JP4512384B2 - Dry backfire preventer - Google Patents

Description

  The present invention intervenes in an apparatus for supplying combustible gas or a supply path for pipes to prevent mixing of combustion-supporting gas at the time of backflow, and to prevent backfire propagation of combustible gas at the time of backfire. In addition, the present invention relates to a dry backfire preventer having a function of shutting off the supply of combustible gas, and more particularly to a backfire preventer when the combustible gas is hydrogen gas.

Conventionally, for example, Japanese Utility Model Publication No. 5-39280 discloses a flashback prevention device that blocks the propagation of flashback of combustible gas and blocks the supply of combustible gas.
As shown in FIG. 3, a flame extinguishing cylinder (52), a check valve body (53) and a shut-off valve body (54) are assembled in a backfire prevention chamber (51) formed in an airtight structure, and one end wall ( 56) is formed in an open shape in the case body (55), and the gas discharge nozzle (60) is fitted and fixed to form a backfire prevention chamber (51) in the case body (55). A shutoff valve holder (61) is fitted and fixed in the prevention chamber (51), and a flame extinguishing cylinder (52) is placed between the shutoff valve holder (61) and the inner surface of the back end wall (64) of the case body (55). The gas outlet port (59) is formed in the gas outlet nozzle (60), and the gas inlet port (58) is formed in the peripheral side wall (57) of the case body (55) corresponding to the arrangement position of the flame extinguishing cylinder (52). ), A shut-off valve chamber (62) is formed inside the extinguishing cylinder (52), and a check valve chamber (63) is formed on the gas outlet nozzle (60) side inside the shut-off valve holder (61). The shut-off valve body (54) constituted by a spool valve is fitted in the shut-off valve holder (61) so as to be movable forward and backward. In addition, the gas communication passage (65) formed between the shut-off valve holder (61) in the shut-off valve chamber (62) and the back end wall (64) of the case body (55) is blocked by the shut-off valve body (54). A check valve body that is configured to be capable of being mounted on the check valve chamber (63) by forming a check valve seat (66) at the end of the shut-off valve body (54) on the check valve chamber (63) side. (53) is elastically biased toward the check valve seat (66) by a check valve spring (67) installed between the gas outlet nozzle (60) and the rear end wall (64) of the case body (55). ) Slidably mount reset 対 向 (68) facing the shut-off valve body (54), and install the reset 杆 (68) between the back end wall (64) of the case body (55). The reset spring (69) was configured to be elastically biased in a direction away from the shut-off valve body (54).
Japanese Utility Model Publication No. 5-39280

  In the above-described dry type flashback device, at the time of forward flow, the check valve body is opened against the check valve spring with the gas pressure, and at the time of backfire, the check valve body is closed with the pressure at the time of the backfire. At the same time, the shut-off valve body is closed by a resultant force of the pressure at the time of backfire acting on the check valve body and the check valve spring force. At this time, since the reset rod does not contact the shut-off valve body, there is a problem that the operating state cannot be visually recognized from the outside.

  Also, when installed in the hydrogen gas supply line, the hydrogen gas becomes negative pressure after explosive combustion when the pressure before the explosion is small. In the backfire, both the check valve and shutoff valve may automatically return due to the pressure phenomenon after the backfire.

  The present invention pays attention to such points, and it is possible to easily recognize from the outside that the backfire preventive device is operating by detecting backfire, and the explosive combustion such as hydrogen gas. An object of the present invention is to provide a flashback prevention device that can reliably perform a flashback prevention operation even for a gas that is in a decompressed state later.

