safety valve

Abstract

Provided is a safety valve capable of minimizing creep of a fusible alloy and promoting smooth flow of the fusible alloy when molten, even in a safety valve in which a member for closing off a flow path presses the fusible alloy directly.　In the present invention: a fusible alloy 6 is arranged between a pressing cap 4 and an occlusion member 3 which blocks the flow of a fluid flowing from a discharge passage 91 of a fluid device 9; a reservoir part 8 where the molten fusible alloy 6 is to be stored is formed in at least one of the occlusion member 3 and the pressing cap 4; two plate members 5A, 5B, which are formed with holes of which the perforation positions do not overlap, are disposed between the reservoir part 8 and the fusible alloy 6; and a cutout part 51, which communicates between the holes 50 of the different plate members 5A, 5B, is formed in at least one surface of the abutting surfaces of the plate members 5A, 5B.

Description

Technical Field

[0001] The present invention relates to a safety valve for safely discharging the fluid inside a device in order to prevent the internal pressure of a fluid device from rising too much when the ambient temperature becomes high, such as during a fire.

Background Art

[0002] As such a safety valve, there is known a safety valve that has a fusible body that melts at high temperatures, and the movable plug moves as the fusible body melts, thereby releasing the gas inside the fluid device (see Patent Documents 1 to 3).

[0003] These safety valves are particularly attached to the open end of a discharge flow path branched from the flow path of a fluid device through which fluid flows inside. When the ambient temperature rises, such as during a fire, fluids such as gas inside the fluid device are released to the outside (atmosphere).

[0004] The safety valve described in Patent Document 1 is attached to the opening of the open end to the outside of the flow path branched from the fluid passage inside the fluid device, and is sealed so that the internal fluid does not leak to the outside under normal conditions. When the temperature rises, the gas inside the fluid device is released, thereby preventing the internal pressure of the fluid device from rising too much.

[0005] This safety valve includes a cylindrical main body composed of a top wall and a peripheral wall, the lower end of the peripheral wall being fixed to the opening edge of the fluid device, a columnar moving member with a flange disposed movably inside the main body, a compression coil spring (elastic member) that biases the moving member upward, and a fusible body for the safety valve (fusible alloy) interposed between the lower surface of the top wall of the main body and the upper surface of the moving member. The inside of the main body is in communication with the outside for the discharge passage.

[0006] Furthermore, the lower end of the peripheral wall is blocked from communication with the inside of the fluid equipment by the tip of the movable member. When the fusible material melts due to high temperatures such as a fire, the movable member moves towards the top wall side due to the biasing force of the compression coil spring, thereby creating communication between the inside of the safety valve body and the inside of the fluid equipment, and the fluid inside the fluid equipment is released to the outside through the discharge passage of the body.

[0007] In the safety valve described in Patent Document 1, in addition to the pressure exerted by a compression coil spring on the fusible material (fusible alloy), the pressure inside the container is applied via a moving member that prevents the flow of the fluid inside the container to the discharge port. As a result, even at a predetermined temperature, the fusible material may gradually deform and flow toward the discharge port of the fusible material in a solid state (creep phenomenon). If this phenomenon progresses excessively, there is a problem that the fluid inside the container may be ejected to the outside even if no fire or other incident has occurred. In this specification, "creep" or "creep phenomenon" refers to the phenomenon in which, due to the sustained pressing force applied to the fusible alloy, the deformed (strained) fusible alloy flows into the recess of the surface in contact with the fusible alloy over time.

[0008] To address this problem, the safety valve described in Patent Document 2 has a separate member (valve member) that prevents the flow of fluid from the container to the discharge port from the movable body that presses the fusible material, and the directions of movement of the two are perpendicular to each other. With this configuration, the valve member is locked to the movable body, and as the temperature rises, the fusible material melts and the movable body is submerged, releasing the lock of the valve member on the movable body, allowing the fluid in the container to be guided to the discharge port.

