JPH0318086B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a backflow and flashback emergency automatic stop device installed in the middle of gas equipment piping to attenuate the shock waves that propagate when backflow and flashback occur, and to diffuse and extinguish the flashback flame. The present invention relates to a gas backflow and flashback emergency automatic stop method that removes carbon particles generated when a flashback occurs, and then closes the inlet hole of the main body case of the stop device to block the path of high-pressure backflow gas.

There have been various types of safety devices in the event of abnormal combustion in gas equipment that uses flammable gases such as acetylene, hydrogen, and methane for welding, cutting, thermal spraying, heating, etc. However, one such device is disclosed in Japanese Patent Application Laid-Open No. 146334/1982, which functions to both reverse flow and backfire of the gas. This device works effectively against both gas backflow and flashbacks, but if abnormal combustion is repeated in the gas equipment piping, carbon particles will adhere to the inside of the device, which is especially important for this device. If even the slightest amount of carbon particles adheres to the inlet valve, which is an important component of the inlet valve, it becomes difficult for the inlet valve to operate smoothly, making it difficult for the inlet valve to fully perform its function of preventing backflow of gas. There was a problem.

The present invention was invented with the aim of improving these problems. In the present invention, in order to solve these problems, the carbon particles that have entered the device are removed by a cylindrical filter built into the main body case of the device. The valve is characterized by ensuring smooth operation at all times.

The details of the method for automatically stopping gas backflow and flashback emergency according to the present invention will be further explained based on the stopping device.

Figure 1 shows an overall explanatory diagram of the equipment for gas welding, etc., which is equipped with a backflow of gas and a backfire emergency automatic stop device, and Figure 2 shows a diagram of the gas collecting piping system. There is. As shown in the figure, this stop device 3 is installed near the outlet of the gas cylinders 1, 1a, 1b or in the middle of the piping, and when abnormal combustion occurs in the blowpipe 2 etc. and backflow of flammable gas or flashback occurs,
This stop device 3 automatically shuts off the path of backflow gas.

FIG. 3 shows an internal cross-sectional view of this stopping device. Here, the main body case of this device is divided into an inlet side case 4 and an outlet side case 4a, and these are screwed together to form an integral body.
A gas flow path is provided through the interior of the main body case, and both ends of this flow path are used as an inlet hole 12 and an outlet hole 12a, and threaded portions 5, 5a for connecting to gas equipment piping are provided on the outer periphery of each end. In addition, an inlet valve 6 is provided in the inlet hole 12 of the gas flow path inside the main body case.
An outlet valve 6a is provided at the outlet hole 12a, and a filter unit 7 is provided between the inlet hole 12 and the outlet hole 12a of the gas flow path.
are installed inside each of them. Furthermore, the exit side case 4
A has a screw hole 8 for attaching a valve locking body, which will be described later, and a stopper hole 10 at the bottom 9 of this screw hole 8.
A gas escape hole 11 is provided. In addition, the inlet valve 6 opens the inlet hole 12 when gas pressure is applied to the inlet side A from the gas cylinders 1, 1a, etc., and gas pressure in the opposite direction occurs due to backflow of gas, backfire, etc. That is, when gas pressure is applied from the outlet side B, the inlet hole 12 is closed. In the illustrated embodiment, a substantially cylindrical body with one end closed is partially inserted into the inlet hole 12, and a plurality of gas inflow holes 16, for example, are formed in a circumferential manner on the outer periphery. An annular closing member 13 such as a rubber O-ring is provided in one or two stages to improve the sealing performance of the inlet valve 6, and when a normal gas inflow pressure is applied behind the inlet valve 6, the inlet valve 6 opens. A resilient body 14 made of a spring or the like having a resilient force sufficient to bring about this state is disposed in contact with the resilient body 14 . Note that the closing member 13 is the inlet valve 6
This closure member 13 is provided to improve the sealing performance and prevent gas leakage, and there is no need to necessarily use this closure member 13. Further, when two O-rings are used side by side as shown in the figure, the sealing performance of the inlet valve 6 can be further improved compared to when one O-ring is used.

