JP2019019942A - Gas discharge prevention apparatus - Google Patents

Abstract

To resume supply of a gas from a bulk storage tank to a gas apparatus through simple operation while eliminating the need of valve opening work using a tool or recovery work after the gas supply resumption.SOLUTION: When a quantity of gas is discharged at a piping side of a gas apparatus, a pressure of a downstream-side channel 55 is reduced and a differential pressure exceeding a preset pressure is generated from a pressure of an upstream-side channel 53, a valve body 71 is moved to a valve closing position, a valve seat 51 is closed by a valve main body 73 and gas supply of a bulk storage tank is cut by a stop valve 7. When resuming the gas supply, a cap 94 of a holder 91 of a recovery mechanism 9 is removed, an operation part 100 of an operation member 92 is pressed, and the operation member 92 is moved to an advanced position. An interference pin 99 of the operation member 92 then moves an interference part 76 of the valve body 71 to the side of the valve seat 51 through slide-contact of an R surface 102 to a tapered surface 77. The valve seat 51 is opened by moving the valve body 71, pressures of the upstream-side channel 53 and the downstream-side channel 55 are made uniform, and the valve body 71 is moved to a valve opening position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas discharge preventer used in a gas supply device using a bulk storage tank.

  When a large amount of gas is released due to damage to piping on the gas equipment side, the bulk supply equipment for consumer use supplies the gas liquefied gas (LP gas) in the bulk storage tank to the gas equipment after adjusting the pressure to low. In addition, a gas discharge preventer that shuts off the gas supply from the bulk storage tank is provided.

  This gas discharge preventer resists the urging force in the valve opening direction by the spring when a gas exceeding the set flow rate is discharged on the piping side of the gas equipment and a differential pressure exceeding the set value occurs between the upstream side and the upstream side. Then, the shut-off valve is closed, and the supply of gas from the bulk storage tank is shut off.

  When resuming the gas supply from the bulk storage tank, the rotary member of the closing valve return mechanism is rotated by valve opening using a tool such as a hexagon wrench or screwdriver, and the upstream side of the closed closing valve. And the downstream side are equalized, and the closing valve is opened by the biasing force of the spring (for example, Patent Documents 1 and 2).

JP 2000-161598 A JP 2001-336653 A

  The gas release preventer is generally housed inside a protective protector along with a bulk reservoir. For this reason, in the above-described conventional gas release preventer, when the gas supply from the bulk storage tank to the gas equipment is resumed, a valve opening operation using a tool must be performed in a narrow space inside the protector.

  In addition, the tools used for the valve opening work may differ depending on the model or manufacturer of the gas emission preventer, and when the tools on hand cannot be used for the valve opening work, the supply of gas from the bulk storage tank to the gas equipment is resumed. It may take a long time to complete.

  Further, in the above-described conventional gas discharge preventer, in order to make the gas discharge preventer function again after the gas supply is resumed, it is further necessary to return the rotating member of the closing valve return mechanism to the original rotation position.

  The present invention has been made in view of the above circumstances, and the object of the present invention is that a valve opening operation using a tool and a return operation after resuming gas supply are not required, and gas supply from a bulk storage tank to a gas device is simplified. An object of the present invention is to provide a gas discharge preventer that can be restarted by operation.

In order to achieve the above object, the gas discharge preventer according to the first aspect of the present invention comprises:
Closed valve that closes the valve seat from the open position that opens the valve seat against the biasing force of the valve body biasing member due to the differential pressure between the upstream side and the downstream side across the valve seat of the flow path A shut-off valve whose valve body moves to a position;
The pressing operation from the outside of the body having the flow path moves against the urging force of the operation portion urging member from the retracted position retracted from the flow path to the advanced position advanced into the flow path, and An operation member that interferes with the valve body at the valve closing position and moves the valve body toward the valve opening position;
Is provided.

  According to the gas discharge preventer according to the first aspect of the present invention, a large amount of gas is released due to damage of the downstream pipe, etc., and the upstream side and the downstream side sandwiching the valve body of the flow path In the meantime, when a differential pressure exceeding the set pressure determined by the urging force of the valve body urging member occurs, the valve body moves from the valve opening position to the valve closing position against the urging force of the valve body urging member, The flow path is closed by a closing valve.

