JPH05172268A - Valve for gas rate-of-flow control device - Google Patents

Abstract

PURPOSE:To eliminate generation of metal dust, etc., due to wear of valve element and suppress the cost by pressing the under-surface of the central plane of a diaphragm directly to the over-surface of a valve seat provided at the opening of the valve body, thereby opening and closing the valve seat, and eliminating provision of any valve element. CONSTITUTION:A valve for a precision gas rate-of-flow control device to control a relatively small rate of gas flow precisely is normally separated from a valve seat 4 by the resilient reaction force of a diaphragm 5, and a valve stem 10 is lifted through a diaphragm spacer 11 and steel ball 9. If in this state a voltage is impressed on a solenoid 14, a magnetic circuit is formed in the area consisting of a lid 61, cover 15, housing 7, and the valve stem 10, which is thus attracted to the housing 7. The valve stem 10 depresses the diaphragm 5 through the steel ball 9 and diaphragm spacer 11 to seat the diaphragm 5 on the valve seat 4, and the valve closed state is generated. The rate of fluid flow is adjusted by controlling the voltage to be impressed on the solenoid 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve section for a precision gas flow rate control device for precisely controlling a relatively small flow rate of gas.

[0002]

2. Description of the Related Art A precision gas flow rate control device is mainly composed of a sensor section, a valve section and a control circuit section. As shown in FIG. 2, the sensor part is composed of a thin conduit through which a fraction of the total gas flow passes and a heating wire coil (not shown) wound around this conduit, that is, a sensor, and the valve part Is connected as a bypass to the inflow passage of. The control circuit is a control circuit that detects the gas flow rate of the sensor unit, controls the gas flow rate of the valve unit, and outputs the driving electricity. The valve section is a valve for a gas flow rate control device, in which a laminated piezoelectric element body is used for a driving section of the valve. A conventional valve for a gas flow control device using a laminated piezoelectric element is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-127923, which is shown in FIG. The valve for the gas flow control device shown in FIG. 3 is a normally open type valve, which is normally open when no voltage is applied. The valve body 51 has a block-shaped horizontal inflow passage 511, an outflow passage 512 including a vertical portion and a horizontal portion, and an opening 513 that is open to the top and communicates with the inflow passage 511 and also with the outflow passage 512. is doing. Valve seat 52
Is a thick plate and is installed on the upper surface of the lower portion of the opening 513 of the valve body 51, and has a valve opening 521 which is a through hole connected to the vertical portion of the outflow passage 512 in the center. The valve body 53 has a cylindrical shape and has a tapered portion on the lower portion, and is located in the opening 513 of the valve body 51 above the valve opening 521 of the valve seat 52, and contacts the valve opening 521 of the valve seat 52. Separate. Diaphragm 54
Is attached in contact with the upper surface of the valve body 53 in the form of a thin disk, and this outer peripheral portion is fixed to the upper side surface of the opening 513 of the valve body 51 to seal the upper surface side and the lower surface side of the diaphragm 54,
That is, the opening 513 is sealed. A tubular member 55 is erected and fixed on the upper surface of the valve body 51 so as to cover the opening 513. The columnar laminated piezoelectric element body 56 is inserted into the tubular member 55, and the valve rod 57 is fixed to the lower end surface thereof. The upper end surface of the laminated piezoelectric element body 56 comes into contact with the lid screwed onto the top of the tubular member 55, that is, the lower surface of the opening adjustment screw 58. The opening adjustment screw 58 is a screw for adjusting the opening degree of the valve body 53.

[0003]

In the conventional valve for a normal flow type gas flow rate control device described above, the valve body exists in the opening of the valve body through which gas passes, and the valve body has a taper portion on the outer peripheral surface. The tapered portion of the valve body comes in contact with and separates from the inner peripheral surface and the end portion of the valve seat / valve opening. That is, the outer peripheral surface of the tapered portion of the valve body and the inner peripheral surface of the valve seat / valve rub against each other, and metal powder and the like generated by abrasion due to this rub against the gas passing through the opening of the valve body. There is a problem. Further, in the case of using the conventional laminated piezoelectric element body, since the displacement of the laminated piezoelectric element body is as small as several tens of Mm, the valve opening is also small and it is difficult to increase the flow rate. Furthermore, the laminated piezoelectric element body is expensive, and an inexpensive valve cannot be obtained. An object of the present invention is to eliminate a valve body having a tapered outer peripheral surface which rubs against an inner peripheral surface end of a valve opening in an opening of a valve main body through which gas passes, which suppresses generation of metal powder or the like at a low cost and opens the valve. It is to provide a valve for a gas flow rate control device of a normal open type having a high degree.

