JPH0539279Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial application field>> This invention can be applied to acetylene, ethylene, propane,
It is installed in a device that supplies flammable gas such as city gas or hydrogen, or in the supply path of piping to prevent the backfire propagation of flammable gas in the event of a backfire, and also to cut off the supply of flammable gas. The present invention relates to a dry flashback preventer having the following characteristics.

<<Prior Art>> Conventionally, there is a flashback prevention device that prevents the 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. 4, a gas outlet 53 is formed in the peripheral wall 52 of a flashback preventer case body 51 that is formed with one end open, and a shutoff valve holder 54 is fitted inside the case body 51. A flashback prevention chamber 55 is formed, a flame extinguishing tube 56 is fitted inside the flashback prevention chamber 55, a shutoff valve chamber 57 is formed inside the shutoff valve holder 54, and gas is introduced into the outer end wall of the shutoff valve chamber 57. Nozzle 5
8, and a nozzle holder 59 is screwed into the open end of the case body 51 so that the cutoff valve holder 54 and the gas introduction nozzle 58 can be fixed in position within the case body 51, and the cutoff valve chamber A cutoff valve body sliding hole 60 is transparently provided at the inner end of the cutoff valve body 57 , a cutoff valve seat 61 is formed on the peripheral wall of the shutoff valve chamber side opening of the shutoff valve body sliding hole 60 , and a shutoff valve seat 61 is formed in the shutoff valve chamber 57 . body 62 with its legs 6
2a is housed in the shutoff valve body sliding hole 60 so as to be able to slide forward and backward, and this shutoff valve body 62 is elastically biased toward the valve closing side by a shutoff valve spring 63 installed between it and the gas introduction nozzle 58. , a flashback prevention chamber 5 is provided inside the shutoff valve body 62.
A gas communication hole 64 is recessed from the 5 side, and a through hole 65 provided through the leg peripheral wall of the shutoff valve body 62 connects the shutoff valve chamber 5.
7 and the backfire prevention chamber 55, a check valve seat 66 is formed at the end of the gas communication hole 64 on the side of the flashback prevention chamber. A sliding support hole 68 is provided in the end wall of the opposite side of the cutoff valve chamber 57 in the central space inside the flame extinguishing tube 56 of the flashback prevention chamber 55. Insert the reset rod 69 so that it can slide freely in the far and near direction facing the shutoff valve chamber 57, and
A check valve spring 70 is disposed between the check valve body 67 and the check valve body 67 to elastically bias the check valve body 67 toward the valve closing side, and a click stop is placed between the reset rod 69 and the sliding support hole 68. The device 71 is interposed, and the click stop device 71
The structure is such that the shutoff valve body 62 is held in the valve open position (reset position) and the valve closed position by the operation of the valve.

《The problem the idea is trying to solve》 However, the above structure has the following problems.

B. In the cutoff valve chamber 57 formed inside the cutoff valve holder 54, the cutoff valve body 62 is inserted into the gas introduction nozzle 5.
A shutoff valve spring 63 installed between the shutoff valve body 62 and the check valve body 62 elastically biases the check valve body 6 to the valve closing side.
7, a sliding support hole 68 is provided in the end wall of the opposite side of the cutoff valve chamber 57 in the central space inside the flame extinguishing tube 56 of the flashback prevention chamber 55, and A click stop device 71 is interposed between the inserted reset rod 69 and the sliding support hole 68, and the operation of the click stop device 71 holds the cutoff valve body 62 at the valve open position and the valve closed position. Since the forward flow gas pressure acts on the clip stop device 71 to close the shutoff valve, if the spring pressure of the clip stop device 71 is set low, the pressure of the downstream gas acts on the clip stop device 71 to close the shutoff valve. There is a problem that the is activated.

(b) For this reason, the spring pressure of the click stop device 71 must be set higher than the resultant force of the forward flow gas pressure, the spring pressure of the shutoff valve spring 63, and the spring pressure of the check valve spring 70, and as a result, backfire occurs. When the flashback pressure caused by
2, there is a problem in that the valve does not close when the flashback pressure is lower than the spring pressure.

Furthermore, since the flashback prevention chamber 55 communicates with the gas outlet 53 via the flame-extinguishing tube 56, the flashback pressure acting on the flashback prevention chamber 55 is weakened when it passes through the flame-extinguishing tube 56. Even if the flashback pressure is lower than the spring pressure of the click stop device 71 and the click stop device 71 does not operate, and the flashback pressure propagates into the flashback prevention chamber 55, the shutoff valve body 62 closes. There was a risk that it might not work.