  In order to achieve the above-mentioned object, the present invention provides a dry flashback prevention device, wherein a gas lead-out nozzle is fitted and fixed in an opening of a case body whose one end wall is open, and a flashback prevention chamber is provided in the case body. A shut-off valve holder is fitted and fixed in the backfire prevention chamber, a flame extinguishing cylinder is disposed between the shut-off valve holder and the inner surface of the back end wall of the case body, and a gas outlet port is provided in the gas outlet nozzle. The gas inlet is formed in the peripheral side wall of the case body corresponding to the arrangement position of the extinguishing cylinder, the shut-off valve chamber is formed inside the extinguishing cylinder, and the gas outlet nozzle side in the shut-off valve holder is formed. A check valve chamber is formed, and a shut-off valve body constituted by a spool valve is fitted into the shut-off valve holder so as to be movable back and forth, and is formed between the shut-off valve holder in the shut-off valve chamber and the back end wall of the case body. The gas communication passage is configured to be closed with a shut-off valve body and shut off. A check valve seat is formed by a check valve spring that is formed between the check valve valve and the check valve body that is mounted on the check valve chamber by forming a check valve seat at the end of the body on the check valve chamber side. The leg part located on the far end side of the shut-off valve body is slidably mounted in the leg slide hole formed in the back end wall of the case body, and the leg of the shut-off valve body is The tip of the part is configured to be able to protrude from the case body to the outside during its operation, and a ball that makes contact with the peripheral surface of the leg part of the shut-off valve body is brought into contact with the meat wall part forming the leg part sliding hole of the case body In addition to being mounted so as to be able to change the pressure, the leg of the shut-off valve body is formed with a recess into which the ball is fitted when the shut-off valve is operated.

  In the present invention configured as described above, the forward gas pressure operates to open the check valve body against the check valve spring, and the reverse fire pressure is reversed by the resultant force of the spring pressure of the check valve spring. Since the stop valve body and the shutoff valve body are closed, the spring involved in the operation of the backfire preventer is only the check valve spring during both the forward flow and backfire. The backfire preventer can be operated with high accuracy only by increasing the accuracy.

  Since the forward gas pressure has no action to operate the shut-off valve body to the valve closing side, it can be used for gases with different pressures in a wide range from low pressure to high pressure just by changing the spring pressure of the biasing spring. .

  At the time of backfire, the backfire pressure propagating from the gas outlet port directly acts on the check valve without passing through the flame extinguishing cylinder, so the backfire pressure acts on the backfire prevention chamber without being weakened. As soon as this occurs, the check valve operates and the shut-off valve body can be closed.

  Since the ball configured to be able to adjust the contact pressure is brought into contact with the leg peripheral surface of the shut-off valve body, the operating pressure of the shut-off valve body can be adjusted.

  Furthermore, since the above-mentioned recess is formed in the leg portion of the shut-off valve body so that the ball is fitted when the shut-off valve is closed, the leg portion is separated from the case body after the valve closing operation. It will be held at the closed valve position in the protruding state, and it can be easily seen from the outside that a backfire has occurred, and even if the gas use side becomes depressurized due to the backfire occurrence, it will shut off Since the valve is held in the closed position, inconvenience caused by the automatic return can be eliminated.

  This backfire preventer has one end wall (6) of the case body (5) formed in an open shape, and a gas lead-out nozzle (10) is fitted in the case body (5) to reverse the case body (5). A fire prevention chamber (1) is formed. A shut-off valve holder (11) is fitted in the backfire prevention chamber (1), and a sintered metal is placed between the shut-off valve holder (11) and the inner surface of the back end wall (14) of the case body (5). The flame extinguishing cylinder (2) made of a porous material such as the above is arranged, and the opening end of the case body (5) is fixed by the nozzle presser (20), and the extinguishing cylinder (2), the shut-off valve holder (11) and the lead-out The nozzle (10) is fixed in position.

  The gas lead-out nozzle (10) is provided with a gas lead-out port (9), and a gas introduction port is provided at a portion corresponding to the disposition position of the extinguishing cylinder (2) on the peripheral side wall (7) of the case body (5). (8) is transparent.

A shut-off valve chamber (12) is formed inside the flame extinguishing cylinder (2), and a part of the back end wall (14) of the case body (5) protrudes in a cylindrical shape in the shut-off valve chamber (12). A gas communication path (15) is formed between the valve holder (11).
The shut-off valve holder (11) is fitted with a shut-off valve body (4) composed of a spool valve so as to be able to move forward and backward, and the gas communication passage (15) can be closed by moving the shut-off valve body (4) forward and backward. It is configured.
A check valve chamber (13) is formed on the gas outlet nozzle (10) side in the shut-off valve holder (11), and a gas is placed in the center of the shut-off valve body (4) fitted in the shut-off valve holder (11). A shut-off valve chamber (12) and a check valve chamber (13) communicate with each other by forming a flow passage.

