JP2002276845A - Adjusting valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adjusting valve instantaneously corresponding to a change of fluid pressure and quickly converging to a set value. SOLUTION: The adjusting valve is provided with a body 1 having an inlet passage 8, an outlet passage 9, a valve chamber 7 in between and an opening part 10 communicating with the inlet passage and diametrally reduced along a flowing direction, a bonnet 2 having an internal void 12 communicated with an air supply port 11, a spring receiver 4 held by the body and the bonnet, a rod 5 having a collar part 15 in an upper part and a lower end piercing the spring receiver, a spring 6 supported between the collar part and the spring receiver and energizing the rod, and a diaphragm 3 with an upper end connected to the rod 5, a circumferential rim part held by the body and the bonnet, and a plug part 18 of a lower end positioned in the opening part 10. The plug part 18 is arranged inside the opening so that an opening area of a passage between the opening part 10 and the plug part 18 changes by a vertical motion of the rod 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve used for a fluid transport pipe requiring a flow rate adjustment. More specifically, the present invention relates to a control valve which is suitably used mainly for ultrapure water lines and various chemical liquid lines in the semiconductor industry and has excellent responsiveness to changes in fluid pressure.

[0002]

2. Description of the Related Art Conventionally, various flow control valves have been proposed. Generally, as shown in FIG. 10, a flow control valve is provided between an inlet flow passage 40 and an outlet flow passage 41 inside a valve body. A partition wall 42 that bends the flow direction, and an opening 43 provided in the partition 42 to communicate the inlet flow path 40 and the outlet flow path 41 and increase in diameter in the fluid downstream direction. A flow control valve in which a cylindrical plug 44 is disposed so as to be able to move up and down coaxially and a fluid control unit 45 is formed with the inner peripheral surface of the opening 43. When using such a flow control valve, the valve is connected to a plug 44 using a motor or air pressure.
Is mounted, and the actuator is operated by an external signal, whereby the plug 44 of the valve moves up and down, and the area of the opening 43 changes. Generally, to adjust the flow rate, a flow meter attached to the same fluid pipe as the valve and a controller for operating the actuator are used. The controller takes in the measured value of the flow meter as an electric signal, calculates the deviation between the target flow rate and the measured value, and outputs a signal for operating the actuator. The flow rate is adjusted by operating the actuator in response to the change in the area of the valve opening 43. For example, when the pressure in the inlet channel 40 increases and the flow rate increases, a signal of the increased flow rate is output from the flow meter to the controller. The controller calculates the amount of valve actuation corresponding to the increase in flow rate and sends a signal to the actuator.
The actuator lowers the plug 44 in response to the signal, reducing the area of the valve opening 43. Therefore,
The flow rate is restored.

[0003]

However, in the above-mentioned flow control valve, the response time of the flow meter or the controller becomes longer after the pressure is increased until the valve starts to be driven, so that the flow rate is stabilized. There was a problem that it took time before.

The present invention has been made in view of the problems of the conventional control valve, and has as its object to provide a control valve that quickly converges to a set value in response to a change in fluid pressure.

[0005]

The structure of the present invention will be described with reference to FIG. 1. A valve chamber 7 and an inlet flow path 8 and an outlet flow path 9 each communicating with the valve chamber 7 are provided at the upper part. A cylinder communicating with an inlet passage 8 at the center of the bottom of the valve chamber and having an opening 10 reduced in diameter along the flow direction of the fluid, and a cylinder communicating with an air supply port 11 provided on the side or top surface. Bonnet 2 having a stepped portion 13 at the lower end inner peripheral portion having a hollow space 12 therein, a spring receiver 4 inserted into the stepped portion 13 of the bonnet 2 and having a through hole 14 at a central portion, A flange 15 is provided, the lower end of which extends through the through hole 14 of the spring receiver 4, and is vertically movable by a spring 6 supported by the lower end surface of the flange 15 and the upper end surface of the spring receiver 4 so as to be vertically movable.
A rod 5 inserted into the inside 2, a peripheral portion 16 is clamped and fixed by the main body 1 and the spring receiver 4, and a joining portion 17 is joined and fixed to the rod 5 at the center of the upper surface, and a plug portion 18 at the tip of the center at the lower surface. Diaphragm 3 with shaft 19 provided
The plug 18 is inserted into the opening 10 so that the opening area of the flow path formed between the inner peripheral surface of the opening 10 and the plug 18 changes as the rod 5 moves up and down. The first feature is that they are arranged.