D In addition to the forward flow gas pressure, the check valve spring 70 and the cutoff valve spring 63 are used to close the flashback preventer.
Since the spring pressure of the spring of the spring of the click stop device 71 is all involved, the error in each spring pressure is added to the pressure fluctuation of the forward flow gas in the operation accuracy of the flashback preventer. Therefore, it was difficult to accurately close the flashback preventer.

The present invention solves the above problems and prevents the shutoff valve from closing even if the downflow gas pressure is high, and also ensures that the shutoff valve closes when backfire pressure acts. The purpose of the present invention is to provide a dry flashback prevention device that operates by closing a valve.

<Means for Solving the Problems> In order to achieve the above object, the present invention includes a flame extinguishing cylinder,
In a dry flashback preventer that incorporates a check valve element and a shutoff valve element, and forms a gas inlet on one of the end wall and the circumferential wall of the case body, and a gas outlet on the other side, The other end wall is formed in an open shape, and a shutoff valve holder is fitted and fixed in the opening to form a flashback prevention chamber in the case body, and a gas inlet is formed in one end wall of the case body. A gas outlet is formed on the peripheral side wall of the
A check valve seat is formed at the end of the gas inlet on the backfire prevention chamber side, and a flame extinguishing tube is arranged to surround this check valve seat, and between the flame extinguishing tube and the inner surface of the case body circumferential side wall. A gas communication space is provided, and a flame extinguishing tube is pressed and fixed to the inner surface of one end wall of the case body using a flame extinguishing tube holder placed in the backfire prevention chamber.A check valve body is placed inside the flame extinguishing tube, and this check valve body is used to extinguish flames. A check valve spring installed between the cylinder holder and the check valve seat is biased toward the check valve seat to form a shutoff valve chamber inside the shutoff valve holder.
The shutoff valve chamber and the gas communication space are communicated through a gas communication hole, and a shutoff valve body sliding support hole is provided in the shutoff valve holder to form a shutoff valve seat at the end on the side of the shutoff valve chamber. A gas outlet path communicating between the support hole and the gas outlet is formed to intersect with the sliding support hole,
A gas communication passage is provided along the inner side of the sliding support hole between the isolation valve seat and the gas outlet passage to communicate the isolation valve sealing part and the gas outlet passage, and the legs of the isolation valve body are arranged in the isolation valve chamber. The cutoff valve body is airtightly supported in a state in which it can move in and out of the cutoff valve body sliding support hole, and the cutoff valve body is elastically biased toward the cutoff valve seat by a cutoff valve spring installed between it and the flame extinguishing cylinder holder, and the cutoff valve is shut off. A click stop device is interposed between the legs of the valve body and the position facing the gas outlet path of the sliding support hole, so that the shutoff valve body can be held in an open position away from the shutoff valve seat. In the open position where the shutoff valve body is away from the shutoff valve seat, the engaging ball of the click stop device faces the gas outlet path, and in the shutoff position where the shutoff valve body is in pressure contact with the shutoff valve seat, the legs of the shutoff valve body The cutoff valve holder is characterized in that the cutoff valve holder is configured such that the portion protrudes from the outer end surface of the cutoff valve holder.

<<Operation>> The present invention provides a gas communication path along the inner side of the sliding support hole between the shutoff valve seat and the gas outlet path, and a gas communication path is provided opposite to the leg of the shutoff valve body and the gas outlet path of the sliding support hole. A click stop device is interposed between the shutoff valve and the opening position, and the engaging ball of the click stop device faces the gas outlet path when the shutoff valve body is in the open position, so that the click stop device can be reset. When combustible gas flows forward, the forward gas pressure has no effect on the opening/closing operation of the shutoff valve body. For example, the shutoff valve body can be held in the open position.

Furthermore, when a flashback occurs, the explosive pressure of the flashback propagating from the outlet to the outlet path acts directly on the engaging ball of the click stop device facing the outlet path, pressing it. As a result, the click stop device is released and the shutoff valve spring presses the shutoff valve element toward the valve seat to close the valve.

In addition, when the click stop device is released due to a flashback, even if the shutoff valve is instantaneously opened due to the instantaneous explosion pressure of the flashback and the flashback pressure propagates into the flashback prevention chamber, the communication will not continue. When propagating from the space to the check valve chamber, the back flame passes through the flame extinguishing tube, so the back flame is extinguished and the back flame pressure is weakened. The low flashback pressure propagated to the check valve chamber, together with the spring pressure of the check valve spring, causes the check valve element to close, thereby reliably preventing the flashback from propagating.

