JPS637760Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is designed to prevent backfire propagation of flammable gases in the event of backfire by intervening in the supply path of equipment or piping for supplying flammable gases such as acetylene, ethylene, propane gas, city gas, etc. The present invention relates to a dry flashback preventer having a mechanism for blocking and cutting off the supply of flammable gas.

Conventionally, various types of flashback preventers for preventing backfire propagation of flammable gas have been proposed. However,
Conventional dry flashback preventers use a flame extinguisher to extinguish the flames when a flashback occurs, and the rapid pressure rise caused by the explosive pressure closes the shutoff valve and stops the gas supply.

However, in this case, when resetting the dry flashback after the shutoff valve has been activated, it is necessary to disassemble the flashback preventer body, remove the gas outlet hose, etc., and reset the shutoff valve.

Further, a gas outlet hole is formed in the lower part of the flashback preventer main body, a communication port with the flame extinguishing chamber is provided in a state perpendicular to the gas outlet hole, and a flashback escape port is formed in a straight line with the gas outlet hole. A safety valve is placed at the backfire relief port, and a cutoff valve is provided at the communication port, and a reset rod that opens the communication port resists a spring that biases the cutoff valve to open, and the safety valve holds the cutoff valve in the open state. Some proposals have also been made to keep it in place.

However, in this case, during forward flow, the gas flows into the outer periphery of the flame extinguisher inside the flashback preventer, passes through the flame extinguisher tube, and then flows out from inside the flame extinguisher to the gas outlet hole. There was a problem in that the flashback valve provided at the inlet of the fire arrester was located outside the flame extinguisher, making the flashback arrester large.

In addition, in the past, the flame extinguishing tube assembly opening of the flashback preventer body was closed with a cap that was fitted onto the flashback preventer body, so this cap could be easily loosened with a spanner, etc. There were problems in that the sealing performance of the flashback preventer was impaired and the operating pressure of the shutoff valve and check valve fluctuated.

The present invention was proposed in view of these points, and includes forming a gas outlet pipe connection part on the wall of the flashback preventer main body which is formed in an open shape at one end, and incorporating a cutoff valve holder into the flashback preventer main body. Fit together to form a flashback prevention chamber.
A flame extinguishing cylinder is installed inside the flashback prevention chamber, a shutoff valve chamber is formed inside the shutoff valve holder, the outer end wall of the shutoff valve chamber is formed with a gas introduction nozzle, and a nozzle is installed at the open end of the flashback prevention device body. The shutoff valve holder and the gas introduction nozzle are configured to be fixed in position within the flashback preventer body by internally fitting and screwing together the presser, and a shutoff valve body sliding hole is provided through the inner end wall of the shutoff valve chamber. A shutoff valve seat is formed on the circumferential wall of the shutoff valve chamber side opening of the shutoff valve body sliding hole, and the shutoff valve body is accommodated in the shutoff valve chamber with its leg portions sliding back and forth within the shutoff valve sliding hole. This shutoff valve body is pressed to the valve closing side by a shutoff valve spring installed between the gas introduction nozzle, and a gas communication hole is formed inside the shutoff valve body from the flashback prevention chamber side, and the shutoff valve body is closed. The cutoff 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, and a check valve seat is formed at the end of the gas communication hole on the flashback prevention chamber side. Position the check valve body facing the seat, make a sliding support hole in the end wall on the opposite side of the shutoff valve chamber in the central space inside the flame extinguishing tube of the flashback prevention chamber, and reset it in the sliding support hole. The rod is slidably inserted into the shutoff valve chamber in the distance direction, and a check valve spring is arranged between the reset rod and the check valve body to close and press the check valve body. A click stop device is interposed between the reset lever and the dynamic support hole, and the reset lever is configured to be switchable and movable between a reset position approaching the shutoff valve chamber and a shutoff position moving away from the shutoff valve chamber. When the rod has advanced to the reset position, the inner end surface of the reset rod comes into contact with the leg of the shutoff valve body due to the position holding force of the click stop device, and the shutoff valve body is moved to the open position against the shutoff valve spring. While being pressed and held, the outer end surface of the reset rod moves back to a position where it does not protrude outside the sliding support hole, and when the reset rod is retracted to the shutoff position, the inner end surface of the reset rod moves the shutoff valve body to the open position. The reset rod is characterized in that it is configured so that it is no longer pressed and the outer end surface of the reset rod advances to a position protruding outside the sliding support hole.

Hereinafter, embodiments of the present invention will be described based on the drawings.

Figure 1 shows the dry flashback preventer during forward flow (normal state)
Figure 2 is a vertical cross-sectional view when a flashback occurs, and this dry type flashback preventer has a cylindrical flashback preventer main body 1 with one end open, and gas is led out to a peripheral wall 2 of the flashback preventer main body 1. A gas outlet pipe connecting portion 4 with a hole 3 provided therethrough is provided protrudingly, and a cutoff valve holder 5 is fitted and fixed to the open end of the flashback preventer main body 1 to form a flashback prevention chamber 6 in the flashback preventer main body 1. A cylindrical flame extinguisher 7 made of a porous material such as sintered metal is disposed within the flashback prevention chamber 6.