  Then, as mass release of gas on the downstream side is resolved, when the operation member is pressed against the urging force of the operation unit urging member from the outside of the body having the flow channel, the operation that has advanced into the flow channel The member interferes with the valve body in the valve closing position. And a valve body is moved to the valve-opening position side by interference with an operation member.

  When the valve body at the valve closing position is moved to the valve opening position side, the valve seat closed by the valve body is opened, and the upstream side and the downstream side across the valve seat in the flow path communicate with each other. Then, the differential pressure exceeding the set pressure generated between the upstream flow path and the downstream flow path of the valve body is eliminated, and the upstream flow path and the downstream flow path of the valve body are The pressure is equalized. For this reason, the valve body moved to the valve opening position side is held at the valve opening position by the biasing force of the valve body biasing member.

  Further, the operation member moved to the advanced position by the pressing operation returns to the retracted position by the urging force of the operation unit urging member when the pressing operation is completed. Therefore, if a differential pressure exceeding the set pressure is generated again between the upstream flow path and the downstream flow path of the valve body, and the valve body at the valve opening position moves to the valve closing position again, the operation of the retracted position is performed. The valve body is held at the valve closing position without interfering with the member, and the flow path is closed by the closing valve.

  For this reason, it is not necessary to open the valve body using a tool or return the operation member after resuming the gas supply, and the gas from the bulk storage tank blocked by the closing of the flow path by the closing valve to the gas equipment is removed. Supply can be resumed by a simple operation.

  The gas discharge preventer according to the second aspect of the present invention is the gas discharge preventer according to the first aspect of the present invention, wherein the valve body is located at the valve closing position downstream of the valve seat. The portion disposed in the path has a valve body-side interference surface inclined with respect to the moving direction of the valve body, and the operating member is located in the flow path downstream of the valve seat at the advanced position. The disposed portion has an operation member side interference surface inclined with respect to the advancing / retreating direction to the flow path intersecting the moving direction of the valve body, and the operation member side interference surface is at the advanced position. It is in sliding contact with the valve element side interference surface.

  According to the gas discharge preventer according to the second aspect of the present invention, in the gas discharge preventer according to the first aspect of the present invention, when the valve body is in the valve closing position, the operating member is pressed to advance the position. If it moves to, the operation member side interference surface will slide-contact with the valve body side interference surface in the flow path downstream from the valve seat of the valve body.

  Here, the valve element side interference surface is inclined with respect to the moving direction of the valve element, and the operation member side interference surface is inclined with respect to the advancing / retreating direction of the operating member intersecting with the moving direction of the valve element. For this reason, as the operating member moves in the forward / backward direction and advances into the flow path, the operating member gradually moves the valve element toward the valve seat, that is, toward the valve opening position.

  For this reason, the movement of the operation member in the forward / backward direction with respect to the flow path is converted into movement in the movement direction of the valve body by the sliding contact between the operation member side interference surface and the valve body side interference surface, and transmitted to the valve body. By the pressing operation, the valve body at the valve closing position can be reliably returned to the valve opening position by the biasing force of the valve body biasing member.

  According to the present invention, there is no need to open the valve body using a tool or return the operating member after resuming gas supply, and the gas from the bulk storage tank blocked by the closing of the flow path by the closing valve is removed. Supply can be resumed by a simple operation.

It is sectional drawing which shows the gas emission preventer which concerns on one Embodiment of this invention. It is the II sectional view taken on the line of the gas emission preventer of FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals.

  The following embodiment exemplifies an apparatus or the like for embodying the technical idea of the present invention. The technical idea of the present invention is based on the material, shape, structure, arrangement, etc. of each component. It is not specified to the following. The technical idea of the present invention can be variously modified within the scope of the claims.

  FIG. 1 is a cross-sectional view showing a gas emission preventer according to an embodiment of the present invention. The gas release preventer 1 of this embodiment shown in FIG. 1 includes a body 3 having a flow path 5 therein, a closing valve 7 that shuts off the flow path 5, and a return that returns the closing valve 7 that shuts off the flow path 5. And a mechanism 9.

  The shut-off valve 7 includes a valve body 71 that opens and closes a valve seat 51 formed on the flow path 5 in the body 3, and an upstream flow path 53 that is located upstream of the valve seat 51 of the flow path 5. And a valve body support member 72 attached to the upstream side of the valve seat in the middle flow path).

