KR20160120420A

KR20160120420A - Back Fire Preventing Device having a Temperature Sensing Closing Valve

Info

Publication number: KR20160120420A
Application number: KR1020150049377A
Authority: KR
Inventors: 강의창
Original assignee: 주식회사 불불
Priority date: 2015-04-08
Filing date: 2015-04-08
Publication date: 2016-10-18
Also published as: KR101761904B1

Abstract

The present invention relates to a backfire preventing device including an overheating detecting closing valve. The backfire preventing device includes: a body unit having a thread on the outer circumference of both ends and a gas supply path penetrated in the longitudinal direction; a check valve unit installed on an inlet of the gas supply path to allow gas to flow inside from the inlet of the gas supply path and prevent the gas from being leaked; and the overheating detecting closing valve installed on an outlet of the gas supply path to close the gas supply path in overheating due to backfire. The backfire preventing device can close the gas supply pipe using high pressure in the overheating caused by the backfire. The backfire preventing device can minimize the degradation of a check valve spring due to the backfire and, therefore, can minimize the degradation of flow path blocking performance of a check valve.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a back-

The present invention relates to an anti-backlash device having an overheat detection shut-off valve, and more particularly, to an anti-backlash device having an overheat detection shut-off valve, capable of closing a gas supply line with high pressure at the time of overheating by back- To an anti-backlash device having an overheat detection shut-off valve, which can minimize the deterioration of the check valve spring.

Generally, a gas cutting torch is used to melt-cut steel materials such as steel plates and steel frames. The gas cutting torch uses oxygen gas and acetylene gas, and backflushing often occurs during the cutting operation.

Backflushing is a phenomenon in which the flame generated when the mixing rate of the gas mixture of oxygen and gas is smaller than the burning rate of the mixed gas is reversed. When this backflushing occurs, the gas cutting torch is overheated, which can cause burns on the hands of the operator, and there is a danger of a large explosion if the flame is backed up to the gas cylinder due to backflushing.

As a countermeasure against this, a backfire prevention device is installed and used in a gas cutting torch and the like. As an example of the technology related to this backfire prevention device, a backfire prevention check valve has been proposed in the following patent document 1, 2, an 'anti-backfire device having a plug integrally' has been proposed. In the following Patent Document 3, an 'automatic backfire prevention device' has been proposed. In the following Patent Document 4, a 'backfire prevention device' has been proposed In the following Patent Document 5, a backfire prevention coupler has been proposed.

Korean Patent Publication No. 10-2003-0046050 (published on October 10, 2003) Registered Utility Model No. 20-0379588 of the Republic of Korea (Announcement Date: March 24, 2005) Korean Registered Patent No. 10-0822635 (Publication date Apr. 16, 2008) Registered Utility Model No. 20-0450037 of the Republic of Korea (Published on August 31, 2010) Korean Registered Patent No. 10-1289980 (Published on July 26, 2013)

Patent Document 3 proposes an automatic backfire prevention device capable of effectively preventing backflow of gas due to explosion pressure at the time of backfire and effectively dispersing backfire flames, A method of regulating a pressure is not possible at all in the case of occurrence of an abnormal pressure at the time of gas supply, hunting or pressure drop, and when the safety film is broken, the safety film must be replaced after the operation is stopped.

The conventional backfire prevention devices disclosed in Patent Documents 1 to 5 are all disposed in the direction in which the backward direction of the spring of the check valve is propagated. Even when the backfire is blocked by the anti-fouling filter or the like before reaching the spring of the check valve, Is heated to a high temperature by the high-temperature gas and is deteriorated, the elastic force is lowered, and the gas supply pipe can not be closed with sufficient pressure.

Especially, the spring used in the check valve of the conventional backfire prevention device can not make the elastic force to be higher than a certain level so that the low-pressure gas can overcome the deflection force of the check valve spring and can be supplied to the gas supply pipe. When the spring is heated and deteriorated at a high temperature and the elastic force is lowered, there is a disadvantage in that the ability to block the flow path of the check valve is significantly lowered.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide an overheat detection shutoff valve that can close a gas supply pipe with high pressure during overheating by backfire, Which is provided with an overheat detection shut-off valve.

