JPH08320075A - Shut-off valve - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to suppress the fluctuation of the gas bag due to the flow of fluid and to quickly and surely return from the expanded state to the original contracted state. [Structure] One end in the fluid flow direction of a gas bag 5 made of an elastic material that is mounted in a straight tubular valve box 2 so as to expand and contract by introducing and removing pressure fluid is fixedly supported by one support member 4. At the same time, the other end is supported by the stiffener 3, which is the other support member, via the spring 13 so that a pulling force in a direction away from the one end acts even when the gas bag 5 is in a contracted state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is installed in an appropriate place such as a polyethylene gas pipe or water pipe, and is used for urgently interrupting the flow of fluid when an internal fluid leakage accident occurs. More specifically, the present invention relates to a shutoff valve in which a gas bag made of an elastic material that expands and contracts when a pressure fluid is introduced and depressurized is mounted in a valve box.

[0002]

2. Description of the Related Art A shutoff valve using a gas bag of this type does not generate a reaction force of an operating torque when opening and closing the valve unlike a shutoff valve made of a general metal valve. Since there is no need to intervene a steel pipe or the like that withstands the reaction torque of the operating torque, it can be easily connected to a polyethylene pipe or the like, and there is an advantage that the installation work cost can be reduced.

By the way, as a shut-off valve utilizing a gas bag, the present applicant has previously proposed a shut-off valve having a structure as shown in Japanese Patent Application No. 6-313881. As shown in FIG. 4, the previously proposed shutoff valve 1 is made of polyethylene (PE).
A parasol-type gas bag 5 made of an elastic material such as rubber is placed inside a straight tubular valve box 2 integrally molded of a plastic material such as, and one end of the gas bag 5 in the fluid flow direction is Through the base 5a attached to the one end,
An elbow 6 connected to the mouthpiece 5a and arranged at the center of the valve box 2, a pipe 7 extending radially outward from the elbow 6, and a fitting 8 for attaching the pipe 7 to the valve box 2, The mounting member 8 is fixed and supported by a support member 4 including a fixing member 9 for fixing the mounting member 8 to the valve box 2.

On the other hand, at the other end of the gas bag 5 in the fluid flow direction, a support metal fitting 5b attached to the other end is attached to the valve box 2.
The outer cylinder 3a slidably contacting the inner peripheral surface of the outer cylinder 3a and the radial plate-like member 3c arranged concentrically inside the outer cylinder 3a.
It is slidably fitted to the inner cylinder 3b of the stiffener 3, which is the other support member composed of the short inner cylinder 3b fixed to the inner cylinder 3b, and is supported so as to be movable only in the fluid flow direction. In addition,
A pressure fluid supply / exhaust pipe 11 connected to an air pump (not shown) for pumping a fluid such as air or nitrogen gas is connected to the mounting bracket 8 on the side of the one supporting member 4, and the mounting bracket 8 Through the gas bag 5 and the pressure fluid supply / exhaust pipe 1
1 is communicated. Further, an opening / closing valve 12 and a pressure gauge (not shown) are interposed in the pressure fluid supply / exhaust pipe 11. 10 is an O-ring.

In the shut-off valve having the above-mentioned structure, the gas bag 5 is normally in the contracted posture as shown by the solid line in FIG. 4, and the fluid such as gas or water flows through the internal flow passage of the valve box 2. . Then, when it is necessary to urgently interrupt the flow of fluid due to the occurrence of a leakage accident, the air pump is driven and the on-off valve 12 is opened to open the pressure fluid supply / exhaust pipe 11, the mounting bracket 8, and the piping. When a pressurized fluid such as air or nitrogen gas is introduced into the gas bag 5 through the 7, the elbow 6 and the mouthpiece 5a, the gas bag 5 swells rapidly, and the outer peripheral surface thereof is shown in the dotted line in FIG. It comes into contact with the inner peripheral surface of 2 and then comes into pressure contact, so that the flow of the fluid is reliably cut off.