[0004]

SUMMARY OF THE INVENTION The present invention comprises an inflow channel,
An outlet flow passage, and a valve body having an opening opening to the top thereof, which opens to these, a valve seat formed between the opening of the valve body and the inflow passage, and directly to the valve seat,
A metal thin plate diaphragm having a flat central portion and an annular portion having a circular cross section outside the flat surface, which is brought into contact with and separated from the valve body and seals the opening, and the diaphragm is A valve for a gas flow rate control device, characterized in that it comprises a normal open type solenoid valve that is a drive source for directly contacting and separating from a valve seat,

Further, a valve body having an inflow passage, an outflow passage, and an opening having an upper opening communicating with the inflow passage and the outflow passage, and between the opening of the valve body and the inflow passage A valve seat having a through hole through which gas passes, a diaphragm retainer fitted into the opening of the valve body, and a thin plate having a flat central portion and an annular portion having a circular cross section outside the flat surface. The outermost peripheral portion is sandwiched between the stepped portion formed on the side surface of the opening of the valve body and the diaphragm retainer, and the lower surface of the central plane directly contacts and separates from the valve seat, A cylindrical member that is hollow and has a metal diaphragm that covers and seals the opening of the valve body, and has a position adjusting means in the upper portion, that is erected on the diaphragm retainer and fixed around the opening of the valve body. And inside this tubular member And a valve rod whose upper surface is in contact with the position adjusting means and whose lower surface is located on the central plane of the diaphragm, and which is outside the tubular member and which pulls down the valve rod when energized. Electromagnetic coil,
It is a valve for a gas flow control device of a normal open type, which is characterized in that

[0006]

In the valve for a gas flow control device according to the present invention, the lower surface of the central plane of the diaphragm is directly pressed against the upper surface of the valve seat provided in the opening of the valve body to make contact with the lower surface and the upper surface. Separate. Therefore, since the valve body does not exist in the opening of the valve body, the valve body and the valve seat do not rub against each other, and there is no metal powder or the like generated by abrasion. Further, since the fluid flow path and the upper valve rod are separated by the metal thin disk-shaped diaphragm, the material of the upper valve rod can be selected so that the magnetic circuit can be effectively constructed. This has the effect of increasing the valve opening.

[0007]

FIG. 1 shows an embodiment of a valve for a gas flow controller according to the present invention. First, an embodiment will be described with reference to FIG. The valve body 3 has an inflow passage 31, an outflow passage 32, and an opening portion 33 that is open to the top and communicates with the inflow passage 31 and the outflow passage 32. The valve seat 4 is formed between the opening 33 of the valve body 3 and the upper side of the inflow passage 31. The valve seat 4 may be formed integrally with the valve body 3 on the lower surface of the opening 33 of the valve body 3, or may be separately formed and fitted and fixed. The valve seat 4 has a substantially cylindrical shape, and this through hole is a valve opening 41, and the valve opening 41 is continuous with the outflow passage 32. Also, this valve seat 4
An annular protrusion is formed on the outer peripheral side of the upper end surface of the. When the valve seat 4 is integrally formed on the lower surface of the opening 33 of the valve body 3, the valve seat 4 is made of the same metal as that of the valve body 3, but
When formed separately from the lower surface of the opening 33, a material suitable for the valve seat 4 such as soft metal can be selected. Further, the material of the valve seat 4 may be plastic. The side surface of the opening 33 of the valve body 3 is provided with an axial step portion in which a ring-shaped upper surface is formed. The circular diaphragm 5 made of metal is placed on the ring-shaped step. At this time,
The lower surface of the outermost peripheral portion of the diaphragm 5 is in contact with the upper surface of the step portion, the central portion of the diaphragm 5 comes to a position in contact with the valve seat 4, and the diaphragm 5 covers the opening 33 of the valve body 3. Alternatively, a groove may be formed on the upper surface of the step portion, a packing may be attached to the groove, and the diaphragm 5 may be placed on the upper surface of the packing. The outer peripheral portion and the central portion of the diaphragm 5 have a planar shape, and a circular portion having a convex arc shape in cross section is formed in a portion between them in the radial direction, that is, the entire outer periphery of the central portion plane.

