JPH0539278Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial application>> The present invention is designed to prevent backfire by intervening in equipment for supplying flammable gas such as acetin, ethylene, propane, city gas, hydrogen, etc. or in the supply path of piping. The present invention relates to a dry flashback preventer that has the function of preventing backfire propagation of flammable gas and cutting off the supply of flammable gas.

<<Prior Art>> Conventionally, there is a flashback prevention device that prevents backfire propagation of flammable gas and cuts off the supply of flammable gas, as disclosed in, for example, Japanese Utility Model Publication No. 7760/1983.

As shown in FIG. 3, a gas outlet pipe connecting portion 53 is formed on the peripheral wall 52 of the flashback preventer main body 51 which is formed in an open shape at one end, and a cutoff valve holder 54 is installed inside the flashback preventer main body 51. A flame extinguishing cylinder 56 is installed inside the flashback prevention chamber 55, a cutoff valve chamber 57 is formed inside the cutoff valve holder 54, and the outer end wall of the cutoff valve chamber 57 is fitted inside to form a flashback prevention chamber 55. is formed by the gas introduction nozzle 58, and a nozzle presser 59 is internally fitted into the open end of the flashback preventer main body 51 to insert the cutoff valve holder 54 and the gas introduction nozzle 58 into the flashback preventer main body 51. A shutoff valve body sliding hole 60 is transparently provided in the inner end wall of the shutoff valve chamber 57, and a shutoff valve seat 61 is formed in the circumferential wall of the shutoff valve chamber side opening of the shutoff valve body sliding hole 60. A shutoff valve body 62 is placed inside the shutoff valve chamber 57.
A cutoff valve spring 6 whose leg portion 62a is accommodated in a state where it can freely slide forward and backward within the cutoff valve body sliding hole 60, and which is installed between the cutoff valve body 62 and the gas introduction nozzle 58.
3, a gas communication hole 64 is recessed into the interior of the cutoff valve body 62 from the flashback prevention chamber 55 side, and a through hole 65 is provided through the leg peripheral wall of the cutoff valve body 62.
A check valve seat 66 is formed at the end of the gas communication hole 64 on the side of the flashback prevention chamber, and is opposed to the check valve seat 66. A sliding support hole 68 is provided in the end wall on the opposite side of the cutoff valve chamber 57 in the central space inside the flame extinguishing cylinder 56 of the flashback prevention chamber 55, and the sliding A reset rod 69 is inserted into the support hole 68 so as to be slidable in the direction of distance from and near the cutoff valve chamber 57, and a check valve spring 7 is inserted between the reset rod 69 and the check valve body 67.
0 to elastically urge the check valve body 67 toward the closing side, and a click stop device 71 is interposed between the reset rod 69 and the sliding support hole 68. The structure is such that the shutoff valve body 62 is held at an open position (reset position) and a shutoff position.

<<Problem to be Solved>> However, in the conventional example, the cutoff valve spring installed between the cutoff valve body 62 and the gas introduction nozzle 58 in the cutoff valve chamber 57 formed inside the cutoff valve holder 54. 63, the check valve body 67 is installed inside the shutoff valve body 62, and the side opposite to the shutoff valve chamber 57 in the central space inside the flame extinguishing tube 56 of the flashback prevention chamber 55 is applied. A click stop device 71 is interposed between the slide support hole 68 and a reset rod 69 inserted into the slide support hole 68 formed through the end wall of the valve. Since the structure is such that the shutoff valve 62 is held in the open position (reset position) and the shutoff position, the downstream gas pressure acts on the shutoff valve closing side with respect to the click stop device 71, causing the click stop device 71 to close. If the spring pressure of the device 71 is set low, the click stop device 71 will be activated during forward flow. For this reason, the spring pressure of the click stop device 71 was set to be stronger than the resultant force of the forward fluid pressure, the cutoff valve spring pressure, and the check valve spring pressure. Therefore, when flashback pressure acts in the flashback prevention chamber 55 due to flashback, the check valve body 67 operates to prevent the flashback pressure from propagating to the shutoff valve chamber 57, and the shutoff occurs. Since backfire pressure acts on the valve body 62 toward the valve opening side, high backfire pressure must act on it to overcome the spring pressure of the click stop device in order for the shutoff valve to operate to shut off the flow path. First, there was a problem that the shutoff valve did not operate when the flashback pressure was low.