[0009] However, the safety valve described in Patent Document 2 had the problem of being large in overall size, having many parts, and high manufacturing costs. Therefore, with the aim of providing a safety valve that can minimize creep of the fusible alloy even in a safety valve in which the member that closes the flow path directly presses the fusible alloy, the present inventors have proposed a safety valve as shown in Figure 8 (see Patent Document 3). In this safety valve, a fusible alloy 6 is placed between a blocking member 3 that blocks the flow of fluid flowing from the discharge passage 91 of the fluid device 9 and a pressing cap 4. A reservoir 8 is formed in at least one of the blocking member 3 and the pressing cap 4 for the accumulation of molten fusible alloy 6. Between the reservoir 8 and the fusible alloy 6, two plate members 59A and 59B whose perforation positions do not overlap are arranged. As a result, when the blocking member 3 is pressed by the fluid pressure in the fluid device, the fusible alloy 6 does not melt, but the creeped fusible alloy 6 flows only into the hole 58 of the first plate member in contact with the fusible alloy 6, and no further creep occurs. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2012-132475 [Patent Document 2] Japanese Patent Publication No. 2016-056822 [Patent Document 3] WO2022 / 030340 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] However, while the safety valve described in Patent Document 3 is effective in suppressing excessive creep, if the fusible alloy completely melts in the event of an abnormal high temperature, the molten fusible alloy passes through a minute gap between the two contacting plate members after passing through the hole in the plate member in contact with the fusible alloy, and then passes through the hole in the other plate member. This has the problem that it takes time for the molten fusible alloy to flow out to the occluding member side.

[0012] The present invention has been made in view of the above, and its objective is to provide a safety valve in which the member that closes the flow path directly presses against the fusible alloy, while minimizing creep of the fusible alloy and promoting the smooth flow of the molten fusible alloy. [Means for solving the problem]

[0013] The safety valve according to the present invention, which was developed to solve the above problems, is a safety valve to be attached to a fluid device having a fluid passage inside and a discharge passage branching off from the fluid passage, A main body attached to the open end of the discharge passage of the fluid device, forming an inlet passage communicating with the discharge passage and a discharge passage connecting the inlet passage to the outside, The system includes a blocking member that prevents the flow of fluid from the inlet passage to the outlet passage, The inflow passage is connected to a contact portion that abuts against a seal portion formed at the tip of the blocking member and obstructs the flow of fluid, and to an open portion with a larger diameter than the contact portion. The open portion communicates with the discharge passage and forms a mounting portion for a pressure cap that biases the sealing portion of the closing member toward the contact portion. A fusible alloy is placed between the closing member and the pressing cap, and a reservoir is formed in at least one of the closing member and the pressing cap for the molten fusible alloy to accumulate. Between the reservoir and the fusible alloy, a plurality of plate members are arranged, each having holes that do not overlap in their positions. At least one of the contact surfaces of the plate members is formed with grooves that allow the holes to communicate with each other.

[0014] In this safety valve, the closing member is pressed by the fluid pressure inside the fluid equipment, and although it does not melt, the creeping fusible alloy flows into the holes of the first plate member in contact with the fusible alloy, and only a small amount flows into the grooves connecting the holes.

[0015] Furthermore, the holes provided in the plate member can be shaped like a frustoconical pyramid, with the fusible alloy side having a smaller diameter. By shaping the holes like a frustoconical pyramid with the fusible alloy side having a smaller diameter, the molten fusible alloy flows smoothly into the groove. [Effects of the Invention]

[0016] According to the fusible plug type safety valve of the present invention, the creeped fusible alloy flows into the hole of the first plate member that abuts the fusible alloy, and also flows slightly into the groove where the holes communicate, but remains there and does not proceed further. Therefore, malfunctions such as the safety valve malfunctioning due to creep caused by the pressure generated by the fluid pressure in the fluid equipment do not occur. Furthermore, since the groove connecting the holes is formed on at least one of the contact surfaces, the molten fusible alloy can flow smoothly from the hole of the first plate member to the hole of the second plate member and be guided to the reservoir. [Brief explanation of the drawing]

