JP2003329159A - Flow control valve - Google Patents

Abstract

(57) [Problem] To provide a flow control valve which is suitable for flowing a small amount of fluid, is easy in valve processing, and has no fear of backlash. A pressing force of a compression spring (57) disposed between a nut member (51) and a piston (56) is adjusted by an output applied to a spindle (12) from a motor (15) or the like, thereby adjusting a flow rate. Features.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve, and more particularly to a flow control valve suitable for flowing a very small amount of fluid such as carbon dioxide gas.

[0002]

2. Description of the Related Art A large amount of ultrapure water is used in the process of cleaning semiconductor and liquid crystal integrated circuits and electronic parts. Such ultrapure water removes almost all impurities,
The pure properties of water appear. For this reason, ultrapure water having a high insulating property generates static electricity when contacted with a solid and is charged. Therefore, if ultrapure water is jetted onto the wafer surface by a high-pressure jet in the manufacturing process of LSI or the like, Pure water is electrically charged, and static electricity is prone to damage. It is known that the generation of such static electricity can be effectively suppressed by dissolving a small amount of carbon dioxide gas in ultrapure water.

By the way, such a processing liquid is, for example,
As shown in FIG. 5, the carbon dioxide injection amount is calculated based on the actual flow rate entered into the ultrapure water flow rate sensor 30 and the set specific resistance value, and the mass flow controller 31 is calculated with this calculated value.
It is obtained by injecting carbon dioxide gas into the ultrapure water line 32 and passing it through the mixing filter 33 while adjusting the opening degree of the carbon dioxide gas and simultaneously measuring the amount of carbon dioxide gas.

Further, since the amount of CO ₂ used in such an ultrapure water supply device may be extremely small, for example, the valve opening of the control valve used in the mass flow controller 31 in FIG. Can be extremely small. Conventionally, as shown in FIG. 6, a needle valve 37 is used as a flow rate control valve used for such an application, and a spire-shaped valve element 37a of the needle valve 37 moves up and down into an opening 38. By doing so, the valve opening was adjusted.

[0005]

By the way, when the needle valve 37 using such a steeple-shaped valve body 37a is used as a flow rate control valve, the opening 38 is extremely small in order to set a small flow rate of the fluid. It must be formed small, and the diameter of the valve body 37a must be set extremely small.

However, it goes without saying that such processing is difficult, and the steeple-shaped valve portion 37a may fit into the opening 38 and may not come off. Further, since the needle valve 37 has a structure in which the rotational driving force of the motor is transmitted to the valve element 37a through the meshing of the screw, backlash is likely to occur and it is difficult to adjust the valve opening degree of the valve element 37a. There was a problem.

Further, the fluid characteristic of the needle valve 37 is that the flow amount of the fluid is large immediately after the valve is opened and then becomes gentle.
In No. 7, the amount of fluid flowing immediately after the valve started opening was large, and it was not suitable for use for flowing a trace amount of fluid. In view of such circumstances, an object of the present invention is to provide a flow rate control valve which is suitable for flowing a trace amount of fluid, which is easy in valve processing, and which has no risk of backlash.

[0008]

A flow control valve according to the present invention for achieving the above object is provided with an actuator housed in a cover member and a through hole which is attached to a lower end surface of the cover member and which extends in an axial direction. A tubular bonnet member formed with, and attached to the lower end surface of the bonnet member,
A valve body having a fluid passage formed therein, a spindle housed between the cover member and the bonnet member, rotated by an output from the actuator, and a nut member movably screwed to a screw portion of the spindle. A piston arranged on the valve body side of the nut member and movable in a direction traversing the fluid passage; and a force conversion mechanism for converting rotational movement of the spindle into linear movement and transmitting the linear movement to the nut member. A compression spring which is interposed between the nut member and the piston, and which urges the piston in a direction in which the piston is always separated from the nut member; and a valve device configured in a fluid passage of the valve body. A force applied from the actuator to the spindle is converted from a rotational movement of the spindle into a linear movement by the force converting mechanism, The compression spring is compressed as it is transmitted to the material, and the force applied from this spring moves the piston to the fluid passage side, whereby the flow control valve that adjusts the flow rate of the valve device is used. And the pressing force of the compression spring arranged between the nut member and the piston is adjusted by the output applied to the spindle from the actuator, thereby adjusting the flow rate of the valve device. Is characterized by.

According to the present invention having such a configuration, the piston is constantly pressed by the compression spring, and a force is applied via this compression spring, so that backlash does not occur. Here, the tip portion of either the valve body or the valve seat of the valve device may be formed of an elastic member.