[0006]

However, in the conventional shut-off valve having the above-mentioned structure, one end of the gas bag 5 is fixedly supported by the support member 4, but the other end of the stiffener 3 is provided with the support fitting 5b. Since it is slidably fitted in the inner cylinder 3b and supported so as to be movable in the fluid flow direction, the gas bag 5 tends to fluctuate and expand due to the fluid flow not only during normal operation but also during the shutoff operation. When the gas bag 5 is contracted, it takes time to return to the original contracted state only by releasing the pressure from the gas bag 5, and in the case of a parasol type, it can be returned to the original folded state. However, there is a problem that it adversely affects the flow of the fluid at normal times.

The present invention has been made in view of the above circumstances, and provides a shutoff valve that can suppress the fluctuation of a gas bag due to the flow of fluid and can quickly and surely return from an expanded state to an original contracted state. The purpose is to do.

[0008]

In order to achieve the above object, a shut-off valve according to the present invention is a straight tubular valve box integrally formed of a plastic material, and a shut-off valve installed in the valve box to control a pressure fluid. A gas bag made of an elastic material that expands and contracts by introducing and depressurizing it, and a pair of support members that support both ends of the gas bag in the fluid flow direction in the valve box. In the shutoff valve in which one end side of is connected to the pressure fluid supply / exhaust means outside the valve box,
One end of the gas bag in the fluid flow direction is fixedly supported by one supporting member, and the other end is provided with a spring so that a pulling force acts in a direction away from the one end even when the gas bag is in a contracted state. And is supported by the other support member.

[0009]

According to the present invention, the gas bag is exposed to the flow of the fluid at a normal time when the gas bag contracts and the fluid flows, but one end portion in the flow direction is fixed to one supporting member. Since the other end is supported by the other support member in a tensioned state via the spring, it does not sway due to the flow of the fluid and does not adversely affect the flow of the fluid. Also, when it is necessary to urgently interrupt the flow of fluid due to the occurrence of a leakage accident, the pressure fluid is supplied to the inside of the gas bag by the pressure fluid supply / exhaust means to expand the gas bag and expand When the outer peripheral surface of the gas bag is pressed against the inner peripheral surface of the straight tubular valve box, the flow of the fluid is surely shut off. Since it does not generate an operating torque like the above, it is not necessary to interpose a steel pipe or the like that withstands the operating torque reaction force before and after the shutoff valve,
Not only can it be easily connected to a polyethylene pipe, but the length of the gas bag tends to become shorter as the gas bag expands.Therefore, an extension force acts on the spring to expand the gas bag. At that time, a stronger pulling force will be exerted than in normal times, and the gas bag will not wobble.

Further, when decompressing and contracting from the expanded gas bag, since the strong pulling force of the spring acts in the contracting direction, the gas bag contracts quickly and surely and returns to the original flow state. Will be done. In particular, even in the case of a parasol type gas bag, the original folded state can be quickly restored.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional side view of a shutoff valve according to an embodiment of the present invention, FIG. 2 is a plan view of the shutoff valve, and FIG. 3 is a front view of a main part of the shutoff valve. Three
Since a to 3c and 5a to 5c are the same structural members as the conventional shutoff valve shown in FIG. 4, the same reference numerals are given to those structural members, and detailed description will be omitted. Further, the straight tubular valve box 2 integrally molded with a plastic material such as polyethylene has a uniform inner diameter and is formed such that both axial end portions 2a and 2b have the same size as the adjacent fluid pipe. The central portion 2c is formed to have a tube wall that is somewhat thicker than the end portions 2a and 2b.

In the shut-off valve having the above structure, a base 5a attached to one end of the parasol type gas bag 5 in the fluid flow direction.
Is fixedly supported by one of the support members 4, and the support metal fitting 5b attached to the other end portion in the fluid flow direction is attached to the bottom wall portion 3 of the inner cylinder 3b of the stiffener 3 which is the other support member.
Even when the gas bag 5 is in a contracted state as shown by the solid line in FIG. 1, the coil back 13 is supported via a coiled spring 13 so that a pulling force acting in a direction away from the mouthpiece 5a at one end acts on d. There is.

Next, the operation of the shutoff valve 1 having the above structure will be described. Normally, the gas bag 5 is in a contracted posture as shown by the solid line in FIG. 1, and a fluid such as gas or water flows through the internal flow path of the valve box 2. At this time, one end of the gas bag 5 in the fluid flow direction is fixed to the one support member 4, and the other end is supported by the stiffener 3 in a tensioned state via the spring 13. 5
Does not fluctuate and has no adverse effect on the flow of fluid.