When the backfire subsides, the shutoff valve body is in the closed position due to the release operation of the click stop device, and its legs protrude from the outer end surface of the shutoff valve holder, so when it is pushed into the case body, the shutoff valve body is closed. The stop device is reset and the engaging ball engages between the legs of the shutoff valve body, thereby holding the shutoff valve body in the open position.

<<Effects of the invention>> Since the present invention is constructed and operates as described above, it has the following effects.

B. When a flashback occurs, the flashback pressure propagating from the gas outlet directly acts on and presses the engagement ball of the clickstop device without passing through the flame extinguishing cylinder, so the The fire pressure is not weakened, and when a backfire occurs, the strong explosion pressure can immediately release the click stop device and close the shutoff valve.

(b) During forward flow, the shutoff valve body is held in the open position by the spring pressure of the click stop device against the shutoff valve spring, and during backfire, the backfire pressure is engaged against the spring pressure of the click stop device. By pressing the ball, the click stop device is released and the shutoff valve body is closed.
The spring pressure of the check valve spring and the pressure of the downstream gas are not involved in the release operation of the click stop device, only the spring pressure of the click stop device and the spring pressure of the shutoff valve are involved, and the spring pressure of the click stop device is The flashback preventer can be operated with high accuracy simply by increasing the accuracy of the pressure and shutoff valve spring pressure.

C. The gas pressure of the forward flow gas has no effect of operating the shutoff valve body in the open position toward the valve closing side, so
By simply changing the spring pressure of the check valve spring, it can be used for gases with different pressures over a wide range from low pressure to high pressure.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal side view when the flow is in the forward direction, FIG. 2 is a longitudinal side view when the flow is backward, and FIG. 3 is a longitudinal side view when the flow is at rest.

This flashback preventer has a gas inlet nozzle 28 protruding from one end wall 2 of the case body 1, and a gas inlet 8 at the tip.
A gas introduction passage 29 is transparently provided in the center of the nozzle 28, and the inner surface of the end of the gas introduction passage 29 on the side of the case body 1 is formed into a conical surface that widens toward the tip, and the check valve seat 14 is formed on this conical surface. There is.

The other end wall 4 of the case body 1 is formed in an open shape, and a shutoff valve holder 16 is fitted into this open end to form a flashback prevention chamber 10 in the case body 1.

Inside the flashback prevention chamber 10, a flame extinguishing tube 5 made of a porous material such as sintered metal is arranged to surround a check valve seat 14 formed on one end wall 2, and the flame extinguishing tube 5 and the shutoff valve A flame extinguishing tube holder 12 is fitted between the holder 16 and the holder 16.

The flame extinguishing tube holder 12 has a cylindrical shape with a bottom and a flange whose body protrudes into the inside of the flame extinguishing tube 5, and the flame extinguishing tube 5 is held between the flange and the inner surface of one end wall 2 of the case body. It is structured as follows.

A presser 27 is internally screwed into the open end of the case body 1, and the presser 27 presses the flame extinguishing tube 5, the flame extinguisher tube holder 12, and the cutoff valve holder 16 toward the one end wall 2 of the case body. It is fixed.

A check valve body 6 is disposed inside the flame extinguishing tube 5 to form a check valve chamber 13, and one end of the check valve body 6 extends in a cylindrical shape, and this cylindrical portion is connected to the gas introduction path 29. The check valve chamber 13 and the gas introduction port 8 are slidably fitted into each other, and an opening is provided in the peripheral wall at the rear end of the cylindrical portion so that the check valve chamber 13 and the gas inlet 8 can communicate with each other.

Also, a check valve spring 15 is installed between the check valve body 6 and the body of the flame extinguishing tube holder 12, and the check valve spring 15 presses the check valve body 6 toward the check valve seat 14. It is strong.

A circumferential cylindrical gas communication space 11 is provided between the outer periphery of the flame extinguishing tube 5 and the inner circumferential surface of the case body peripheral side wall 3, and communicates with the check valve chamber 13 via the flame extinguishing tube 5.

The shutoff valve holder 16 has a sealing ring on its disk-shaped outer circumferential surface to airtightly seal the space between it and the inner surface of the circumferential side wall 3 of the case body, and has a backfire prevention chamber side end surface 1 in the center.
A sliding support hole 21 for the cutoff valve body 7 is transparently provided from the outer end surface 16b to the outer end surface 16b.

The end of the sliding support hole 21 on the side of the flashback prevention chamber is expanded in diameter to form a shutoff valve chamber 17, and a shutoff valve seat 18 is formed on the inner surface of the shutoff valve chamber 17.

Gas communication holes 20 are provided radially through the cutoff valve chamber 17 in a thick wall portion of the cutoff valve holder 16 on the side closer to the flashback prevention chamber 10 than the cutoff valve seat 18 . It is connected.