A second feature is that the plug portion 18 is formed in a disk shape. A third feature is that the plug portion 18 is formed in a hemispherical shape, and a fourth feature is that the plug portion 18 is formed in a conical shape.

In the present invention, the members such as the main body are made of PTF.
Fluororesins such as E and PFA are preferably used, but other plastics and metals such as polyvinyl chloride and polypropylene may be used, and there is no particular limitation. The material of the diaphragm is preferably a fluororesin such as PTFE, but may be rubber or metal, and is not particularly limited.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings, but it is needless to say that the present invention is not limited to the embodiments.

FIG. 1 is a longitudinal sectional view showing one embodiment of the control valve of the present invention, in which the pressure of the compressed air supplied to the gap 12 is small. FIG. 2 is a longitudinal sectional view of the control valve showing another state of FIG. 1 and shows a case where the pressure of the compressed air supplied to the gap 12 is large. FIG. 3 shows a plan view of the main body. FIG. 4 is an exploded perspective view of the rod, the spring, the spring receiver, and the diaphragm. 5 and 6 are longitudinal sectional views showing another embodiment of the plug shape of the diaphragm. FIG. 7 is a diagram showing one embodiment of the feedback loop of the control valve of the present invention. FIG. 8 is a graph showing the characteristics of the present invention and the conventional control valve. FIG. 9 is a graph showing the responsiveness of the present invention and the conventional control valve.

In FIG. 1, reference numeral 1 denotes a main body made of PTFE.
A cylindrical valve chamber 7 is provided at an upper portion, and an inlet channel 8 and an outlet channel 9 are provided at a lower portion so as to communicate with the valve chamber 7. An opening 10 whose inner diameter is reduced along the flow direction of the fluid is provided in a communicating portion between the inlet flow path 8 and the valve chamber 7. On the upper surface of the main body 1, there is provided an annular groove 20 into which the annular projection 21 of the diaphragm 3 is fitted.

Reference numeral 2 denotes a bonnet made of PVC, which has a cylindrical space 12 inside, and an air supply port 11 communicating with the space 12 is provided on a side surface. In this embodiment, the air supply port 11 is provided on the side surface of the bonnet 2, but may be provided on the upper surface. Further, a step portion 13 into which the spring receiver 4 is fitted is provided on the inner peripheral portion of the lower end of the bonnet 2.

The diaphragm 3 is made of PTFE, and has a shaft 19 having a disk-shaped plug portion 18 at the front end at the lower center, and is screwed to the rod 5 at the upper center. A joint 17 is provided. In this embodiment, the joint 17, the plug 18, the shaft 19, and the membrane 22 are integrally formed.
It is not necessary to integrally form the 7, the plug portion 18 and the shaft 19, but they may be formed separately and then integrated by screwing or the like. An annular projection 21 having a rectangular cross section is provided on the outer peripheral edge of the diaphragm 3 and is fitted in the annular groove 20 of the main body 1 to join the main body 1 and the bonnet 2 with bolts (not shown). As a result, the main body 1 and the spring receiver 4 fitted to the step portion 13 of the hood 2 sandwich the main body 1.

The plug 18 is arranged so as to be always located inside the opening 10 of the main body 1, and the diameter of the plug 18 is formed to be larger than the cross-sectional dimension of the shaft 19. The shape of the plug portion 18 is not limited to a disk shape, but may be a hemispherical or conical shape as shown in FIGS.

The spring receiver 4 is made of PVC, is fitted to the step 13 of the bonnet 2, has a through hole 14 at the center, and supports the spring 6 on the upper end surface.

The rod 5 is disposed in the gap 12 of the bonnet 2 and is made of PVC.
And the lower end is joined to the joint 17 of the diaphragm 3.
And are joined. A flange 15 is provided at the upper end, and the lower surface supports the upper end of the spring 6.

The spring 6 includes a spring receiver 4 and a flange 15 of the rod 5.
, And is always stretched upwardly. The spring 6 can be used as appropriate by changing the spring constant depending on the diameter of the control valve and the operating pressure range. A plurality of springs 6 may be used.

FIG. 4 shows the three-dimensional shape of the diaphragm 3, the spring receiver 4, the rod 5, and the spring 6.

Next, the operation of the present embodiment will be described.

