JP2011094777A - Dry type safety switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry type safety device capable of stably operating even at low pressure in a reverse flow and at a backfire and high in reliability. <P>SOLUTION: The dry type safety switch includes a flame extinction filter 2, a shut-off switch 3 spring-biased toward a downstream side, a lock pin 4 stopping the shut-off switch 3 at a predetermined position, and a shut-off valve 5 contacting with the shut-off switch 3 in a pressing manner to shut off a flow passage in the reverse flow and at the backfire. A pressure receiving face 4a is formed at the lock pin 4 for receiving pressure during the shut-off, and tapered faces 21, 31 are formed in mutual abutting portions of the shut-off switch 3 and the lock pin 4 for catching and locking the lock pin 4 at a predetermined position. The tapered faces 21, 31 are formed slidably for moving the shut-off switch 3 and the lock pin 4 in directions separating from each other by the pressure of a predetermined value or higher generated in the reverse flow and at the backfire to release the locking. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dry safety device that is inserted into a flow path of combustible gas.

  A dry safety device is known as a device that performs a shut-off operation when a backflow or backfire occurs in a flow path of a combustible gas. FIG. 8 shows a conventional dry safety device described in Patent Document 1.

  In the body case 51 of the dry safety device, there are disposed a flame extinguishing filter 52 for preventing the passage of backfire, and a circuit breaker 53 and a shutoff valve 55 having a check valve structure. A circuit breaker spring 60 is further disposed in the main body case 51, and the circuit breaker spring 60 biases the circuit breaker 53 toward the upstream side in the flow direction (arrow direction in the figure). The slide of the circuit breaker 53 by the spring bias is stopped at a predetermined position shown in the figure by the lock pin 54 coming into contact with the side. The lock pin 54 is urged by the lock spring 61 toward the circuit breaker 53 with a predetermined urging force.

  In this dry safety device, a space for enabling the valve opening operation of the shut-off valve 55 is formed between the shut-off device 53 stopped at a predetermined position shown in the figure and the shut-off valve 55. When backflow / backfire occurs, the lock pin 54 is pushed up against the urging force of the locking spring 61 by the large pressure generated during the backflow / backfire, and the lock pin 54 is separated from the circuit breaker 53. . When the lock pin 54 is separated, the circuit breaker 53 presses against the upstream shut-off valve 55 by the spring bias of the circuit breaker spring 60 and disables the valve-opening operation of the shut-off valve 55.

  In other words, in the conventional dry safety device shown in FIG. 8, a predetermined pressure at which the lock pin 54 operates (pressure in the flow path caused by backflow / backfire) is appropriately set by mechanical incorporation of the lock spring 61. It was. In this structure, when the lock pin 54 is set to operate even at a low pressure, it is required to stably apply a small urging force to the lock pin 54 by the lock spring 61.

  However, it is not easy to stably apply a minute urging force over a long period of time by such mechanical incorporation of the locking spring 61. Therefore, the conventional dry safety device has a problem that it is very difficult to set it to operate stably even at a low pressure over a long period of time.

JP-A-11-223331

  The present invention has been invented in view of the above problems, and provides a highly reliable dry safety device that can be stably operated against a low pressure during backflow and flashback. Let it be an issue.

  The dry safety device of the present invention that can solve the above-mentioned problems is a flame extinguishing filter 2 that prevents the passage of backfire, and a circuit breaker 3 that is slidable in the flow direction and is spring-biased toward the downstream side. The lock pin 4 that stops the slide to the downstream side of the circuit breaker 3 at a predetermined position by coming into contact with the circuit breaker 3 and slidable in the flow direction and pressed against the circuit breaker 3 at the time of backflow / backfire And a shutoff valve 5 for shutting off the flow path.

  The lock pin 4 is provided with a pressure receiving surface 4a for receiving pressure at the time of interruption, and a taper surface 21 for hooking and locking the lock pin 4 at a predetermined position at a contact position between the breaker 3 and the lock pin 4. , 31 are formed. The taper surfaces 21 and 31 are slidably provided so that the circuit breaker 3 and the lock pin 4 are moved away from each other by a pressure of a predetermined value or more generated during backflow or flashback to release the locking. It is.