The cylindrical member 6 has a substantially cylindrical shape, and a lid 61 made of an iron-based material is provided on the upper portion of the cylindrical member 6 by screwing. A lower portion of the cylindrical member 6 is made of an iron-based material. The housing 7 is provided by screwing. Further, at the bottom of the housing 7, the diaphragm retainer 8 is provided with a valve body 3
It is loosely fitted on the upper side of the step portion of the opening 33. The lower surface of the diaphragm retainer 8 is in contact with the upper surface of the outermost peripheral surface of the diaphragm 5, and the outermost peripheral surface of the diaphragm 5 is sandwiched between the stepped portion of the opening 33 of the valve body 3. Housing 7
Is a quadrangular outer circumference and a circular inner circumference, and has a through hole for a bolt in the annular axial direction, and is fixed to the upper surface around the opening 33 of the valve body 3 by bolt fastening. At this time, the diaphragm retainer 8 is simultaneously pressed to fix the outermost peripheral portion of the diaphragm 5, the upper surface side and the lower surface side of the diaphragm 5 are sealed, and the opening 33 of the valve body 3 is sealed. The cylindrical member 6 is erected and fixed around the inside of the opening 33 of the valve body 3. Here, the cylindrical member 6 is not limited to a cylindrical shape and may have another cylindrical shape. Valve rod 10
Is an iron-based material having a large diameter in the upper portion and a small diameter in the lower portion, and a conical concave portion is formed on the lower surface. A spherical steel ball 9 is fitted into the conical recess on the lower surface of the valve rod 10, and the lower part of the steel ball 9 is fitted into the conical recess formed on the upper surface of the diaphragm spacer 11. The diaphragm spacer 11 has a thick disk shape, and the conical concave portion is formed on the upper surface of the diaphragm spacer 11. The lower surface of the diaphragm spacer 11 abuts on the central upper surface of the diaphragm 5.
The opening adjustment screw 12 has a headless bolt shape, and this screw portion is an adjustment screw. The opening adjusting screw 12 is screwed into the female threaded hole of the lid 61 so that the lower end surface of the opening adjusting screw 12 contacts the upper end surface of the valve rod 10. Here, in order to securely fix the opening adjusting screw 12 and the lid 61, the nut 13 may be connected to the thread portion of the opening adjusting screw 12 to form a double nut type. Here, the nut 13, the opening adjusting screw 12, and the penetrating female screw hole of the lid 61 constitute a position adjusting means. This position adjusting means adjusts the lower end position of the opening adjusting screw 12. An electromagnetic coil 14 wound around a bobbin is provided on the outer peripheral portion of the cylindrical member 6. A cover 15 made of an iron-based material is provided on the outer peripheral portion of the electromagnetic coil 14 to form a magnetic circuit.
The cover 15 is attached by a cover fixing nut 16 screwed to the outer peripheral thread portion of the lid 61.

Next, the opening and closing of the valve for the normally open type gas flow rate control device described above will be described.
The valve is always separated from the valve seat 4 by the elastic reaction force of the diaphragm 5, and pushes the valve rod 10 upward through the diaphragm spacer 11 and the steel ball 9. Next, when a voltage is applied to the electromagnetic coil 14, a magnetic circuit is formed between the lid 61, the cover 15, the housing 7 and the valve rod 10. At this time, the valve rod 10 is magnetically attracted to the housing 7.
Although it is sucked by the gap between the large-diameter portion and the housing 7, the position is adjusted by the opening adjustment screw so that the suction amount does not stick to the housing 7. Valve rod 10 is housing 7
When magnetically attracted to the valve rod 10, the valve rod 10 pushes down the diaphragm 5 through the steel ball 9 and the diaphragm spacer 11 to seat the diaphragm 5 and the valve seat 4, thereby closing the valve. At this time, the fluid flow rate is adjusted by controlling the voltage applied to the electromagnetic coil 14. Next, when the voltage applied to the electromagnetic coil 14 is removed, the magnetic circuit is removed and the valve rod 10 is no longer magnetically attracted to the housing 7, and the valve rod 10 is pushed upward by the elastic reaction force of the diaphragm 5 to open the valve. ..