The gas flow passage in the shut-off valve body (4) has a check valve chamber (13) side end portion formed on a conical inner surface which is widened, and a check valve seat (16) is formed on the conical inner surface.
The check valve body (3) mounted in the check valve chamber (13) is elastically pressed toward the check valve seat (16) by a check valve spring (17) installed between the gas lead-out nozzle (10) and the check valve body (3). Energized.

  The back end wall (14) of the case body (5) is provided with a slide hole (19) for slidingly supporting the leg portion (18) of the shutoff valve body (4). The leg (18) of the shut-off valve body (4) is inserted into (19) so as to be able to slide forward and backward, and the end face of the leg of the shut-off valve body (4) is in a state where the shut-off valve body (4) is in the valve-opening position. Thus, it is formed flush with the end surface of the case body (5). The ball (22) constituting the operating pressure adjusting mechanism (21) is brought into contact with the peripheral surface of the leg (18) of the shut-off valve body (4), and the shut-off valve body (4) is moved to the operating position (shut off). The concave portion (23) for receiving the ball (22) of the operating pressure adjusting mechanism (21) in the state at the position) is formed as an annular groove on the peripheral surface of the leg portion (18) of the shut-off valve body (4).

  The operating pressure adjusting mechanism (21) includes a spring mounting hole (24) that is pierced from the outer peripheral surface to the inner peripheral surface of the sliding hole (19) in the back end wall (14) portion of the case body (5). The ball (22) and the urging spring (25) are accommodated in the spring, and a spring pressure adjusting screw (26) is screwed into the opening of the spring mounting hole (24) on the outer peripheral surface of the case body. The contact pressure of the ball (22) on the peripheral surface of the leg portion of the shutoff valve body (4) is adjusted by the tightening state of the spring pressure adjusting screw (26).

  In the dry flashback preventer having the above-described configuration, in the normal state shown in FIG. 1, the shut-off valve body (4) opens the gas passage (15) and flows forward from the gas inlet (8). The gas passes through the flame extinguishing cylinder (2) and flows into the shut-off valve chamber (12), passes through the gas flow passage in the shut-off valve body (4), and flows into the check valve chamber (13). The valve body (3) is pressed to open it, and flows out from the check valve chamber (13) through the gas outlet port (9). At this time, since the forward flow gas flows smoothly, the gas pressure acting on the shut-off valve body (4) is small, and the operating pressure adjusting mechanism acting on the leg (18) of the shut-off valve body (4). Since the contact pressure of (21) becomes a resistance and the shut-off valve element (4) that is opened is not moved, there is no action for closing the valve.

  When backfire occurs, as shown in FIG. 2, flammable gas flows into the check valve chamber (13) from the gas lead-out rod (9) due to the explosion pressure of the backfire, and the check valve body (3 The check valve body (3) is pressed against the check valve seat (16) side together with the elastic force of the check valve spring (17) to close the valve. Further, the backfire pressure acting on the shutoff valve body (4) at the time of backfire is much larger than the contact pressure of the operating pressure adjusting mechanism (21). The shut-off valve body (4) closes the gas passage (15) by instantaneously moving in the direction of the back end wall (14). Then, due to the movement of the shut-off valve body (4) by the valve closing operation, the ball (22) of the operating pressure adjusting mechanism (21) is fitted into the recess (23) formed in the leg portion of the shut-off valve body (4). Thus, the shut-off valve body (4) is held in the closed position.

  By closing the shut-off valve body (4), the gas communication passage (15) is shut off, preventing the propagation of flashback and shutting off the supply of combustible gas. 21) Since the ball (22) rolls in contact with the leg (18) of the shut-off valve body (4), this operating pressure adjustment mechanism (21) is operated to close the shut-off valve body (4). Is not a large operating resistance.

