JPS6367481A - Diaphragm valve - Google Patents

Abstract

PURPOSE:To prevent the fatigue breakdown by concentrically providing an annular recess on a diaphragm and mitigating the internal stress of the diaphragm due to deflection with the annular recess. CONSTITUTION:When a pressing force is applied to the center section of a diaphragm 31 by a valve stem 32, the predetermined deflection is generated. The bending stress in the thickness direction and the stress in the radial direction are generated against the predetermined deflection quantity in the thickness direction of the diaphragm 31, but an annular groove 39 is formed on the diaphragm 31, thus the actual diameter length when the diaphragm 31 is extended becomes long. Accordingly, various stress values such as the bending stress in the thickness direction and the stress in the radial direction are mitigated, and fatigue breakdown is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a diaphragm valve as a super-talin valve used in a piping line of an LSI or super LSI device.

[Prior Art] Conventionally, as this type of diaphragm valve, a horizontally sized diaphragm valve as shown in FIG. 5 has been used. 1 in the figure is the valve box,
It consists of a main body 2 and a beneficial body 3. The main body 2 includes channels 7 and 8 that communicate the fluid port 4 and the fluid outlet 5 with a valve chamber 6, and a valve seat 9 is formed at the inner end of the inlet channel 7. Valve seat 9
A valve element 10 is provided in the valve chamber 6 so as to be movable toward and away from the valve element 10, and is biased in the opening direction by a spring member 11. Lid body 3
is provided with a valve shaft 12 that is slidable in the axial direction, and the inner end of the valve shaft 12 faces the valve body 10 with a spacer 13 interposed therebetween. A diaphragm 14 interposed between the valve body 10 and the spacer 13 is supported by the valve body 1 with its peripheral edge being held between the main body 2 and the lid body 3.

In a diaphragm valve having such a structure, when the valve stem 12 is pushed down, the tip of the valve stem 12 pushes down the diaphragm 14 via the spacer 13, and this pushing down force causes the valve body 10 to be pushed down by the spring of the spring member 11. The lower surface of the valve body 10 is pressed against the valve seat 9 against the force, and the flow path 7 reaching the fluid inlet 4I and the flow path 8 reaching the fluid outlet are blocked, and the internal fluid is The flow stops. Valve stem 12
When the pressing force is released, the valve body 10 is pushed back by the spring member 11, which also pushes back the diaphragm 14, and further pushes the spacer 13 and valve @12 back to their original positions. In this process, the lower surface of the valve body 10 separates from the valve seat 9,
Flow path 7 and flow path 8 communicate with each other, and internal fluid flows through the valve.

In the process of operation of the diaphragm valve, the lid body 3 and the valve stem 12
The diaphragm 14 prevents metal particles from falling downward due to friction and entering the inside of the valve body 10. However, if the diaphragm 14 is a normal thin metal plate, the valve body 10 has It is not possible to provide sufficient deflection to make it possible. If the amount of deflection corresponding to the stroke (lift) required by the valve body 10 is applied to the diaphragm 14, the diaphragm 14 will be plastically deformed and the deflection will remain as it is. In order to prevent this, it may be possible to increase the diameter of the diaphragm 14, but if this is done, the valve itself will become large, making it unsuitable for use in the piping line of LSI or VLSI manufacturing equipment. . It is also possible to use a rubber diaphragm that does not undergo plastic deformation, but it is inferior in durability and has problems such as minute rubber pieces falling into the valve body due to deterioration.

For this reason, recently, valves have been proposed that have a diaphragm made of a superelastic metal material that has a large area of elastic deformation and has the property of returning to its original state like rubber even if it is greatly deformed. (Japanese Patent Publication No. 80-263793), this may cause ultrafine particles to enter the gas contact part of the inner surface of the valve body from the outside of the valve, or the sliding action of the valve stem may cause deterioration of the backing material or metal abrasion. This prevents rubber and metal particles from falling into gas contact areas.

[Problems to be Solved by the Invention] However, diaphragms made of superelastic metal materials used in such conventional diaphragm valves cannot escape the phenomenon of fatigue failure, just like ordinary metals. Therefore,
Even a diaphragm valve equipped with the above-mentioned diaphragm had the disadvantage that if the valve was opened and closed 105 times, it would break due to metal fatigue. For this reason, the life of the diaphragm valve was short and maintenance was extremely troublesome.

[Object of the Invention] The present invention has been made to solve the above-mentioned problems, and it is possible to keep the diameter of the diaphragm small and to reduce the stress value associated with the deflection of the diaphragm to a stress level that does not cause fatigue failure. It is an object of the present invention to provide a diaphragm valve which has a long service life and eliminates the trouble of maintenance.

[Means for Solving the Problems 1] The diaphragm valve of the present invention for solving the above-mentioned problems includes a superelastic metal material whose peripheral portion is supported by the valve body and which is interposed between the valve stem and the valve body. A valve having a thin disk-shaped diaphragm is characterized in that the diaphragm is provided with at least one annular recess concentrically.

[Function] The diaphragm valve of the present invention configured as described above, when a predetermined deflection is applied to the diaphragm by the operation of the valve,
The internal stress of the diaphragm due to deflection is reduced by at least one annular recess, and the stress value is lowered below the fatigue limit of the metal forming the diaphragm, thereby avoiding fatigue failure.