When it is necessary to urgently shut off the flow of fluid due to the occurrence of a leakage accident, the air pump is driven and the on-off valve 12 is opened to open the pressure fluid supply / exhaust pipe 11 and the mounting bracket. When a pressurized fluid such as air or nitrogen gas is introduced into the inside of the gas bag 5 through 8, the pipe 7, the elbow 6, and the base 5a, the gas bag 5 swells rapidly and its outer peripheral surface is as shown by the dotted line in FIG. Since it contacts the inner peripheral surface of the valve box 2 and is pressed against it, the flow of the fluid is surely blocked. At this time, since no twisting torque or the like is generated in the shutoff valve 1, there is no need to interpose a steel pipe or the like that withstands the operating torque reaction force in front of and behind the shutoff valve 1, and it can be easily connected to a polyethylene pipe or the like. It is possible.

Further, since the length of the gas bag 5 tends to be shortened as the gas bag 5 expands, when the expansion force acts on the spring 13 against the elasticity, the gas bag 5 expands. Then, a stronger tensile force is exerted than in the normal state, and the gas bag 5 does not fluctuate during the expansion process.

Further, when the fluid is depressurized from inside the expanded gas bag 5 to contract, the strong pulling force of the spring 13 acts in a direction to contract the gas bag 5, so that the gas bag 5 is swift and reliable. It will shrink back to its original folded state.

When the other end of the gas bag 5 in the fluid flow direction is supported in a tensioned state via the spring 13, in the above embodiment, the inner cylinder 3b of the stiffener 3 and the other end of the gas bag 5 are connected. Although the spring 13 is interposed therebetween, a supporting plug may be used as the supporting member and the spring 13 may be interposed between the supporting plug and the other end of the gas bag 5.

[0018]

As described above, according to the present invention, at the time of normal contraction of the gas bag, one end portion of the gas bag in the fluid flow direction is fixed to one support member and the other end portion is fixed. Since it is configured to be supported by the other support member in a tensioned state via a spring, it is possible to eliminate the fluctuation of the gas bag due to the flow of fluid, keep the fluid flow smooth, and prevent the occurrence of leakage accidents. Along with that, when inflating the gas bag to perform a predetermined shutoff operation,
Taking advantage of the fact that the length of the gas bag is becoming shorter,
It is possible to exert a stronger tensile force on the gas bag to prevent wobbling. Moreover, when decompressing from inside the inflated gas bag to cause it to contract, since the strong pulling force of the spring acts in the direction of contraction, it is faster and more reliable than when the gas bag is contracted only by decompressing. Can be returned to. As described above, by making a very simple improvement such as adding a spring to the shutoff valve of the applicant's earlier application, it is possible to reduce the installation work cost and improve the shutoff and shutoff release operability at the same time. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a shutoff valve according to an embodiment of the present invention.

FIG. 2 is a plan view of the shutoff valve according to the embodiment.

FIG. 3 is a front view of a main part of the shutoff valve according to the embodiment.

FIG. 4 is a vertical sectional side view of a conventional shutoff valve.

[Explanation of symbols]

 1 Shut-off valve 2 Valve box 3 Stiffener (the other supporting member) 4 One supporting member 5 Gas bag 11 Pressure fluid supply / exhaust pipe 13 Spring

Claims (1)

[Claims] 1. A straight tubular valve box integrally formed of a plastic material, a gas bag made of an elastic material which is mounted in the valve box and expands and contracts by introducing and depressurizing a pressure fluid, and the gas bag. A pair of supporting members for supporting both ends in the fluid flow direction of the inside of the valve box, and connecting one end side of the gas bag in the fluid flow direction to a pressure fluid supply / exhaust means outside the valve box. In the shutoff valve, one end of the gas bag in the fluid flow direction is fixedly supported by one supporting member, and the other end of the shutoff valve has a pulling force acting in a direction away from the one end even when the gas bag is in a contracted state. A shut-off valve which is supported by the other support member via a spring.