JP3291063B2 - Overflow prevention valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mainly used in gas supply facilities of semiconductor manufacturing plants and the like.
The present invention relates to an improvement of an overflow prevention valve which prevents the occurrence of a disaster by shutting off a gas supply when an unexpected situation such as an accident occurs.

[0002]

2. Description of the Related Art Generally, in a facility using a hazardous gas such as a semiconductor manufacturing plant, an overflow prevention valve is installed on a gas supply source side, and a supply gas amount is rapidly increased due to an accident of a gas-using device or the like. In such a case, the supply is automatically cut 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 circulation gas.

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

[0004]

The overflow check valve shown in FIG. 8 has a relatively stable operation characteristic and a partition wall 29.
Since a is provided to reduce the internal volume of the valve chamber 29, the gas exchangeability is excellent, and a high practical utility is obtained. However, the overflow prevention valve is a so-called gravity type valve body 28.
Therefore, the mounting posture is limited to a horizontal state, and there is a disadvantage that the mounting cannot be performed in an arbitrary direction. In addition, in the overflow prevention valve, since the outer peripheral surface of the valve body 28 slides on the wall surface side of the valve box 23 when the valve body moves, generation of particles due to wear is inevitable, and gas purity is maintained. There is a problem. Further, since the valve element 28 is of a so-called gravity type, it is extremely difficult to set the blocking flow rate with high precision, and it is not possible to manufacture a blocking valve having both high sensitivity and high precision at low cost. There's a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional overflow check valve, has excellent accuracy and operating sensitivity, can be manufactured relatively inexpensively, and is particle-free. In addition, the present invention provides an overflow check valve having excellent gas replacement properties.

[0006]

Means for Solving the Problems The invention of claim 1 of the present invention is:
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, the main valve chamber 2 communicating with the sub-fluid passage 8, and the fluid outlet 3 communicating with the fluid outlet 3 through the communication passage 11, respectively. A valve box 1 having a sub-valve chamber 4 which is provided; a main plate seat 6 and a main valve body 7 formed in the main valve chamber 2 and having a through-hole 7e. The main valve body 7 fixed to the center thereof by the elastic force of the holding body 7b
From the main valve B, which is kept in the unseated position over a certain flow rate range and is in the open state during steady state; and from the sub-valve seat 9 and the diaphragm valve body 10 into the sub-valve chamber 4. An overflow prevention valve formed of a sub-valve C, which is closed during normal operation; and an actuator 22 for opening and closing the sub-valve C, has a stepped inner wall near the bottom of the main valve chamber 2. In addition to forming the portion 2a, the outer surface of the stepped portion 2a is an inclined surface whose inner portion is located on the bottom surface side in cross-sectional view, and the outer peripheral edge of the holding body 7b inserted into the main valve chamber 2 is formed as described above. The first bonnet 1 is brought into contact with the stepped portion 2a from outside the holding body 7b.
2 is inserted into the main valve chamber 2, and the outer peripheral edge of the holding body 7b is hermetically sandwiched between the stepped portion 2a and the tip end surface of the first bonnet 12 having an inclined surface matching the stepped portion 2a. The basic structure of the present invention is that, by applying pressure, a holding body made of a thin metal plate or a thin metal plate is bent substantially in a dish shape to obtain an elastic force for holding the valve body 7a in a detached state. It is assumed that.

[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 holding the valve body 7a at the unseated 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 fluid use side or the like, the pressure difference between the fluid inlet 13 and the fluid outlet 3 increases, and when the value exceeds a predetermined value, it opposes the elastic force of the holder 7b. As a result, the valve element 7 a snaps to the valve seat side and abuts on the main valve seat 6. Thereby, 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 Pressure difference is reduced.
As a result, the valve element 7a of the main valve element 7 returns to the unseated position by the elastic force of the holding member 7b, and then the auxiliary valve C is closed by the actuator 22, whereby the blocking valve A returns to the steady state.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a longitudinal 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 longitudinal sectional view of the valve body. In FIG. 1, 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, 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. 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, 18 is a second bonnet, and 22 is an actuator.