In this valve for gas flow control device,
The shape of the diaphragm 5 is a flat surface in the central portion and the outermost peripheral portion, and an intermediate portion of the flat surfaces near the outer periphery in the radial direction, that is, a convex arc-shaped annular portion in the entire outer circumference of the central portion flat surface in cross section. It is provided as described below. First, the central portion of the diaphragm 5 is displaced in a substantially flat state, and the sealing property is good when it comes into contact with the upper end surface of the protrusion on the outer peripheral side of the valve seat 4. Next, the deformation amount of the central portion of the diaphragm 5 and this deformation This is because the relationship with the load for is linear. If the deformation amount of the diaphragm 5 and the load at this time have a linear relationship, there is an effect that the deformation amount of the diaphragm 5 can be easily controlled. Further, the reason that the outermost peripheral portion of the diaphragm 5 is a flat surface is to facilitate the sandwiching between the stepped portion formed in the valve body 3 and the opening 33 and the cylindrical member 6. Diaphragm spacer 11 and steel ball 9
Since they are in contact with each other, there is also an effect that they do not receive biased loads. Finally, since the upper surface projection of the valve seat 4 is formed on the outer peripheral portion, there is also an effect that a large flow rate can be secured when fully opened.

[0011]

As described above, the normally open solenoid valve for a gas flow rate control device according to the present invention has no valve body in the valve body through which gas passes. Therefore, since the valve body does not rub against the valve opening or the like, there is an effect that the generation of metal powder or the like due to the wear is not generated in the valve body. Also,
There is an effect that it is possible to form an inexpensive valve that can have a large opening degree and is not restricted by the material forming the solenoid valve.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a normally open type solenoid valve showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a sensor unit and a valve unit of the gas flow rate control device.

FIG. 3 is a vertical cross-sectional view of a valve for a gas flow rate control device using a conventional normally open type laminated piezoelectric element body.

[Explanation of symbols]

 3 ... Valve body 4 ... Valve seat 5 ... Diaphragm 6 ... Cylindrical member 61 ... Lid 7 ... Housing 8 ... Diaphragm retainer 9 ... Steel ball 10 ... Valve rod 11 ... Diaphragm spacer 12 ... Opening adjustment screw 13 ... Nut 14 ... Electromagnetic Coil 15… Cover 16… Cover fixing nut 31… Inflow channel 32… Outflow channel

Claims (3)

[Claims] 1. A valve body having an inflow passage, an outflow passage, and an opening portion open to the upper portion, the valve seat being formed between the opening portion of the valve body and the inflow passage. And a metal thin plate shape having a flat central portion and an annular portion having a circular cross section outside the flat surface by directly contacting with and separating from the valve seat to cover and seal the opening of the valve body. And a normally open solenoid valve which is a drive source for directly bringing the diaphragm into contact with and separating from the valve seat. 2. A valve body having an inflow passage, an outflow passage, and an opening having an upper opening communicating with the inflow passage and the outflow passage, and between the opening of the valve body and the inflow passage. A valve seat having a through hole through which gas passes, a diaphragm retainer fitted in the opening of the valve body, and a thin plate shape having a flat central portion and an annular portion having a circular cross section outside the flat surface. The outermost peripheral portion is sandwiched between the stepped portion formed on the side surface of the opening of the valve body and the diaphragm retainer, and the lower surface of the central plane directly contacts and separates from the valve seat, A metal diaphragm that covers and seals the opening of the valve body, and a hollow member having a position adjusting means on the top, which is a cylindrical member that stands upright on the diaphragm retainer and is fixed around the opening of the valve body. And inside this tubular member A valve rod whose upper surface is in contact with the position adjusting means and whose lower surface is located on the central plane of the diaphragm, and an electromagnetic valve which is outside the tubular member and which pulls down the valve rod when energized. A valve for a gas flow control device of the normal open type, which is characterized by consisting of a coil and. 3. The valve for a gas flow control device according to claim 1 or 2, wherein a plate-like spacer is placed on an upper surface of a central plane of the diaphragm, and an upper surface of the spacer and a lower surface of the valve rod are provided. A valve for a gas flow control device, characterized in that a sphere is provided between the valves.