JPH06281034A - Excessive flow rate inhibiting valve - Google Patents

Abstract

PURPOSE:To provide an excessive flow rate inhibiting valve having excellent accuracy and operating sensitivity by deviating a valve body against elastic force of a holder according to a difference in pressure between a fluid inlet and a fluid outlet in a snap manner in the case where an outlet flow rate is rapidly increased due to an accident on a side of fluid use. CONSTITUTION:In an excessive flow rate inhibiting valve A disposed, e.g. in the vicinity of an outlet of a gas tank, fluid D flows from a fluid inlet 13, a through hole 7e of a main valve body holder 7b, a main valve chamber 2, a main fluid passage 5, and a fluid outlet 3 in sequence. In this state, when a pipeline path is broken and an outlet rate of the fluid is rapidly increased, a difference in pressure between a fluid outlet and a fluid inlet is increased so that the valve body 7a is pushed out onto a side of the main valve seat 6 against elastic force of the holder 7b in a snap manner and the main valve B is closed, thus stopping the supply of the fluid D. After restoring, an actuator 22 releases pressing force of a diaphragm presser 17, to thereby open a diaphragm valve body 10. Consequently, the difference in pressure is eliminated so that the valve body 7a is returned to a valve opening position by the elastic force of the holder 7b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly used in gas supply facilities such as semiconductor manufacturing plants.
The present invention relates to improvement of an overflow prevention valve that prevents the occurrence of a disaster by cutting off the gas supply when an unexpected situation such as an accident occurs.

[0002]

2. Description of the Related Art Generally, in facilities that use dangerous gases such as semiconductor manufacturing plants, an overflow prevention valve is installed on the gas supply source side, and the amount of supplied gas has rapidly increased due to an accident such as equipment using gas. In some cases, the supply is automatically shut off. FIG. 8 shows an example of a conventional overflow prevention valve, in which 23 is a valve box, 24 is a gas inlet,
25 is a gas outlet, 26 is a valve seat, 27 is a fluid passage, 28 is a valve body, 29 is a valve chamber, 30 is a spring, 31 is a magnet type poppet, 32 is a magnet type reset button, 3
3 is a circulating gas.

If the flow rate of gas passing through the overflow prevention valve is within a predetermined flow rate range, the gas 3 flowing from the inlet 24
3 flows as shown by the arrow and flows out from the outlet 25.
On the other hand, if an accident such as pipe breakage occurs on the gas use side, the gas inlet 24 side and the gas outlet 25 of the blocking valve
The pressure difference on the side increases, whereby the valve body 28 is pushed up and abuts on the valve seat 26. As a result, the fluid passage 27 is closed and the supply of the gas 33 is blocked. Further, after the recovery of the accident or the like, the reset button 32 is pushed down, the poppet 31 in the valve chamber 29 is pushed down by magnetic force, and the valve body 28 is pushed down, so that the fluid passage 27 is opened. .

[0004]

The overflow prevention valve shown in FIG. 8 has a relatively stable operation characteristic and has a partition wall 29.
Since the inner volume of the valve chamber 29 is made smaller by providing a, it has an excellent gas displacing property and has a high practical utility. However, the overflow prevention valve is a so-called gravity type valve body 28.
Since it is equipped with, the mounting posture is limited to the horizontal state, and there is a drawback that it cannot be mounted in any direction. Further, in the overflow prevention valve, since the outer peripheral surface of the valve body 28 is in sliding contact with the wall surface side of the valve box 23 during its movement, it is inevitable to generate particles due to wear, and the gas purity is maintained. I have a problem with. Further, since the valve body 28 is of a so-called gravity type, it is extremely difficult to set the blocking flow rate value with high accuracy, and it is impossible to inexpensively manufacture a blocking valve having both high sensitivity and high accuracy. There's a problem.