FIG. 1 shows a case where the pressure of the compressed air supplied to the gap 12 of the bonnet 2 is kept low and the flow rate is set small. Here, the plug 18 is moved upward by the repulsive force of the spring 6 sandwiched between the flange 15 of the rod 5 and the spring receiver 4 and the fluid pressure on the lower surface of the membrane 22 of the diaphragm 3 and the lower surface of the plug 18. Since it is pushed up and further pushed down by the pressure of the compressed air on the upper surface of the membrane portion 22 of the diaphragm 3, it is stationary at a position where those forces are balanced.

When the pressure on the upstream side of the valve decreases from the state shown in FIG. 1, the pressure in the valve chamber 7 necessarily decreases. Therefore, the fluid pressure received by the lower surface of the plug portion 18 and the lower surface of the membrane portion 22 of the diaphragm 3 decreases, and the plug portion 18 is pushed down by the pressure of the compressed air in the gap 12 of the bonnet 2 and the opening area increases (see FIG. 2). Status). Since these operations occur instantaneously, the change in the flow rate is kept small. After a delay, the feedback loop, that is, the flow meter readings were taken as electrical signals to the controller,
The controller calculates the deviation from the set value, outputs the valve drive electric signal, converts the electric signal into an air signal with the electropneumatic regulator, and adjusts the air pressure (see Fig. 7).
Thereby, the pressure of the compressed air in the gap 12 is finely adjusted, and the flow rate is stabilized at the set value.

On the other hand, when the pressure on the upstream side of the valve increases from the state shown in FIG. 1, the pressure in the valve chamber 7 increases. Therefore, the fluid pressure received by the lower surface of the plug portion 18 and the lower surface of the membrane portion 22 of the diaphragm 3 increases, and the plug portion 18 is pushed up, and the opening area decreases. Since these operations also occur instantaneously as in the case where the pressure on the upstream side of the valve decreases, the change in the flow rate is kept small. Later, the pressure of the compressed air in the gap 12 is finely adjusted by the feedback loop, and the flow rate is stabilized at the set value.

FIG. 2 also shows the case where the flow rate is set large. By keeping the pressure of the compressed air supplied to the gap 12 of the bonnet 3 large, the pressure of the compressed air applied to the upper surface of the membrane portion 22 of the diaphragm 3 becomes larger than in the state of FIG. I do. Therefore, the opening area between the plug part 18 and the opening part 10 is large, and the flow rate is large.

When the pressure on the upstream side of the valve decreases from the state shown in FIG. 2, as in the case of FIG.
Due to the force of the compressed air inside, the plug portion 18 is momentarily pushed down to suppress the change in the flow rate to a small extent. Further, the pressure of the compressed air in the gap 12 is finely adjusted by the feedback loop, and the flow rate is stabilized at the set value.

On the other hand, when the pressure on the upstream side of the valve increases from the state shown in FIG. 2, the plug portion 18 is momentarily pushed up as in the case shown in FIG. Further, the pressure of the compressed air in the gap 12 is finely adjusted by the feedback loop, and the flow rate is stabilized at the set value.

Therefore, when it is desired to keep the flow rate constant even when the pressure of the fluid changes, it is necessary to adjust the opening area of the flow passage by changing the position of the plug portion 18 by increasing or decreasing the pressure inside the gap 12. However, by the above-described operation, the width of increase or decrease in the flow rate is suppressed to be narrow, and the adjustment width of the pressure inside the gap 12 is also suppressed to be narrow.

Next, in the embodiment, the diameter is 1/2 inch (1 inch).
FIG. 8 shows the result of measuring the relationship between the pressure on the upstream side of the valve and the fluid flow rate using a control valve (2.7 mm). Here, the horizontal axis represents the pressure on the upstream side of the valve, and the vertical axis represents the flow rate. The broken line shows the flow characteristics of the conventional fluid control valve having the same diameter, and the solid line shows the flow characteristics of the control valve of the present invention. As is clear from the figure, the flow rate of the conventional flow control valve increases with an increase in the pressure on the upstream side of the valve, but in the control valve of the present invention, when the pressure on the upstream side of the valve is 0.1 (MPa) or more, The flow rate is almost constant even if the pressure of the fluid changes. Therefore, the set flow rate can be maintained without substantially changing the pressure inside the gap of the bonnet.