According to an aspect of the present invention, there is provided a backfire prevention device having an overheat sensing shutoff valve, comprising: a body portion having a thread formed on an outer peripheral surface of both ends thereof and having a gas supply path penetrating the inside thereof in the longitudinal direction; A check valve unit provided on an inlet side of the gas supply path to allow a gas to flow from an inlet of the gas supply path and to prevent the gas from flowing out; And an overheating sensing / closing valve portion provided on an outlet side of the gas supply passage so as to close the gas supply passage at the time of overheating due to backfire.

Here, the body portion may include: a joint pipe fixing jaw portion formed on an inner side surface of an end portion of the gas supply passage on an inlet side; A first step formed at a central portion of the gas supply path; And a decontamination element fixing step portion formed on an inner surface of an end portion of the gas supply path on the side of the outflow port, wherein the overheat detection shutoff valve portion has a flange portion formed at one end portion to be contacted with and fixed to the fixed element portion, And the other end of the coupling shaft is coupled to the center of the coupling shaft; A closed valve head fixed to the connection shaft so as to be disposed between the decontamination element and the first step portion and having a closed valve packing at the outer periphery of one end thereof; A spring supporting plate disposed between the first step portion and the joint pipe fixing jaw portion and having a plurality of through holes formed in a circumferential direction around the connecting shaft fixed to the center portion with the other end portion of the connecting shaft fixed at a central portion; And a closing valve spring installed between the first stepped portion and the spring support plate such that the connection shaft receives a biasing force in a direction in which the closed valve head is in contact with the first stepped portion, The coupling between the decontamination element and one end of the coupling shaft is released, and one end of the coupling shaft is separated from the decontamination element.

Here, the check valve unit may include a guide part guiding one end of the check valve to slide along the gas supply path, a plurality of gas flow holes formed on the outer circumference of the central part, A check valve head having a check valve packing at an outer periphery of the other end in contact with a second step portion of the joint pipe inserted into the end portion of the inlet port; And a check valve spring installed between the spring support plate and the check valve head to receive a biasing force in a direction in which the check valve head is brought into contact with the second stepped portion.

Here, the check valve spring has an elastic force such that the check valve head is spaced from the second step portion by the supply pressure of the gas supplied to the inlet of the gas supply path so that the gas can flow into the check valve head, Wherein the spring is biased by the supply pressure of the gas such that the closing valve head is brought into contact with the first stepped portion by releasing the engagement between the subsidiary element and the connecting portion of the connecting shaft, And has an elastic force not to be separated from the step portion.

Here, the decontamination element may be manufactured by press-sintering any one selected from brass particles and stainless particles at a high temperature.

Here, one end of the subsidiary element and the connection shaft may be joined together by thermoplastic resin adhesive or brazing, or may be coupled by a snap ring of a thermoplastic resin material.

According to the backfire prevention apparatus having the overheat detection shutoff valve according to the present invention, the overheat detection shutoff valve can be provided to close the gas supply pipe with high pressure when the overheat due to backfire is provided.

Further, deterioration of the check valve spring due to occurrence of backfire can be minimized, so that the deterioration of the flow path blocking ability of the check valve can be minimized.

Further, even when the check valve spring is deteriorated due to backfire and the flow path can not be blocked by the check valve, the effect of closing the gas supply pipe with high pressure by the overheat detection close valve is obtained.