The cutoff valve holder 5 is formed into a bottomed cylindrical shape with a flange whose central portion protrudes into the inside of the flame extinguisher 7. A gas introduction nozzle 10 having a gas introduction hole 9 formed through the opening 8 of the cutoff valve holder 5 is fitted and fixed to form a cutoff valve chamber 11 in the cutoff valve holder 5. is forming.

A nozzle presser 12 is fitted and screwed into the open end of the flashback preventer main body 1.
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 body sliding hole 13 is transparently provided in the center of the inner end wall of the cutoff valve holder 5, and a cutoff valve seat 14 is formed in the surrounding wall of the opening of the cutoff valve body sliding hole 13 on the side of the cutoff valve chamber 11. is formed. A cutoff valve body 15 is disposed in the cutoff valve chamber 11 with a leg portion 15a of the cutoff valve body sliding hole 13.
The shutoff valve body 15 is housed in a state where it can slide forward and backward inside the valve body, and the shutoff valve body 15 is elastically biased toward the valve closing side by a shutoff valve spring 16 installed between the shutoff valve body 15 and the gas introduction nozzle 10.

The end of the gas introduction hole 9 on the cutoff valve chamber side is connected to the cutoff valve chamber 11.
The tip of the nozzle inner cylindrical portion 17 that protrudes into the interior opens toward the shutoff valve body 15, and gas holes 18 open in the radial direction on the peripheral wall of the proximal portion of the nozzle inner cylindrical portion 17 for gas ventilation. By forming a large cross-sectional area,
It is designed to reduce gas flow resistance.

A gas communication hole 19 is recessed from the flashback prevention chamber 6 side in the leg portion 15a of the cutoff valve body 15.
The shutoff valve chamber 11 is connected to the through hole 20 provided in the circumferential wall of 5a.
and the flashback prevention chamber 6 are configured to be able to communicate with each other through a gas communication hole 19.

A check valve seat 21 is formed at the end of the gas communication hole 19 on the side of the flashback prevention chamber 6, and a check valve body 22 is positioned opposite to the check valve seat 21. The leg portion 22a of the check valve body 22 is inserted into a gas communication hole 19 formed in the cutoff valve body 15 so as to be able to move forward and backward.
A check valve spring 24 installed between the valve 3 and the valve 3 is elastically biased toward the valve closing side. The check valve body 22 is opened against the check valve spring 24 by the inflow gas pressure acting on the gas communication hole 16.

Flashback preventer body 1 facing shutoff valve holder 5
A reset rod holder 26 is fixed penetratingly to the end wall 25 of the reset rod holder 26, and a reset rod 23 is fitted into the reset rod holder 26 so as to be slidable forward and backward. A click stop device 29 consisting of a ball 27 and a spring 28 is attached to a portion near the outer end of the reset rod 23. By fitting the ball 27 of the top device 29, the outer end of the reset rod 23 is connected to the reset rod holder 2.
The reset rod holder 26 is configured to maintain its posture at a reset position where it does not protrude from the outer end surface of the reset rod holder 26 and at a cutoff position where the outer end protrudes from the outer end surface of the reset rod holder 26.

The click stop device 29 is configured such that the spring 29 has a locking force slightly larger than the resultant force of the shutoff valve spring pressure, the check valve spring pressure, and the fluid pressure flowing into the flashback prevention chamber at the reset position. The spring pressure is set.

When the reset rod 23 is at the reset position, the inner end surface of the reset rod 23 is aligned with the shutoff valve body 1.
5 is pressed against the cutoff valve spring 16 to maintain the cutoff valve chamber 11 and the flashback prevention chamber 6 in a communicating state.

In the dry flashlight constructed as described above, under normal conditions, the cutoff valve body 15 is opened by the reset rod 23, and the check valve body 22 is pushed open by the gas pressure flowing in from the gas introduction hole 9, so that the gas is released. The gas flows out from the gas outlet hole 3 via the shutoff valve body 11, the flashback prevention chamber 6, and the flame extinguisher 7.

When a flashback occurs, the backflowing flame is extinguished by the flame extinguisher 7 as it flows in from the gas outlet 3, and the explosion pressure flowing into the flashback prevention chamber 6 shuts off the reset rod 23 from the reset position. position, and operates the shutoff valve body 15 to open the shutoff valve chamber 11.
communication with the backfire prevention chamber 6 is cut off. Shutoff valve body 1
5 is closed, gas pressure no longer acts on the gas communication hole 19, so the check valve body 22 also closes.