For this reason, conventional flashback preventers are not suitable for hydrogen gas or hydrocarbon gases used at low pressures.

The present invention was developed with attention to these points, and although the shutoff valve can be operated reliably against low flashback pressure, the dry reverser does not operate even under high forward pressure. The purpose is to provide fire arrestors.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention forms a gas outlet pipe connection part on the peripheral wall of the flashback preventer main body which is formed in an open shape at one end, and A cutoff valve holder is fitted inside to form a backfire prevention chamber, a flame extinguishing tube is installed inside the backfire prevention chamber, a cutoff valve chamber is formed inside the cutoff valve holder, and the outer end wall of the cutoff valve chamber is covered with gas. The cutoff valve holder and the gas introduction nozzle are configured to be fixed in position within the flashback arrester main body by screwing a nozzle holder into the open end of the flashback arrester main body. A shutoff valve body sliding hole is provided in the inner end wall of the valve chamber, a shutoff valve seat is formed in the peripheral wall of the opening of the gas introduction nozzle in the shutoff valve chamber on the shutoff valve chamber side, and the shutoff valve body is inserted into the shutoff valve chamber. The legs are housed in the shutoff valve body sliding hole so that they can move forward and backward, and a spring holder is attached to the back end wall of the flashback prevention chamber so that it can move forward and backward. A shutoff valve spring installed between the shutoff valve spring and the end wall closes and presses the shutoff valve body toward the valve closing side via a spring holder, and a gas communication hole is formed in the interior of the shutoff valve body from the flashback prevention chamber side. The shutoff valve chamber and the flashback prevention chamber are configured to communicate with each other through a through hole provided in the peripheral wall of the leg portion of the shutoff valve body, and a check valve seat is formed at the end of the gas communication hole on the side of the flashback prevention chamber, A check valve body is positioned facing this check valve seat, and a check valve spring is placed between the check valve body and the spring holder to elastically bias the check valve body toward the closing side and shut off. The present invention is characterized in that a click stop device is interposed between the valve holder and the shutoff valve element to hold the shutoff valve element in the valve open position against the closing force of the shutoff valve spring.

<Operation> In the present invention, a shutoff valve chamber is formed inside a shutoff valve holder fitted inside the flashback preventer body, and a shutoff valve seat is formed on the peripheral wall of the opening of the gas introduction nozzle on the shutoff valve chamber side in the shutoff valve chamber. The cut-off valve body is housed in the cut-off valve chamber with its legs able to slide forward and backward in the cut-off valve body sliding hole formed on the inner end side of the cut-off valve holder, A spring holder installed on the back end wall of the fire prevention chamber so that it can slide forward and backward and a shutoff valve spring installed between the back end wall of the backfire prevention chamber presses the shutoff valve body toward the valve closing side via the spring holder. Configure it to
A gas communication hole is recessed into the interior of the cutoff valve body from the backfire prevention chamber side, and the cutoff valve chamber and the flashback prevention chamber are configured to be able to communicate with each other through the through hole provided in the leg peripheral wall of the cutoff valve body. ,
A check valve seat is formed on the side of the flashback prevention chamber of the gas communication hole, a check valve body is positioned opposite to the check valve seat, and the check valve is installed between the check valve body and the spring holder. A spring is arranged to elastically bias the check valve element toward the closing side, and a click stop device is interposed between the isolation valve holder and the isolation valve element to apply the closing force of the isolation valve spring to the isolation valve element. Since the shut-off valve is configured to be held in the valve open position, the forward flow gas pressure acts on the open side of the shut-off valve during forward flow when the clip-stop device is reset, so the spring of the clip-stop device is The pressure may be a spring pressure that overcomes the differential force between the resultant force of the spring pressure of the shutoff valve spring and the spring pressure of the check valve spring and the downflow gas pressure, and the spring pressure of the click stop device can be set low. As a result, the shutoff valve will operate reliably even if low flashback pressure is applied.