FIG. 1 is a cross-sectional view showing an internal configuration of a backfire prevention device having an overheat detection shut-off valve according to the present invention,
FIG. 2 is a cross-sectional view illustrating a state where a gas is supplied to a gas supply path in a backfire prevention device having an overheat detection shut-off valve according to the present invention;
Fig. 3 is a cross-sectional view showing a state in which the gas supply passage is closed by releasing the coupling between the subsidiary portion of the subsidiary portion of the connection shaft and the decontamination element;
FIG. 4 is a view showing a state where a backfire prevention device having an overheat detection shut-off valve is installed in a gas supply pipe of a gas cutter,
5 is a side view of a gas cutter equipped with an anti-backfire device having an overheat shut-off valve according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the present invention is not limited to the embodiments.

Hereinafter, the configuration of the backfire prevention device 1 having the overheat detection shutoff valve according to the preferred embodiment of the present invention will be described.

FIG. 1 is a cross-sectional view illustrating an internal configuration of a backfire prevention device having an overheat sensing shutoff valve according to the present invention.

The backfire prevention device 1 having the overheat sensing shutoff valve according to the present invention includes the body 10, the overheat sensing shutoff valve 20, and the check valve 30.

The body 10 has an outer shape and a skeleton of the backfire prevention device 1 having the overheat detection shutoff valve according to the present invention and has a shape substantially like a cylindrical tube. And the other end is coupled with and joined to the joint pipe 50 by the fastening member 60 so that the gas supply pipe 941 is connected to the gas supply pipe 941, .

A gas supply passage 12 penetrating in the longitudinal direction is formed inside the body portion 10, and a gas introduced into one end portion (an inlet port (right end portion of the body portion in FIG. 1) To the other end (outlet: the left end of the body in Fig. 1).

On the inner surface of the inlet side end portion of the gas supply path 12, a joint pipe fixing step 15 is formed. The end of the joint pipe 50 is caught by the joint pipe fixing jaw portion 15 when the end of the joint portion 50 on the inlet side of the body portion 10 is fastened to the joint pipe 50 by the fastening member 60, The second step portion 51 of the gas supply passage 12 can be disposed at the correct position in the gas supply passage 12. [

A first step 14 is formed at a central portion of the gas supply path 12 so as to be in close contact with the check valve head 310 of the check valve unit 30. More specifically, one side of the first stepped portion 14 is formed in a shape that can be brought into close contact with the check valve head 310, and a stepped portion is formed on the other side to which the closing valve spring 240 can be supported.

A decontamination element fixing step (13) is formed on the inner surface of the gas outlet side end of the gas supply path (12). The flange portion 211 of the decanter 210 can be caught by the decantering element fixing jaw portion 13 when the decantering element 210 is fitted inwardly from the outlet side end of the gas supply passage 12. [

The overheat detection shut-off valve unit 20 is a part that closes the gas supply path 12 at the time of overheating by backfire and is provided at the outlet side of the gas supply path 12 and includes a decontamination element 210, A valve head 220, a spring support plate 230, and a closing valve spring 240.

The decontamination element 210 is a part which functions to flow back the gas flow path and extinguish a flame which has reached the decontamination element 210. The decontamination element 210 is formed of a sintered metal having fine pores and a clearance, .

The flame retarding element 210 rapidly decreases the temperature of the flame reaching the barbiturizing element 210, which has a high thermal conductivity coefficient and is excellent in endothermic performance, thereby extinguishing the flame. For this purpose, the anti-microbial element 210 is preferably produced by pressing and sintering brass or stainless particles (diameter of 1 mm or less) at a high temperature.

A flange portion 211 is formed at one end of the decontamination element 210 so that the decontamination element 210 can be fixed while being fitted inward from the outlet side end portion of the gas supply path 12. [ The flange portion 211 is brought into contact with and fixed to the decantering element fixing jaw portion 13 when the auxiliary element 210 is fitted inwardly from the outlet side end portion of the gas supply path 12. [

One end of the connection shaft 40 is inserted into the central portion of the other end of the anti- However, when the anti-inflammatory element 210 is heated by backfire, the coupling between the anti-inflammatory element 210 and one end of the connection shaft 40 is released, and one end of the connection shaft 40 is separated from the anti-

To this end, one end of the subsidiary element 210 and the connecting shaft 40 may be joined together by a thermoplastic resin adhesive such as an ethylene-vinyl acetate copolymer (EVA) or soldering or by a snap ring or the like of a thermoplastic resin material It is preferable that they are coupled to each other.