  The valve body 71 is erected from the center of the valve body 73 that opens and closes the valve seat 51, the O-ring 74 attached to the peripheral surface of the valve body 73, and the end surface of the valve body 73 on the upstream flow path 53 side. The valve shaft 75 has an interference portion 76 that protrudes from the end surface of the valve body 73 opposite to the valve shaft 75.

  The interference unit 76 has a downstream flow passage 55 located downstream of the valve seat 51 of the flow passage 5 (with the valve seat of the flow passage in the claims interposed therebetween) in a state where the valve body 73 closes the valve seat 51. It has a tapered surface 77 (corresponding to the valve element side interference surface in the claims) disposed on the downstream side.

  The taper surface 77 of the interference portion 76 has an axial direction X (vertical direction in FIG. 1, movement of the valve body in the claims) in which the valve body 71 moves when the valve body 73 opens and closes the valve seat 51. Is equivalent to the direction).

  The valve body support member 72 has a cylindrical shape that is screwed and fixed to the upstream flow path 53, and a shaft hole 78 that supports the valve shaft 75 of the valve body 71 movably in the axial direction X at the center thereof. have. A coil spring 80 in a contracted state between the E-ring 79 of the valve shaft 75 and the valve body support member 72 of the valve shaft 75 supported by the shaft hole 78 (corresponding to a valve body urging member in claims) Is wound.

  Therefore, in the valve body 71 in which the valve shaft 75 is supported by the shaft hole 78 of the valve body support member 72, the valve main body 73 moves along the axial direction X of the valve shaft 75 by the elastic force of the coil spring 80. The valve seat 51 is moved away from the valve opening position (the position shown in FIG. 2, which is a cross-sectional view taken along the line II in FIG. 1).

  The shut-off valve 7 configured in this manner is configured so that the pressure of the upstream flow path 53 received by the end face on the valve shaft 75 side of the valve body 73 and the downstream side received by the end face on the interference portion 76 side of the valve body 73 higher than that. When a differential pressure exceeding the set pressure determined by the coil spring 80 occurs between the pressure of the flow path 55 and the valve body 71 moves to the valve seat 51 side against the biasing force of the coil spring 80. By this movement, the valve body 71 moves to a valve closing position (position shown in FIG. 1) where the valve body 73 closes the valve seat 51.

  The valve body support member 72 has a passage 81 extending in parallel with the shaft hole 78. The passage 81 secures a flow path that connects the upstream side and the downstream side of the valve body support member 72 in the upstream flow path 53.

  The return mechanism 9 is a cylindrical holder 91 attached to the body 3, and is inserted into the holder 91 to slide in the axial direction Y (the horizontal direction in FIG. 1, corresponding to the advancing / retreating direction of the operating member in the claims). It has a columnar operation member 92 that is supported in a possible manner and a cap 94 that closes one opening 93 of the holder 91 that is open to the outside of the body 3. The axial direction Y of the operating member 92 intersects the axial direction X of the valve shaft 75.

  The holder 91 is fixed by being screwed into a bottomed columnar mounting portion 31 formed at a position facing the downstream flow path 55 of the body 3, and the opening 95 of the holder 91 is fixed to the mounting portion 31. It is contact | abutted to the stopper ring 96 arrange | positioned at the bottom part. On the opening 95 side of the holder 91, a spring accommodating chamber 97 having an inner diameter larger than that of the opening 93 side of the holder 91 is formed.

  The operation member 92 includes a main body 98 penetrating the inside of the holder 91, an interference pin 99 protruding from one end of the main body 98 in the axial direction Y of the operation member 92, and a main body in the axial direction Y of the operation member 92. 98 has an operation portion 100 projecting from the other end of 98 and a flange portion 101 formed on the peripheral surface of the main body 98.

  The interference pin 99 protrudes outward from the opening 95 of the holder 91 and is inserted into the through-hole 33 that communicates the attachment portion 31 of the body 3 and the side surface of the downstream flow path 55. The interference pin 99 inserted through the through hole 33 is sealed by the O-ring 35. The tip of the interference pin 99 extends from the side surface of the downstream channel 55 through the through-hole 33 to the inside. An R surface 102 (corresponding to an operation member side interference surface in claims) is formed at the tip of the interference pin 99. The R surface 102 has a curved surface that is inclined with respect to the axial direction Y of the operation member 92 at the corner.