The elastic member may be rubber. Further, the tip of either the valve body or the valve seat of the valve device may be formed of a rigid body having a smooth surface. With such a configuration, a minute flow rate can be flowed. Further, in the valve device, the fluid passage may be opened when the piston moves to the fluid passage side based on the output from the actuator.

Further, the valve device has a valve closing spring for constantly urging the valve body so as to contact the valve seat, and
It is preferable that a first elastic airtight member that hermetically seals the inside of the valve body is interposed at a connecting portion between the bonnet member and the valve body. Further, in the valve device, it is preferable that the fluid passage is closed when an output from the actuator is applied to the spindle and the piston moves to the fluid passage side in response to the output.

Further, in the valve device, when the pressure in the fluid passage on the secondary side becomes higher than the pressure in the fluid passage on the primary side, the pressure difference causes the valve passage to close the fluid passage. You may have the 2nd elastic airtight member which presses a body.
Even with such a configuration, it is possible to flow a minute flow rate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a flow control valve according to an embodiment of the present invention. The flow rate control valve 40 is provided with a fluid passage 20 a in the valve body 7 as the motor 15 housed in the cover member 16 rotates.
The flow rate of the fluid flowing between 20b can be adjusted to a predetermined flow rate, and the piston 9 for pressing the valve body 5 is used.
A compression spring 10 is interposed between the outer periphery of the nut and the nut member 11. The piston 9 is pressed downward in the figure by the urging force of the compression spring 10.

That is, the cylindrical bonnet member 14 having the flange portions 18a and 18b formed at both ends is attached to the lower end surface of the cover member 16 in which the motor 15 as the actuator is housed by the screw 19. A through hole 17 is formed in the bonnet member 14 in the axial direction. The bottom surface of the bonnet member 14 has a through hole 1
The valve body 7 having the fluid passages 20a and 20b formed therein is attached in a direction substantially orthogonal to the valve body 7. The valve body 7 includes, in addition to the primary side fluid passage 20a and the secondary side fluid passage 20b, An opening is also formed in a direction orthogonal to (vertical direction in FIG. 1).

Of these openings in the valve body 7, an upper opening 70 on the flange portion 18b side of the bonnet member 14
Is hermetically sealed by interposing a bellows flam 8. In addition, the opening 71 on the lower side of the valve body 7 is O
The lower lid 2 is attached via the ring 27, and the screw 21 is screwed into the lower lid 2 to hermetically seal. Motor 15
The spindle 12 for transmitting the rotational force of the above is inserted into the bonnet member 14 at the tip side and screwed into the female screw of the nut member 11 arranged on the outer peripheral side. As a result, it is rotatable and is prevented from moving in the vertical direction in FIG.

The nut member 11 has an outer peripheral projection 11a on a rotation stop pin 13 inserted in an inner peripheral groove of the bonnet member 14.
Is locked so that it cannot be rotated. Therefore, by the force conversion mechanism having such a configuration, the rotational driving force applied to the spindle 12 is transmitted to the nut member 11 as a linear motion. Therefore, the nut member 11 linearly moves in the through hole 17.

In the through hole 11b of the nut member 11, the shaft portion of the piston 9 having a substantially convex cross section is slidably accommodated. Then, on the tip end side of the piston 9, a bellows flammer 8 as a first elastic hermetic member is provided.
It is interposed between the valve body 4 and the valve body 7. The screw portion 6a of the retainer 6 is screwed onto the tip of the piston 9. The retainer 6 is formed in a substantially cylindrical shape, and a screw portion 6a is screwed so that the tip end portion of the piston 9 is covered back to back. Further, the retainer 6 is provided with a cylindrical leg portion 6c in which a fluid passage 6b in the same direction as the fluid passages 20a and 20b of the valve body 7 is formed.

Further, the inner shaft portion 6d projectingly formed in the central portion of the tubular leg portion 6c is formed such that the base side is thick and the tip side is thin. The inner shaft portion 6d is formed longer than the protruding length of the leg portion 6c as a whole.
Further, the thin rod-shaped portion 6e protruding toward the tip side of the inner shaft portion 6d has a central opening 4 of the valve seat forming member 4 formed in a tubular shape.
It is inserted in a.

On the other hand, a receiving seat surface 22 is formed inside the upper opening 70 formed on the bonnet member 14 side of the valve body 7. The leg portion 6c formed on the retainer 6 is in contact with the receiving seat surface 22. Further, the valve seat forming member 4 having a substantially hat-shaped cross section is inserted into the lower opening 71 of the valve body 7 via the O-ring 23.
The upper surface of the valve seat forming member 4 and the receiving seat surface 22 of the valve body 7 are flush with each other.

