JPS6321840Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is designed to prevent flames caused by backfire that may occur when performing gas welding, gas cutting, or gas heating using flammable gases such as acetylene gas or natural gas. This invention relates to a flashback preventer for preventing backflow accidents.

BACKGROUND ART Conventionally, water seal type flashback prevention devices and detour type dry flashback prevention devices have been widely used as flashback prevention devices.

Recently, dry flashback prevention devices have been developed as shown in Japanese Utility Model Application Publication No. 53-113231 and Japanese Utility Model Application Publication No. 55-135864.

Problems to be solved by the invention However, the above-mentioned water seal type flashback prevention device and detour type dry type flashback prevention device are both large and have drawbacks in terms of workability and safety. Jitsukai Showa 53-
Although the dry flashback prevention devices shown in Publication No. 113231 and Publication No. 135864 of 1983 are smaller in size, there is only one point where gas is cut off in the event of a flashback. The shut-off sealing material is easily damaged due to the severe sliding of the shut-off valve due to pressure, resulting in poor durability and low reliability in preventing flashback.

The present invention relates to a completely new technique developed in view of these conventional drawbacks.

Means for Solving the Problems The present invention provides a flashback preventer in which a piston, a main body, and a filter are built concentrically in an outer case, and a gas passage is provided between each of these members and each member. A pressure receiver is connected to the tip end of the cylindrical body, and a check valve is provided to the rear end of the cylindrical body, in which several stepped portions formed on the inner wall surface are tapered. This is a flashback preventer that includes a slidably built-in piston with a sealing material attached at a position corresponding to the surface.

Function As described above, the flashback preventer according to the present invention has a cylindrical main body with several tapered steps formed on the inner wall surface, a pressure receiver connected to the tip end, and a backfire prevention device at the rear end. A valve is provided, and a piston with a sealing material attached at a location corresponding to the tapered surface of the stepped portion of the main body is slidably built in, so in the event of backfire, the pressure receiver connected to the tip of the piston will By applying fire pressure and retracting the connected piston, it is possible to block the gas passage in the pressure receiver, sealing material, and check valve to stop the gas supply and prevent the reverse flame from flowing back. As the fire passes through the filter, it can be cooled and extinguished.

Therefore, since the gas passage can be blocked at multiple locations, backfire can be reliably and completely prevented.

Embodiment One embodiment of the present invention will be explained with reference to the drawings.
In the drawings and FIG. 2, reference numeral 1 denotes a cylindrical body built into an outer cylinder 4 consisting of a left case 2 and a right case 3, and has an annular groove 5 and a first taper 6 at predetermined positions on the inner wall surface. and a second taper 7 are provided, and the inner wall of the tip is formed wide with an annular step 8 interposed therebetween, and a gas passage hole 9 is bored in the step 8. Reference numeral 10 denotes a piston that can slide inside the main body 1, and has a gas passage hole 11 at the tip, a stop ring 12 on the outer periphery that can be fitted into the annular groove 5, and a stop ring 12 that can be fitted into the annular groove 5 at a predetermined position on the outer periphery of the central part. A sealing material 13 that can be brought into close contact with the first taper 6 of the main body 1 is attached to the main body 1 . Also, the piston 1
A check valve 15 biased by a spring 14 is fitted into the rear end of the check valve 15, and a check valve seal 16 that can be brought into close contact with the second taper 7 of the main body 1 is fitted at the rear end of the check valve 15. is installed. Next, reference numeral 17 is a pressure receiver built in so as to be able to slide inside the tip of the main body 1, and is connected to the tip of the piston 10, and in the event of backfire, it comes into close contact with the stepped portion 8 of the main body 1 to close the gas vent 9. It is possible. Also, a filter 18 for extinguishing back flame is attached to the outside of the main body 1 concentrically with the main body 1, and there are also filters 18 between the piston 10 and the main body 1, between the main body 1 and the filter 18, and between the filter 18 and the outer cylinder 4. Gaps are formed between them to form gas passages 19, 20 and 21, respectively. 22 and 23 are an O-ring and a seat, respectively, for maintaining airtightness, and 24 is a nut attached to the rear end of the right case 3.

To explain the operation of the flashback preventer according to the present invention configured as described above, under normal conditions, the piston 10, the pressure receiver 17, and the check valve 15 are in the front as shown in FIG. The inflowing gas flows through the passage 19, the through hole 11 of the piston 10, and
It passes through the through hole 9 of the main body 1, the passage 20, the filter 18, and the passage 21 in order and flows out from the left case 2,
It is supplied to the torch via a gas hose or the like connected to the tip of the left case 2.

Next, at the time of flashback, as shown in Figure 2, the flashback flame flows back from the left case 2 at a pressure higher than the gas inflow pressure (generally flashback pressure is approximately 80 times the gas inflow pressure). In order to press the pressure receiver 17, the pressure receiver 17 and the piston 10 move back inside the main body 1, and the pressure receiver 17 comes into close contact with the stepped portion 8 to close the gas passage hole 9. At the same time, the first taper 6 in the main body 1 is closed. The seal material 13 of the piston 10 and the check valve seal 16 of the check valve 15 come into close contact with the second taper 7, respectively, to block the gas passage 19. The backfire flame is cooled and extinguished as it passes through the gas passage 21 and the filter 18. Furthermore, when the piston 10 retreats, the stop ring 12 fits into the annular groove 5 of the main body 1, and the piston 10, check valve 15, and pressure receiver 17 are locked with the gas passages cut off, so that flashback pressure is reduced. The gas supply remains stopped even if the flame is attenuated, thereby preventing raw gas from flowing out after the flashback is extinguished.

If you want to supply gas again after the flashback has been extinguished, close the gas supply valve of the cylinder, etc., and insert the flashback preventer into the right case 3.
Reset pin 2 removed from the section and prepared separately
5 or the like to release the lock between the stop ring 12 and the annular groove 5, and at the same time, the piston 10, the check valve 15, and the pressure receiver 17
The gas passages can be opened by moving them forward.

Effects of the invention The flashback preventer according to the invention has the above-mentioned structure, and unlike the conventional technology, it has several gas cut-off points in the event of a flashback. Even if it is damaged, it can reliably and completely prevent backfire, has excellent durability, and is compact and lightweight as a whole, so it has excellent workability.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of the flashback preventer according to the present invention in normal operation, and FIG. 2 is an explanatory cross-sectional view during flashback. 1 is the main body, 4 is the outer cylinder, 6 and 7 are the tapers, 8 is the stepped portion, 9 and 11 are the through holes, 10 is the piston, 13,
16 is a sealing material, 15 is a check valve, 17 is a pressure receiver,
18 is a filter, and 19, 20, and 21 are passages.

Claims (1)

[Scope of utility model registration request] In a flashback preventer that has a piston, a main body, and a filter concentrically built into an outer case, and gas passages are provided between each of these members, several steps formed on the inner wall surface are used. A piston in which a pressure receiver is connected to the tip part and a check valve is provided to the rear end part in a cylindrical body with a tapered part, and a sealing material is attached to a position corresponding to the tapered part of the step part of the main body. A flashback preventer characterized by having a slidably built-in device.