FIG. 9 shows a change in the flow rate when the pressure upstream of the valve is rapidly increased from 0.1 (MPa) to 0.4 (MPa) using the same control valve. Here, the horizontal axis represents time, and the vertical axis represents flow rate. The broken line and the solid line indicate the flow rate changes of the conventional flow control valve and the control valve of the present invention, respectively. The experiment was performed with the flow rate set to (11 L / min). In the conventional flow control valve, the time until stabilization was about 28 seconds, and the maximum change amount of the flow rate was 8.5 (L / min), whereas in the control valve of the present invention, the time until stabilization was obtained. About 5 seconds, the maximum change amount of the flow rate was 1 (L / min) or less. As described above, it can be seen that the time required for stabilization and the amount of change in the flow rate after the pressure change are excellent.

[0028]

As described above, the control valve of the present invention has an effect of automatically stabilizing the flow rate even if the pressure of the fluid changes, and minimizes external operations. As compared with the flow control valve, the pressure quickly converges to the set value in response to a change in the pressure of the fluid upstream of the valve. That is, the control valve has excellent responsiveness.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a control valve of the present invention.

FIG. 2 is a longitudinal sectional view showing another state of the control valve of FIG. 1;

FIG. 3 is a plan view of the main body.

FIG. 4 is an exploded perspective view of a rod, a spring, a spring receiver, and a diaphragm.

FIG. 5 is a longitudinal sectional view showing another embodiment of a plug shape.

FIG. 6 is a longitudinal sectional view showing still another embodiment of a plug shape.

FIG. 7 is a diagram showing one embodiment of a feedback loop of the control valve of the present invention.

FIG. 8 is a graph showing flow characteristics of the control valve of the present invention and a conventional flow control valve.

FIG. 9 is a graph showing the responsiveness of the control valve of the present invention and the conventional flow control valve.

FIG. 10 is a longitudinal sectional view showing a conventional flow control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main body 2 ... Bonnet 3 ... Diaphragm 4 ... Spring receiving 5 ... Rod 6 ... Spring 7 ... Valve chamber 8 ... Inlet flow path 9 ... Outlet flow path 10 ... Opening 11 ... Air supply port 12 ... Void 13 ... Stepped part 14 ... through-hole 15 ... flange 16 ... peripheral part 17 ... joining part 18 ... plug 19 ... shaft 20 ... annular groove 21 ... annular protrusion 22 ... membrane part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H052 AA01 BA03 BA35 CA01 DA01 EA09 3H056 AA01 BB02 CA07 CB03 CD04 EE08 GG11 GG14 5H307 DD03 EE02 EE08 EE12 GG20 HH04

Claims (4)

[Claims] A valve chamber (7) and an inlet flow path (8) and an outlet flow path (9) each communicating with the valve chamber (7) are provided at an upper portion, and an inlet flow is provided at the center of the bottom of the valve chamber. A body (1) provided with an opening (10) having a diameter reduced along the flow direction of the fluid through a passage (8) and an air supply port (11) provided on a side surface or an upper surface. A bonnet (2) having a cylindrical gap (12) inside and a stepped portion (13) provided at the inner peripheral portion at the lower end; and a bonnet (2) fitted into the stepped portion (13) and penetrated to the central portion. Spring receiver (4) having mouth (14)
A flange (15) is provided on the upper part, and a lower end of the flange (15) passes through the through hole (14) of the spring receiver (4) and is supported by the lower end surface of the flange (15) and the upper end surface of the spring receiver (4). Spring (6)
The rod (5) inserted into the gap (12) of the bonnet (2) so as to be able to move up and down, and the peripheral portion (16) are clamped and fixed by the main body (1) and the spring receiver (4), and are fixed at the center of the upper surface. A diaphragm (3) having a joint (17) joined and fixed to the rod (5) and a shaft (19) provided with a tip plug (18) at the center of the lower surface is provided, and the plug (18) is provided. ) In the opening (10) such that the opening area of the flow path formed between the inner peripheral surface of the opening (10) and the plug (18) changes as the rod (5) moves up and down. A control valve, characterized in that the control valve is disposed in the control valve. 2. The control valve according to claim 1, wherein the plug part (18) is formed in a disk shape. 3. The control valve according to claim 1, wherein the plug part (18) is formed in a hemispherical shape. 4. The control valve according to claim 1, wherein the plug (18) has a conical shape.