[0017] [Figure 1] This shows a safety valve according to an embodiment of the present invention, where (a) is a front cross-sectional view showing the state within a predetermined temperature range, and (b) is a front cross-sectional view showing the state exceeding the differential temperature of the safety valve. [Figure 2] The following shows a safety valve according to another embodiment of the present invention: (a) a front cross-sectional view showing the state within a predetermined temperature range, and (b) a front cross-sectional view showing the state exceeding the differential temperature of the safety valve. [Figure 3] The images show the plate members used in the safety valve, with (a) being a plan view of plate member 1, (b) being a cross-sectional view of plate member 1 along the line X1-X1, (c) being a plan view of another plate member superimposed on plate member 1, and (d) being a cross-sectional view of (c) along the line X2-X2. [Figure 4] The images show the plate members used in the safety valve. (a) is a perspective view of the state just before overlapping plate member 1 with another plate member, (b) is a perspective view of the overlapped state, (c) is a Y1-Y1 cross-sectional view of (b), and (d) is a Y2-Y2 cross-sectional view of a partial cutout illustrating the creep state of the fusible alloy when the overlapped plate members are assembled into the safety valve. [Figure 5]Another plate member used for the safety valve is shown. (a) is a plan view of the plate member 1, (b) is a cross-sectional view of the plate member 1 taken along the line X3-X3, and (c) is a perspective view of the state where the plate member 1 and another plate member are overlapped. [Figure 6] Another plate member used for the safety valve is shown. (a) is a perspective view of the plate member 1, (b) is a cross-sectional view of the plate member 1 taken along the line X4-X4, and (c) is a perspective view of the state where the plate member 1 and another plate member are overlapped. [Figure 7] Another plate member used for the safety valve is shown. (a) is a perspective view of the plate member 1, (b) is a cross-sectional view of the plate member 1 taken along the line X5-X5, and (c) is a perspective view of the state where the plate member 1 and another plate member are overlapped. [Figure 8] A conventional safety valve is shown. (a) is a front cross-sectional view showing the state within a predetermined temperature, (b) shows two types of plate members used for the safety valve, and (c) shows a cross-sectional view when the two plate members are overlapped.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses.

[0019] <Embodiment 1> FIG. 1 shows an embodiment of the safety valve of the present invention.

[0020] <Safety Valve> The safety valve 1 shown in FIGS. 1 and 2 is a safety valve attached to a fluid device 9 having a fluid passage 90 inside and an exhaust passage 91 branched from the fluid passage 90. The fluid device 9 is not particularly limited, and examples include, for example, a tank for storing fuel hydrogen of a fuel cell vehicle.

[0021] The safety valve 1 is attached to the open end of the discharge passage 91 of the fluid device 9 and comprises a main body 2 that forms an inlet passage 20 communicating with the discharge passage 91 and a discharge passage 23 connecting the inlet passage 20 to the outside, and a blocking member 3 that prevents the flow of fluid from the inlet passage 20 to the discharge passage 23. The inlet passage 20 abuts against a seal portion 31 formed on the tip 30 of the blocking member 3 and is connected to a contact portion 21 that prevents the flow of fluid from the discharge passage 91 of the fluid device 9 and an open portion 22 that has a larger diameter than the contact portion 21. In this embodiment, the seal portion 31 formed on the tip 30 of the blocking member 3 is composed of an O-ring 31a and a backup ring 31b, but the tip 30 can also be made into a frustoconical shape, and the stepped portion between the inlet passage 20 and the contact portion 21 can be used as a valve seat to seal the fluid. Furthermore, the blocking member 3 is biased by an elastic member 32 such as a spring in a direction that connects the inflow passage 20 and the contact portion 21.

