JP2008298128A - High pressure gas safety device - Google Patents

Abstract

There is a need for a high-pressure gas safety device that has both a high-pressure gas sealing function and a safety function that can achieve both a normal sealing performance and safety at an abnormally high temperature with a simple configuration.
A high-pressure gas safety device according to the present invention has a valve rod (4) for a valve pin (8) that opens and closes a passage (2) on a primary gas passage (2) provided in a main body (1). To intervene. An annular groove (17) is provided on the opposite side surface of the valve rod (4) and the main body (1), and the annular groove (17) communicates with the discharge passage (18) and the primary gas is introduced into the annular groove (17). An O-ring (19) is inserted on the upstream side of the leakage flow path, and a soluble backup ring (20) is inserted on the downstream side. A restraining member (12) having a gas supply hole (13) controlled by the valve pin (8) is attached to the main body (1) to connect the valve rod (4) and the soluble backup ring (20). Deter.
[Selection] Figure 1

Description

  The present invention relates to a high-pressure gas safety device.

As means for preventing the explosion of the container body by letting the gas pressure to the outside when an abnormally high pressure occurs, the following (1) to (3) are well known.
(1) Safety valve using an elastic material such as a spring The elastic material bends when an abnormally high pressure occurs and releases the valve to release gas.
(2) Rupture plate A rupture disc that ruptures and escapes gas when abnormally high pressure occurs.
(3) Fusible plug A low melting point alloy that melts away when an abnormally high pressure occurs, allowing gas to escape.
Japanese Patent Application Laid-Open No. 7-167321 discloses a high-pressure gas safety device developed by the present applicant.
JP-A-7-167321

  In the case of well-known means, all are attached to the product as independent elements, so that there is a disadvantage that the product configuration becomes complicated, the size is increased, and the cost is increased. In addition, in the case of a fusible stopper, since a low melting point alloy is adopted, the mechanical strength is weakened, and a creep phenomenon may occur, and there is a concern about a lack of regular seal (more).

The above-mentioned safety means developed by the applicant of the present application has both a normal sealing function and a safety function in the event of an abnormality, and there are advantages and features that it is installed inside the product in a small space, but on the other hand, the compression packing As such, there are drawbacks such as “no rubber elasticity” and “heat resistance is poor (low temperature shrinkage, curing), etc., and the range of use thereof is limited. The
(Example) Experimentally, when a nitrogen cylinder was attached, leakage occurred at a low temperature of 0 ° C. (internal pressure of about 15 MPa).
The present invention aims to provide a high-pressure gas safety device that has both a sealing function and a safety function for high-pressure gas, and can achieve both a normal sealing performance and safety at an abnormally high temperature with a simple configuration. And

  In the high-pressure gas safety device according to the present invention, a valve pin for a valve pin for opening and closing the passage is provided on a passage for a primary gas provided in the main body. An annular groove is provided on the opposite side surface of the valve rod and the main body. The annular groove communicates with a discharge path whose inner end is open to an annular opening having a larger diameter than the annular groove connected to the annular groove, and is connected to the annular groove on the primary gas leakage channel. An O-ring is inserted on the upstream side, and a fusible backup ring made of thermoplastic resin is inserted on the downstream side. A restraining member having a gas supply hole controlled by the valve pin is attached to the main body to restrain the valve rod and the soluble backup ring.

A high-pressure gas container is directly attached to the main body, and a primary (high-pressure) gas is supplied to the passage.
When the valve pin moves to open and close the supply hole, the gas passage is opened and closed, and the high-pressure gas flows to the demand side through the passage or stops.
When the passage is closed, the primary gas leaks into the gap between the valve rod and the main body, but is blocked by the O-ring and does not leak beyond the primary gas. This O-ring can be made of a normal material.
The O-ring is provided with a fusible backup ring on the downstream side of the primary gas leakage passage, and the fusible backup ring is restrained by a restraining member. If the temperature of the main body becomes abnormally high, such as when the body is heated, the fusible backup ring melts, deforms, and breaks due to these causes. It cannot resist the pressing force of the ring, allowing deformation of the O-ring. Therefore, the O-ring loses its sealing function, and the gas is released to the outside through the discharge path, preventing the gas container from exploding.

The restraining member may include an opening groove communicating with the discharge path on the restraining surface of the soluble backup ring.
In this way, when the fusible backup ring is overheated and deformed, a local stress concentration can be generated in a portion related to the opening groove, and the fusible backup ring is broken at this portion, and O A part of the ring can be protruded to release abnormally high pressure to the atmosphere.

The soluble backup ring may be made of a low density polyethylene resin or an ethylene vinyl acetate copolymer resin.
In this way, use as a compression packing alone has been refrained from the lack of rubber elasticity, poor heat resistance such as low-temperature shrinkage and curing, and the possibility of deterioration in sealing performance at low temperatures and high pressures. This can be solved by using together with a normal O-ring and can be used safely.