The closing valve head 220 closes the gas supply path 12 by being brought into close contact with the first step portion 14 when one end of the connecting shaft 40 is disconnected from the decontamination element 210 by backfilling , And a closed valve packing (221) is provided on the outer circumferential edge of one end which is brought into close contact with the first step portion (14). The closed valve packing 221 is preferably made of a fluorine rubber material so as to prevent slippage and to prevent damage by flame. The closed valve head 220 is fixed to the connection shaft 40 so as to be disposed between the minor stage element 210 and the first step 14.

The spring support plate 230 is a member inserted into the gas supply path 12 so as to be movable in the longitudinal direction of the body 10 by the elastic force of the closing valve spring 240, And the spring support plate 230 fixed to the other end of the connection shaft 40 is disposed between the first step portion 14 and the joint pipe fixing step 15. [

A plurality of through holes 231 are formed in the spring support plate 230 in the circumferential direction around the connection shaft 40 fixed at the center of the spring support plate 230 so that a plurality of gas Through the through holes 231. [

The closing valve spring 240 is a member that applies a biasing force to the spring supporting plate 230 and the connecting shaft 40 in the direction in which the closing valve head 220 comes into contact with the first step portion 14, (14) and the spring support plate (230). 1, the closed valve spring 240 is installed between the first step portion 14 and the spring support plate 230 in a compressed state. Accordingly, the closed valve head 220, the connecting shaft 40, and the spring support plate 230 coupled to each other are biased in the direction in which the closed valve head 220 comes into contact with the first step portion 14.

With this configuration, when one end of the connection shaft 40 is separated from the anti-decaying element 210 by backfire, the closed valve head 220, the connection shaft 40, and the spring support plate 230, which are coupled to each other, The closed valve head 220 having the closed valve packing 221 is brought into close contact with the first step portion 14 to close the gas supply path 12. [

In the case of the conventional backfire prevention devices, the spring of the check valve is installed closer to the gas outlet side than the head of the check valve. That is, the spring of the check valve is disposed in the direction in which the backwashing is propagated. Even when the backwash is blocked by the anti-fouling filter before reaching the spring of the check valve, the spring of the check valve is heated to a high temperature by the high temperature gas The elasticity is deteriorated and the gas supply pipe can not be closed with sufficient pressure.

However, in the overheat sensing / closing valve portion 20 of the back fire prevention device 1 having the overheat sensing / closing valve according to the present invention, since the closing valve spring 240 is positioned closer to the gas supply passage 12 than the closing valve head 220, As shown in FIG.

Thus, the heat generated as the flame by backfire disappears by the decanter 210 will be affected by the closing valve spring 240 after being absorbed to some degree by the closing valve head 220 and the first step 14 The deterioration of the closing valve spring 240 can be minimized and the deterioration of the flow path blocking capability of the overheat detection closing valve portion 20 can be minimized compared to the conventional configuration.

On the other hand, in the closed valve spring 240, even when one end of the connecting shaft 40 is disconnected from the quenching element 210 by backfire and the gas supply passage 12 is closed, The second step portion 220 should be compressed so as to have an elastic force not to be separated from the first step portion 14. [

Therefore, even when the check valve spring 320 of the check valve unit 30, which will be described later, is heated to a high temperature and deteriorated to decrease the elastic force and can not close the gas supply path 12 due to the hot gas by backfire, The closed valve head 220 provided with the valve packing 221 can be brought into close contact with the first step portion 14 by the elastic force of the closing valve spring 240 to close the gas supply path 12.

