JP3212484B2 - Shut-off valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is installed at an appropriate place such as a polyethylene gas pipe or a water pipe, and is used for urgently interrupting the flow of a fluid when an internal fluid leakage accident or the like occurs. More specifically, the present invention relates to a shut-off 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 shut-off valve using a gas bag of this type does not generate a reaction force of an operating torque at the time of opening and closing the valve, unlike a shut-off valve composed of a general metal valve. There is an advantage that it is not necessary to interpose a steel pipe or the like that withstands the operation torque reaction force, so that it can be easily connected to a polyethylene pipe or the like, thereby reducing the installation work cost.

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

On the other hand, the other end of the gas bag 5 in the fluid flow direction is connected to a support fitting 5b attached to the other end of the gas bag 5,
An outer cylinder 3a slidingly in contact with the inner peripheral surface of the outer cylinder 3a and an outer cylinder 3a formed by a radial plate-like member 3c concentrically disposed inside the outer cylinder 3a.
Is slidably fitted to the inner cylinder 3b of the stiffener 3, which is the other support member made up of the short inner cylinder 3b fixed to the support member, and is movably supported 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 one support member 4 side. Through the gas bag 5 and the pressure fluid supply / exhaust pipe 1
1 is communicated. The pressure fluid supply / exhaust pipe 11 is provided with an on-off valve 12 and a pressure gauge (not shown). 10 is an O-ring.

In the shut-off valve having the above configuration, the gas bag 5 is normally in a contracted position as shown by a solid line in FIG. 4, and a fluid such as gas or water flows through the internal flow path of the valve box 2. . If it is necessary to urgently shut off the flow of the 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 fitting 8, the piping 7, when a pressurized fluid such as air or nitrogen gas is introduced into the gas bag 5 through the elbow 6 and the base 5a, the gas bag 5 quickly expands, and the outer peripheral surface thereof becomes a valve case as shown by a dotted line in FIG. 2 comes into contact with the inner peripheral surface, and is then pressed against the inner peripheral surface, so that the flow of fluid is reliably shut off.

[0006]

However, in the conventional shut-off valve having the above-described structure, one end of the gas bag 5 is fixedly supported by the support member 4, but the other end of the gas bag 5 is supported by the stiffener 3b. The gas bag 5 is slidably fitted to the inner cylinder 3b and is supported so as to be movable in the fluid flow direction. When the gas bag 5 is contracted, it takes time to return to the original contracted state only by depressurizing the gas bag 5, and especially in the case of a parasol type, it can be returned to the original folded state. However, there is a problem that the flow of the fluid during normal operation is adversely affected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a shut-off valve which can suppress the fluctuation of a gas bag due to the flow of a fluid and can quickly and surely return from an expanded state to an original contracted state. It is intended to be.

[0008]

In order to achieve the above-mentioned object, a shut-off valve according to the present invention comprises a straight tubular valve box integrally formed of a plastic material, and a pressure fluid mounted in the valve box for pressure fluid. A gas bag made of an elastic material that expands and contracts when introduced and depressurized, and a pair of support members that support both ends of the gas bag in the fluid flow direction in the valve box; In one end side of the shut-off valve is connected to the pressure fluid supply and exhaust means outside the valve box,
One end of the gas bag in the fluid flow direction is fixedly supported on one support member, and the other end is interposed via a spring such that a pulling force acts in a direction away from the one end even when the gas bag is in a contracted state. And supported by the other support member.

[0009]

According to the present invention, the gas bag is exposed to the flow of the fluid during the normal time when the gas bag contracts and the fluid flows, but one end in the flow direction is fixed to one support member. Since the other end is supported by the other supporting member in a tensioned state via a spring, the other end does not fluctuate due to the flow of the fluid and does not adversely affect the flow of the fluid. Also, when it is necessary to urgently shut off the flow of the fluid due to the occurrence of a leak accident or the like, the pressure fluid supply / exhaust means supplies the pressure fluid into the gas bag to expand the gas bag, and the gas bag expands. By pressing the outer peripheral surface of the gas bag against the inner peripheral surface of the straight tubular valve box, the flow of the fluid is surely shut off. Since no such operating torque is generated, there is no need to interpose a steel pipe or the like that withstands the operating torque reaction force before and after the shut-off valve,
Not only can the gas bag be easily connected to a polyethylene tube, etc., but also the gas bag expands due to the expansion force acting on the spring in order to shorten the length of the gas bag as the gas bag expands. At this point, a stronger pulling force is applied than at normal times, and the gas bag does not fluctuate.