The gas communication hole 20 may be formed by providing a radial groove in the end face 16a of the cutoff valve holder 16 on the backfire prevention chamber side, or may be formed in the flame extinguishing tube holder 12.

The cutoff valve body 7 disposed in the cutoff valve chamber 17 is inserted into the body cylinder of the flame extinguishing cylinder holder 12 at one end, and the leg 7a at the other end is inserted into the sliding support hole 21 so that it can freely slide forward and backward. It is pressed toward the shutoff valve seat 18 by a shutoff valve spring 19 disposed within the flame extinguishing tube holder 12.

A sealing ring is fitted around the circumferential surface of the distal end portion of the cutoff valve body leg 7a, thereby airtightly sealing the space between the leg portion 7a and the sliding support hole.

A gas outlet passage 22 is provided between the central part of the sliding support hole 21 and the gas outlet port 9 of the case main body peripheral side wall 3, and a cutoff valve is provided on the opposite side of the sliding support hole 21 from the gas outlet passage 22. A click stop device 24 is disposed within the thickness of the holder 16 facing the sliding support hole 21.

Furthermore, the inner diameter of the sliding support hole 21 a between the gas outlet passage 22 and the cutoff valve seat 18 is expanded to form a gas communication passage 23 , and the sealing part of the cutoff valve and the gas outlet passage 22 are connected to each other. It's communicating. This gas communication passage 23 may be provided between the gas outlet passage 22 and the cutoff valve seat 18, or may be provided on the cutoff valve body 7 side by reducing the outer diameter of the cutoff valve body leg 7a. .

An engagement hole 26 is provided in the cutoff valve body leg 7a at a position opposite to the engagement ball 25 of the click stop device 24 in the valve open position, and the other end of the engagement hole 26 is connected to the gas outlet path 22. The engaging ball 25 of the click stop device 24 faces the gas outlet path 22 through the inclined hole 26.

In the dry flashback preventer having the above-mentioned configuration, when the click stop device 24 is reset and the flow is forward, the cutoff valve body 7 is held in an open position, and the forward flow gas flowing in from the gas inlet 8 is prevented from flowing back. The valve body 6 is opened against the check valve spring 15, and the flame extinguishing cylinder 5 is opened.
from the gas communication space 11 through the gas communication hole 20
It flows into the shutoff valve chamber 17 through the. The downstream gas that has flowed into the cutoff valve chamber 27 does not act on the click stop device 24, and therefore does not close the cutoff valve body 7 which is in the open position, but rather closes the gas communication passage 23 and gas flow. The gas flows out from the gas outlet 9 via the outlet path 22 .

When a flashback occurs, the explosion pressure of the flashback propagates from the gas outlet 9 into the gas outlet path 22, passes through the engagement hole 26 provided in the cutoff valve body leg 7a, and enters the gas outlet path 22. Click stop device 2
It acts directly on the engagement ball 25 of No. 4. As a result, the backfire pressure pushes the engaging ball 25 against the spring pressure, releasing the click stop device 24, and thereby the shutoff valve body 7 is pressed toward the shutoff valve seat 18 by the shutoff valve spring 19. The valve closes and the supply of flammable gas is cut off.

In addition, when the flashback pressure is extremely high and the flashback pressure propagates from the gas communication passage 23 to the shutoff valve sealing part and causes the shutoff valve body 7 to open instantaneously, the flashback prevention chamber is opened from the gas communication hole 20. The backfire pressure that entered the flame extinguishing cylinder 5
When passing through the gas, the pressure is weakened and the flash back flame is extinguished. The weak flashback pressure that has entered the check valve chamber 13 causes the check valve body 6 to close due to the combined force of the spring pressure of the check valve spring 15, thereby reliably preventing the spread of flashback pressure. be able to.

When backfire occurs, the shutoff valve body 7 is held in the closed position by the release operation of the click stop device 24 and the pressing force of the shutoff valve spring 19, and the leg portion 7a is held against the outer end surface of the shutoff valve holder. It protrudes from 16b.

When the backfire subsides, the click stop device 24 is reset by pushing the protruding cutoff valve leg 7a into the case body 1, and the engagement ball 25 is inserted into the cutoff valve leg 7a. The shutoff valve body 7 is held in the open position by being engaged with the engagement hole 26 .