The lower lid 2 seals the valve seat forming member 4 in the valve body 7 and immovably supports it.
A central convex portion 2a is formed on the inner surface side, and a concave portion 24 is formed in the central convex portion 2a. And this recess 24
A guide pin 25 having a through hole 25a formed therein is planted therein. The shaft portion 5a of the valve body 5 is slidably inserted into the through hole 25a of the guide pin 25. A valve closing spring 3 that constantly presses the valve body 5 upward is mounted between the base side of the valve body 5 and the lower lid 2 so as to surround the guide pin 25. An annular groove is formed on the upper surface of the valve body 5 thus formed, and an E groove is formed in the annular groove.
An elastic member 41 made of rubber such as DPM (ethylene / propylene / diene copolymer) is embedded.

A central opening 4a in the valve seat forming member 4
An annular inward projection 4b is formed downward on the inner peripheral edge of the valve, and the inward projection 4b constitutes a valve seat for the valve body 5. Therefore, the inward projection 4 of the valve seat forming member 4
b is in contact with the elastic member 41 of the valve body 5 pressed upward by the urging force of the valve closing spring 3. On the contrary, the biasing force of the compression spring 10 is applied from the upper side, but when the spring force exceeds a predetermined force, the rod-shaped portion 6e of the retainer 6 moves the elastic member 41 downward. Then, the valve portion V configured here is opened.

Thus, for example, the flow control valve 40 suitable for flowing a small amount of carbon dioxide gas is constructed. The operation of the flow control valve 40 will be described below.
Here, in using the flow rate control valve 40, it is necessary to perform initialization (initialization) in advance. In that case, first, with the upper surface of the nut member 11 in contact with the flange portion 12a of the spindle 12, as a reference. Is done. At this time, the elastic member 41 is in contact with the inward projection 4b of the valve seat forming member 4. If the elastic member 41 is made of rubber or the like, the load applied to the valve seat forming member 4 is small, so that the influence on the sealing surface of the valve seat forming member 4 is reduced. Thus
For example, when the flow rate is set for the rotation angle of the motor, the flow rate control valve 40 can be used.
The flow rate can be proportionally controlled by the output from the motor 15.

The flow rate control valve 40 is used as a gas injection control valve for preventing ultrapure water from being charged, for example, in the mass flow controller 31 shown in FIG. By adjusting the opening degree here, for example, a small amount of carbon dioxide gas can be introduced into the pure water line 32.
The valve portion V of the flow control valve 40 is closed. From this state, when the rotational driving force is applied to the motor 15,
The spindle 12 is rotated accordingly. When the spindle 12 is rotated, this rotational driving force is transmitted to the nut member 11 via the force conversion mechanism. Even if the rotational driving force is transmitted to the nut member 11, the outer peripheral protrusion 11a is locked to the rotation stop pin 13, so that the nut member 11 cannot rotate and makes a linear motion only in the axial direction. . Therefore, at this time, the compression spring 10 is compressed, and the piston 9 is pressed downward and moves according to the compression spring force. In FIG. 1, when the piston 9 moves downward, the retainer 6 integrated with the piston 9 also moves downward, and the rod-shaped portion 6e at the tip of the retainer 6 presses the valve body 5 downward. When the rod portion 6e presses the valve element 5 downward by a predetermined amount, the engagement between the inward projection 4b of the valve seat forming member 4 and the elastic member 41 of the valve element 5 is released. That is, the valve portion V is opened. in this way,
When the valve portion V is opened, the fluid passage 20a on the primary side, the narrow groove passage 7a of the valve body 7, the lower opening 7 in the valve seat forming member 4 are opened.
1. Further, the liquid passage 6b formed in the leg portion 6c of the retainer 6, the upper opening 70 in the valve body 7, the narrow groove passage 7b of the valve body 7, and the secondary side fluid passage 20b communicate with each other. Thereby, for example, from the cylinder of carbon dioxide gas or the like, the fluid passage 20
A small amount of carbon dioxide can be introduced to the b side.