  According to the dry safety device of the present invention having the above-described configuration, if the lock pin 4 is hooked and locked to the circuit breaker 3 by the contact of the tapered surfaces 21 and 31, and a pressure of a predetermined value or more is generated during backflow and backfire. The circuit breaker 3 and the lock pin 4 can be moved away from each other by sliding between the tapered surfaces 21 and 31 to release the locking. Therefore, by appropriately setting the angle α of the tapered surfaces 21 and 31, it is possible to stably operate even at a low pressure during backflow and backfire. In other words, it is a highly reliable dry safety device that operates stably over a long period of time even at a low pressure.

  In the dry safety device of the present invention, the lock pin 4 is rotatable about the shaft center, and the locking projection 20 protrudes from the eccentric position toward the circuit breaker 3 side. 3 is formed on the outer surface thereof with a concave step portion 30 on which the locking convex portion 20 is hooked and locked, and the tapered surfaces 21, 31 are formed on the locking convex portion 20 and the concave step portion 30, respectively. Is preferred.

  In this way, in order to return the lock pin 4 released from the latching engagement with the circuit breaker 3 to the initial position, it is only necessary to rotate the lock pin 4 toward the circuit breaker 3 while making one rotation about the axis. Smooth return work becomes possible. At this time, if the taper surface 21 of the locking projection 20 of the lock pin 4 is pressed against the taper surface 31 of the concave step portion 30 of the circuit breaker 3, the taper surfaces 21 and 31 are then engaged by sliding contact. The breaker 3 as a whole can be smoothly slid by the eccentric rotation of the locking projection 20 while maintaining the stopped state.

  According to the dry safety device of the present invention, there is an effect that it is possible to provide a highly reliable dry safety device that operates stably even at a low pressure during backflow and flashback.

It is a sectional side view of an example dry type safety device in an embodiment of the present invention. The behavior of the first stage at the time of backflow and flashback of the dry safety device is shown, (a) is a sectional side view of the main part, (b) is the positional relationship of each member when viewed from the direction in which the lock pin protrudes. It is explanatory drawing shown. The behavior of the second stage at the time of backflow and flashback of the dry safety device is shown, (a) is a sectional side view of the main part, (b) is the positional relationship of each member when viewed from the direction in which the lock pin protrudes. It is explanatory drawing shown. The behavior of the third stage during backflow and flashback of the dry safety device is shown, (a) is a cross-sectional side view of the main part, (b) is the positional relationship of each member when viewed from the direction in which the lock pin protrudes. It is explanatory drawing shown. The behavior of the fourth stage during backflow and flashback of the dry safety device is shown, (a) is a cross-sectional side view of the main part, (b) is the positional relationship of each member when viewed from the direction in which the lock pin protrudes. It is explanatory drawing shown. The state in the returning operation | work of a dry type safety device same as the above is shown, (a) is principal part sectional drawing, (b) is explanatory drawing which shows the positional relationship of each member when it sees from the direction which a lock pin protrudes. The state after the return | restoration of a dry type safety device same as the above is shown, (a) is principal part sectional drawing, (b) is explanatory drawing which shows the positional relationship of each member when it sees from the direction which a lock pin protrudes. It is side sectional drawing of the conventional dry safety device.

  The present invention will be described based on embodiments shown in the accompanying drawings.

  FIG. 1 shows a structure of an example of a dry safety device in the embodiment of the present invention. The direction of the arrow in the figure is the normal flow direction. In this text, “upstream” and “downstream” are used based on the normal flow direction.

  In an example of the dry safety device, a flame extinguishing filter 2, a circuit breaker 3, and a shut-off valve 5 are arranged in this order from an upstream side to a downstream side in a main body case 1 formed in a generally circular tube shape as a whole. The circuit breaker 3 is connected to a circuit breaker spring 10 that biases the circuit breaker 3 toward the downstream side. Further, the shutoff valve 5 is connected to a shutoff valve spring 11 that biases the shutoff valve 5 toward the upstream side.

  The main body case 1 has a flow path R of a combustible gas such as hydrogen formed therein, and has an upstream opening 1a and a downstream opening 1b. A lock pin 4 is arranged in the main body case 1 so as to be protruded and retractable from the side with respect to the flow path R (that is, from a direction perpendicular to the axial direction of the flow).