In the above embodiment, the cutoff valve holder 16 is brought into contact with the flame extinguishing tube holder 12 to position and fix the flame extinguishing tube holder 12. In addition to fixing the cutoff valve holder 16, the cutoff valve holder 16 may also be positioned and fixed in a state apart from the flame extinguishing cylinder holder 12. In this case, the cutoff valve holder 1
6 and the flame extinguishing tube holder 12 is formed in the gas communication hole 20, so there is no need to provide a separate gas communication hole 20 in the cutoff valve holder 16 or the flame extinguishing tube holder 12.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a longitudinal side view when flowing in a forward direction, Figure 2 being a longitudinal side view when flowing backward, and Figure 3 being a longitudinal side view when at rest. FIG. 4 is a diagram corresponding to FIG. 1 showing the prior art. 1...Case body, 2...One end wall of 1, 3...
1 peripheral side wall, 4... 1 other end wall, 5... flame extinguishing cylinder,
6... Check valve body, 7... Shutoff valve body, 7a... Shutoff valve body leg, 8... Gas inlet, 9... Gas outlet, 10... Flashback prevention chamber, 11... Gas Communication space, 12... Flame extinguishing tube holder, 14... Check valve seat, 15... Check valve spring, 16... Shutoff valve holder, 16b... Outer end surface of 16, 17... Shutoff valve chamber, 18... ...Shutoff valve seat, 19...Shutoff valve spring, 2
0...Gas communication hole, 21...Sliding support hole, 21a
...inner part of 21, 22... gas outlet path, 23...
...Gas communication path, 24...Click stop device,
25...24 engaging balls.

Claims (1)

[Claims for Utility Model Registration] A flame-extinguishing tube 5, a check valve body 6, and a cutoff valve body 7 are incorporated into a flashback preventer case body 1 formed in an airtight structure, and one end wall 2 and peripheral side wall 3 of the case body 1 are assembled. In a dry flashback preventer in which a gas inlet port 8 is formed on one side and a gas outlet port 9 is formed on the other side, the other end wall 4 of the case body 1 is formed in an open shape, and a shutoff valve is installed in the opening. A flashback prevention chamber 10 is formed in the case body 1 by fitting and fixing the holder 16 therein, a gas inlet 8 is formed in one end wall 2 of the case body 1, and a gas inlet is formed in the peripheral side wall 3 of the case body 1. An outlet 9 is formed, a check valve seat 14 is formed at the end of the gas inlet 8 on the side of the flashback prevention chamber 10, and a flame extinguishing tube 5 is arranged to surround the check valve seat 14. 5 and the inner surface of the case body peripheral side wall 3, a gas communication space 11 is provided between the flame extinguishing tube holder 1 and the flame extinguishing cylinder holder 1, which is arranged in the flashback prevention chamber 10.
2, the flame extinguishing tube 5 is pressed and fixed to the inner surface of the one end wall 2 of the case body, a check valve body 6 is arranged inside the flame extinguishing tube 5, and the check valve body 6 is installed between the flame extinguishing tube holder 12 and the reverse side. The stop valve spring 15 is elastically biased in the direction of the check valve seat 14 to form a cutoff valve chamber 17 inside the cutoff valve holder 16, and the cutoff valve chamber 17 and the gas communication space 11 are communicated through the gas communication hole 20. , A shutoff valve body sliding support hole 21 is provided in the shutoff valve holder 16.
A cut-off valve seat 1 is provided at the end of the cut-off valve chamber 17 side through the cut-off valve chamber 17.
8, and a gas outlet passage 22 communicating between the sliding support hole 21 and the gas outlet 9 is formed to intersect with the sliding support hole 21, and between the cutoff valve seat 18 and the gas outlet passage 22. A gas communication passage 23 is provided along the inner side 21a of the sliding support hole to communicate the cutoff valve sealing part and the gas outlet passage 22, and the leg part 7a of the cutoff valve body 7 disposed in the cutoff valve chamber 17.
The cutoff valve body 7 is airtightly supported in the cutoff valve body sliding support hole 21 so as to be movable in and out.
The shutoff valve seat 1 is connected to the shutoff valve seat 1 by the shutoff valve spring 19 installed between the
8, and a click stop device 24 is interposed between the leg portion 7a of the cutoff valve body 7 and the position facing the gas outlet path 22 of the sliding support hole 21, and the cutoff valve body 7 is configured to be able to be held in the open position where the shutoff valve body 7 is away from the shutoff valve seat 18, and in the open position where the shutoff valve body 7 is away from the shutoff valve seat 18, the engaging ball 25 of the click stop device 24 is connected to the gas outlet path 22. In the shutoff position where the shutoff valve body 7 is in pressure contact with the shutoff valve seat 18, the legs 7a of the shutoff valve body 7 are in contact with the shutoff valve holder 1.
6. A dry flashback preventer characterized in that it is configured to protrude from an outer end surface 16b of the device.