Next, the outlet valve 6a is normally temporarily locked by the valve locking body 19, leaving the outlet hole 12a in an open state, and gas freely passes through the outlet hole 12a, but when backflow or flashback occurs. When high-pressure backflow gas pressure acts near the outlet valve 6a, the temporarily locked state is released, and the outlet valve 6a has sufficient elastic force to resist the shock waves and backfire that occur during backflow and backfire. The outlet hole 12a is closed by the action of an elastic body 15, such as a spring having a spring. In the illustrated embodiment, the tapered outlet hole 12a is formed into a tapered shape that allows the tip to come into close contact with the outlet hole 12a, and an inlet valve is provided at the tip if necessary. A closing member 13a similar to 6 is attached, and a gas flow hole 16 is attached to the rear of the tip.
For example, a plurality of cylindrical bodies 17 are formed in a circumferential manner, and an elastic body 15 such as a spring is incorporated inside the cylindrical body 17 that is continuous with the tip of the cylindrical body 17. A recess 18 is provided. This valve locking body 19 has a function of temporarily locking the outlet valve 6a, and in the illustrated embodiment, a stopper 21 is pressed by an elastic body 20 such as a spring.
Attach the valve locking body case 22 with the valve locking body case 22 inside the screw hole 8 of the outlet side case 4a so that the inside of the case 22 communicates with the gas escape hole 11 in the bottom part 9 of the screw hole 8, and connect the shaft part 21a of the stopper 21 to the outlet valve. It is shown fitted into the recess 18 on the outer periphery of 6a. Furthermore, in the illustrated example, an opening 23 for blowing gas is formed in the upper part of the valve locking body case 22 in order to make the operation of the stopper 21 smoother.
A cap 2 has an opening 28 at the top, on which a pusher 25 having a packing material 24 is placed, and is pressed by an elastic body 26 such as a spring.
7 is installed. The filter unit 7 prevents carbon particulates from adhering to the inlet valve 6 and maintains smooth operation at all times, and also attenuates shock waves and back flames that enter the main body case in the event of backflow or backfire. It diffuses and extinguishes inflammation. And this filter unit 7
A cylindrical filter 30 made of a sintered alloy has a continuous through hole so as to cover a gas passage hole 32 formed in a substantially cylindrical filter case 29, and the wall thereof crosses the gas flow path, and A gas flow path communicating with the inlet hole 12 is formed between the outer periphery and the main body case. Here, if necessary, if a cylindrical flow obstruction pipe 33 is loosely fitted between the cylindrical filter 30 and the case 29, the backflow gas can be directly passed through the cylindrical filter 30 from the passage hole 32 at the time of backflow or flashback. The water does not flow toward the cylindrical filter 30, but is dispersed and spread on both sides by the flow obstruction pipe 33 and flows into the entire cylindrical filter 30. For this reason, the gas flow path becomes a maze, and the cylindrical filter 3
The zero through holes can prevent backflow and flashbacks, attenuate shock waves during backflow and flashbacks, and diffuse and extinguish flashback flames. Due to the characteristics of this device, the cylindrical filter 30 is made of impact-resistant and fire-resistant sintered alloy that can withstand generated shock waves and back flames, such as stainless steel, nickel, chrome, etc.
Examples include sintered metals such as titanium materials.
In addition, it is effective to arrange the filter 31 inside the filter case 29 as necessary, and if a fibrous stainless steel material or the like is used, it will particularly attenuate propagated shock waves and prevent back flames. Effective in spreading and extinguishing inflammation.

In such a stop device 3, combustible gas from the cylinders 1, 1a, etc. as a gas supply source is normally transferred from the gas inlet hole 16 to the device by pushing the inlet valve 6 with the gas inflow pressure to open the inlet hole 12. flowing into the
The gas passage hole 3 passes through the cylindrical filter 30.
2. The gas passes through the gas outlet hole 16a and flows out through the open outlet hole 12a.

On the other hand, when backflow or flashback occurs due to abnormal combustion, that is, when the gas pressure becomes higher on the outlet side B than on the inlet side A, the gas body flows backward in the opposite direction to the above-mentioned flow, and from the outlet valve 6a. As it flows towards the inlet valve 6, the pressure of the gas itself acts behind the inlet valve 6 and as a result automatically closes the inlet hole 12. Furthermore, even if carbon particles generated as a result of flashback enter the device 3 when the gas flows back into the device 3, they are removed by the cylindrical filters 30 and 31. It has no impact.