  Hereinafter, each configuration will be further described in detail. The flame extinguishing filter 2 is a cylindrical member made of porous sintered metal. When a backfire enters the flow path R from the downstream opening 1b, the fire extinguishing filter 2 extinguishes the fire and backfires to the upstream opening 1a. Is provided so as to prevent it from reaching.

  The circuit breaker 3 has an upstream opening 3a into which combustible gas that has passed through the flame extinguishing filter 2 flows and a downstream opening 3b through which the combustible gas that has passed through the inside flows out further downstream. It is a cylindrical member. The upstream opening 3 a is opened on the side surface of the upstream end of the circuit breaker 3, and the downstream opening 3 b is opened on the end surface of the downstream end of the circuit breaker 3. The circuit breaker 3 is fitted in the flow path R in the main body case 1 so as to be slidable in the flow direction.

  The shut-off valve 5 has a cylindrical valve body 6 that is slidably fitted into the downstream opening 3b of the circuit breaker 3. On the downstream side, the combustible gas that has passed through the valve body 6 is further added. An introduction body 7 to be introduced into the downstream flow path R is integrally provided. The valve body 6 has an upstream opening 6a through which flammable gas flows normally and a downstream opening 6b through which the flammable gas flows out downstream. The upstream opening 6 a is opened on the upstream end face of the valve body 6, and the downstream opening 6 b is opened in a plurality of windows on the downstream side wall of the valve body 6. The introduction body 7 has a cylindrical shape larger than the valve body 6, and a plurality of introduction openings 7a are provided in the shape of windows on the side walls.

  The lock pin 4 is a columnar member formed with a flat pressure receiving surface 4a for receiving pressure at the time of shut-off facing the flow path R side. From this pressure receiving surface 4a, the latching convex part 20 which is hooked and latched on the circuit breaker 3 to stop the slide to the downstream side of the circuit breaker 3 is orthogonal to the flow direction (that is, the sliding direction of the circuit breaker 3). It protrudes in the direction to do.

  The lock pin 4 is slidably disposed within a certain range in a direction perpendicular to the flow direction in a cylindrical lock pin guide 8 provided in the main body case 1. The cylindrical lock pin 4 is disposed in the lock pin guide 8 so as to be rotatable about the axis. Between the inner peripheral surface of the lock pin guide 8 and the outer peripheral surface of the lock pin 4, a pair of O-rings 9 that secure sliding resistance of the lock pin 4 with the lock pin guide 8 are interposed.

  The locking projection 20 of the lock pin 4 is projected toward the circuit breaker 3 from the eccentric position of the lock pin 4 (that is, the position on the pressure receiving surface 4a spaced from the central axis of the lock pin 4). It is provided so that the front end side portion is locked to the concave step portion 30 formed on the outer peripheral surface of the cylindrical circuit breaker 3.

  The outer peripheral surface of the circuit breaker 3 has a central large-diameter portion that is in sliding contact with the inner peripheral surface of the main body case 1 and a small-diameter portion that is formed on the downstream side with a smaller diameter than the large-diameter portion. Between the large diameter portion and the small diameter portion, a concave step portion 30 is provided over the entire circumference.

  The locking projections 20 and the recessed step portions 30 are tapered surfaces 21, 31 so that the lock pin 4 is hooked and locked to the circuit breaker 3 spring-biased by the circuit breaker spring 10 downstream. Is forming. The distal end portion of the locking projection 20 is formed in a truncated cone shape whose diameter increases as it approaches the distal end side, and the side circumferential surface of the truncated cone-shaped distal end portion approaches the distal end side. In other words, the tapered surface 21 increases in diameter (as it approaches the circuit breaker 3 side).

  The recessed step portion 30 of the circuit breaker 3 is inclined so that the boundary portion with the small diameter portion is located on the upstream side than the boundary portion with the large diameter portion. In other words, the tapered surface 31 formed on the entire circumference of the concave step portion 30 has a direction inclined by an angle α from the direction in which the downstream side of the flow path R is straightened to the inside of the flow path R. The surface is inclined like a mortar over the entire circumference.

  Here, both the taper surfaces 21 and 31 are formed so that the mutual inclinations coincide at the contact portion. Specifically, when the surface orthogonal to the axial direction of the flow path R is used as a reference, the tapered surface 21 of the locking convex portion 20 is formed so that the contact portion forms an angle α with respect to the reference surface, Further, the tapered surface 31 of the recessed step portion 30 is formed so that the contact portion thereof has the same angle α with respect to the reference surface.