<<Example>> The drawings show an example of the dry flashback preventer according to the present invention, in which FIG. 1 is a vertical side view when the flow is forward, and FIG. 2 is a side view when the flow is reverse.

This dry type flashback preventer has a cylindrical flashback preventer body 1 with one end open, and a gas outlet pipe portion 4 with a gas outlet hole 3 formed therethrough protruding from the peripheral wall 2 of the flashback preventer body 1. A flashback prevention chamber 6 is formed within the flashback preventer main body 1 by fitting and fixing the shutoff valve holder 5 into the open end of the flashback preventer body 1;
A flame extinguishing cylinder 7 made of a porous material such as sintered metal is arranged within the flashback prevention chamber 6.

The cutoff valve holder 5 has a cylindrical shape with a bottom and a flange whose body protrudes into the flame-extinguishing cylinder 7. A gas introduction nozzle 10 having a gas introduction hole 9 transparently formed in the opening 8 of the cutoff valve holder 5 is fitted and fixed inside the cutoff valve holder 5. A shutoff valve chamber 11 is formed.

A nozzle presser 12 is fitted and fixed at the open end of the flashback preventer main body 1, and this nozzle presser 12
The cutoff valve holder 5 and the gas introduction nozzle 10 are configured to be able to be fixed in position within the flashback preventer main body 1.

A cutoff valve sliding hole 13 is transparently provided in the center of the bottom wall of the cutoff valve holder 5, that is, the inner end wall, and a cutoff valve seat 14 is formed in the opening surrounding wall of the gas introduction nozzle 10 on the cutoff valve chamber side. It has been done. Inside the cutoff valve chamber 11 is a cutoff valve body 15 whose legs 15a are inserted into the cutoff valve body sliding hole 13.
It is housed in a state where it can slide forward and backward inside. Moreover, this cutoff valve body 15 is located closer to the gas introduction nozzle 1 than the sealing part.
A cylindrical body 16 is integrally protruded from the cylindrical body 1.
6 is slidably inserted into the gas introduction hole 9 of the gas introduction nozzle 10. Further, gas holes 17 are opened in the peripheral wall of the cylinder 16 in a radial direction so that the gas introduction hole 9 and the shutoff valve chamber 11 can communicate with each other.

The back end wall 18 of the flashback preventer main body 1 located inside the flame extinguishing tube 7 in the flashback prevention chamber 6 is composed of a plug, and a spring holder 19 is attached to the plug 18 so as to be able to slide forward and backward. There is. This spring holder 19 is constituted by a stepped rod, and is disposed such that its large diameter portion is located within the flashback prevention chamber 6. A shutoff valve spring 20 is installed between the plug 18 and the side surface of the large diameter portion of the spring holder 19 on the plug side, and the elastic force of the shutoff valve spring 20 causes the shutoff valve body 15 to be Pressure is applied to the valve closing side.

A gas communication hole 21 is recessed from the backfire prevention chamber 6 side in the leg portion 15a of the cutoff valve body 15.
A through hole 22 provided through the circumferential wall of 5a connects the shutoff valve chamber 11.
and the flashback prevention chamber 6 are configured to be able to communicate with each other.

A check valve seat 23 is formed at the end of the gas communication hole 21 on the side of the flashback prevention chamber 6, and a check valve body 24 is disposed opposite to the check valve seat 23. This check valve element 24 has a leg part 24a protruding from the sealing part toward the gas introduction nozzle 9 side, which is fitted into the gas communication hole 21 formed in the cutoff valve element 15 in a state where it can freely slide forward and backward. The check valve body 24 is elastically biased toward the valve closing side by a check valve spring 25 installed between the check valve body 24 and the spring holder 19. The leg portion 24a of the check valve body 24 is recessed from the gas introduction nozzle 9 side, and gas holes 26 are opened in the radial direction in the peripheral wall portion thereof. The check valve body 24 is configured to open against the check valve spring 25 due to the inflow gas pressure acting on the gas communication hole 21.