  According to the high-pressure gas safety device according to the present invention, when the high-pressure gas passage provided in the main body is closed, the high-pressure gas leaks into the gap between the valve rod and the main body, but is blocked by the O-ring. Since this O-ring does not require a safety function, it can be made of ordinary materials, and this O-ring has a fusible backup ring on the downstream side of the primary gas leakage passage. Since this fusible backup ring is restrained by the restraining member, if the temperature becomes abnormally high due to heating of the main body, etc., the fusible backup ring will melt and deform, and further It is not possible to resist the pressing force of the O-ring subjected to the primary gas pressure that has been broken and abnormally high, allowing the O-ring to deform and losing its sealing function, and the gas is released to the outside through the discharge passage. The To prevent explosion of the gas container.

  According to claim 2, since the restraining member includes an opening groove communicating with the discharge path on the restraining surface of the soluble backup ring, the opening is formed when the soluble backup ring is overheated and deformed. A local stress concentration can be generated in a portion related to the groove, and the soluble backup ring is broken in this portion, and a part of the O-ring is caused to protrude, and abnormal high pressure is released to the atmosphere. Can do.

  According to claim 3, since the soluble backup ring is made of low-density polyethylene resin or ethylene-vinyl acetate copolymer resin, it is not used as a compression packing alone. Due to the drawbacks such as poorness, the sealability could be lowered at low temperatures and high pressures, so it was possible to solve this problem by using it together with a normal O-ring.

  1 is a cut-away side view showing a specific example of a high-pressure gas safety device according to the present invention, FIG. 2 is a cut-away side view of another embodiment, and FIG. 3 is a view taken in the direction of arrow A in FIG. Reference numerals indicate the same or corresponding parts.

  The on-off valve mechanism has a normal configuration. That is, 1 is a main body, 2 is a primary gas passage provided in the main body 1, and the upstream side 3 of the passage 2 is connected to a primary gas supply source (not shown), for example, a high-pressure gas cylinder. Reference numeral 4 denotes a valve rod, which has a control path 5 on the axis X communicating with the passage 2 on the upstream side. The control path 5 is provided with a storage chamber 6 at the downstream end, and an O-ring 7 is stored in the storage chamber 6. A valve pin 8 has a large-diameter portion 10 on one side and a small-diameter portion 11 on the other side with a truncated cone portion 9 interposed therebetween. The valve pin 8 has a large-diameter portion 10 slidably inserted into the control path 5, and a small-diameter portion 11 slides through the supply hole 13 of the restraining member 12 attached to the main body 1 through the O-ring 7. It is freely loose.

  A spring 14 is inserted into the control path 5. One end of the spring 14 is restrained by the main body 1, and the other end presses the large-diameter portion 10 of the valve pin 8. In general, the filter 15 is provided at the upstream inlet of the control path 5, the spring 14 is restrained by the filter 15, and a relief hole 16 that opens to the side surface of the filter 15 is formed on the side wall of the valve rod 4. Pierced for release. The valve pin 8 presses the O-ring 7 against both surfaces of the truncated cone portion 9 and the restraining member 12 by the pressing force of the spring 14 to block the flow of the primary gas.

  As usual, by pushing the valve pin 8 against the spring 14, the O-ring 7 is separated from the surface of the truncated cone part 9, the control path 5, that is, the supply hole 13 is opened, and the high-pressure gas flows out. Supplied to the side.

  In the on-off valve mechanism of the present invention, an annular groove 17 is provided on the opposite side of the valve rod 4 and the main body 1. The annular groove 17 may be provided in the valve rod 4 but may be provided in the main body 1. The main body 1 is provided with a discharge path 18 that is open to the atmosphere, and the annular groove 17 communicates with the discharge path 18. The O-ring 19 and the fusible backup ring 20 are inserted into the annular groove 17 so that the O-ring 19 is located on the upstream side and the fusible backup ring 20 is located on the downstream side of the primary gas leakage passage. . And the suppression member 12 is attached to the main body 1, and the valve rod 4 and the soluble backup ring 20 are suppressed by this suppression member 12. The suppression member 12 is preferably a screw plug type, but may be a lid plate attached by a screw or the like.

  Normally, the gas from the gas supply source flows through the passage 2 of the main body 1 and enters the control passage 5 of the valve rod 4 and flows to the demand side through the supply hole 13 of the suppression member 12. Due to the action, the valve pin 8, the O-ring 7 and the restraining member 12 cooperate to block the supply hole 13, and do not flow to the demand side. A part of the gas reaches the O-ring 19 through the gap between the valve rod 4 and the main body 1, but is blocked by the O-ring 19 and does not flow downstream.