The check valve spring 320 must have an elastic force such that the check valve head 310 to be described later can be separated from the second step portion 51 by the supply pressure of the gas, Must have an elastic force such that the closed valve head 220 is not separated from the first step portion 14 by the supply pressure of the gas. Therefore, it is preferable that the closed valve spring 240 be made to have a sufficiently strong elastic force in case the valve is heated to a high temperature by the hot gas due to the backfire and is deteriorated.

The check valve unit 30 is provided at the inlet side of the gas supply path 12 and functions as a stopper for allowing the gas to flow from the inlet of the gas supply path 12 and preventing the flow out of the gas supply path 12, 310 and a check valve spring 320.

The check valve head 310 is brought into close contact with the second step portion 51 when the pressure in the gas supply path 12 becomes higher than the gas supply pressure due to the low or reverse gas supply pressure, It is the function of closing.

One end of the check valve head 310 is formed with a guide part 311 which guides the check valve head 310 to slide along the gas supply path 12 while maintaining the arrangement direction thereof .

A plurality of gas flow holes 312 are formed in the outer periphery of the central portion of the check valve head 310. Therefore, when the check valve head 310 is separated from the second step portion 51 by the supply pressure of the gas, the gas is supplied to the inlet side of the gas supply path 12 through the plurality of gas flow holes 312 To the outlet side.

In addition, a check valve packing 315 is provided at the outer periphery of the other end of the check valve head 310.

The end portion of the joint pipe 50 is caught by the joint pipe fixing jaw portion 15 when the joint pipe 50 is fastened to the end of the body portion 10 at the inlet port side by the fastening member 60. In this joint pipe 50 are formed at the end of the check valve head 310 with a second stepped portion 51 having a shape close to the check valve head 310.

The check valve head 310 equipped with the check valve packing 315 is moved to the second step 51 (see FIG. 5) when the gas supply pressure is low or the backpressure causes the pressure in the gas supply path 12 to become higher than the gas supply pressure. So that the gas supply passage 12 is closed. The check valve seal 315 is preferably made of fluoro rubber so as to prevent slippage and to prevent damage by flame.

The check valve spring 320 is a member that applies a biasing force to the check valve head 310 in a direction in which the check valve head 310 comes into contact with the second stepped portion 51, (310).

The check valve spring 320 should have an elastic force such that the check valve head 310, which will be described later, can be separated from the second step portion 51 by the supply pressure of the gas. Accordingly, since the check valve spring 320 has a relatively weak elastic force, the check valve spring 320 is heated to a high temperature by the hot gas due to backfire and is liable to deteriorate in elasticity.

However, the check valve unit 30 of the backfire prevention apparatus 1 having the overheat detection shutoff valve according to the present invention is constructed such that the check valve spring 320 is connected to the quenching element 210 provided on the outlet side of the gas supply path 12 To the inlet side of the gas supply passage 12 remote from the gas supply passage 12.

Therefore, the heat generated as the flame by the back flushing is extinguished by the flushing element 210 is discharged by the closing valve head 220, the first step 14, the closing valve spring 240 and the spring supporting plate 230 The deterioration of the check valve spring 320 can be minimized and the deterioration of the flow path blocking ability of the check valve portion 30 can be minimized as compared with the conventional configuration .

Even when the check valve spring 320 is heated and deteriorated due to the high temperature gas caused by the backfire so that the elastic force is lowered and the gas supply path 12 can not be closed with sufficient pressure, The spring support plate 230 and the check valve head 310 are moved to the inlet side of the gas supply path 12 when the gas supply path 12 is closed by the sensing / The check valve spring 320 is further compressed, so that the check valve portion 30 of the lowered check valve portion 30 is reinforced.

Accordingly, it is possible to double-close the gas supply passage 12 in the overheat detection shut-off valve portion 20 and the check valve portion 30, so that the risk of explosion of the gas cylinder due to back- .

Hereinafter, a description will be made of a state in which the backfire prevention device 1 having the above-described structure according to the present invention is installed in the gas cutter 900.