The present invention is intended to solve the above-mentioned problems in the conventional overflow prevention valve, has excellent accuracy and operating sensitivity, and can be manufactured at a relatively low cost and is particle-free. In addition, an overflow prevention valve having excellent gas replacement property is provided.

[0006]

The invention according to claim 1 comprises a main valve chamber 2 communicating with a fluid inlet 13, and a fluid outlet 3 communicating with the main valve chamber 2 through a main fluid passage 5. By the elastic force of the holding body 7b which is formed in the main valve chamber 2 from the valve box 1 and the main valve seat 6 and the main valve body 7, and has the through hole 7e,
The main valve B, which is fixed to the center of the valve body 7a of the main valve body 7 and is kept open in a steady state by holding the valve body 7a of the main valve body 7 in the separated position over a certain flow rate range, is a basic configuration of the invention. . In the invention according to claim 2, the main valve chamber 2 communicating with the fluid inlet 13, the fluid outlet 3 communicating with the main valve chamber 2 through the main fluid passage 5, and the auxiliary fluid passage 8 with the main valve chamber 2. And a valve box 1 provided with a sub-valve chamber 4 that communicates with the fluid outlet 3 through a communication passage 11, respectively; a main valve seat 6 and a main valve body 7 formed in the main valve chamber 2; Due to the elastic force of the holding body 7b having 7e, the valve body 7a of the main valve body 7 fixed to the center of the valve body 7a is kept in the separated position over a certain flow rate range and is in the open state in the steady state. And; Sub valve seat 9 and diaphragm valve body 10
And an auxiliary valve C which is formed in the auxiliary valve chamber 4 and which is closed in a steady state; and an actuator 2 for opening and closing the auxiliary valve C.
2 is a basic configuration of the invention.

[0007]

In the steady state, the sub valve C is closed, and the main valve body 7 of the main valve B is opened by the valve body 7a being held in the separated position by the elastic force of the holding body 7b. ing. As a result, the fluid (gas) flowing from the fluid inlet 13
D enters the main valve chamber 2 through the through hole 7e of the holder 7b and flows through the main fluid passage 5 to the fluid outlet 3 side. Further, when the flow rate of the fluid D suddenly increases due to an accident on the side using the fluid, the pressure difference between the fluid inlet 13 and the fluid outlet 3 increases, and when the value exceeds a predetermined value, the elastic force of the holding body 7b is resisted. The valve body 7a snaps to the valve seat side and abuts against the main valve seat 6. As a result, the main valve B is closed and the flow of the fluid D is shut off. On the other hand, by actuating the actuator 22 to open the sub valve C, the fluid D flows from the main valve chamber 2 to the main fluid passage 5 through the sub fluid passage 8 and the communication passage 11, and the fluid D 3 is discharged between the fluid outlet 3 and the fluid inlet 13. The pressure difference is reduced.
As a result, the valve body 7a of the main valve body 7 is returned to the separated position by the elastic force of the holding body 7b, and then the auxiliary valve C is closed by the actuator 22, so that the blocking valve A is returned to the steady state.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a vertical sectional view of an overflow prevention valve A according to the present invention, FIG. 2 is a plan view of a valve body, and FIG. 3 is a vertical sectional view of a valve body. In FIG. 1, A is an overflow prevention valve, B is a main valve, and C
Is a sub valve, D is a fluid, 1 is a valve box, 2 is a main valve chamber, 3 is a fluid outlet, 4 is a sub valve chamber, 5 is a main fluid passage, 6 is a main valve seat, 7 is a main valve body, and 8 is a main valve body. Sub-fluid passage, 9 sub-valve seat, 10 diaphragm valve body, 11 communicating passage, 12 first bonnet, 13 fluid inlet, 18 second bonnet, and 22 actuator.

