Safety valve

Abstract

To provide a safety valve which allows easy maintenance work.SOLUTION: The safety valve includes: a valve seat 12 having a valve seat-side flange 12F separably connected to a tank-side flange 5F of a pipe 5 communicating with a pressurized tank; a valve body 15 movable to a closing position for closing an opening 12c of the valve seat 12 and an opening position for opening the opening 12c; an urging member 17 for applying an urging force for maintaining the valve body 15 at the closing position; and a valve case 11 accommodating the valve body 15 and the urging member 17 and having a case-side flange 11F separably connected to the valve seat-side flange 12F.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a safety valve. [Background technology]

[0002] Patent Document 1 discloses a safety valve that includes a seat (52) inside a valve body (50 in the document, and the same reference numerals are used hereinafter), a valve (valve body) (64) positioned so that an opening at the upper end of the seat (52) can be opened and closed, and a spring (82) that maintains the valve (64) in a closed state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-295952 Summary of the Invention [Problem to be solved by the invention]

[0004] The safety valve described in Patent Document 1 has a configuration in which the inlet portion (88) of the valve body (50) is directly connected to the primary container. Therefore, for example, when performing maintenance on the safety valve, it can be difficult to perform the maintenance work if the valve remains connected to the primary container. Furthermore, when performing maintenance such as partially disassembling the safety valve or visually checking the valve status, the safety valve needs to be separated from the primary container.

[0005] In order to separate the safety valve from the upstream pipe, it is necessary to disconnect the inlet portion 88 of the valve body 50 from the upstream pipe, and then to reconnect it by welding or the like after maintenance. However, such disconnection and welding are inefficient and time-consuming.

[0006] In particular, in the case of a structure in which the primary side pipes are connected by welding technology, the heat generated during welding may cause distortion in the valve body, reducing the airtightness of the valve (64) against the seat (52), and there was concern that this would impair proper operation as a safety valve.

[0007] For these reasons, there is a demand for a safety valve that is easy to maintain. [Means for solving the problem]

[0008] The safety valve according to the present invention is characterized by comprising: a valve seat having a valve seat-side flange detachably connected to a tank-side flange of a pipe communicating with a pressure tank; a valve body that is movable between a closed position where it closes the opening of the valve seat and an open position where it opens the opening; a biasing member that applies a biasing force to maintain the valve body in the closed position; and a valve case that houses the valve body and the biasing member and has a case-side flange detachably connected to the valve seat-side flange.

[0009] In this configuration, by connecting the valve seat flange and the case flange, a safety valve in which the valve seat and valve case are integrated can be provided. Therefore, by separating the valve seat flange from the tank flange, it is possible to separate the safety valve, in which the valve seat and valve case are connected, from the tank flange. Furthermore, by separating the case flange from the valve seat flange of a safety valve in a state separated from the tank flange, the valve case can be opened, allowing for maintenance and replacement of the internal valve element, biasing member, etc. Therefore, a safety valve that is easy to maintain has been configured. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 4 is a circuit diagram showing the relationship between the tank and the gas discharge unit. [Figure 2] FIG. 2 is a vertical cross-sectional side view of the safety valve. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is an exploded cross-sectional view taken along line IV-IV in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of a safety valve according to the present invention will be described with reference to the drawings. In this embodiment, a safety valve provided in a tank for storing liquid hydrogen will be described as an example of a safety valve. However, the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the invention.

[0012] [Basic configuration] FIG. 1 shows a tank T (an example of a pressure tank) that stores hydrogen gas in a liquid state to be supplied to a hydrogen engine (not shown) in a vehicle that runs on the driving force of the hydrogen engine.

[0013] The tank T has an outer wall 1 made of a heat insulating material to maintain the liquid hydrogen L at an extremely low temperature, and is equipped with a supply line F for replenishing the liquid hydrogen L into the supply tank from an external hydrogen supply facility 2, and a gas discharge line Ex for discharging gas from inside the tank. Note that the tank T may also store a gas with a low boiling point other than liquid hydrogen L in liquid form.

[0014] This tank T is equipped with a pump unit P that extracts liquid hydrogen L, and a gas discharge unit GR that controls the gas pressure inside the tank by discharging hydrogen gas inside the tank.