In the flow rate control valve 40 having such a configuration, the flow rate of a small amount of gas flowing through the valve portion V can be adjusted by electrically controlling the spring force of the compression spring 10. When the pressure in the secondary side fluid passage 20b becomes higher than that in the primary side fluid passage 20a, the pressure in the fluid passage 20b pushes up the bellows flammer 8 which is the first airtight elastic member. Thus, the piston 9 and the retainer 6 are automatically pressed upward against the biasing force of the compression spring 10. Then, the rod-shaped portion 6e at the tip of the retainer weakens the force of pressing the valve body 5 downward, whereby the valve body 5 moves upward.
That is, since the urging force of the valve closing spring 3 and the force that applies the differential pressure between the primary side and the secondary side act on the valve body 5, the valve body 5 automatically moves upward, and the flow rate of the flowing gas is limited. To be done. The pressure in the fluid passage 20b on the secondary side further increases,
When the secondary side becomes abnormally high, the valve body 5 rises to the uppermost position and the valve portion V is completely closed. Therefore,
Fluid flow is blocked.

On the other hand, when the pressure in the primary side fluid passage 20a becomes abnormally high, the primary side fluid pressure forcibly moves the valve element 5 upward, so that the valve portion V is closed. Therefore, the flow of fluid is blocked. Such a flow control valve 4
In No. 0, the compression spring 10 is interposed between the piston 9 and the nut member 11, and the valve closing spring 3 is interposed on the back surface side of the valve body 5, so in the case of a needle valve driven by a screw. Unlike, you can eliminate the effects of backlash.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example,
In the above embodiment, the flow rate control valve 40 having the configuration in which the valve portion V is opened by the downward movement of the piston 9 has been described, but the present invention is characterized by the downward movement of the piston.
The present invention can also be applied to a flow rate control valve in which the valve portion V is closed.

FIGS. 3 and 4 show such a flow rate control valve 50, and the same elements as those in FIG. 1 are designated by the same reference numerals. In this embodiment, the second retainer 52 is screwed to the bottom portion of the nut member 51 screwed to the spindle 12, so that the second retainer 52 and the nut member 51 move up and down together with the rotation of the spindle 12. It is configured. Further, on the lower end face side of the bonnet member 14, a valve body composed of two divided bodies of a first body 53 and a second body 54 is installed. A diaphragm 55 as a second airtight elastic member is interposed between the first main body 53 and the second main body 54. Further, the second main body 54
The bellows flammer 8 serving as a first airtight elastic member is interposed between and the bonnet member 14. Further, the bellows flam 8 is sandwiched between the tip end portion of the nut member 51 and the second retainer 52. In the second body 54,
A substantially cylindrical piston 56 is slidably accommodated, and a compression spring 57 is interposed between the piston 56 and the second retainer 52. Therefore, the piston 5 according to the present embodiment
6 is always in contact with the diaphragm 55 and is pressed downward in FIG. Further, the shaft portion 58a of the valve body 58 is screwed into the through hole 56a formed in the central portion of the piston 56. And this valve body 5
A first retainer 59 is interposed between the diaphragm 8 and the diaphragm 55.

At the lower end of the valve body 58, a cylindrical portion 58c is formed so as to project. Further, in the central portion of the valve body 58,
A through hole 58b is formed. On the other hand, a concave portion is formed in the central convex portion 53a formed in the first main body 53, and the elastic member 41 made of rubber or the like is accommodated in the concave portion. The elastic member 41 is prevented from falling off by caulking the peripheral surface of the recess.

Further, in such a flow control valve 50,
A primary side fluid passage 20a is formed in the first main body 53, and a secondary side fluid passage 20b is formed in the second main body 54. In such a flow rate control valve 50, the valve portion V is constituted by the elastic member 41 and the tubular portion 58c of the valve body 58, as in the above embodiment. Then, in the valve portion V, when the piston 56 is pressed downward by the urging force of the compression spring 57, the tubular portion 58c of the valve body 58 comes into contact with the elastic member 41 of the first main body 53, and the valve V becomes To be closed.

Further, in the initialization (initialization), the nut member 51, the bellows flam 8 and the second retainer 52 are integrally lowered, and the second retainer 52 is moved to the second main body 64.
Is performed with reference to the state of contact with. In such a flow rate control valve 50, if the valve opening pressure by the compression spring 57 is determined, the valve portion V can be opened when the primary side becomes higher than this valve opening pressure. In addition, the valve portion V can be closed when the differential pressure across the diaphragm 55 disappears. Therefore, the pressure P before and after the diaphragm 55 is
It is possible to deal with any numerical value of 1 and P2.

Therefore, even with such a flow rate control valve 50, the biasing force of the compression spring 57 can be adjusted by controlling the rotational driving force of the motor 15, and as a result, the valve portion V The gas flow rate can be adjusted. Thus, the urging force of the compression spring 57 causes the valve portion V
The present invention can be applied even to a flow control valve that acts in the direction of closing the valve.