A click stop device 30 consisting of a ball 27 and a stop spring 28 is located in the center of the shutoff valve body 15.
is attached, and the ball 27 of the click stop device 30 engages with the engaging portion 31 formed in the shut-off valve body sliding hole 13 of the shut-off valve holder 5.
The shutoff valve body 15 is maintained at the reset position. This click stop device 30 has a locking force slightly larger than the combined force of the spring pressure of the cutoff valve spring 20 and the spring pressure of the check valve spring 15 at the reset position, and prevents the gas from flowing backward through the gas outlet hole 3. Even a small amount of pressure associated with gas or backfire acts on the flashback prevention chamber 6, and the back pressure is applied to the shutoff valve spring 2.
When added to the resultant force of the zero spring pressure and the spring pressure of the check valve spring 25, the stop spring 28 is activated so that the click stop device 30 is disengaged and the cutoff valve 15 is in the cutoff state. The spring pressure is set.

Reference numeral 32 in the figure is a reset return rod for forcibly returning the shutoff valve body 15 to the reset position after activation.

In the above embodiment, the back end wall of the flashback prevention chamber 6 was formed with a plug, but it may also be a fixed wall that is integrated with the flashback prevention device body, and as in this embodiment, the flashback prevention chamber 6 is formed with a plug. When configuring the far end wall of 6,
There is an advantage that the spring pressure of the cutoff valve spring 20 and the check valve spring 25, that is, the operating pressure of the cutoff valve 15 can be adjusted by operating the plug.

In the dry flashback preventer configured as described above, in a normal state, the shutoff valve body 15 is held in the reset position, so the shutoff valve body 15 is held in an open state away from the shutoff valve seat 14. Since the check valve body 24 is pressed open by the gas pressure flowing in from the gas introduction hole 9, the inflowing gas passes through the cutoff valve chamber 11, the flashback prevention chamber 6, the flame extinguishing tube 7, and then exits from the gas outlet hole 3. leak.

When a flashback occurs, when the backflow flame flows into the flashback prevention chamber 6 from the gas outlet hole 3,
The flame is extinguished by the flame extinguishing cylinder 7, and the explosion pressure flowing into the flashback prevention chamber 6 causes the check valve body 24 to close, and the shutoff valve body 15 is actuated to bring the shutoff valve body 15 into contact with the shutoff valve seat 14. to prevent the inflow of downstream gas.

In addition, this flashback preventer is used not only for flashbacks, but also for
Even when slight pressure is generated in the flashback preventer main body due to gas backflow, the pressure rise causes the check valve body 24 to operate, shutting off the cutoff valve body 15 and cutting off the gas supply. .

<<Effects>> The present invention forms a cutoff valve chamber inside a cutoff valve holder fitted inside the flashback preventer body, and a cutoff valve seat is formed on the circumferential wall of the opening on the cutoff valve chamber side of the gas introduction nozzle in the cutoff valve chamber. The cut-off valve body is housed in the cut-off valve chamber with its legs movable forward and backward in the cut-off valve body sliding hole formed in the inner end wall of the cut-off valve holder, A spring holder installed on the back end wall of the fire prevention chamber so that it can slide forward and backward and a shutoff valve spring installed between the back end wall of the backfire prevention chamber presses the shutoff valve body toward the valve closing side via the spring holder. A gas communication hole is recessed into the interior of the shutoff valve body from the backfire prevention chamber side, and a through hole formed in the leg peripheral wall of the shutoff valve body connects the shutoff valve chamber and the flashback prevention chamber. A check valve seat is formed at the end of the gas communication hole on the side of the flashback prevention chamber, and the check valve body is positioned opposite to the check valve seat, and the check valve body and the spring are configured to communicate with each other. A check valve spring is disposed between the check valve holder and the check valve body to pressurize it toward the closing side, and a click stop device is interposed between the shutoff valve holder and the shutoff valve body to close the shutoff valve body. Since the shutoff valve is configured to be held in the open position against the closing force of the shutoff valve spring, the forwardflow gas pressure will not act on the open side of the shutoff valve during forward flow when the click stop device is reset. The spring pressure of the click stop device can be the spring pressure that overcomes the differential force between the resultant force of the spring pressure of the shutoff valve spring and the spring pressure of the check valve spring, and the downflow gas pressure. The pressure can now be set low,
The shutoff valve can be operated reliably even when low flashback pressure is applied.

