JPH08159308A - Diaphragm type automatic valve - Google Patents

Abstract

PURPOSE: To provide a diaphragm type automatic valve which serves as both an opening/closing valve and flow regulating valve so that a device can be miniaturized and a cost can be reduced, and can individually or simultaneously execute flow rate fine regulating operation without any trouble so as to be easily controlled. CONSTITUTION: A cylinder 17 is provided, which is equipped with a piston 15 having an air introducing opening 19 energized by a spring 18 to actuate a diaphragm piece 13 for pressing a diaphragm 9. A flow rate fine regulating mechanism 20 arranged on the upper side of the cylinder, consists of a cylindrical stem 21 equipped with a stem support 25, an inner screw member 27 fitted to the upper part of the stem support 25, and an outside screw member 28 equipped with a screw threadedly engaged with a screw arranged on the outside of the upper part of a cylinder cover. The pitch of the outside screw member 28 is formed larger than that of the inside screw member 27, and also the inside screw member 27 and the outside screw member 28 are integrally rotated by being fixed by a set screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm type automatic valve provided in a gas introduction line in a semiconductor manufacturing apparatus, and more particularly to a diaphragm type automatic valve capable of adjusting a minute flow rate.

[0002]

2. Description of the Related Art S shown in FIG.
In the iO ₂ oxidation system, valves V ₁ , V ₂ , V ₃ and V ₄ were provided in the four gas introduction lines 2 of the quartz chamber 1 heated by the heater, respectively. MFC (master flow controller) for V ₁ for H ₂ purge during power failure, V ₂ for N ₂ supply, V ₃ and V ₄ for H ₂ and O ₂
It is for the safety measure at the time of runaway of and also for the explosion prevention of the quartz chamber 1. Among these, for V ₁ , V ₃ and V _{4, the} on-off valve 3 and the flow rate adjusting valve 4 are arranged in series. When the on-off valve 3 and the flow rate adjusting valve 4 are arranged in series in each system of the gas introduction line 2 as described above, the control becomes complicated, the apparatus becomes large, and the cost becomes high.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to provide a diaphragm-type automatic valve which doubles as an on-off valve and a flow rate control valve, which simplifies the control and can reduce the size and cost of the device. To do.

[0004]

SUMMARY OF THE INVENTION A diaphragm type automatic valve of the present invention for solving the above-mentioned problems is a diaphragm valve for pressing a diaphragm against a valve seat of a valve box to shut off a gas fluid flowing inside the valve box. Where a cylinder provided with a piston having a spring-biased air introduction port for operating a diaphragm piece that presses the diaphragm is provided, and a fine flow rate adjusting mechanism is provided above the cylinder, and the fine flow rate adjusting mechanism is the piston A cylindrical shape with a stem support that fits the upper rod of the lower inside and is vertically and non-rotatably supported by a cylindrical cylinder cover on the outside of the middle part and has a screw on the outside of the upper part and an air supply port on the inside of the upper part Of the stem and a screw to be screwed to the screw on the outside of the upper part of the stem are provided on the inside of the lower part, and the outside of the lower part can be moved up and down inside the upper part of the cylinder cover The inner screw member is fitted and the upper inner part is fitted to the upper part of the stem support, and the upper inner part is fitted to the upper outer part of the inner screw member and is screwed to the screw provided on the upper outer part of the cylinder cover inside the intermediate part. An outer screw member provided with a matching screw, and the screw pitch of the outer screw member is made larger than the screw pitch of the inner screw member, and the inner screw member and the outer screw member are fixed by a set screw. It is characterized in that it is designed to rotate integrally.

[0005]