  The operation unit 100 projects outward from the opening 93 of the holder 91 and is exposed to the outside of the body 3. The operation part 100 of the operation member 92 exposed to the outside of the body 3 is covered with a cap 94 attached to the opening 93.

  The flange portion 101 is accommodated in the spring accommodating chamber 97 of the holder 91 and is configured to be movable along the axial direction Y of the operation member 92. A coil spring 103 in a contracted state (corresponding to an operation portion biasing member in claims) is wound around a main body 98 between the flange portion 101 and the stopper ring 96.

  Therefore, the operating member 92 slidably supported by the holder 91 has a retracted position in which the interference pin 99 is retracted from the downstream channel 55 along the axial direction Y of the operating member 92 by the elastic force of the coil spring 103. It is biased in the direction of moving to the (position indicated by the phantom line in FIG. 1) side.

  When the operation member 92 configured in this manner is pressed in the axial direction Y toward the inside of the body 3 against the biasing force of the coil spring 103, the operation member 92 advances into the downstream channel 55. The R surface 102 of the interference pin 99 is in sliding contact with the tapered surface 77 of the interference portion 76 of the valve body 71 in the valve closing position.

  When the operation member 92 is pressed to the limit position where the stepped portion between the main body 98 of the operation member 92 and the interference pin 99 abuts against the stopper ring 96, the interference pin 99 is moved to the periphery of the R surface 102 on the main body 98 side. The surface advances into the downstream flow path 55 to an advance position (corresponding to an advance position in claims) that reaches a position on the center side of the taper surface 77 in the interference portion 76 of the valve body 71.

  When the pressed operating member 92 reaches the advanced position, the valve shaft 75 of the valve body 71 at the valve closing position in the axial direction X is brought into sliding contact with the R surface 102 of the interference pin 99 with respect to the tapered surface 77 of the interference portion 76. Gradually push up toward the valve seat 51 side. As a result, the valve body 71 is opened away from the valve seat 51.

  Next, the operation of the gas emission preventer 1 of this embodiment will be described. The upstream flow path 53 of the gas release preventer 1 is connected to the bulk storage tank side (not shown), and the downstream flow path 55 is connected to the piping side to the gas equipment (not shown).

  When a large amount of gas is not released on the piping side of the gas equipment, the pressure of the upstream flow path 53 received by the end surface of the valve body 73 of the shut-off valve 7 on the valve shaft 75 side and the interference part 76 of the valve body 73 The differential pressure with the pressure of the downstream flow path 55 received by the end face on the side becomes equal to or lower than the set pressure determined by the coil spring 80.

  For this reason, the closing valve 7 is in a valve-opening state in which the valve body 71 is moved to the valve opening position by the biasing force of the coil spring 80 and the valve body 73 opens the valve seat 51. Therefore, the gas from the bulk storage tank flows into the downstream channel 55 from the upstream channel 53 via the valve seat 51 and is supplied to the gas device side (not shown).

  On the other hand, when a large amount of gas is released on the piping side of the gas equipment, the pressure in the downstream flow path 55 decreases, and a differential pressure exceeding the set pressure is generated between the pressure in the upstream flow path 53.

  For this reason, the valve body 71 is moved to the valve closing position against the urging force of the coil spring 80 by the differential pressure between the upstream flow path 53 and the downstream flow path 55. However, the valve seat 51 is closed. Therefore, the gas supply of the bulk storage tank from the upstream flow path 53 to the downstream flow path 55 is shut off by the shutoff valve 7, and gas is not supplied to the gas equipment side (not shown).

  And if the mass release of the gas by the piping side of gas equipment is canceled, the pressure fall of the downstream channel 55 will stop. However, since there is no change in the state in which there is a differential pressure exceeding the set pressure with the pressure in the upstream flow path 53, the valve element 71 of the closing valve 7 remains moved to the valve closing position. For this reason, the gas supply of the bulk storage tank from the upstream flow path 53 to the downstream flow path 55 remains blocked by the stop valve 7.

  Therefore, when the mass release of the gas on the piping side of the gas device is resolved, the cap 94 of the holder 91 of the return mechanism 9 is removed to expose the opening 93, and the operation member 92 protruding outward from the opening 93. The operation unit 100 is pressed against the urging force of the coil spring 103 to move the operation member 92 to the advanced position.