  The circuit breaker 3 held at a predetermined position by engaging with the lock pin 4 at the tapered surfaces 21 and 31 has a space for enabling the valve opening operation of the shut-off valve 5 at the predetermined position on the downstream side. To form. The valve opening operation is an operation in which the shutoff valve 5 slides to the downstream side, and the slide opening causes the downstream opening 6b of the valve body 6 forming the upstream portion of the shutoff valve 5 to pass through the side flow path R. To open.

  At this time, the combustible gas that has flowed into the circuit breaker 3 through the upstream opening 3 a flows out into the downstream flow path R through the upstream opening 6 a and the downstream opening 6 b provided in the valve body 6 of the cutoff valve 5. Then, after flowing into the introduction body 7 through the opening 7a, it flows into the flow path R on the further downstream side.

  In the dry safety device of the present example having the above-described configuration, the concave step portion of the circuit breaker 3 is caused by the urging force applied to the downstream side by the circuit breaker spring 10 during the normal flow as shown by the arrow in FIG. 30 is hooked and locked on the locking projection 20 of the lock pin 4 to hold the circuit breaker 3 in the illustrated position. The lock pin 4 is prevented from being raised by a normal pressure due to the above-described hooking engagement with the spring biasing to the downstream side. At this time, the rotation position of the lock pin 4 in the lock pin guide 8 is set so that the eccentric locking projection 20 is located on the most upstream side.

  2 to 8 sequentially show the behavior of the dry safety device during backflow and flashback. In each figure, (a) is a cross-sectional side view of the main part, and (b) is an explanatory view showing the positional relationship between the lock pin 4 and the circuit breaker 3 when viewed from the direction in which the lock pin 4 protrudes.

  As shown in FIGS. 2 and 3, when a backflow / backfire occurs from the downstream side in the combustible gas flow path R, the backflowed flame is extinguished by the extinguishing filter 2 arranged in the flow path R. . Further, the shutoff valve 5 slidably disposed in the flow path R slides upstream, and the introduction body 7 of the shutoff valve 5 presses against the downstream opening 3 b of the circuit breaker 3. At this time, the downstream opening 6 b of the valve body 6 fitted in the circuit breaker 3 is sealed by the inner wall of the circuit breaker 3.

  When the reverse flow is interrupted by the sealing, the pressure in the flow path R increases on the downstream side from the blocking position, and the pressure in the flow path R pushes the upstream of the circuit breaker 3 to the upstream side, The pressure receiving surface 4a of the lock pin 4 works in a direction to push it up away from the circuit breaker 3. Here, since both the taper surfaces 21 and 31 of the lock pin 4 and the circuit breaker 3 are inclined by an angle α, when the pressure at the time of backflow / backfire exceeds a predetermined value, the both taper surfaces 21 and 31 are brought into sliding contact. However, the circuit breaker 3 is slid to the upstream side against the spring biasing force, and the lock pin 4 is pushed sideways away from the circuit breaker 3.

  As shown in FIG. 4, when both the tapered surfaces 21 and 31 are separated and the hooking and locking of the lock pin 4 with respect to the circuit breaker 3 is released, the lock pin 4 is moved to the position where it is farthest from the circuit breaker 3. Move the slide. The lock pin 4 that has reached this position has its end 4b protruding from the lock pin guide 8, and visually notifies the user that a backflow has occurred.

  Thereafter, when the reverse flow is settled, the circuit breaker 3 pushed to the upstream side starts to slide to the downstream side again by the biasing force of the circuit breaker spring 10, and as shown in FIG. Slide to the side. At this time, since the lock pin 4 is in the pushed-up position, the circuit breaker 3 is slid to the most downstream position together with the shut-off valve 5 without being stopped by the lock pin 4. The introduction body 7 of the shut-off valve 5 is continuously pressed against the downstream opening 3 b of the breaker 3 by the biasing force exerted by the breaker spring 10. Accordingly, the flow path R is continuously blocked until the lock pin 4 is externally operated and returned to the initial position as described later.