FIG. 4 is a view showing a state in which a back fire prevention apparatus having an overheat sensing shutoff valve is installed in a gas supply pipe of a gas cutter, and FIG. 5 is a cross sectional view of a back fire prevention apparatus having an overheat sensing shutoff valve according to the present invention. Fig. 3 is a side view showing a gas cutter installed; Fig.

The gas cutter 900 includes a head 910, an oxygen gas supply pipe 920, a valve bundle 930 and a handle 940. The gas cutter 900 includes a back- The apparatus 1 is installed between the gas inlet pipe 941 inside the handle 940 and the gas inlet of the valve bundle 930.

A preheated oxygen supply pipe 921, a preheated gas supply pipe 922 and a cutoff oxygen supply pipe 923 are connected to one side of the bent head 910. A preheated oxygen supply pipe 921, a preheated gas supply pipe 922, And the cut oxygen supply pipe 923 supplies the incoming oxygen and gas from the valve bundle portion 930 to the head portion 910. [

The valve bundle portion 930 is a portion for supplying oxygen separately into preheated oxygen and cut oxygen and is provided with a preheating oxygen valve 931, a cutoff oxygen valve 932 and a preheating gas valve 933, A gas supply pipe 941 and an oxygen supply pipe 942 are coupled to one side of the gas supply pipe 930.

The gas supply pipe 941 and the oxygen supply pipe 942 are disposed inside the handle 940 and are provided outside the gas supply pipe 941 and the oxygen supply pipe 942, The handle cover 945 is provided.

The anti-backfire device 1 having the overheat detection shut-off valve according to the present invention is installed between the gas inlet of the valve bundle portion 930 of the gas cutter 900 of this basic configuration and the gas supply pipe 941.

That is, the outlet end side of the body portion 10 is fastened to the gas inlet of the valve bundle portion 930 and the end portion of the gas inlet pipe 941 is connected to the inlet side end portion of the body portion 10 by using the connecting pipe 50 . At this time, between the end on the inlet side of the body 10 and one end of the joint pipe 50, and between the other end of the joint pipe 50 and the end of the gas supply pipe 941 are fastened using the fastening member 60 .

In this way, the backfire prevention device 1 equipped with the overheat detection shut-off valve according to the present invention has an advantage that it can be easily installed and used on the flow path where gas is supplied even in a conventional gas cutter without the backfire prevention device .

Hereinafter, the operating states of the backfire prevention device 1 having the overheat detection shutoff valve according to the present invention will be described.

FIG. 2 is a cross-sectional view illustrating a state in which gas is supplied to the gas supply path in the backfire prevention device having the overheat sensing shutoff valve according to the present invention, FIG. 3 is a cross- Is closed and the gas supply path is closed.

FIG. 1 shows a state in which a gas cutter 900 is not used after the backflushing prevention device 1 equipped with the overheat detection shutoff valve according to the present invention is installed in the gas cutter 900. This state is a state in which the gas is not supplied, and the inlet side of the gas supply path 12 is closed by the check valve unit 30.

When the gas cutter 900 is used, as shown in FIG. 2, the check valve head 310 is separated from the second step portion 51 by the supply pressure of the gas, so that the gas is introduced. At this time, the overheat detection shutoff valve unit 20 is in a state in which the gas supply path 12 is not closed, and the gas is smoothly supplied through the backfire prevention apparatus 1 of the present invention.

3, the check valve unit 30 closes the gas supply path 12, and when the overheat is overheated, the overheat detection shut-off valve unit 20 is also closed to the gas supply path 12 Lt; / RTI >

The backfire prevention device having the overheat detection shutoff valve according to the present invention has an advantage that the gas supply pipe can be closed at a high pressure when the overheat due to backfire is provided by the overheat detection shutoff valve.

Further, deterioration of the check valve spring due to occurrence of backfire can be minimized, so that deterioration of the flow path blocking ability of the check valve can be minimized.