[Embodiment] An embodiment of the diaphragm valve of the present invention will be described with reference to FIG. 1. Reference numeral 20 is an inverted T-shaped valve box, in which a valve chamber 21 is formed in a vertical portion 20a, and a fluid inlet 22 and a fluid inlet 22 are formed in a horizontal portion 20b. Flow paths 24 and 25 are formed that communicate the fluid outlet 23 and the valve chamber 21, and the inner end of the inlet flow path 24 is perpendicular to the valve chamber 21, and its periphery is connected to the valve seat 26. It has become. The valve body 21 is provided at the center of the valve chamber 21 so as to be in close contact with the valve seat 26, and is urged upward by a spring 28. A stepped portion 29 is provided on the upper inner peripheral surface of the valve chamber 21,
A seal ring 30 is disposed on the stepped portion 29, on which the periphery of a diaphragm 31 made of a metal material exhibiting a superelastic phenomenon is supported, and a cylindrical guide fitted into the valve body 32 is placed on the periphery of the diaphragm 31. 33 is supported, this cylindrical guide 33 is fitted on the outer periphery, and the vertical part 2 of the valve body 20
It is tightened and fixed by a nut 34 screwed onto the outer periphery of the diaphragm 31, and the periphery of the diaphragm 31 is also fixed. The valve stem 32 has a base end connected to a piston 36 of an air cylinder 35, and the air cylinder 35 is connected to an air cylinder lid 37.
is screwed onto the outer periphery of the cylindrical guide 33 and connected to the valve box 20. 38 is a return spring inside the air cylinder 35.

The diaphragm 31 made of a metal material exhibiting the above-mentioned superelastic phenomenon is made into a thin disc shape as shown in FIGS. It is formed by

Note that the diaphragm 31 is not limited to that shown in FIG.
A diaphragm 40 in which the annular groove 39 is formed in two or three concentric grooves as shown in FIGS. 3a and b, or a plurality of recesses 41 having a wave-shaped cross section in the radial direction as shown in FIGS. 4a and b A diaphragm 43 may be used in which convex portions 42 and convex portions are alternately formed.

In the diaphragm valve of FIG. 1 configured as described above, when operating air is introduced into the upper chamber of the air cylinder 35 and the piston 36 is pushed downward, the valve stem 3
2 also falls downward. Accordingly, the valve body 27 is pushed down via the diaphragm 31, and the lower surface of the valve body 27 is pressed against the valve seat 26 on the bottom surface of the valve chamber 21, causing the flow path 24.
5 is shut off, stopping the flow of internal fluid.

When the air pressure in the air cylinder 35 is removed, the piston 36 is pushed back to its original position by the return force of the return spring 38, and the valve rod 32 also rises upward, causing the valve body 2 to move upward.
7 and the diaphragm 31 are lifted upward by the force of the spring 28, the lower surface of the valve body 27 is separated from the valve seat 26 on the bottom surface of the valve chamber 21, the flow passages 24 and 25 are communicated, and the internal fluid flows through the valve. .

In opening and closing such a diaphragm valve, the diaphragm 3
1 causes a predetermined deflection when a pushing force from the valve stem 32 is applied to its center. Because the outer circumference of the diaphragm 31 is fixed due to the structure of the valve, bending stress in the thickness direction, stress in the radial direction, stress in the circumferential direction, etc. occur for a predetermined amount of deflection in the thickness direction. Since the single annular groove 39 is formed in the diaphragm 31, the actual diameter length becomes longer when the diaphragm 31 is stretched. Therefore, various stress values such as the bending stress in the plate thickness direction, the radial stress, and the circumferential stress are significantly reduced. This phenomenon is similar to the physical phenomenon seen in bellows and helical springs. In this way, various stress values are reduced below the fatigue limit of the diaphragm 31, and fatigue failure is avoided.

It goes without saying that such a stress reduction phenomenon also occurs in the diaphragm valve having the diaphragm 40, 43 shown in FIGS. 3 and 4.

[Effects of the Invention] As can be seen from the above description, the diaphragm valve of the present invention has a thin disc-shaped diaphragm made of a superelastic metal material and provided with at least one annular recessed part, which is connected to the valve body and the valve stem. Even if the diameter of the diaphragm is small, when the diaphragm is deflected during valve operation, the internal stress associated with the deflection is reduced by the annular unevenness, and the stress value is below the fatigue limit of the superelastic metal material. It is possible to avoid fatigue failure. Therefore, even if the valve is opened and closed 107 times, it will not break, and the life of the diaphragm valve will be significantly extended, and the troublesome maintenance will be eliminated.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of a diaphragm valve according to the present invention, Figs. 2 a and b are a plan view and a sectional view of a diaphragm installed in the diaphragm valve, and Figs. 3 a and b are views of the diaphragm. FIGS. 4a and 4b are a plan view and a sectional view showing another modification of the diaphragm, and FIG. 5 is a longitudinal sectional view showing a conventional diaphragm valve. 20... Valve box 27... Valve body 31, 4
0.43...Diaphragm 32...Valve stem 39...Annular groove 41.
...Concave portion 41...For convex portion Request person
Nippon Benkan Kogyo Co., Ltd. Representative Patent Attorney Yujibe Taka. Figure 1 Figure 2 Figure 3 Figure 4 (a) Figure 5

Claims (1)

[Claims] In a valve having a thin disk-shaped diaphragm made of a superelastic metal material and having a peripheral edge supported by a valve body and interposed between a valve stem and a valve body, at least one annular recess is formed in the diaphragm. A diaphragm valve characterized by being installed concentrically.