The valve box 1 is substantially inverted T-shaped (or substantially L-shaped).
The main valve chamber 2 communicating with the fluid inlet 13 is provided on one side thereof, the fluid outlet 3 is provided on the side facing the main valve chamber 2, and the main valve chamber 2 and the fluid outlet 3 are further provided. Sub valve chambers 4 are formed on the sides orthogonal to the main fluid passages 5 that communicate with each other. The main valve chamber 2 and the fluid outlet 3 are communicated with each other by a linear main fluid passage 5, and the main valve seat 6 is provided in the main valve chamber 2.
A main valve B is formed by a main valve body 7 which is pressed against and separates from the main valve. Further, the main valve chamber 2 and the sub-valve chamber 4 are communicated with each other by a sub-fluid passage 8, and in the sub-valve chamber 4, a sub-valve seat 9 and a diaphragm valve body 10 that abuts / separates from the sub-valve seat 9 are provided. A sub valve C is formed. Reference numeral 11 is a communication passage communicating between the sub valve chamber 4 and the main fluid passage 5.

The main valve body 7 forming the main valve B is hermetically sealed to the outer peripheral edge 2a of the bottom surface of the main valve chamber 2 by the front end surface of the first bonnet 12 inserted into the main valve chamber 2 from the outside. The valve body 7a of the main valve body 7 is always held at a position away from the main valve seat 6 as described later. Further, the bonnet 12 has a fluid inlet 13 and a connecting external screw 1
4 and the like are formed and are pressed and fixed to the main valve chamber 2 side of the valve box 1 by the first bonnet nut 15.

In the sub-valve chamber 4 of the valve box 1, a diaphragm valve body 10 forming a sub-valve C, a diaphragm packing 16, a diaphragm retainer 17 and a second bonnet 1 are provided.
8 are inserted in each, and by tightening the second bonnet nut 19, the outer peripheral edge of the diaphragm valve body 10 is pressed and fixed to the bottom surface of the sub valve chamber 4 by the tip end surface of the second bonnet 18 in an airtight manner. . 20 is the actuator 2
2 is a shaft, 21 is an O-ring, and 22 is a solenoid drive type (or air drive type) actuator.

As shown in FIGS. 2 and 3, the main valve body 7 is formed of a central cylindrical valve body 7a and a metal thin plate holder 7b for supporting the valve body 7a. Valve body 7a
A disk body 7c made of a synthetic resin, which is seated on the main valve seat 6, is fitted in. Further, the holding body 7b made of a thin metal plate that supports the valve body 7a is formed by forming a spiral through hole 7e in a circular thin plate made of stainless steel, and the outer peripheral edge of the holding body 7b is slightly inclined. By pressing the outer peripheral edge 2a of the bottom of the main valve chamber 2 by the tip surface of the first bonnet 12,
The valve body 7a is held at a position separated from the main valve seat 6 with a constant elastic force.

In the present embodiment, the outer peripheral edge 2a of the bottom surface of the main valve chamber 2 is formed into an inclined surface, and the outer peripheral edge of the holding body 7b is pressed and fixed to this, whereby the valve body 7a of the main valve body 7 is closed. Although it is configured to be held at a position separated from the seat 6 with a constant elastic force, the outer peripheral edge 2a of the bottom surface is formed in a planar shape, and the valve body 7a fixed to the center of the holder 7b itself is separated. The elastic force in the direction may be applied in advance.

FIG. 4 and FIG. 5 show another embodiment of the main valve body 7. In this embodiment, the valve body 7a is connected to the collar-shaped body 7g through a plurality of columns 7f. Supported,
The collar-shaped body 7g is first attached to the bottom peripheral edge 2a of the main valve chamber 2.
By pressing and fixing by the front end surface of the bonnet 12, the valve body 7a at the central portion is held at the separated position by a predetermined elastic force. In this embodiment, the gap between the columns 7f serves as the through hole 7e for the fluid D.

6 and 7 show a third embodiment of the main valve body 7, and in this embodiment, a valve body is provided at the center of the tip of a spring body 7h formed by spirally winding a thin wire rod. 7a is fixed. The spring body 7 that forms the holding body
The h is wound so as to hold a predetermined elastic force, and the valve body 7a is held at the separated position by the elastic force. Further, the fluid D flows into the main valve chamber 2 through the gap of the spring body 7h.