[0022] The male threaded portion 24 of the safety valve 1 is screwed into the female threaded portion 93 formed in a space communicating with the discharge passage 91 of the fluid device 9. This screwing is done by twisting the tip of the main body 2 until it contacts the annular protruding seal portion 92 provided on the periphery of the discharge passage 91, which is located in the space communicating with the discharge passage 91.

[0023] The open portion 22 connected to the inlet passage 20 communicates with the discharge passage 23 and also forms the mounting portion 25 for the pressure cap 4 that fixes the sealing portion 31 of the closing member 3 to the contact portion 21. The discharge passage 23 opens in a direction substantially perpendicular to the axis of the cylindrical body 2, whereas the inlet passage 20, the contact portion 21, and the open portion 22 are concentric with the axis of the body 2.

[0024] The pressing cap 4 has a male threaded portion 41 on its circumferential surface and an engaging portion 42 on its top surface for engaging a jig or tool for rotating the pressing cap 4. The mounting portion 25 of the main body 2 is engraved with a female thread into which the male threaded portion 41 formed on the pressing cap is screwed.

[0025] A fusible alloy 6 that melts when it reaches a predetermined temperature is placed between the closing member 3 and the pressing cap 4. A reservoir 8 is formed in at least one of the closing member 3 and the pressing cap 4 for the molten fusible alloy 6 to accumulate. In Figure 1, the reservoir 8 is formed on the closing member 3 side, and in Figure 2, the reservoir 8 is formed on the pressing cap 4. At least two plate members 5A and 5B are placed between the reservoir 8 and the fusible alloy 6, so that their perforation positions do not overlap.

[0026] <Plate member-Configuration 1> As shown in Figures 3 and 4, the plate member 5 has multiple holes 50 drilled in a thin plate (for example, a metal plate of 0.1 to 0.5 mm thickness). The number of holes is not particularly limited, but multiple holes are arranged on the same radius, for example, three in this embodiment. The two plate members 5A and 5B have the same outer diameter, and the drilled holes 50 are on the same radius. Positioning notches 53 are formed to indicate the mounting position so that they are not in the same position when superimposed, and markings (not shown) are applied to the surface to prevent mixing up the front and back.

[0027] Furthermore, at least one of the plate members 5, in this embodiment plate member 5A, is provided with a groove 51 that connects each of the holes 50. In this embodiment, the groove 51 is an annular groove whose central axis has the same radius as the distance (same radius) from the center of the plate member 5 to each hole.

[0028] In this embodiment, an example is shown in which two plate members 5A and 5B are used in stacked form. However, for example, three plate members 5A, 5A, and 5B may be used in that order, but at least one groove 51 should be formed on each contact surface.

[0029] Furthermore, although the grooves 51 connecting the multiple holes 50 on the surface of the plate member 5 are shown as one set in the illustrated example, multiple sets with different radii can be provided. In addition, it is preferable that the shape of the holes 50 be a frustoconical shape with a smaller diameter on the fusible alloy side. In the plate member 5A that is in contact with the fusible alloy 6, the molten fusible alloy 6 spreads out and flows into the grooves 51, thereby promoting a smooth flow of the fusible alloy.

[0030] <Plate member-Configuration 2> As shown in Figure 5, one of the plate members 5A has a notch 51A made of an annular groove on the surface that abuts against the other plate member 5B, and a hole 50A connected to the notch 51A by a communication groove 51B at a different position from the notch 51A. The other plate member 5B that is superimposed on the one plate member 5A has a hole 50 at a position that coincides with the notch 51A made of an annular groove. This makes it possible to avoid overlapping the drilled positions of the holes 50 and 50A in each plate member 5 when multiple plate members 5 are superimposed, without providing the positioning notch 53 mentioned above.