  Then, the interference pin 99 of the operation member 92 moves the interference portion 76 of the valve body 71 of the shut-off valve 7 to the valve seat 51 side by the sliding contact of the R surface 102 of the interference pin 99 with respect to the taper surface 77 of the interference portion 76. . Due to the movement of the valve body 71, the valve body 73 is separated from the valve seat 51 and opens the valve seat 51.

  When the valve seat 51 is opened, the upstream channel 53 and the downstream channel 55 are equalized, and the pressure of the upstream channel 53 received by the end surface of the valve body 73 on the valve shaft 75 side, and the valve body The differential pressure with respect to the pressure of the downstream flow path 55 received by the end surface on the interference part 76 side of 73 is equal to or lower than the set pressure determined by the coil spring 80.

  For this reason, the closing valve 7 returns to the valve-opened state by moving the valve element 71 to the valve-opening position by the biasing force of the coil spring 80. Therefore, the gas from the bulk storage tank again flows from the upstream channel 53 to the downstream channel 55 via the valve seat 51, and the supply of gas to the gas device (not shown) is resumed.

  When the pressing operation of the operating member 92 is finished after the closing valve 7 is returned to the open state, the operating member 92 is self-returned to the retracted position by the urging force of the coil spring 103. When the operation member 92 returns to the retracted position, the cap 94 is attached to the opening 93 of the holder 91 to cover the operation unit 100 of the operation member 92 protruding from the opening 93.

  As described above, according to the gas release preventer 1 of the present embodiment, when the shutoff valve 7 that shuts off the flow path 5 is returned, the operation portion 100 of the operation member 92 is against the biasing force of the coil spring 103. The valve body 73 of the valve body 71 of the shut-off valve 7 is separated from the valve seat 51 by simply pressing and moving from the retracted position to the advanced position, and the valve body 71 is moved to the valve open position by the biasing force of the coil spring 80. Can be moved.

  Moreover, after the valve element 71 has moved to the valve open position, the operation member 92 is returned from the advanced position to the original retracted position by the biasing force of the coil spring 103 by ending the pressing operation of the operation portion 100 of the operation member 92. Thus, when a large amount of gas is released on the piping side of the gas equipment, the closing valve 7 can be brought into a state where the flow path 5 can be blocked again.

  For this reason, the operation of returning the closing valve 7 that shuts off the flow path 5 and the operation of returning the return mechanism 9 that has been operated for the return operation to the original state can be performed without pressing a suitable tool. It can be performed easily and quickly only by operation. Therefore, it is possible for the user of the gas equipment to perform the return work of the shut-off valve 7 and the return mechanism 9 by himself / herself by referring to the description or listening to the explanation by telephone without dispatching a specialized worker to the site. Can be.

  In this embodiment, the taper surface 77 is provided on the interference part 76 of the valve body 71 and the R surface 102 is provided on the interference pin 99 of the operation member 92. However, both the interference part 76 and the interference pin 99 have a taper surface. The taper surface may be provided on only one of the interference part 76 and the interference pin 99.

  However, when a tapered surface is provided on both the interference portion 76 and the interference pin 99, for example, the inclination of the taper surface on the interference portion 76 side with respect to the horizontal direction in FIG. Is larger, the lower end in the vertical direction in FIG. 1 of the tapered surface on the interference pin 99 side makes point contact with the tapered surface on the interference portion 76 side.

  On the contrary, if the inclination of the taper surface on the interference portion 76 side with respect to the horizontal direction is smaller than the inclination of the taper surface on the interference pin 99 side, the upper end in the vertical direction of the taper surface on the interference pin 99 side is the interference portion 76 side. Point contact with the taper surface.

  Even when either the taper surface on the interference portion 76 side or the taper surface on the interference pin 99 side is greatly inclined with respect to the horizontal direction, the taper surface on the interference pin 99 side has a strength on the center side or on the outer peripheral side. The relatively low corner portion makes point contact with the tapered surface on the interference portion 76 side.

  For this reason, when the taper surface on the interference portion 76 side and the taper surface on the interference pin 99 side have different inclinations in the horizontal direction, the corner portion of the taper surface on the interference pin 99 side is the taper surface on the interference portion 76 side. Measures such as reinforcement to prevent deformation (dents, etc.) and damage due to repeated contact with the substrate may be taken.