The valve box 1 is substantially inverted T-shaped (or substantially L-shaped).
The main valve chamber 2 communicates with the fluid inlet 13 on one side, the fluid outlet 3 on the side facing the main valve chamber 2, and the main valve chamber 2 and the fluid outlet 3. The sub-valve chambers 4 are formed on the sides orthogonal to the main fluid passages 5 communicating 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 a main valve seat 6 is provided in the main valve chamber 2.
A main valve B is formed which comprises a main valve body 7 and a main valve body 7 which is in contact with 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. Is formed. Reference numeral 11 denotes a communication passage that communicates 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 face of the first bonnet 12 inserted into the main valve chamber 2 from the outside. The valve 7a of the main valve 7 is always held at a position away from the main valve seat 6 as described later. The bonnet 12 has a fluid inlet 13 and a connection external thread 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.

The sub valve chamber 4 of the valve box 1 is provided with a diaphragm valve element 10, a diaphragm packing 16, a diaphragm presser 17, and a second bonnet 1 forming a sub valve C.
8 are inserted, and by tightening the second bonnet nut 19, the outer peripheral edge of the diaphragm valve body 10 is air-tightly pressed and fixed to the bottom surface of the sub-valve chamber 4 by the distal end surface of the second bonnet 18. . 20 is the actuator 2
Reference numeral 2 denotes a shaft, 21 denotes an O-ring, and 22 denotes a solenoid-driven (or air-driven) actuator.

As shown in FIGS. 2 and 3, the main valve body 7 is formed of a cylindrical valve body 7a at a central portion and a thin metal supporting member 7b for supporting the valve body 7a. Valve body 7a
Is fitted with a disc body 7c made of synthetic resin which abuts on the main valve seat 6. Further, a metal thin plate holding member 7b supporting the valve element 7a is formed by forming a spiral through hole 7e in a stainless steel thin thin plate. By pressing against the outer peripheral edge 2a of the bottom surface of the main valve chamber 2 by the distal end surface of the first bonnet 12,
The valve element 7a is held at a position separated from the main valve seat 6 with a certain elastic force.

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

FIGS. 4 and 5 show another embodiment of the main valve body 7. In this embodiment, the valve body 7a is connected to a flange 7g via a plurality of columns 7f. Supported,
The flanged body 7g is firstly moved to the outer peripheral edge 2a of the bottom surface of the main valve chamber 2.
By pressing and fixing by the front end surface of the bonnet 12, the valve element 7a at the center is held at the unseated position with a predetermined elastic force. In this embodiment, the gap between the columns 7f is a through hole 7e for the fluid D.

FIGS. 6 and 7 show a third embodiment of the main valve body 7. In this embodiment, a valve body is provided at the center of the tip of a spring body 7h in which a thin wire is spirally wound. 7a is fixed. The spring body 7 forming the holding body
h is wound so as to maintain a predetermined elastic force, and the valve element 7a is held at the unseated position by the elastic force. 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 an outlet of a fluid source such as a gas container or a gas tank. Fluid D from a fluid source (not shown) flows in the following order: 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 element 10 in the sub-valve chamber 4 is constantly pressed toward the sub-valve seat 9 via the diaphragm retainer 17 by the actuator 22, and the sub-fluid passage 9 and the main fluid passage 5 are shut off. Also,
The valve element 7a of the main valve element 7 is held at the unseated position by a holding member 7b with a constant elastic force, the flow rate of gas flowing out of the fluid outlet 3 is within a predetermined flow rate range, and the fluid inlet 13 When the pressure difference between the fluid and the fluid outlet 3 is within the set value,
The main valve B is kept open.

If an accident such as breakage of a pipe line occurs on the fluid outlet 3 side, the fluid flow rate on the fluid outlet 3 side (secondary side) increases, and the Pressure decreases. As a result, the pressure difference on the fluid outlet / inlet side increases, and when this pressure difference exceeds the set value, the valve body 7a
The elastic force b is pushed out to the main valve seat 6 side by overcoming the elastic force of “b”, and abuts on the main valve seat 6. Thereby, 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 piping path is eliminated, the pressing force of the diaphragm presser 17 is released by the actuator 22, and the diaphragm valve body 10 is separated from the auxiliary valve seat 9, and
The fluid B flows 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. Thereby, the pressure difference between the fluid inlet 13 and the fluid outlet 3 decreases, 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 element 7a separates, the diaphragm valve element 10 is pushed down by the actuator 22, and the auxiliary valve C
Is 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]