[0031] <Plate member - configuration 3> As shown in Figure 6, one of the plate members 5A has a notch 51C, which is an annular groove with a width greater than the diameter of the hole 50B, on the surface that abuts against the other plate member 5B, and a hole 50B that opens on the inner circumference side of the notch 51C. The other plate member 5B that is superimposed on the one plate member 5A is configured to have a hole 50 at a position that coincides with the outer circumference side of the annular groove notch 51C. In this way, similar to configuration 2, when multiple plate members 5 are superimposed, the drilled positions of the holes 50 and 50B provided in each plate member 5 do not overlap without providing a positioning notch 53.

[0032] <Plate member-Configuration 4> As shown in Figure 7, one of the plate members 5A has multiple holes 50C on the surface that abuts against the other plate member 5B, a disc-shaped notch 51E cut concentrically with the plate member 5A, and a groove-shaped notch 51D connecting the holes 50C and the notch 51E. The other plate member 5B that is superimposed on the one plate member 5A is configured to have a hole 50F in its center that is approximately the same diameter as the disc-shaped notch 51E. This makes it possible, similar to configuration 2, to avoid overlapping the drilled positions of the holes 50C and 50F in each plate member 5 when multiple plate members 5 are superimposed, without providing a positioning notch 53.

[0033] The plate members 5 of the above configuration are combined and the safety valve 1 is attached to the fluid device 9. When the fluid device 9 is activated, the fluid pressure and the pressing force of the spring are applied to the closure member 3, and the rear end of the closure member 3 presses against the fusible alloy 6 via the plate members 5A and 5B.

[0034] If this condition persists for a long time, the fusible alloy 6 will not melt, but creep will progress between it and the plate member 5A. In the case of the plate member 5 of configuration 1, it will flow into the hole 50 of the plate member 5A from the state shown in Figure 1, and a small amount will also flow into the groove 51 (see Figure 4(d)).

[0035] For example, as shown in Figure 4, due to the creep phenomenon, the fusible alloy 6 that has flowed into the hole 50 of the abutting plate member 5A also flows into the groove 51. However, because the groove 50 is a closed space that expands in a direction perpendicular to the pressing force that presses the fusible alloy 6 between the first plate member 5B and the second plate member 5B, further creep is suppressed. As a result, the inflow due to the creep phenomenon is limited to only a small amount flowing from the hole 50 of the first plate member 5A into the groove 51.

[0036] Normally, the fluid passage 90 of the fluid device 9 and the discharge passage 91 branching off from the fluid passage 90 are filled with fluid flowing through the fluid device 9, and fluid pressure is applied to the tip 30 of the closure member 3 of the safety valve 1 attached to the fluid device 9. Due to this pressure, the fusible alloy 6 flows into the hole 50 of the plate member 5A that is in contact with the fusible alloy 6 by creep, and although a small amount also flows into the groove, it is blocked by the other surfaces of the plate member 5B. Then, if a fire or the like occurs and the ambient temperature around the fluid device 9 exceeds a predetermined temperature (the melting point of the fusible alloy 6), the fusible alloy 6 begins to melt.

[0037] The fusible alloy 6, which has begun to melt, becomes liquid and flows through the holes 50 in the plate member 5A and the grooves 51 formed in the plate member 5A, passes through the holes 50 in the plate member 5B which are in communication with the grooves 51, and flows into the reservoir 8.

[0038] As a predetermined amount of fusible alloy 6 flows into the reservoir 8, the occluding member 3, which is biased towards the fusible alloy 6 by the elastic member 32, moves toward the fusible alloy 6, and the seal portion 31 formed on the tip portion 30 disengages from the contact portion 21 of the main body 2. As a result, the fluid inside the fluid device 9 is discharged from the inlet passage 20 of the safety valve 1 through the contact portion 21 and the open portion 22 toward the discharge passage 23 (see Figure 1(b)).

[0039] <Embodiment 2> Figure 2 shows another embodiment of the safety valve of the present invention.