  Once the flashback occurs, the shut-off valve body (4) is held in the valve closing operation position as described above. Therefore, after the flashback is stopped, the pressure on the gas consumption side is reduced. Even if the pressure is reduced, the shut-off valve body (4) maintains the operating position, so that the shut-off valve body (4) does not return automatically. Therefore, after an operator or the like takes measures against the cause of backfire, the operator manually returns the shut-off valve body (4) by pushing it into the case body (5). Therefore, even if it is installed in a gas supply system that reduces the gas pressure as a result of the occurrence of flashback, such as hydrogen gas, the flashback prevention operation is ensured, and the flashback protector prevents flashback. It can be easily recognized from the outside that it is sensing and operating.

  It can be used in various combustion gas supply systems such as hydrogen gas and other combustion gases whose gas pressure decreases due to combustion.

It is a vertical side view at the time of forward flow. It is a vertical side view at the time of backflow. FIG. 1 is a diagram corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Backfire prevention chamber, 2 ... Flame extinguishing cylinder, 3 ... Check valve body, 4 ... Shut-off valve body, 5 ... Case main body, 6 ... One end wall of case main body, 7 ... Perimeter side wall of case main body, 8 ... Gas introduction 9 ... Gas outlet, 10 ... Gas outlet nozzle, 11 ... Shut-off valve holder, 12 ... Shut-off valve chamber, 13 ... Check valve chamber, 14 ... Back end wall of the case body, 15 ... Gas communication passage, 16 ... Check valve seat, 17 ... Check valve spring, 18 ... Leg part of shut-off valve body, 19 ... Leg part sliding hole, 20 ... Nozzle presser, 21 ... Working pressure adjustment mechanism, 22 ... Ball, 23 ... Recessed part, 24 ... Spring mounting hole, 25 ... Biasing spring, 26 ... Spring pressure adjusting screw.

Claims (2)

A flame-extinguishing cylinder (2), a check valve body (3) and a shut-off valve body (4) are incorporated into a backfire prevention chamber (1) formed in an airtight structure, and gas is placed on the peripheral side wall (7) of the case body (5) In the dry backfire preventer in which the inlet (8) is formed and the gas outlet (9) is formed in the one end wall (6) of the case body (5) ,
A gas discharge nozzle (10) is fitted and fixed in the opening of the case body (5) with one end wall (6) open, and a backfire prevention chamber (1) is formed in the case body (5).
A shut-off valve holder (11) is fitted and fixed in the backfire prevention chamber (1), and a flame extinguishing cylinder is provided between the shut-off valve holder (11) and the inner surface of the back end wall (14) of the case body (5). Place (2),
A gas outlet port (9) is formed in the gas outlet nozzle (10), and a gas inlet port (8) is formed in the peripheral side wall (7) of the case body (5) corresponding to the disposition position of the flame extinguishing cylinder (2). And
A shut-off valve chamber (12) is formed inside the flame extinguishing cylinder (2), a check valve chamber (13) is formed on the gas outlet nozzle (10) side inside the shut-off valve holder (11),
A shut-off valve body (4) constituted by a spool valve is fitted into the shut-off valve holder (11) so as to be movable forward and backward, and the shut-off valve holder (11) in the shut-off valve chamber (12) and the back of the case body (5) The gas communication path (15) formed between the end wall (14) and the shut-off valve body (4) can be closed.
A check valve body (3) mounted on the check valve chamber (13) with a check valve seat (16) formed at the end of the shut-off valve body (4) on the check valve chamber (13) side is gas. The check valve spring (17) installed between the outlet nozzle (10) and the check valve spring (17) is urged toward the check valve seat (16),
A leg part (18) located on the far end side of the shut-off valve body (4) is slidably mounted in a leg slide hole (19) formed in the rear end wall (14) of the case body (5). The tip of the leg of the shut-off valve body (4) is configured to be able to protrude from the case body (5) when operating,
A ball (22) that comes into contact with the peripheral surface of the leg (18) of the shut-off valve body (4) is brought into contact with the meat wall portion forming the leg sliding hole (19) of the case body (5). A dry flashback characterized in that it is mounted so that the pressure can be changed, and a recess (23) into which the ball (22) is fitted when the shut-off valve is operated is formed in the leg (18) of the shut-off valve body (4). Preventer. The dry backfire preventer according to claim 1, wherein the recess (23) formed in the leg (18) of the shut-off valve body (4) is formed in an annular groove.

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