In the diaphragm type automatic valve constructed as described above, when the outer screw member and the inner screw member fixed by the set screw are rotated in the opening or closing direction, the screw of the outer screw member and the inner screw member are rotated. The stem moves up and down by the difference in the screw pitch from the screw, and the stop position of the piston, that is, the stop position of the diaphragm piece is changed to adjust the flow rate. Since the pitch difference between the outer threaded member and the inner threaded member is in the hundreds, fine flow rate adjustment is performed. At this time, it can be used as a minute flow rate adjusting valve if air is not supplied or discharged from the air supply port of the stem support, and as an opening / closing valve with a minute flow rate adjusting mechanism if air is supplied or discharged.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a diaphragm type automatic valve of the present invention will be described with reference to the drawing. In FIG. 1, numeral 5 is a valve box having a fluid inflow passage 6 on one side and a fluid outflow passage 7 on the other side. There is. An outlet side of the fluid inflow passage 6 is opened perpendicularly to the center of the valve box 5, and an annular valve seat 8 is embedded and fixed at the periphery of the opening. 9 is a diaphragm formed by forming a special steel thin plate into a circular dish shape, and 10 is a step portion 11 in the periphery of the valve box 5.
With the bonnet that holds down the outer peripheral part of the diaphragm 9,
The bonnet 10 is tightened by a cylinder base 12 screwed onto the outer periphery of the vertical portion 5a of the valve box 5, whereby the outer peripheral portion of the diaphragm 9 is clamped between the lower end surface of the bonnet 10 and the step portion 11. ing. Reference numeral 13 is a diaphragm piece that is vertically movable in the bonnet 10. The diaphragm piece 13 is pressed by a lower rod 15a of a piston 15 that penetrates a hole 14 in the center of the cylinder base 12. . The piston 15 is arranged in a cylinder 17 formed by a cylinder base 12 and a cylinder cover 16 in which a lower portion 16a is airtightly screwed onto the outer circumference of the cylinder base 12, and is biased by a spring 18 toward the diaphragm 9 side. In the center of this piston 15, the upper rod 15
An air inlet 19 is provided from b to the outer circumference of the base of the lower rod 15a. A fine flow rate adjusting mechanism 20 is provided on the upper side of the cylinder 17. In this fine flow rate adjusting mechanism 20, a lower inner side 21a is fitted to an upper rod 15b of the piston 15, and the lower inner side 21a is freely movable up and down inside the intermediate portion 16b of the cylinder cover 16 on the outside of the intermediate portion 21b. A cylindrical stem 21 that is non-rotatably supported, has a screw 23 on the outside of the upper portion 21c, and has a stem support 25 having an air supply port 24 inside the upper portion 21c, and an outer portion of the upper portion 21c of the stem 21. The screw 26 that engages with the screw 23 is provided inside the lower portion 27a, and the lower portion 27a
The inside of the upper part 27b is fitted to the inside of the upper part 16c of the cylinder cover 16 so as to be able to move up and down, and the inside of the upper part 27b is fitted to the upper part of the stem support 25, and the upper part 27b of the inner screw member 27. An outer screw member 28 having an inner side of an upper portion 28a fitted to the outer side of the inner side of the intermediate portion 28b, and a screw 30 provided on the inner side of the intermediate portion 28b to engage with a screw 29 provided on the outer side of the upper portion 16c of the cylinder cover 16; The outer screw member 28 is larger than the pitch of the screw 26 of the inner screw member 27.
The pitch of the screw 30 is increased, and the inner screw member 27 and the outer screw member 28 are fixed by a set screw 31 so as to rotate integrally. 32 is an external screw member 28
Is a set screw that stops the vertical movement of the stem support 33, and 33 is a set screw that fixes the stem support 25 and the inner screw member 27.

In the diaphragm type automatic valve of the embodiment constructed as described above, during normal use, air is supplied from the air supply port 24 of the stem support 25 as shown in FIG.
Air inlet 19 of piston 15 through stem 21
When air is introduced into the lower chamber of the cylinder 17 from the above, the piston 15 rises against the spring 18 and comes into contact with the lower end of the stem 21, the diaphragm piece 13 pressed by the lower rod 15a of the piston 15 is pressed. Is released, and as a result, the diaphragm 9 acts to restore the original dish shape by the elastic restoring force of the diaphragm 9. At that time, the restoring force of the diaphragm 9 overcomes the weight of the diaphragm piece 13 on the upper surface sufficiently, the diaphragm 9 is restored to the original dish shape, the lower surface of the diaphragm 9 is separated from the valve seat 8, and the valve is opened. It becomes a state.

On the contrary, when the air in the lower chamber of the cylinder 17 is evacuated, the pushing force of the piston 15 is lost and the piston 15
Is urged downward by a spring 18, which causes the lower rod 15a of the piston 15 to move toward the diaphragm piece 1.
3 is pushed down, the diaphragm 9 is pushed and the lower surface is pushed against the valve seat 8, and the valve is closed. The above is the mode of use as an on-off valve.