Next, the operation of the overflow prevention valve A according to the present invention will be described. The overflow prevention valve A is usually provided near the outlet of a fluid source such as a gas container or a gas tank. A fluid D from a fluid source (not shown) circulates in the order of fluid inlet 13-through hole 7e of main valve body holder 7b-main valve chamber 2-main fluid passage 5-fluid outlet 3. On the other hand, the diaphragm valve body 10 of the sub valve chamber 4 is constantly pressed by the actuator 22 to the side of the sub valve seat 9 via the diaphragm retainer 17, so that the sub fluid passage 9 and the main fluid passage 5 are shut off from each other. Also,
The valve body 7a of the main valve body 7 is held in a separated position by a holding body 7b with a constant elastic force, the flow rate of gas flowing out from the fluid outlet 3 is within a predetermined flow rate range, and the fluid inlet 13 And the pressure difference between the fluid outlet 3 is within the set value,
The main valve B is kept open.

In the event that an accident such as breakage of the pipeline occurs on the fluid outlet 3 side, the fluid flow rate on the fluid outlet 3 side (secondary side) increases and the inside of the main fluid passage 5 increases. Pressure is reduced. As a result, the pressure difference between the fluid outlet side and the inlet side increases, and when this pressure difference exceeds the set value, the valve body 7a moves to the holding body 7.
It overcomes the elastic force of b and is pushed out to the side of the main valve seat 6 in a snap manner, and abuts against the main valve seat 6. As a result, the main valve B is closed and the supply of the fluid B to the main fluid passage 5 is automatically stopped.

When the failure of the pipe line is eliminated, the actuator 22 releases the pressing force of the diaphragm retainer 17 to separate the diaphragm valve body 10 from the auxiliary valve seat 9.
The fluid B is circulated through the main valve chamber 2-the sub fluid passage 8-the sub valve chamber 4-the communication passage 11-the main fluid passage 5. As a result, the pressure difference between the fluid inlet 13 and the fluid outlet 3 is reduced, and the valve body 7a
Is separated from the main valve seat 6 by the elastic force of the holding force 7b.
When the valve body 7a is separated, the actuator 22 pushes down the diaphragm valve body 10 and the auxiliary valve C
Will be closed. As a result, the overflow prevention valve A returns to the initial steady state. The opening of the sub valve C by the operation of the actuator 22 is also performed when purging the downstream side of the overflow prevention valve A.

[0019]

In the present invention, the main valve B is installed in the valve box 1.
And diaphragm type auxiliary valve C are provided, and main valve B and fluid outlet 3
Between the main valve B and the sub valve C by the sub fluid passage 8, and between the fluid outlet 3 and the sub valve C through the communication passage 1
1, the main valve element 7 of the main valve B, which controls the fluid D flowing from the fluid inlet 13, while communicating with each other through the through hole 7e.
And a valve body 7a fixed to the center thereof, and the elastic force of the holding body 7b holds the valve body 7a in a separated position over a certain flow rate range. Therefore, the main valve body 7 can operate stably regardless of the installation direction, and the installation direction is not limited unlike the conventional overflow prevention valve. In addition, the main valve body 7
Is held at the separated position by the elastic force of the holding body 7b, so that when the pressure difference between the fluid outlet and the inlet exceeds a certain value, the valve body 7a supported by the holding body 7b snaps rapidly to the main position. Since it moves to the valve seat 6 side, high responsiveness to fluid blocking can be obtained. Further, a main valve body 7 forming the main valve B and a diaphragm valve body 10 forming the auxiliary valve C.
Has no contact with the valve box 1 side during operation,
The deterioration of gas purity due to the generation of particles is extremely reduced. In addition, since the main valve chamber 2 and the sub-valve chamber 4 have a small volume and a small gap, the so-called gas displacing property is improved and it is extremely convenient for maintaining the gas purity. Moreover, by opening the auxiliary valve C after the operation,
The main valve B can be easily returned to the steady state, and the purge gas can be supplied to the fluid outlet side.
The present invention has excellent practical utility as described above.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an overflow prevention valve according to the present invention.

