JPH0583545U - Metal diaphragm valve - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a metal diaphragm valve having good sealing characteristics even though the metal diaphragm and the metal valve seat are in contact with each other. A metal valve box, a valve seat integrally formed with the valve box, and a metal having a peripheral portion hermetically sandwiched between the valve box and a central portion facing the valve seat so as to be directly contactable and separable. In a metal diaphragm valve having a diaphragm and a load means for displacing a central portion of the metal diaphragm in the valve seat direction, the valve seat is a convex annular valve seat, and an inner peripheral surface or an outer peripheral surface of the valve seat is provided. Metal diaphragm valve with a radial groove.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metal diaphragm valve, and more particularly to an all-metal metal diaphragm valve that directly seats or separates a metal diaphragm on or from a metal valve seat.

[0002]

[Prior Art]

 Conventionally, as an on-off valve used in a piping system of a semiconductor manufacturing apparatus or the like, there has been a demand for a valve that has no sliding portion that produces fine particles due to wear in a valve internal flow path and has no dead space. As a solution to this, for example, there is a metal diaphragm valve disclosed in Japanese Patent Laid-Open No. 63-285373 and Japanese Utility Model Laid-Open No. 2-29361. This metal diaphragm valve has a metal diaphragm with a central portion that bulges upward and a valve seat made of resin.The metal diaphragm is deformed within the elastic deformation range and directly seated on or released from the valve seat. It was made to sit and open and close the valve. However, recently, as semiconductors have been highly integrated, it has been required that the impurity concentration in the raw material gas be at a ppt level below the ppb level. In order to meet this requirement, one solution and a challenge are to minimize the amount of water and impurities adsorbed on the material forming the valve internal flow path and released therefrom. However, the above-mentioned conventional metal diaphragm valve using the resin valve seat has the following problems. A) Since the resin material is essentially hygroscopic, it is difficult to completely release and remove the water and impurities adsorbed and absorbed by the resin valve seat. B) Baking at high temperature is limited. C) It is highly corrosive, and there is concern about its corrosion resistance against various raw material gases.

From the above reasons, it has recently been considered that the metal diaphragm valve having the following configuration is optimal. a) A metal valve seat in which the valve seat and the valve box are integrally formed. b) All surfaces that come into contact with the fluid should be mirror-finished. c) In addition, it has a resin valve seat equal to or more sealing properties (about ^{1 × 10- 7 ~10- 9 a tmcc} / sec). Therefore, even if the metal diaphragm and the metal valve seat are in contact with each other, sealing characteristics equivalent to or better than those of the conventional ones are required.

[0004]

[Problems to be solved by the device]

 By the way, in the case of metal-to-metal contact, a major factor for improving the sealing property is that it depends on the surface condition of the contact surface between the metal diaphragm and the metal valve seat, that is, the surface roughness. The surface roughness of this contact surface is usually possible up to about Rmax 0.1 μm, but in order to achieve the required sealing performance, it must be finished to an order of magnitude higher than this. From the above, when considering only the surface roughness, mirror finishing with extremely high precision is required, which causes problems in terms of equipment and cost. The present invention has been made to solve the above-mentioned problems, and provides a metal diaphragm valve having good sealing characteristics by changing the shape of the valve seat even when the metals are in contact with each other. With the goal.

[0005]

[Means for Solving the Problems]

 According to the present invention, a metal valve box, a valve seat integrally formed with the valve box, and a peripheral edge portion hermetically sandwiched between the valve box and a central portion directly contact and separate from the valve seat. In a metal diaphragm valve having a metal diaphragm and a load means for displacing a central portion of the metal diaphragm in the valve seat direction, the valve seat is a convex annular valve seat, and an inner peripheral surface or an outer circumference of the valve seat is provided. A radial groove is formed on the surface.

[0006]

[Action]

 The metal diaphragm valve of the present invention focuses on generating elastic repulsive force on the contact surfaces of metals to seal up. With the configuration as described above, the metal diaphragm is pushed when the valve is closed. The valve seat flexes elastically due to the force. This makes it possible to correct the distortion and inclination of the contact surface and improve the sealing performance by the repulsive force of the valve seat itself generated on the metal diaphragm side. It is preferable that the groove formed in the valve seat is provided on the inner peripheral surface side and the valve seat is bent toward the inner diameter side following the deformation of the metal diaphragm.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing a fully closed state of a manually openable / closable metal diaphragm valve. Reference numeral 1 is a valve box of a metal diaphragm valve, which is made of stainless steel having corrosion resistance. An inflow passage 2 is formed on the left side and an outflow passage 3 is formed on the right side in a substantially L-shape, and these passages are communicated with each other through an upper opening. A convex annular valve seat 4 protruding upward is integrally formed with the valve box 1 at the upper end of the inflow passage 2. A step surface is formed on the periphery of the upper opening of the valve box 1, a peripheral part of a metal diaphragm 5 to be described later is placed here, and a lid 7 is screwed onto the valve box 1 via a diaphragm retainer 6. By doing so, the peripheral portion of the metal diaphragm 5 is sandwiched and held in the valve box 1. As a result, the sealed fluid chamber 11 is formed.