Next, a mode of use as a flow rate adjusting valve will be described. FIG. 1 shows a usage state in which the valve is opened to the maximum and the flow rate is maximized. In order to adjust the flow rate of the diaphragm type automatic valve in this state to be decreased, the set screw 32 fixing the outer screw member 28 to the cylinder cover 16 is loosened, and then the outer screw fixed by the set screw 31. Member 2
8 and the inner screw member 27 are rotated together in the closing direction. Then, as shown in FIG. 2, the stem 21 descends as much as the difference in the thread pitch between the screw 30 of the outer screw member 28 and the screw 26 of the inner screw member 27, and the piston 15 rises up. The ascending end position becomes low, and thus the diaphragm 9 when the valve is opened does not completely return to the original state, but is restored halfway, and the gap between the lower surface of the diaphragm 9 and the valve seat 8 becomes small, and the flow rate adjustment is performed. Is done.
In this flow rate adjustment, the pitch difference between the screw 30 of the outer screw member 28 and the screw 26 of the inner screw member 27 is in the order of one hundredth,
As can be seen from the comparison between FIG. 1 and FIG. 2, even if the amount of downward rotation of the outer screw member 28 and the amount of inner screw member 27 is large, the amount of lowering of the stem 21 is extremely small. Therefore, the upper limit position of the piston 15 and the diaphragm piece 13 is increased. And the restoration amount of the diaphragm 9 are small, and the valve opening is finely adjusted.
Fine flow rate adjustment is performed. Then, the outer screw member 28 is fixed to the cylinder cover 16 with the set screw 32. In the diaphragm type automatic valve with the fine flow rate adjusted in this way, if air is supplied or discharged from the air supply port 24 of the stem support 25 as described above, it can be used as an on-off valve.

[0010]

As can be seen from the above description, the diaphragm type automatic valve of the present invention serves both as an on-off valve and a flow rate adjusting valve. Two purge on-off valves and two flow rate adjusting valves were provided in series, and only one was required, and the size and cost of the apparatus can be reduced. Further, the diaphragm type automatic valve of the present invention can perform the opening / closing operation as the opening / closing valve and the fine flow rate adjusting operation as the flow rate adjusting valve individually or simultaneously without any trouble, so that the control is extremely simple.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a diaphragm type automatic valve of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state in which the diaphragm type automatic valve of FIG. 1 has a flow rate adjusted.

FIG. 3 is a diagram showing a gas introduction line of a quartz chamber heated by a heater in a SiO ₂ oxidation system in a semiconductor manufacturing apparatus.

[Explanation of symbols]

 5 Valve Box 8 Valve Seat 9 Diaphragm 12 Cylinder Base 13 Diaphragm Piece 15 Piston 15a Piston Lower Rod 15b Piston Upper Rod 16 Cylinder Cover 17 Cylinder 18 Spring 19 Air Inlet 20 Fine Flow Control Mechanism 21 Stem 22 Rotation Stopper 23 Stem screw 24 Air supply port 25 Stem support 26 Internal screw member screw 27 Inner screw member 28 External screw member 29 Cylinder cover screw 30 External screw member screw 31 Set screw

Claims (1)

[Claims] 1. In a diaphragm valve for pressing a diaphragm against a valve seat of a valve box to shut off a gas fluid flowing inside the valve box, a spring-biased air inlet for operating a diaphragm piece for pressing the diaphragm is provided. A cylinder with a piston having is provided, a fine flow rate adjusting mechanism is provided on the upper side of the cylinder, and the fine flow rate adjusting mechanism is such that a lower inner side is fitted to an upper rod of the piston, and a cylindrical cylinder cover is provided on an outer side of an intermediate portion. A cylindrical stem equipped with a stem support that is vertically movable and non-rotatably supported, has a screw on the outside of the upper part, and has an air supply port on the inside of the upper part, and a screw that is screwed to a screw on the outside of the upper part of the stem is attached to the inside of the lower part. An inner threaded member having a lower outer side fitted to the upper inner side of the cylinder cover in a vertically movable manner and an upper inner side fitted to the upper side of the stem support, and the inner thread member The outer side of the upper part of the screw member is fitted to the inner side of the upper part, and the inside of the intermediate part is provided with an outer screw member provided with a screw to be screwed into a screw provided on the outer side of the upper part of the cylinder cover, and the screw pitch of the inner screw member Also, the diaphragm type automatic valve is characterized in that the screw pitch of the outer screw member is increased and the inner screw member and the outer screw member are fixed by a set screw so as to rotate integrally.