  By the way, when hydrogen and oxygen burn, for example, the inside of the flow path R after the reverse flow becomes negative pressure and acts to lower the lock pin 4. On the other hand, the lock pin 4 is covered with an O-ring 9 which gives an appropriate sliding resistance, and after the circuit breaker 3 slides to the most downstream side and reaches the position shown in FIG. It is set to pull down until it hits 3. The lock pin 4 pulled down by the negative pressure stops its pulling operation at a position where the tip of the locking projection 20 hits the large diameter portion of the circuit breaker 3.

  Thereafter, in order to return the dry safety device to the initial state, the end portion 4b of the lock pin 4 protruding to the outside from the lock pin guide 8 may be rotated about the shaft center while being pushed into the inside of the main body case 1. Since the end 4b of the lock pin 4 is provided with a single groove 4c, an appropriate tool tip may be fitted into the groove 4c and rotated as it is.

  At this time, until the lock pin 4 is rotated by, for example, about 60 °, the locking convex portion 20 in the eccentric position rotates eccentrically while applying the tip to the large-diameter portion of the circuit breaker 3, and thereafter, until about 240 °, The locking projection 20 rotates eccentrically within a range that deviates downstream from the large-diameter portion of the circuit breaker 3 (see FIGS. 5B, 6B, etc.).

  Then, when the lock pin 4 is pushed in and rotated about 240 °, the taper surface 21 of the locking projection 20 contacts the taper surface 31 of the circuit breaker 3 as shown in FIG. If the lock pin 4 is further rotated here, the latching protrusion 20 that rotates eccentrically integrally with the lock pin 4 slides the circuit breaker 3 upstream while sliding the taper surfaces 21 and 31 together. When reaching the stage where the lock pin 4 is rotated 360 °, the circuit breaker 3 and the lock pin 4 are returned to their intended positions in FIG.

  At this time, the circuit breaker 3 is pushed upstream while maintaining the state of being hooked and locked to the lock pin 4 by the sliding contact of the tapered surfaces 21 and 31 inclined by the angle α. Therefore, once the locking projection 20 of the lock pin 4 is hooked and locked to the concave step portion 30 of the circuit breaker 3, the circuit breaker 3 can be pushed in by smoothly rotating the lock pin 4 thereafter.

  In the above-described dry safety device of the present invention, when the taper surfaces 21 and 31 are brought into contact with each other and the circuit breaker 3 is hooked and locked with the lock pin 4 and a pressure of a predetermined value or more is generated during backflow or backfire, the taper surface The circuit breaker 3 and the lock pin 4 are moved away from each other by sliding between 21 and 31 to release the lock. Therefore, by appropriately setting the angle α of the tapered surfaces 21 and 31, it is possible to operate stably even at a low pressure during backflow and backfire. That is, it becomes a highly reliable dry safety device that operates stably over a long period of time even at a low pressure.

  The angle α is preferably set within a range of 20 to 35 °, and most preferably 30 °. Thereby, even if it is a low pressure of 0.15 MPa or less, it becomes a dry safety device which operates stably over a long period of time.

  The present invention has been described above based on the embodiments shown in the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and appropriate design changes may be made within the intended scope of the present invention. Is possible.

DESCRIPTION OF SYMBOLS 2 Flame extinguishing filter 3 Circuit breaker 30 Concave step part 4 Lock pin 4a Pressure receiving surface 5 Shut off valve 20 Locking convex part 21 Tapered surface 30 Concave step part 31 Tapered surface

Claims (2)

  A flame extinguishing filter that prevents the passage of flashback, a circuit breaker that is slidable in the flow direction and is spring-biased toward the downstream side, and abuts the circuit breaker to slide the circuit breaker downstream. A lock pin that stops at a predetermined position and a shut-off valve that is slidable in the flow direction and that shuts off the flow path by pressing against the circuit breaker during backflow and backfire are received. A dry safety device is provided with a pressure receiving surface, and a taper surface is formed at a contact position between the circuit breaker and the lock pin to hook and lock the lock pin at a predetermined position. A dry safety device characterized by being slidably provided so that the circuit breaker and the lock pin are moved away from each other by a pressure of a predetermined value or more generated at the time of flashback to release the lock.   The lock pin is rotatable about an axis and has a locking projection protruding from the eccentric position toward the circuit breaker. The circuit breaker is hooked and locked by the locking projection. 2. The dry safety device according to claim 1, wherein a concave step portion is provided on an outer surface thereof, and the tapered surface is formed on the locking convex portion and the concave step portion.

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