Further, when the gas bag is decompressed and contracted from the expanded gas bag, the gas bag contracts quickly and surely and returns to the original flow state because the strong tensile force of the spring acts in the contracting direction. Will do. In particular, even in the case of a parasol-type gas bag, it can be quickly returned to the original folded state.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional side view of a shut-off valve according to an embodiment of the present invention, FIG. 2 is a plan view of the shut-off valve, and FIG. 3 is a front view of a main part of the shut-off valve. , 3
Since a to 3c and 5a to 5c are the same components as those of the conventional shut-off valve shown in FIG. 4, the same reference numerals are given to those components and detailed description is omitted. Further, the straight tubular valve box 2 integrally formed of a plastic material such as polyethylene is formed so as to have a uniform inner diameter and to have both ends 2a and 2b in the axial direction of the same size as the adjacent fluid pipe. The central portion 2c is formed to have a somewhat thicker tube wall 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 support member 4 and a support member 5b attached to the other end in the fluid flow direction is connected to the bottom wall 3 of the inner cylinder 3b of the stiffener 3 serving as the other support member.
The gas bag 5 is supported via the coil-shaped spring 13 so that a tensile force in the direction away from the base 5a at one end acts even when the gas bag 5 is in a contracted state as shown by the solid line in FIG. I have.

Next, the operation of the shut-off valve 1 having the above configuration will be described. Normally, the gas bag 5 is in a contracted posture as shown by a 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 one support member 4, and the other end is supported by the stiffener 3 in a tensioned state via a spring 13. 5
Does not fluctuate and does not adversely affect the flow of the fluid.

If it is necessary to urgently shut off the flow of the 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, and the like. When a pressurized fluid such as air or nitrogen gas is introduced into the gas bag 5 through the pipe 8, the pipe 7, the elbow 6, and the base 5a, the gas bag 5 expands quickly, and its outer peripheral surface is as shown by a dotted line in FIG. As a result, it comes into contact with and presses against the inner peripheral surface of the valve box 2, and the flow of the fluid is reliably shut off. At this time, since no torsional torque or the like is generated in the shut-off valve 1, there is no need to interpose a steel pipe or the like withstanding the reaction torque of the shut-off valve 1 before and after the shut-off valve 1, and the shut-off valve 1 is easily connected to a polyethylene pipe or the like. It is possible.

In order to reduce the length of the gas bag 5 as the gas bag 5 expands, the gas bag 5 expands when the gas bag 5 expands due to the expansion force acting on the spring 13 against the elasticity. In this case, a stronger pulling force is applied than in the normal case, and the gas bag 5 does not fluctuate during the expansion process.

Further, when the fluid is depressurized and contracted from inside of the expanded gas bag 5, the strong tension of the spring 13 acts in the direction of contracting the gas bag 5, so that the gas bag 5 is quickly and reliably. To return to the 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 support plug may be used as a support member, and the spring 13 may be interposed between the support plug and the other end of the gas bag 5.

[0018]

As described above, according to the present invention, when the gas bag is contracting normally, one end of the gas bag in the fluid flow direction is fixed to one support member, and the other end is fixed to the support member. Since the other support member is supported in a tensioned state via a spring, the gas bag does not fluctuate due to the flow of the fluid. Also, when performing a predetermined shut-off operation by inflating the gas bag
Utilizing the fact that the length of the gas bag is going to be shorter,
By applying a stronger pulling force to the gas bag, it is possible to prevent wobble. Moreover, when the gas bag is decompressed and contracted from within the expanded gas bag, the strong contraction force of the spring is applied in the contraction direction. Can be restored. As described above, by applying a very simple improvement by simply adding a spring to the shut-off valve of the prior application by the present applicant, it is possible to reduce the installation work cost and simultaneously improve the shut-off and shut-off release operability. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a vertical side view of a shut-off valve according to an embodiment of the present invention.

FIG. 2 is a plan view of the shut-off valve according to the embodiment.

FIG. 3 is a front view of a main part of the shut-off valve according to the embodiment.

FIG. 4 is a vertical sectional side view of a conventional shut-off valve.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-30511 (JP, A) JP-A 61-54560 (JP, U) JP-A 4-31371 (JP, U) Jiko 37- 13670 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16K 7/10 F16K 7/02

Claims (1)

(57) [Claims] 1. A straight tubular valve box integrally formed of a plastic material, a gas bag which is mounted in the valve box and is made of an elastic material which expands and contracts by introduction and decompression of a pressurized fluid, A pair of support members for supporting both ends in the fluid flow direction of the gas bag in the valve box. One end of the gas bag in the fluid flow direction is communicated with a pressure fluid supply / exhaust means outside the valve box. In the shut-off valve, one end of the gas bag in the fluid flow direction is fixed and supported by one support member, and the other end of the gas bag acts in a direction in which the gas bag moves away from the one end even when the gas bag is in a contracted state. Characterized by being supported by the other support member via a spring.