[0015] The pump unit P is mechanically operated to extract the liquid hydrogen L from the tank into the extraction line 3. The liquid hydrogen L thus extracted through the extraction line 3 is vaporized in a vaporizer (not shown) and then supplied to a hydrogen engine (not shown). A hydrogen engine has a basic configuration similar to that of a four-stroke engine, and generates driving force by burning a mixture of supplied hydrogen gas and air in a combustion chamber.

[0016] As shown in FIG. 1, the gas discharge unit GR includes a gas pressure acquisition unit 4 provided on the outer surface of the tank T in communication with the space inside the tank, a first pipe 5 (an example of a pipe) in communication with the gas pressure acquisition unit 4, and a second pipe 6 branching off from the first pipe 5 (pipe).

[0017] The first pipe 5 is equipped with a safety valve S and a safety device D. The safety valve S opens when the gas pressure inside the tank rises to a set value, thereby releasing hydrogen gas to the outside and suppressing the rise in gas pressure (the details of the safety valve S will be described later).

[0018] The safety device D is equipped with a rupture disk (not shown), and if the gas pressure inside the tank rises excessively, the rupture disk is ruptured by the gas pressure, and hydrogen gas is discharged from the ruptured part, thereby achieving a rapid reduction in gas pressure.

[0019] A pressure regulating valve C that functions as a boil-off valve is detachably attached to the extending end of the second pipe 6, and a purge valve Q is attached to a line branching off from the second pipe 6. The pressure regulating valve C has a common configuration with the safety valve S, and the gas pressure required to open the valve body (not shown) is set to a value lower than the gas pressure required to open the safety valve S.

[0020] Tank T is filled with an inert gas such as nitrogen gas before storing liquid hydrogen L, and purge valve Q is opened to discharge the inert gas when supplying liquid hydrogen L. Furthermore, the hydrogen gas discharged when pressure regulating valve C is opened is oxidized by oxygen contained in the outside air in combustion catalyst 7, and is discharged after this oxidation.

[0021] 〔safety valve〕 The safety valve S can be used in any position, but in this embodiment, the up-down relationship will be described based on the position shown in Fig. 2. The valve axis X shown in the figure is in a vertical position, and the safety valve S has a valve disc 15 arranged coaxially with the valve axis X, which moves along the valve axis X. In other words, the valve disc 15 is configured to be movable between the closed position shown in Fig. 2 and an open position which is moved upward from this closed position.

[0022] As shown in Figures 2 to 4, the safety valve S has the lower end of a case side flange 11F at the lower end of the valve case 11 detachably connected to the upper surface of a valve seat side flange 12F of the valve seat 12, and the lower surface of this valve seat side flange 12F detachably connected to the tank side flange 5F.

[0023] With this configuration, the safety valve S allows the valve seat side flange 12F to be separated without separating the valve case 11 and the valve seat 12. Furthermore, by separating the valve case 11 and the valve seat 12, the safety valve S allows for maintenance of the inside of the valve case 11, etc.

[0024] As shown in Figures 2 to 4, the safety valve S includes a valve case 11, a valve seat 12, a control ring 13, a ring fixing screw 14, a valve body 15, an operating rod 16, a compression coil spring 17 (an example of a biasing member), a pair of spring seats 18, an adjustment cylindrical shaft 19, a lock nut 20, and a cap 21.

[0025] The valve case 11 is integrally formed with a case body 11a and a spring accommodating portion 11b. The case body 11a has a case-side flange 11F formed in an area surrounding the opening at the lower end of the valve space 11v. The valve case 11 has an exhaust pipe 11R protruding laterally, which connects the valve space 11v with the outside space.

[0026] The valve case 11 defines a spring space 11s, which is continuous with the upper side of the valve space 11v of the spring accommodating portion 11b, as a cylindrical internal space coaxial with the valve axis X.

[0027] The valve seat 12 has a valve-seat-side flange 12F that is disk-shaped in a plan view, and a fitting portion 12a on the upper surface of the valve-seat-side flange 12F and a lead-out tube 12b on the upper surface of the fitting portion 12a are integrally formed. The valve seat 12 has an opening 12c formed at the upper end of the lead-out tube 12b.

[0028] The control ring 13 is screwed onto the outer periphery of the upper part of the outlet tube 12b of the valve seat 12, and by rotating around the valve axis X, the amount of upward protrusion from the upper end of the outlet tube 12b can be set as desired.

