valve body 26 at the normal time. Therefore, the size of the fuse piece 26 can be reduced, and the safety valve 20 can be downsized.

  In an emergency, when the fluid drive start position is pressed and displaced by the pressing force from the spring member 27, the valve body 26 is opened in the opening direction by a large pressing force obtained by adding the pressing force by the primary pressure P1 to the pressing force by the spring member 27. X1 can be quickly displaced at a high speed. Therefore, a quick opening operation in a short time can be achieved. Further, since the pressing force by the primary pressure P1 can also be used for driving the valve body 26, the spring member 27 only needs to obtain a pressing force that can displace the valve body 26 to the fluid drive start position. The spring member 27 can be made small.

  As described above, it is possible to realize a small safety valve 20 that can suppress the pressing force to the fuse piece 28 that prevents the opening operation in the normal time, and can achieve a quick opening operation in an emergency.

  Further, as shown in FIG. 2, the safety valve 20 is blocked, and the secondary port 57 is provided with a nipple 70 for connecting a pipe for guiding the exhausted gas to a predetermined place. The gas can be suitably discharged from the tank 21 that is restricted.

  FIG. 4 is a sectional view showing a safety valve 20A according to another embodiment of the present invention. The safety valve 20A of the present embodiment is similar to the safety valve 20 of FIGS. 1 to 3, and the same reference numerals are given to corresponding portions, and only different configurations will be described. In the safety valve 20 </ b> A of the present embodiment, a recess 83 is formed in the piston 41 of the valve body 26 so as to open in one axial direction X <b> 1, specifically, open to the fuse piece chamber 60. With such a configuration, the melt produced by melting the fuse piece 28 can be caused to flow into the recess 83, and the valve body 26 can be easily displaced. In such a case, smooth displacement of the valve body 26 can be achieved even if a fuse piece that does not have a through hole facing the melt discharge passage 34 is used as the fuse piece 28. Other effects can be achieved as well.

  FIG. 5 is a sectional view showing a safety valve 20B according to still another embodiment of the present invention. The safety valve 20B is similar to the safety valve 20 of FIGS. 1 to 3, and the same reference numerals are given to corresponding portions, and only different configurations will be described. The safety valve 20B of the present embodiment is not provided with the pressure adjusting passage 37 and the check valve 65 provided in the safety valve 20 of FIGS. Even in such a configuration, if the displacement distance of the valve body 26 from the closed position to the fluid drive start position is reduced, the displacement operation of the valve body 26 is not hindered, and is the same as that of the safety valve 20 of FIGS. The same effect can be achieved.

  Each above-mentioned embodiment is only illustration of this invention, and can change a structure within the scope of the present invention. For example, the outer diameters of the first and second opening / closing control units 47 and 48 are made different so that the resultant force of the pressing force by the primary pressure P1 acts on either the opening direction X1 or the closing direction X2 in a normal state. Also good.

It is sectional drawing which shows the safety valve apparatus 20 of one Embodiment of this invention. 2 is a cross-sectional view showing the safety valve device 20 mounted on a high-pressure gas tank 21. FIG. 4 is a cross-sectional view for explaining an operating state of the safety valve 20. FIG. It is sectional drawing which shows the safety valve 20A of the other form of implementation of this invention. It is sectional drawing which shows the safety valve 20B of other form of implementation of this invention. It is sectional drawing which shows the safety valve 1 of a prior art. It is sectional drawing which shows the safety valve 10 of another prior art.

Explanation of symbols

20, 20A, 20B Safety valve 25 Housing 26 Valve element 27 Spring member 28 Fuse piece 47 First opening / closing control part 48 Second opening / closing control part 51 First rod guide part 52 Second rod guide part 55 Valve passage 56 Primary port 57 Secondary Port 61 Drive pressure chamber 65 Check valve means

Claims (3)

A housing in which a valve passage communicating from the primary port to the secondary port is formed;
A valve body that is disposed at a closed position that closes the valve passage and is displaceable in an opening direction toward the open position that opens the valve passage, and is close to the open position including the fluid drive start position between the closed position and the open position. In the state arranged at the position, the resultant force of the primary pressure of the fluid guided to the primary port is received in the opening direction, and in the state arranged closer to the closed position than the fluid drive start position, the fluid drive start position A valve body provided so that the resultant force of the pressing force due to the primary pressure received in the opening direction is smaller than the state of being arranged at a position closer to the opening position including
Pressing means for pressing the valve body in the opening direction;
Displacement preventing means that is made of a material that melts at a predetermined melting temperature or higher, is provided in a space that is opened to the external space, and supports a valve element disposed in the closed position to prevent displacement in the opening direction. A safety valve device comprising:   2. The safety valve device according to claim 1, wherein the resultant force of the pressing force applied to the valve body by the primary pressure is zero when the valve body is disposed closer to the closed position than the fluid drive start position. With the valve body and the housing, the valve body is placed at a position closer to the open position including the fluid drive start position, and is shut off from the primary port, and the valve body is placed closer to the open position than the fluid drive start position. In this state, a pressure chamber connected to the primary port is formed,
The valve body receives a pressing force in the opening direction from the fluid in the pressure chamber,
The housing is formed with a pressure adjusting passage that communicates the pressure chamber with the external space,
A check valve means is provided interposed in the pressure adjusting passage, and the check valve means allows the flow of fluid from the external space to the pressure chamber and prevents the flow of fluid from the pressure chamber to the external space. The safety valve device according to claim 1 or 2, characterized in that

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