FIG. 2 is a plan view of a main valve body used in the overflow prevention valve of the present invention.

FIG. 3 is a sectional view taken along the line E-I of FIG.

FIG. 4 is a plan view showing another embodiment of the main valve body.

FIG. 5 is a sectional view taken along the line E-I of FIG.

FIG. 6 is a plan view showing a third embodiment of the main valve body.

FIG. 7 is a sectional view taken along the line E-I of FIG.

FIG. 8 is a vertical sectional view of a conventional overflow prevention valve.

[Explanation of symbols]

A is an overflow prevention valve, B is a main valve, C is a sub valve, D is a fluid, 1
Is a valve box, 2 is a main valve chamber, 2a is a peripheral edge of a bottom surface, 3 is a fluid outlet, 4 is a sub valve chamber, 5 is a main fluid passage, 6 is a main valve seat, 7 is a main valve body, 7a is a valve body, 7b is a holding body, 7c is a disc body,
7e is a spiral through hole, 7f is a pillar, 7g is a collar body, 7h is a spiral spring body, 8 is a sub-fluid passage, 9 is a sub-valve seat,
10 is a diaphragm valve body, 11 is a communication passage, 12 is a first bonnet, 13 is a fluid inlet, 14 is an external screw for connection, 15
Is the first bonnet nut, 16 is the diaphragm packing, 17 is the diaphragm retainer, 18 is the second bonnet,
Reference numeral 19 is a second bonnet nut, 20 is a shaft, 21 is an O-ring, and 22 is an actuator.

Claims (5)

[Claims] 1. A valve box (1) having a main valve chamber (2) communicating with a fluid inlet (13) and a fluid outlet (3) communicating with the main valve chamber (2) through a main fluid passage (5). ) And ;; due to the elastic force of the holding body (7b) formed in the main valve chamber (2) from the main valve seat (6) and the main valve body (7) and having the through hole (7e), The valve body (7a) of the fixed main valve body (7)
Is an over-flow prevention valve that is composed of a main valve (B) that is kept open in a seated position over a certain flow rate range and is normally open. 2. A main valve chamber (2) communicating with the fluid inlet (13), a fluid outlet (3) communicating with the main valve chamber (2) through a main fluid passage (5), and a main valve chamber (2). A valve box (1) provided with a sub-valve chamber (4) communicating with the sub-fluid passage (8) and the fluid outlet (3) through the communication passage (11).
And a holding body (7) formed in the main valve chamber (2) from the main valve seat (6) and the main valve body (7) and having a through hole (7e).
The main valve body (7) fixed to the center by the elastic force of b)
A main valve (B) that keeps the valve body (7a) in the separated position over a certain flow rate range and is in a normally open state; a sub valve seat (9) and a diaphragm valve body (10). From the sub valve chamber (4), which is closed in a steady state, and an actuator (22) for opening and closing the sub valve (C). 3. A main valve body (7) is fixed to a holding body (7b) formed by forming a spiral through hole (7e) in a disc made of a thin metal plate, and a central portion of the holding body (7b). The overflow prevention valve according to claim 1 or 2, which is constituted by a valve body (7a) provided. 4. The main valve body (7) is provided with a plurality of struts (7f) in the center of a collar-shaped body (7g) made of a thin metal plate.
The overflow prevention valve according to claim 1 or 2, wherein a) is held and fixed. 5. The overflow prevention valve according to claim 1 or 2, wherein the main valve body (7) has a structure in which the valve body (7a) is held and fixed in the center of a spiral spring body (7h). .