[0040] <Safety valve> The safety valve 1 shown in Figure 2 is a safety valve to be attached to a fluid device 9, which, like Embodiment 1, has a fluid passage 90 inside and a discharge passage 91 branching off from this fluid passage 90. The safety valve is attached to the open end of the discharge passage 91 of the fluid device 9 and has a main body 2 that forms an inlet passage 20 and a discharge passage 23 that connect the discharge passage 91 to the outside (atmosphere), and a blocking member 3 that blocks and connects both passages, which is the same as in Embodiment 1, so a description will be omitted.

[0041] In this embodiment, the safety valve 1 is modified so that the reservoir 8, which was formed on the closing member 3 in the safety valve 1 shown in Figure 1, is formed on the pressing cap 4 side. Structurally, the diameter of the closing member 3 is small enough to secure space for an elastic member 32, such as a spring, to be placed in the relatively small diameter open portion 22. Therefore, if the reservoir 8 is formed on the closing member 3, it is difficult to secure sufficient volume. However, the pressing cap 4 has a relatively large diameter, which has the advantage of easily forming a reservoir 8 with sufficient volume.

[0042] Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to these specific embodiments, and various forms that do not depart from the spirit of the invention are also included in the present invention. Furthermore, the embodiments and modifications described above are merely examples of one embodiment, and it is possible to combine each embodiment as appropriate. [Industrial applicability]

[0043] The safety valve of the present invention can be suitably used in systems where the ambient temperature rises rapidly, such as in the event of a fire, and it is necessary to release the fluid inside the fluid equipment to the outside. Furthermore, by utilizing a discharge direction restricting member, it can be suitably used in environmental equipment where it is necessary to restrict the discharge direction of the fluid ejected in the event of a fire or other incident, thereby preventing secondary disasters. [Explanation of symbols]

[0044] 1. Safety valve 2 Main unit 20 Inflow channel 21 Contact part 22 Open part 23 Exhaust channel 25 Mounting part 3. Closure member 30 Tip 31 Seal part 4. Pressure cap 5 Plate members 50 holes 51 Notch 6 Fusible alloy 8. Accumulation area 9. Fluid Machines 90 Fluid passage 91. Drainage pathway

Claims

1. A safety valve to be attached to a fluid device having a fluid passage inside and a discharge passage branching off from the fluid passage, A main body attached to the open end of the discharge passage of the fluid device, forming an inlet passage communicating with the discharge passage and a discharge passage connecting the inlet passage to the outside, The system includes a blocking member that prevents the flow of fluid from the inlet passage to the outlet passage, The inflow passage is connected to a contact portion that abuts against a seal portion formed at the tip of the blocking member and obstructs the flow of fluid, and to an open portion with a larger diameter than the contact portion. The open portion communicates with the discharge passage and forms a mounting portion for a pressure cap that biases the sealing portion of the closing member toward the contact portion. A fusible alloy is placed between the closing member and the pressing cap, and a reservoir is formed in at least one of the closing member and the pressing cap for the molten fusible alloy to accumulate. A safety valve is provided in which multiple disc-shaped plate members are arranged between the reservoir and the fusible alloy, each having a hole through which the molten fusible alloy passes, and notches are formed on at least one of the contact surfaces of the plate members so as to connect the holes of different plate members, and the positions of the holes provided in each plate member do not overlap when the multiple plate members are stacked on top of each other.

2. The safety valve according to claim 1, wherein the notch is an annular groove.

3. The safety valve according to claim 1, wherein one of the plate members has a notch made of an annular groove on the surface that abuts against the other plate member, and a hole connected to the notch by a communication groove at a position different from the notch, and the other plate member that is superimposed on the first plate member has a hole at a position coinciding with the annular groove.

4. The safety valve according to claim 1, wherein one of the plate members has a hole drilled near the outer edge of the plate member, and the other plate member that overlaps with the first plate member has a hole in the center of the plate member that is larger in diameter than the hole in the first plate member.

5. The safety valve according to claims 1 to 4, wherein the hole has a frustoconical shape with a smaller diameter on the fusible alloy side.

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