[0029] A plurality of engagement portions 13a, each of which has a gear-like shape in an external plan view, are formed on the outer periphery of the control ring 13. Ring fixing screws 14 penetrate the wall surface of the valve case 11 in a state where they are threadedly engaged with the wall surface.

[0030] The control ring 13 can be moved in the vertical direction by rotating it around the valve axis X, allowing adjustment of the gas flow when the valve element 15 is separated from the outlet tube 12b. After the vertical position of the control ring 13 has been set, the tip of the ring fixing screw 14 is engaged with the engagement portion 13a to restrict the rotation of the control ring 13, and the position of the control ring 13 in the vertical direction is determined.

[0031] An upper guide tube portion 15a and a lower sealing portion 15b are integrally formed in the valve body 15. The guide tube portion 15a is formed with an abutment recess 15c that opens upward.

[0032] As shown in FIGS. 1 and 4, the valve body 15 has a guide tube portion 15a at the bottom of the spring space 11s of the valve case 11, which is capable of moving up and down.

[0033] The safety valve S has an adjustment cylindrical shaft 19 that is coaxial with the valve axis X and is screwed onto the upper part of the spring accommodating portion 11b of the valve case 11. A lock nut 20 is screwed onto the portion of the adjustment cylindrical shaft 19 that is exposed above the valve case 11.

[0034] As shown in Fig. 2, the safety valve S accommodates a spring 17 in the spring space 11s, and a pair of spring seats 18 are arranged in contact with both ends of the spring 17. The operating rod 16 is arranged coaxially with the valve axis X and passes vertically through the interior of the spring 17. The lower end of the operating rod 16 abuts against the abutment recess 15c, and the upper end is fitted into the adjustment cylinder shaft 19.

[0035] The pair of spring seats 18 are configured as annular bodies with a through hole formed in the center. Of the pair of spring seats 18, the upper one abuts against the lower end of the adjustment cylindrical shaft 19, and the lower one abuts against the upper surface of the flange-shaped portion 16a of the operating rod 16.

[0036] The valve case 11 accommodates the sealing portion 15b of the valve element 15 in the valve space 11v. The lower end of the actuating rod 16 abuts against the abutment recess 15c of the valve element 15, and the biasing force of the spring 17 acts on the actuating rod 16, causing the annular end 15d formed at the lower end of the valve element 15 to abut directly against the upper end of the outlet tube 12b of the valve seat 12. This abutment maintains the valve element 15 in the closed position shown in Figure 2, and closes the opening 12c at the upper end of the outlet tube 12b.

[0037] The adjustment cylinder shaft 19 can be rotated around the valve axis X to change the position of the lower end of the upper spring seat 18, thereby making it possible to adjust the biasing force of the spring 17 acting on the valve body 15 from the operating rod 16.

[0038] After adjusting the biasing force of the spring 17 by rotating the adjustment cylindrical shaft 19, the rotation of the adjustment cylindrical shaft 19 is restricted by operating the lock nut 20, thereby fixing the biasing force acting from the spring 17 on the valve body 15. When the cap 21 is attached, it protects the upper end of the adjustment cylindrical shaft 19 and prevents hydrogen from leaking from the spring space 11s through the gap on the outer periphery of the threaded portion of the adjustment cylindrical shaft 19 to the outside.

[0039] As a result, the gas pressure acting from the first pipe 5 exceeds the biasing force of the spring 17, causing the valve element 15 to move upward against the biasing force of the spring 17, separating the annular end portion 15d of the valve element 15 from the upper end of the outlet tube 12b of the valve seat 12, and discharging the gas in the first pipe 5 to the outside through the exhaust tube 11R of the valve case 11. As a result, an excessive pressure increase acting on the tank T is suppressed, and the tank T is protected.

[0040] [Detachable structure] As shown in Figures 2 to 4, multiple (three in this embodiment) screw holes are formed in the bottom surface of the case side flange 11F along the vertical direction, and multiple (three in this embodiment) through holes are formed in the valve seat side flange 12F in the vertical direction corresponding to the positions of these screw holes.

[0041] As a result, the bottom surface of the case side flange 11F and the valve seat side flange 12F are overlapped with a downstream seal 25 (an example of a second sealing material) sandwiched therebetween, and a connecting bolt 8 (an example of a second fastening member) is inserted from the underside of the valve seat side flange 12F and screwed into the threaded hole in the case side flange 11F, thereby connecting (fastening) the valve case 11 and the valve seat 12.