Further, even when the check valve spring is deteriorated due to backfire and the flow path can not be blocked by the check valve, there is an advantage that the gas supply pipe can be closed with a high pressure by the overheat detection close valve.

Further, since the gas supply passage can be closed at the overheat detection shut-off valve portion and the check valve portion, it is possible to minimize the risk of explosion of the gas cylinder due to backfire.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, such modifications or changes should be construed as being included within the scope of the present invention.

1: Backflushing device with overheat detection shut-off valve
10: body part 11:
12: gas supply path 13: decontamination element fixing jaw
14: first step 15: joint pipe fixing jaw
20: Overheat detection closing valve part
210: decontamination element 211: flange portion
220: Closing valve head 221: Closing valve packing
230: spring support plate 231: through hole
240: closing valve spring
30: Check valve section
310: check valve head 311: guide portion
312: Gas flow hole 315: Check valve packing
320: Check valve spring
40: connection axis
50: joint pipe 51: second step
60: fastening member

Claims

A body portion in which a thread is formed on an outer peripheral surface of both end portions and a gas supply path is formed through the body in a longitudinal direction;
A check valve unit provided on an inlet side of the gas supply path to allow a gas to flow from an inlet of the gas supply path and to prevent the gas from flowing out; And
And an overheat sensing shutoff valve provided on an outlet side of the gas supply passage so as to close the gas supply passage at the time of overheating by backfilling.

The method according to claim 1,
The body portion
A joint pipe fixing step formed on an inner surface of an end portion of the gas supply passage on the side of an inlet port;
A first step formed at a central portion of the gas supply path; And
And a decontamination element fixing step formed on an inner surface of an end portion of the gas supply passage on the side of the outlet,
The overheat detection shut-off valve unit includes:
A flushing element having a flange formed at one end thereof to be held in contact with and fixed to the fixed-element fixing pin, and one end of the connecting shaft being coupled to the center of the other end,
A closed valve head fixed to the connection shaft so as to be disposed between the decontamination element and the first step portion and having a closed valve packing at the outer periphery of one end thereof;
A spring supporting plate disposed between the first step portion and the joint pipe fixing jaw portion and having a plurality of through holes formed in a circumferential direction around the connecting shaft fixed to the center portion with the other end portion of the connecting shaft fixed at a central portion; And
And a closing valve spring installed between the first step portion and the spring supporting plate such that the connecting shaft receives a biasing force in a direction in which the closing valve head is in contact with the first step portion,
Wherein the connection between the decontamination element and one end of the connection shaft is released when the heat is overheated by the backflushing so that one end of the connection shaft is separated from the decontamination element.

3. The method of claim 2,
The check valve unit
A plurality of gas flow holes are formed in the outer periphery of the central portion, and a plurality of gas flow holes are formed in the outer periphery of the central portion in such a manner that the joints inserted into the inlet side end portions of the gas supply passages A check valve head having a check valve packing at the outer periphery of the other end in contact with the second step portion of the pipe; And
And a check valve spring installed between the spring support plate and the check valve head to receive a biasing force in a direction in which the check valve head is in contact with the second stepped portion, Backfire protection device.

The method of claim 3,
Wherein the check valve spring has an elastic force such that the check valve head is separated from the second step portion by a supply pressure of the gas supplied to the inlet of the gas supply path,
Wherein the closed valve spring is configured such that the closed valve head is closed by the supply pressure of the gas in a state in which the closed valve head is brought into contact with the first stepped portion, Wherein the elastic member has an elastic force not to be separated from the first step portion.

5. The method according to any one of claims 2 to 4,
Characterized in that the anti-flame element is manufactured by press-sintering any one selected from brass particles and stainless particles at a high temperature.

6. The method of claim 5,
The backfire prevention device with the overheat detection shut-off valve according to any one of the preceding claims, wherein one end of the subsidiary shaft and the subsidiary shaft are joined together by a thermoplastic resin adhesive or brazing or are coupled by a snap ring of a thermoplastic resin material.