In addition, when backflow of gas or flashback occurs,
Generally, there is a discrepancy in the propagation speed of the shock wave caused by a flashback and the flashback flame, and the shock wave first reaches the outlet hole 12a in the open state from the exit side B, and the
At the same time when the gas enters the outflow hole 16a of
1, the shock wave acts on the lower surface of the stopper 21 in the valve locking body 19, pushes up the stopper 21, and releases the locked state of the outlet valve 6a. Then, the outlet valve 6a strongly closes the outlet hole 12a by the force of the elastic body 15, and confines the high-pressure backflow gas between the inlet valve 6 and the outlet valve 6a, that is, inside the main body case. 6a is pressed outward, the inlet hole 12 and the outlet hole 12a are closed, thereby blocking the path of the subsequent backflow gas.

Furthermore, even if there is a flashback that enters the device 3 through the outlet hole 12a before the stopper 21 is activated, the shock wave and flashback flame are attenuated, diffused, and extinguished by the cylindrical filters 30 and 31. Carbon fine particles contained therein are also removed. Therefore, the inlet valve 6 is always protected from carbon adhesion by the cylindrical filters 30 and 31, and the valve function is not deteriorated.

The stopper 21 activated by this backfire can be reused by pushing the outlet valve 6a into the device 3 with a shaft or the like from the outlet side B, engaging the recess 18 of the outlet valve 6a again. Moreover, this device 3 can be used for a long period of time by disassembling the inlet side case 4 and the outlet side case 4a and cleaning them regularly, and by replacing the cylindrical filter 30 and filter 31. can do.

Incidentally, a triggering body 1 that triggers the inlet valve 6 and the outlet valve 6a
4 and 15 are provided separately, so if you select and use one with an elastic force that can be adapted to the target gas pressure, the operation of the inlet valve 6 and outlet valve 6a can be ensured. It is effective for

In the present invention as described above, the inlet valve 6 provided in the inlet hole 12 of the main body case of the stop device 3 smoothly receives the inflow of flammable gas under normal gas inflow pressure, and also prevents backflow and backfire. At this time, the inlet hole 12 in the main body case is closed by the inlet valve 6 using high gas backflow pressure to cut off the path of the backflow gas. At this time, the shock wave and back flame are filtered through the cylindrical filter 30.
The flame is attenuated, diffused, and extinguished by the flame. Furthermore, since a cylindrical filter 30 is provided in the gas flow path in the main body case between the inlet valve 6 and the outlet valve 6a so that its wall crosses the gas flow path, carbon particles generated due to flashback can be prevented. can be reliably adsorbed by this cylindrical filter 30, and these carbon particles can be prevented from affecting the operation of the inlet valve 6.

[Brief explanation of the drawing]

Fig. 1 is an overall explanatory diagram of equipment such as gas welding equipped with a device used for the automatic backflow and flashback emergency stop method of the present invention, Fig. 2 is a diagram of the gas collecting piping system, and Fig. 3 is a diagram of this equipment. It is a cross-sectional explanatory view of a stop device. 1, 1a, 1b: gas cylinder, 3: stop device,
6: Inlet valve, 6a: Outlet valve, 7: Filter unit, 11: Gas escape hole, 12: Inlet valve, 12a:
Outlet valve, 13: Closure member, 14: Bullet body, 15:
Bullet body, 21: Stopper, 29: Filter case, 30: Cylindrical filter, 31: Filter, 32: Gas passage hole, 33: Flow obstruction pipe.

Claims (1)

[Claims] 1 Under normal gas supply conditions, the inlet hole 1 of the main body case of the device 3 stops the flammable gas supplied to the supply destination.
2, the inlet valve 6 provided in the inlet hole 12 is biased from the inside of the main body case, and the gas inflow pressure is used to open the inlet valve 6, allowing the gas to flow into the main body case, and then the continuous valve 6 provided by penetrating the inside of the main case. When a backflow or flashback occurs, shock waves and flashback flames that enter the main body case from the outlet hole 12a are discharged through the gas flow path from the outlet hole 12a on the opposite side to the inlet hole 12 of the gas flow path. By passing through the wall of a cylindrical filter 30 made of sintered alloy, which is installed in the gas flow path in the case so that the wall crosses this gas flow path, it attenuates, diffuses, and extinguishes the flame, and also prevents backfire. The carbon particles generated when generated are adsorbed by a cylindrical filter 30, and then the inlet valve 6 is pressed from behind by the increasing pressure inside the main body case to close the inlet hole 12 and cut off the path of backflow gas. Backflow of gas body, backfire emergency automatic stop method.