[0042] This connection forms a safety valve S, which houses the valve element 15, operating rod 16, spring 17, etc. inside the valve case 11. This connection also causes the heads 8a of the multiple connecting bolts 8 to protrude downward from the underside of the valve seat flange 12F. Note that the downstream seal 25 is not limited to being made of an annular resin material, and an annular metal material, rubber, etc. may also be used.

[0043] As shown in FIG. 3, the tank flange 5F is formed with a notch 5Fa to prevent the heads 8a of the multiple connecting bolts 8 from contacting each other when viewed from the bottom.

[0044] In this detachable structure, when the case-side flange 11F, the valve seat-side flange 12F, and the tank-side flange 5F are overlapped, a plurality of (six in this embodiment) through-holes are formed coaxially through these flanges. When overlapping in this manner, an upstream seal 26 (an example of a first seal material) is sandwiched between the valve seat-side flange 12F and the tank-side flange 5F.

[0045] These through holes are positioned at the middle of the notch 5Fa in the circumferential direction on the tank side flange 5F, and multiple (six in this embodiment) fastening bolts 9 (an example of a first fastening member) are inserted from top to bottom into each of these through holes, and nuts 9b are screwed onto the lower ends of the fastening bolts 9 to perform co-tightening.

[0046] By this fastening, the safety valve S is fixed to the tank side flange 5F, and by releasing the fastening, the safety valve S can be separated from the tank side flange 5F.

[0047] [Effects of the embodiment] In this way, the safety valve S can be attached to and detached from the tank-side flange 5F by operating the fastening bolts 9. To enable this attachment and detachment, for example, a configuration in which the valve seat 12 is integrally formed on the extending end of the first pipe 5 allows the safety valve S to be separated for maintenance or part replacement without cutting the first pipe 5.

[0048] In other words, by operating the fastening bolt 9, not only can the safety valve S be separated from the tank side flange 5F, but in this separated state, the valve seat 12 can be separated from the valve case 11, thereby separating the valve body 15 and the spring 17 (biasing member), making it possible to adjust and maintain them.

[0049] As shown in Figure 1, the gas discharge unit GR is equipped with a safety valve S and a safety device D. Therefore, in a situation where the gas pressure inside the tank rises and the pressure rise cannot be reduced by the safety valve S, the safety device D discharges gas, allowing the gas pressure in the tank T to rise excessively.

[0050] Furthermore, since the gas discharge unit GR is provided with a pressure regulating valve C, it is possible to supply hydrogen gas to the pump unit P at a set pressure.

[0051] [Another embodiment] The present invention may be configured as follows in addition to the above-described embodiments (common numbers and symbols are used to designate components having the same functions as those in the embodiments).

[0052] (a) As a configuration for connecting the valve case 11 and the valve seat 12, for example, a configuration can be adopted in which a male thread portion centered on the valve axis X is formed on the outer periphery of the fitting portion 12a of the valve seat 12, and a female thread portion that screws into this male thread portion is formed on the inner periphery of the valve case 11, and these are integrated by screwing them together.

[0053] In the configuration of this alternative embodiment (a), the connecting bolt 8 described in the embodiment is not necessary, and it is possible to bring the lower surface of the valve seat side flange 12F of the valve seat 12 into contact with the upper surface of the tank side flange 5F over a wide area, thereby achieving a simple connection.

[0054] (b) For example, without using connecting bolts 8, multiple fastening bolts 9 are inserted into the through holes of the case side flange 11F of the valve case 11, the valve seat side flange 12F of the valve seat 12, and the tank side flange 5F, and these are fastened together by tightening them.

[0055] The configuration of this alternative embodiment (b) simplifies the fastening structure, although the valve case 11 and the valve seat 12 are separated from the tank-side flange 5F when the fastening by the fastening bolts 9 is released. Furthermore, in the configuration of this alternative embodiment (b), similar to alternative embodiment (a), the connecting bolts 8 are not necessary, and it is possible to bring the lower surface of the valve seat-side flange 12F of the valve seat 12 into contact with the upper surface of the tank-side flange 5F over a wide surface, thereby realizing a simple connection.