  When the gas container is heated by a fire or the like and the gas pressure becomes abnormally high, a high pressure is applied to the O-ring 19. If the fusible backup ring 20 is melted, deformed, broken or the like due to overheating, the fusible backup ring 20 cannot support the high pressure applied to the O-ring 19 and allows the deformation. It is discharged from the discharge path to the atmosphere through the gap that appears in the deformation. This prevents the high pressure gas container from bursting.

The restraining member 12 includes an opening groove 32 communicating with the discharge path 18 on the restraining surface 31 of the fusible backup ring 20.
In this case, when the fusible backup ring 20 is overheated and deformed, local stress concentration can be generated in a portion related to the opening groove 32, and the fusible backup ring 20 is broken at this portion, It is possible to cause a part of the O-ring 19 to protrude and release an abnormally high pressure to the atmosphere.

The soluble backup ring 20 is made of a low density polyethylene resin or an ethylene vinyl acetate copolymer resin.
In this case, the use of the compression packing alone has been refrained from the lack of rubber elasticity, low heat resistance such as low-temperature shrinkage and curing, and the possibility of deterioration in sealing performance at low temperatures and high pressures. This can be solved by using together with a normal O-ring and can be used safely.

  When the airtight characteristics and operating characteristics of the safety device manufactured according to the present invention were verified, the following results were obtained. From these verifications, it is judged that this safety device has sufficient practicality.

"Example 1 (airtight characteristics)"
Table 1 shows the verification results of the hermetic performance when a nitrogen cylinder is attached to each of the safety device and the conventional safety device and left standing. Analyte < 1 > is this safety device, the sample < 2 > is a gas supply using a conventional safety device.
Incidentally, both specimens although the components of the low-density polyethylene resin ring, analyte < 1 > is soluble backup ring, analyte < 2 > is used as a soluble seal.
As can be seen from Table 1, sample < 1 > for the analyte < 2 > in were tested under severe conditions than the leakage generated conditions, sample < 1 > to leakage did not occur. That is, it can be seen that the sealing performance is enhanced.

(Table 1)

"Example 2 (operating characteristics)"
When a liquefied carbon dioxide gas cylinder (filling ratio 1.3) having a large pressure change with respect to temperature fluctuations was attached to a safety device prototyped in accordance with the present invention and left in a constant temperature bath at about 90 ° C., the surface temperature of the cylinder was When the temperature reached 70 to 80 ° C., gas was released from the discharge path (safety device was activated).
Further, when the safety device after the operation is disassembled and inspected, the fusible backup ring 20 is broken at the portion facing the opening groove 32, and the O-ring 19 protrudes or is cut, which causes the gas leakage. I think that there is no error in the judgment that it is.

  In the temperature range (0 to 40 ° C.) in which this safety device is expected to be encountered (from storage to use), problems such as leakage are not observed, and it is considered that the safety device is sufficiently practical.

It is a vertical front view which shows the specific example of the high pressure gas safety device concerning this invention. It is a vertical front view which shows another specific example of the high-pressure gas safety device concerning this invention. FIG. 3 is a view taken in the direction of arrow A in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Passage 3 Upstream side 4 Valve rod 5 Control path 6 Accommodating chamber 7 O ring 8 Valve pin 9 Frustum part 10 Large diameter part 11 Small diameter part 12 Suppression member 13 Supply hole 14 Spring 15 Filter 16 Escape hole 17 Annular groove 18 Discharge path 19 O-ring 20 Soluble backup ring 31 Suppression surface 32 Opening groove 33 Annular opening

Claims (3)

A valve rod (4) for a valve pin (8) for opening and closing the passage (2) is provided on a primary gas passage (2) provided in the main body (1), and the valve rod (4) and the valve An annular groove (17) is provided on the opposite side surface of the main body (1), and the annular groove (17) has an inner end larger in diameter than the annular groove (17) connected to the annular groove (17). The annular opening (33) communicates with the discharge passage (18), and the annular groove (17) has an O-ring (19) on the upstream side in the primary gas leakage passage, and a thermoplastic resin on the downstream side. And a restraining member (12) having a gas supply hole (13) controlled by the valve pin (8) is attached to the main body (1). A high-pressure gas safety device characterized by suppressing the bag (4) and the soluble backup ring (20). The high-pressure gas safety device according to claim 1, wherein the restraining member (12) comprises an opening groove (32) communicating with the discharge passage (18) on the restraining surface (31) of the fusible backup ring (20). . The high-pressure gas safety device according to claim 1 or 2, wherein the soluble backup ring (20) is made of low-density polyethylene resin or ethylene-vinyl acetate copolymer resin.