  Such a measure is that the corner of the taper surface on the interference pin 99 side is deformed or damaged, and the contact point or contact angle with respect to the taper surface on the interference portion 76 side changes compared to the initial time, and the valve opening position direction This is effective in preventing the movement of the valve body 71 from becoming constant and unstable.

  Further, when the tapered surface is provided on both the interference portion 76 and the interference pin 99, the inclination of the taper surface on the interference portion 76 side with respect to the horizontal direction is the same as the inclination of the taper surface on the interference pin 99 side. The taper surface on the 99 side and the taper surface on the interference portion 76 side are in line contact and the taper surface on the interference pin 99 side is in point contact with the taper surface on the interference portion 76 side.

  Therefore, when the taper surface on the interference portion 76 side and the taper surface on the interference pin 99 side have the same inclination in the horizontal direction, the taper surface on the interference pin 99 side and the taper surface on the interference portion 76 side are Because of the increased sliding resistance, a measure may be taken so that a large operating force is not required for the pressing operation of the operating member 92 for moving the valve body 71 in the valve opening position direction.

  On the other hand, when the interference portion 76 is provided with the tapered surface 77 and the interference pin 99 is provided with the R surface 102 as in the present embodiment, the same point on the R surface 102 is obtained when the interference portion 76 and the interference pin 99 interfere. Point contact with the tapered surface 77 at the same angle. Further, while the valve element 71 moves to the valve opening position due to interference between the interference portion 76 and the interference pin 99, the same point on the R surface 102 slides linearly on the taper surface 77 along the inclination.

  For this reason, the valve body 71 can be stably moved linearly in the valve opening position direction by the pressing operation of the operation member 92. The operation of moving the valve element 71 to the valve opening position by the interference between the interference unit 76 and the interference pin 99 can be easily performed with a small operation force. The same effect can be obtained by providing the interference portion 76 with an R surface and providing the interference pin 99 with a tapered surface.

  Further, the position where the valve element 71 at the valve closing position interferes with the operation member 92 at the advanced position may be the upstream flow path 53 instead of the downstream flow path 55 shown in the present embodiment. In that case, the valve element 71 at the valve closing position is moved in the direction in which the valve main body 73 is separated from the valve seat 51 (the valve opening position direction) due to the interference between the two.

  The present invention is extremely useful when applied to a gas discharge preventer used in a gas supply apparatus using a bulk storage tank.

DESCRIPTION OF SYMBOLS 1 Gas emission preventer 3 Body 5 Flow path 7 Stop valve 9 Return mechanism 31 Attachment part 33 Through-hole 35 O-ring 51 Valve seat 53 Upstream flow path 55 Downstream flow path 71 Valve body 72 Valve body support member 73 Valve body 74 O-ring 75 Valve shaft 76 Interference section 77 Tapered surface (valve element side interference surface)
78 Shaft hole 79 E ring 80 Coil spring (valve element biasing member)
81 Valve body support member passage 91 Holder 92 Operation member 93 One opening of the holder 94 Cap 95 The other opening of the holder 96 Stopper ring 97 Spring housing chamber 98 Operation member main body 99 Interference pin 100 Operation portion 101 Flange portion 102 Operation R surface of the member (operation member side interference surface)
103 Coil spring (operating part biasing member)
X Axial direction of valve shaft (movement direction of valve body)
Y Axial direction of operating member (advancing and retracting direction of operating member)

Claims (2)

Closed valve that closes the valve seat from the open position that opens the valve seat against the biasing force of the valve body biasing member due to the differential pressure between the upstream side and the downstream side across the valve seat of the flow path A shut-off valve whose valve body moves to a position;
The pressing operation from the outside of the body having the flow path moves against the urging force of the operation portion urging member from the retracted position retracted from the flow path to the advanced position advanced into the flow path, and An operation member that interferes with the valve body at the valve closing position and moves the valve body toward the valve opening position;
A gas emission preventer comprising:   The valve body has a valve body-side interference surface that is inclined with respect to the moving direction of the valve body at a portion disposed in the flow path downstream of the valve seat at the valve closing position, The operation member is inclined at an advancing / retreating direction to the flow path intersecting the moving direction of the valve body at a portion arranged in the flow path downstream of the valve seat at the advanced position. The gas emission preventer according to claim 1, further comprising an interference surface, wherein the operation member side interference surface is in sliding contact with the valve body side interference surface at the advanced position.

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