The metal diaphragm 5 is made of a suitable elastically deformable metal material, and is used by stacking two or three sheets of which the central portion is bulged upward. The central portion is arranged as described above so that it can directly open and close (seating or separating) the valve seat so as to open and close. On the other hand, the loading means 10 is equipped with a valve rod 8 that fits in a through hole in the center of the lid 7 and is screwed in part, and a handle 9 provided at the outer end of the valve rod 8. Here, the valve rod may be moved up and down by fluid pressure such as air pressure or magnetic force. Although the tip end surface of the valve rod 8 has an appropriate curved surface shape, a pressing member made of a soft material may be interposed between the curved end surface and the metal diaphragm 5.

Then, by rotating the handle 9, the valve rod 8 is moved up and down, the central portion of the metal diaphragm is brought into contact with and separated from the valve seat, and the valve is opened and closed. That is, when the valve rod 8 is lowered, the curved bottom end surface presses the metal diaphragm 5, and the metal diaphragm elastically deforms and the central portion moves downward, but within the elastic deformation range of the metal diaphragm. Then, the distance between the metal diaphragm and the valve seat, that is, the lift is determined so that the central portion is pressed against the valve seat 4 to close the valve. Then, after this, when the valve rod 8 is raised, the metal diaphragm 5 follows the valve rod 8 and is raised, so that the metal diaphragm 5 is elastically restored to its original shape. That is, the valve is opened and closed by deforming the metal diaphragm within the elastic deformation range. The surface roughness of the contact surfaces of the valve seat 4 and the metal diaphragm 5 is Rmax 0.2 μm, which are almost the same as each other, and the other fluid contact surfaces are also appropriately mirror-finished. .

In the metal diaphragm valve configured as described above, the one shown in FIG. 1 has an annular recessed groove 41 cut from the inner diameter side of the valve seat 4. Therefore, when the valve is closed, the valve seat 4 easily bends in the inner diameter direction in response to the pressing force of the valve rod 8, and the elastic effect thereof can correct the distortion and inclination of the contact surface and the repulsion of the valve seat itself. The force improves the sealing performance. Further, in this case, the metal diaphragm and the valve seat are deformed like a wedge along the curved surface of the tip of the valve rod, so that the sealing performance is further enhanced. FIG. 2 is an enlarged sectional view of a valve seat portion showing another embodiment of the present invention. In this embodiment, the annular recessed groove 42 cut from the outer diameter side of the valve seat is formed, and the sealing performance can be improved by utilizing the elasticity effect of the valve seat as described above. FIG. 3 shows still another embodiment, in which concave grooves 43 and 44 are formed on the inner diameter side and the outer diameter side of the valve seat. In addition, an example in which the shape of the groove is changed may be considered.

[0011]

[Effect of the device]

 According to the present invention, it is possible to provide a metal diaphragm valve having good sealing characteristics while being in contact with each other.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a metal diaphragm valve according to an embodiment of the present invention.

FIG. 2 is a sectional view of a valve seat portion showing another embodiment of the present invention.

FIG. 3 is a sectional view of a valve seat portion showing still another embodiment of the present invention.

[Explanation of symbols]

 1 ... Valve box 2 ... Inflow channel 3 ... Outflow channel 4 ... Valve seat 5 ... Metal diaphragm 6 ... Diaphragm retainer 7 ... Lid 8 ... Valve rod 9 ... Handle 10 ... Loading means 11 ... Fluid chamber 41, 42, 43, 44, groove

Claims (1)

[Scope of utility model registration request] 1. A valve box made of metal, a valve seat integrally formed with the valve box, a peripheral edge portion hermetically sandwiched between the valve box and a central portion facing the valve seat so as to be directly contactable and separable. In a metal diaphragm valve having a metal diaphragm and a load means for displacing a central portion of the metal diaphragm in the valve seat direction, the valve seat is a convex annular valve seat, and an inner peripheral surface or an outer circumference of the valve seat is provided. A metal diaphragm valve having a radial groove formed on its surface.