According to the present invention, the main valve B is provided in the valve box 1.
And a diaphragm type auxiliary valve C, a main valve B and a fluid outlet 3
Between the main valve B and the sub-valve C by a sub-fluid passage 8, and between the fluid outlet 3 and the sub-valve C by a communication passage 1.
1, the main valve body 7 of the main valve B for controlling the fluid D flowing from the fluid inlet 13 through a through hole 7e.
And a valve body 7a fixed to the center thereof, and the valve body 7a is held at the unseated position over a certain flow rate range by the elastic force of the support body 7b. Therefore, the main valve element 7 can operate stably irrespective of the installation direction, and the mounting direction is not limited as in the conventional overflow prevention valve. Also, the main valve body 7
Is held at the unseated position by the elastic force of the holding member 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 member 7b snaps quickly to the main position. Since it moves to the valve seat 6 side, a high responsiveness to the fluid blocking can be obtained. Further, the main valve body 7 forming the main valve B and the diaphragm valve body 10 forming the sub valve C
Does not come into contact with the valve box 1 at the time of operation,
A decrease in gas purity due to 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 replacement property is improved, which is extremely convenient for maintaining gas purity. In addition, by opening the auxiliary valve C after 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 the drawings]

FIG. 1 is a longitudinal sectional view of an overflow check 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 cross-sectional view taken along the line II in FIG. 2;

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

FIG. 5 is a cross-sectional view taken along the line E in FIG. 4;

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 in FIG. 6;

FIG. 8 is a longitudinal 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,
Is a valve box, 2 is a main valve chamber, 2a is a bottom peripheral edge, 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 disk body,
7e is a spiral through hole, 7f is a support, 7g is a flange, 7h is a spiral spring, 8 is a secondary fluid passage, 9 is a secondary valve seat,
10 is a diaphragm valve element, 11 is a communication passage, 12 is a first bonnet, 13 is a fluid inlet, 14 is an external thread for connection, 15
Is the first bonnet nut, 16 is the diaphragm packing, 17 is the diaphragm holder, 18 is the second bonnet,
19 is a second bonnet nut, 20 is a shaft, 21 is an O-ring, and 22 is an actuator.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16K 17/20-17/34 G05D 7/00

Claims (3)

(57) [Claims] A main valve chamber (2) communicating with a 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). (1) having a sub-valve chamber (4) communicating with a sub-fluid passage (8) and a fluid outlet (3) through a communication passage (11), respectively.
Made of a thin metal plate 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 valve element (7a) of the main valve element (7) fixed at the center is held at the unseated position over a certain flow rate range by the elastic force of the holder (7b) made of a disc or a thin metal plate. The main valve (B) is opened in the steady state, and is formed in the sub-valve (4) by the sub-valve seat (9) and the diaphragm valve element (10). A bottom valve of the main valve chamber (2) in an overflow prevention valve constituted by a sub-valve (C), which is provided; and an actuator (22) for opening and closing the sub-valve (C).
A step (2a) is formed on a nearby inner wall surface, and the step
The outer surface of the portion (2a) has a bottom portion on the bottom side in a sectional view.
And inserted into the main valve chamber (2).
The outer peripheral edge of the holder (7b) is brought into contact with the step (2a).
And the first bonnet from outside of the holding body (7b).
(12) is inserted into the main valve chamber (2), and the step (2a) is inserted.
Of the first bonnet (12) with an inclined surface that matches
Outside the holding body (7b) between the surface and the step (2a).
By pressing the periphery in an airtight manner,
Is a plate made of a thin metal plate that is bent almost like a dish.
To obtain the elastic force to hold the valve body (7a) in the unseated state.
An overflow check valve characterized by the following . 2. A main valve body (7) comprising: a holding member (7b) formed by forming a spiral through hole (7e) in a thin metal plate; and a central part of the holding member (7b). 2. The overflow prevention valve according to claim 1, comprising a valve body provided. 3. A main valve element (7) comprising a thin metal-plate-shaped flange (7g) and a support (7f) radially fixed inside thereof.
From consisting holder (7b), a flange-shaped body (7 g) over flow gate valve according to claim 1 in which the holding fixed configuration the valve body (7a) via a plurality of struts (7f) in the center of.