[0056] (c) A threaded hole is formed in the case-side flange 11F, and through holes are formed in the valve seat-side flange 12F and the tank-side flange 5F at positions that overlap the threaded hole in a plan view. In this configuration, fastening bolts 9 are inserted through the through holes in the tank-side flange 5F and the valve seat-side flange 12F and screwed into the threaded holes in the case-side flange 11F.

[0057] The configuration of this alternative embodiment (c), like alternative embodiment (b), enables the fastening of the case side flange 11F of the valve case 11, the valve seat side flange 12F of the valve seat 12, and the tank side flange 5F, respectively, without using a connecting bolt 8 and further without using a nut 9b.

[0058] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention.

[0059] In the above-described embodiment, the following configurations are envisioned. (1) A safety valve S comprising: a valve seat 12 having a valve seat side flange 12F detachably connected to a tank side flange 5F of a pipe communicating with a pressure tank (tank T); a valve element 15 movable between a closed position for closing an opening 12c of the valve seat 12 and an open position for opening the opening 12c; a biasing member (spring 17) that applies a biasing force to maintain the valve element 15 in the closed position; and a valve case 11 accommodating the valve element 15 and the biasing member (spring 17) and having a case side flange 11F detachably connected to the valve seat side flange 12F.

[0060] As a result, the valve seat side flange 12F and the case side flange 11F are connected to form a safety valve S in which the valve seat 12 and the valve case 11 are integrated. Therefore, when the valve seat side flange 12F is separated from the tank side flange 5F, the safety valve S in which the valve seat 12 and the valve case 11 are connected can be separated from the tank side flange 5F. Furthermore, by separating the case side flange 11F from the valve seat side flange 12F, the valve case 11 can be opened, allowing for maintenance and replacement of the internal valve element 15, biasing member (spring 17), etc.

[0061] (2) In the safety valve S of (1), it is preferable that the tank side flange 5F and the valve seat side flange 12F are fastened together by a first fastening member (fastening bolt 9) with a first sealing material (upstream seal 26) sandwiched therebetween.

[0062] According to this, when the tank side flange 5F and the valve seat side flange 12F are fastened together with the first fastening member (fastening bolt 9), the first sealing material (upstream side seal 26) prevents gas leakage.

[0063] (3) In the safety valve S of (1) or (2), it is preferable that the valve seat side flange 12F and the case side flange 11F are fastened together by a second fastening member (connecting bolt 8) with a second sealing material (downstream seal 25) sandwiched therebetween.

[0064] With this, the second sealing material (downstream seal 25) prevents gas leakage when the valve seat flange 12F and the case flange 11F are fastened together with the second fastening member (connecting bolt 8). In addition, by removing the second fastening member (connecting bolt 8), maintenance and replacement of the valve body 15, the biasing member (spring 17), etc. can be performed.

[0065] (4) In the safety valve S of any one of (1) to (3), it is preferable that the pressure tank (tank T) stores liquid hydrogen L.

[0066] According to this, hydrogen gas is generated from the liquid hydrogen L stored in the pressure tank (tank T), and when the pressure inside the tank rises, the hydrogen gas is released, thereby protecting the pressure tank (tank T). [Industrial Applicability]

[0067] The present invention can be used in a safety valve. [Explanation of symbols]

[0068] 5: Piping (first piping), 5F: Tank side flange, 8: Connecting bolt (second fastening member), 9: Fastening bolt (first fastening member), 11: Valve case, 11F: Valve case side flange, 12: Valve seat, 12F: Valve seat side flange, 12c: Opening, 17: Spring (biasing member), 25: Downstream side seal (second sealing material), 26: Upstream side seal (first sealing material), L: Liquid hydrogen, T: Tank (pressure tank)

Claims

1. a valve seat having a valve seat-side flange detachably connected to a tank-side flange of a pipe communicating with the pressure tank; a valve body that is movable between a closing position that closes an opening of the valve seat and an opening position that opens the opening; a biasing member that applies a biasing force to maintain the valve body in the closed position; a valve case that houses the valve body and the biasing member and has a case-side flange that is detachably connected to the valve seat-side flange.

2. 2. The safety valve according to claim 1, wherein the tank flange and the valve seat flange are fastened together by a first fastening member with a first seal material sandwiched therebetween.

3. 3. The safety valve according to claim 2, wherein the valve seat flange and the case flange are fastened together by a second fastening member with a second seal material sandwiched therebetween.

4. 2. The safety valve according to claim 1, wherein the pressure tank stores liquid hydrogen.

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