The actuator is not limited to the motor, and may be driven by electromagnetic force. Further, in the first embodiment, the elastic member 41 is attached to the tip portion of the valve body 5, but this elastic member can also be attached to the valve seat side. The point is that it may be attached to either the valve seat or the valve body.

Further, instead of the elastic member 41, a metal plate or a resin plate made of a smooth body can be used. Even with such a configuration, when the valve seat and the valve body are slightly opened from the abutting state, a small amount of gas can flow.

[0034]

As described above, in the flow rate control valve according to the present invention, the urging force of the compression spring is adjusted according to the output from the actuator to control the flow rate, so that a trace amount of gas is allowed to flow. Suitable for Furthermore, since these constituent elements can be manufactured by general machining, they can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of a flow control valve according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG.

FIG. 3 is a sectional view of a flow control valve according to another embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a main part of FIG.

FIG. 5 is a flowchart when manufacturing ultrapure water.

FIG. 6 is a cross-sectional view showing the structure of a conventionally used needle valve.

[Explanation of symbols]

3 valve closing spring 4 valve seat forming member 4b inward protrusion 5 valve body 7 valve body 8 Bellow flam (1st elastic airtight member) 9 pistons 10 Compression spring 11 Nut member 12 spindles 13 Rotation stop pin 14 Bonnet material 15 Motor (actuator) 16 Cover member 17 Through hole 20a fluid passage 20b fluid passage 37a valve part 40 Flow control valve 41 Elastic member 50 Flow control valve 51 Nut member 52 retainer 53 First body 54 Second body 55 Diaphragm (second elastic airtight member) 56 pistons 57 Compression spring 58 Disc 58c tubular part V valve

Continued front page    F-term (reference) 3H062 AA02 AA15 BB04 CC01 DD01                       EE06 EE11 HH02 HH06                 3H063 AA01 BB24 DA14 DB02 FF02                       FF03 GG15

Claims (8)

[Claims] 1. An actuator housed in a cover member, a tubular bonnet member attached to a lower end surface of the cover member and having a through hole formed in an axial direction, and attached to a lower end surface of the bonnet member. A valve body in which a fluid passage is formed, a spindle housed between the cover member and the bonnet member, and rotated by an output from the actuator, and a nut movably screwed to a screw portion of the spindle. A member, a piston arranged on the valve body side of the nut member and movable in a direction traversing the fluid passage, and a force conversion mechanism for converting the rotational movement of the spindle into a linear movement and transmitting the linear movement to the nut member. A compression bar that is interposed between the nut member and the piston and that urges the piston in a direction that always separates the piston from the nut member. And a valve device configured in a fluid passage of the valve body, wherein the force applied from the actuator to the spindle is converted from a rotational motion of the spindle into a linear motion by the force conversion mechanism, and The compression spring is compressed as it is transmitted to the nut member, and the force applied from this spring moves the piston to the fluid passage side, whereby the flow rate of the valve device is adjusted. The pressing force of the compression spring arranged between the nut member and the piston is adjusted by the output applied to the spindle from the actuator, thereby adjusting the flow rate of the valve device. A flow control valve characterized in that 2. The flow control valve according to claim 1, wherein a tip end of one of a valve body and a valve seat of the valve device is formed of an elastic member. 3. The flow control valve according to claim 2, wherein the elastic member is rubber. 4. The flow control valve according to claim 1, wherein the tip end of either the valve body or the valve seat of the valve device is formed of a rigid body having a smooth surface. . 5. The valve device according to claim 1, wherein the fluid passage is opened when the piston moves to the fluid passage side based on an output from the actuator. The flow control valve according to any of the above. 6. The valve device has a valve closing spring for constantly urging the valve body so as to abut against the valve seat, and the valve body has a valve body at a connecting portion between the bonnet member and the valve body. The flow control valve according to claim 5, wherein a first elastic airtight member that seals airtightly is interposed. 7. The valve device is characterized in that the fluid passage is closed when an output from the actuator is applied to the spindle and the piston moves to the fluid passage side in response to the output. The flow control valve according to any one of claims 1 to 4. 8. The valve device according to claim 8, wherein when the pressure in the fluid passage on the secondary side becomes higher than the pressure in the fluid passage on the primary side, the differential pressure causes the valve device to close the fluid passage. The flow control valve according to claim 7, further comprising a second elastic airtight member that presses the body.