Note that this flashback preventer operates not only when a flashback occurs, but also when abnormal pressure is generated within the flashback preventer, the reset rod 23 is activated by the pressure, and the shutoff valve body 15 is activated.
is activated and cuts off the gas supply.

As described in detail in the embodiments above, the dry flashback device of the present invention allows the gas to flow from the inside of the flame extinguisher to the outside during forward flow, and to one side of the inside of the flame extinguisher inside the flashback prevention chamber. A shutoff valve chamber is formed, a shutoff valve body is placed in the shutoff valve chamber, and the check valve body is brought into contact with the end of the shutoff valve body on the side of the flashback prevention chamber. Since both valves of the check valve body are housed in the space within the flame-extinguishing cylinder, the flashback preventer can be made compact.

Further, the shutoff valve body is urged to close through the shutoff valve body sliding hole formed in the shutoff valve holder that partitions the shutoff valve chamber and the flashback prevention chamber, and is opposed to the shutoff valve holder of the flashback prevention chamber. The reset rod is inserted into the sliding support hole formed in the wall so that it can slide in and out, and the reset position is set at the inner end surface of the reset rod to open the shutoff valve body against the shutoff valve spring. Since the end face is configured to be able to maintain its position between the shutoff position and the shutoff position where it is separated from the shutoff valve body, in the event of flashback or an abnormal pressure rise within the flashback preventer, the reset rod will protrude from the sliding support hole and prevent the abnormality. The occurrence of flashback can be easily confirmed from the outside, and by pushing in the reset rod, the flashback preventer can be reset without disassembling it.

Furthermore, in the present invention, the nozzle holder is internally fitted into the assembly opening of the flame extinguishing tube, etc. of the flashback preventer body, and the cutoff valve holder, etc. is positioned and fixed, so a special tool is required to disassemble it. This makes it difficult to disassemble the flashback preventer at the site of use, etc.
Settings such as sealing performance and operating pressure will not be destroyed, operation will be accurate, and safety will be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal sectional view in a normal use state, and FIG. 2 being a longitudinal sectional view in the event of an abnormality. 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 tube, 10...Gas introduction nozzle, 12...Nozzle holder, 13...Shutoff valve body sliding hole, 14...Shutoff valve seat, 15...Shutoff valve body , 15a... Leg portion of 15, 16... Shutoff valve spring, 19... Gas communication hole, 20... Through hole, 21...
... Check valve seat, 22 ... Check valve body, 23 ... Reset rod, 24 ... Check valve spring, 29 ... Click stop device, 30 ... Sliding support hole.

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 cutoff valve body sliding hole 13 is transparently provided in the inner end wall of the cutoff valve chamber 11. A cutoff valve seat 14 is formed on the circumferential wall of the cutoff valve chamber side opening of the cutoff valve chamber 13, and a cutoff valve body 15 is accommodated in the cutoff valve chamber 11 in a state in which its legs 15a can freely slide forward and backward within the cutoff valve sliding hole 13. The shutoff valve body 15 is pressed toward the valve closing side by a shutoff valve spring 16 installed between it and the gas introduction nozzle 10, and a gas communication hole 19 is formed inside the shutoff valve body 15 from the backfire prevention chamber 6 side. The cutoff valve chamber 1 is formed by a through hole 20 formed in the leg portion of the cutoff valve body 15 and provided through the leg peripheral wall of the cutoff valve body 15.
1 and the flashback prevention chamber 6, a check valve seat 21 is formed at the end of the gas communication hole 19 on the side of the flashback prevention chamber. body 2
2, a sliding support hole 30 is formed in the end wall of the central space inside the flame extinguishing cylinder 7 of the flashback prevention chamber 6 on the side opposite to the shutoff valve chamber 11, and a reset rod 23 is inserted into the sliding support hole 30. The check valve spring 24 is inserted between the reset rod 23 and the check valve body 22 to press the check valve body 22 toward the closing side. A click stop device 29 is interposed between the reset rod 23 and the sliding support hole 30, and the reset rod 23 is moved to a reset position approaching the shutoff valve chamber 11 and a shutoff position moving away from the shutoff valve chamber 11. When the reset lever 23 is moved forward to the reset position, the inner end surface of the reset lever 23 presses against the leg 15a of the shutoff valve body 15 due to the position holding force of the click stop device 29. The shutoff valve body 15 is pressed and held in the valve open position against the shutoff valve spring 16, and the outer end surface of the reset rod 23 is pushed into the sliding support hole 3.
When the reset rod 23 is retracted to the position where it does not protrude outward, and the reset rod 23 is retracted to the shutoff position, the inner end surface of the reset rod 23 no longer pushes the shutoff valve body 15 to the open position, and the outer end surface of the reset rod 23 2. A dry type flashback preventer characterized in that the device is configured such that the flashback preventive device is configured such that it extends to a position where it projects outside the sliding support hole 23.