In addition, since the shutoff valve and check valve are housed in the flame-extinguishing tube, backfire flames do not directly act on these valve bodies, and the flashback preventer can be made smaller. can get.

Moreover, the nozzle holder is screwed into the opening of the flashback preventer body, which incorporates the internal mechanisms such as the flame extinguishing tube, to position and fix the shutoff valve holder and the flame extinguishing tube, making it easy to disassemble. However, special tools are required and disassembly at the site of use is difficult, and the sealing performance and operating pressure settings are not destroyed, resulting in improved safety.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention, Figure 1 is a longitudinal side view when the flow is forward, Figure 2 is a side view when the flow is reversed, and Figure 3 shows the prior art. This is a diagram equivalent to Figure 1. 1... Flashback preventer main body, 2... Peripheral wall of 1, 4...
... Gas outlet pipe connection part, 5 ... Shutoff valve holder, 6
...Flashback prevention chamber, 7...Flame extinguishing cylinder, 10...Gas introduction nozzle, 11...Shutoff valve chamber, 12...Nozzle holder, 13...Shutoff valve body sliding hole, 14...Shutoff valve seat , 15... cutoff valve body, 15a... leg portion of 15,
18... Rear end wall of 6, 19... Spring holder, 2
0...Shutoff valve spring, 21...Gas communication hole, 22...
...Through hole, 23...Check valve seat, 24...Check valve body,
25...Check valve spring, 30...Click stop device.

Claims (1)

[Scope of utility model registration request] A gas outlet pipe connecting portion 4 is formed on the peripheral wall 2 of the flashback preventer main body 1 formed with one end open, and a cutoff valve holder 5 is fitted inside the flashback preventer main body 1 to form a flashback prevention chamber 6. A flame extinguishing tube 7 is installed inside the backfire prevention chamber 6, a cutoff valve chamber 11 is formed inside the cutoff valve holder 5, and an outer end wall of the cutoff valve chamber 11 is formed with a gas introduction nozzle 10 to prevent backfire. The nozzle holder 12 is fitted into the open end of the preventer body 1 and screwed together to form the shutoff valve holder 5.
and the gas introduction nozzle 10 are configured to be able to be fixed in position within the flashback preventer main body 1, and a shutoff valve body sliding hole 13 is transparently provided in the inner end wall of the shutoff valve chamber 11. A cutoff valve seat 14 is formed on the circumferential wall of the opening of the gas introduction nozzle 10 on the cutoff valve chamber side, and a cutoff valve body 15 is placed in the cutoff valve chamber 11 so that its legs 15a can freely slide forward and backward within the cutoff valve body sliding hole 13. A spring holder 19 is attached to the back end wall 18 of the flashback prevention chamber 6 so as to be able to slide forward and backward, and a shutoff valve spring is installed between the spring holder 19 and the back end wall 18 of the flashback prevention chamber 6. At 20, the shutoff valve body 15 is closed and pressed to the valve closing side via the spring holder 19, and a gas communication hole 21 is recessed into the interior of the shutoff valve body 15 from the flashback prevention chamber 6 side. The cutoff valve chamber 11 and the flashback prevention chamber 6 are configured to communicate with each other through a through hole 22 provided in the peripheral wall of the leg, and the gas communication hole 2
A check valve seat 23 is formed at the end of the flashback prevention chamber side of 1,
The check valve body 24 is positioned facing the check valve seat 23, and the check valve spring 25 is arranged between the check valve body 24 and the spring holder 19, so that the check valve body 24 is on the closing side. Pressure energizes the shutoff valve holder 5 and the shutoff valve body 1
5, a click stop device 30 is interposed between the shutoff valve body 15 and the shutoff valve spring 20 to hold the shutoff valve body 15 in the open position against the closing force of the shutoff valve spring 20. preventer.