JPH04370480A - On-off valve - Google Patents

Abstract

PURPOSE:To provide an opening/closing valve which not only has excellent airtightness between a valve body and a valve seat during closing of a valve but also rapidly produces ultrahigh vacuum when it is used for an ultra vacuum device by suppressing adsorbing gas and discharging gas as much as possible. CONSTITUTION:An opening/closing valve comprises a valve seat 6 formed on a fluid passage 2 in a body 1 and a diaphragm 9 arranged facing the valve seat. The fluid passage 2 is closed when the diaphragm 9 is brought into contact with the valve seat 6, and the fluid passage 2 is opened when the two members 6 and 9 are separated away from each other. A film 19 of silver being a ductile and malleable metal is formed on the valve seat 6 by an ion cluster beam deposition method. A film 20 of silicon oxide being a material different from silver is formed on the diaphragm 9 by an ion cluster beam deposition method.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-off valve that opens and closes a fluid passage by moving a valve seat formed on a fluid passage in a main body into and out of contact with a valve body disposed opposite the valve seat.

0002

[Prior Art] As a conventional device of this type, JP-A-2-26
An on-off valve disclosed in Japanese Patent No. 6171 is known. In all of these conventional devices, gold or silver is applied to at least one of the valve body or the valve seat by plating, vapor deposition, etc. in order to improve the contact airtightness of the contact area between the metal valve body and the valve seat. A highly ductile metal film is formed. The sealing action of the highly extensible metal film formed in this way reliably prevents fluid leakage when the valve is closed, and also eliminates the generation of metal dust caused by repeated contact and separation between the valve body and valve seat. .

0003

[Problems to be Solved by the Invention] However, the metal body that is the material of the valve body or valve seat, or the metal film formed by plating, sputtering, electron beam (EB), etc., cannot be seen microscopically. In such cases, they exhibit porosity, and a small amount of gas such as oxygen is inevitably adsorbed within the pores of the metal body and metal film. Even if an attempt is made to achieve an ultra-high vacuum using an ultra-high vacuum device using such an on-off valve, the adsorbed gas in the hole will be released little by little, and it will take a long time to achieve an ultra-high vacuum. Furthermore, if the valve is opened to release the vacuum state after achieving an ultra-high vacuum, the gas will be adsorbed onto the metal film again, so it always takes time to achieve an ultra-high vacuum.

The present invention was made in view of the above problems, and its purpose is to not only improve the airtightness between the valve body and the valve seat when the valve is closed, but also to prevent gas adsorption and gas release. It is an object of the present invention to provide an on-off valve that can quickly achieve an ultra-high vacuum even when used in an ultra-vacuum device by suppressing the pressure as much as possible.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention includes a valve seat formed on a fluid passage in a main body, and a valve body disposed opposite to the valve seat. In the on-off valve, which closes the fluid passage by contacting the valve body with the valve seat, and opens the fluid passage by separating the two, a ductile metal film is applied to either the valve body or the valve seat using the ion cluster beam evaporation method. On the other hand, a film of a different material was formed using ion cluster beam evaporation.

[0006]

[Operation] Since fluid leakage is prevented by the ductile metal film formed on either the valve body or the valve seat, an excellent airtight condition can be maintained between the two when the valve is closed. Furthermore, since the membrane on the valve body side and the membrane on the valve seat side are made of different materials, adhesion and transfer, which is likely to occur when similar materials come together and separate, is eliminated. Furthermore, according to the above-mentioned vapor deposition method in which film formation is performed using ion clusters of a film-forming substance generated in a high vacuum, a non-porous and extremely dense film that does not contain gas can be formed on the valve body and valve seat. . If such a nonporous membrane is formed over a wider area, gas release and gas adsorption within the on-off valve can be suppressed as much as possible, and the time required to achieve an ultra-high vacuum in an ultra-vacuum device using such an on-off valve will be reduced. is shortened.

[0007]

[Embodiment] An embodiment embodying the present invention will be described below with reference to FIGS. 1 to 5. As shown in FIG. 1, a fluid passage 2 is formed inside a cylindrical main body 1, and an input port 3 and an output port 4 are formed at both ends of the fluid passage 2, respectively. A circular opening 5 communicating with the input port 3 is formed on the upper side of the central portion of the main body 1, and the outer peripheral portion of this opening 5 serves as a valve seat 6. Another opening 7 communicating with the output port 4 is formed near the outer periphery of the valve seat 6 .

A spring housing 8 is disposed above the main body 1, and a stainless steel diaphragm 9 is held between the spring housing 8 and the main body 1 as a valve body, and these 8, 9 are fastened with tightening screws. It is joined and fixed to the main body 1 by 10. The periphery of the diaphragm 9 is the main body 1
It is supported by a joining seal surface 11 provided in an annular shape on the upper side, and only the central portion can move up and down.

A support rod 12 is slidably housed within the spring housing 8 , and the lower end of the support rod 12 is fixed to the diaphragm 9 . A spring 13 is arranged around the outer circumference of the support rod 12. One end of the spring 13 is in contact with a step 14 in the spring housing 8, and the other end is in contact with a spring seat 15 provided on the support rod 12, and the urging force of the spring 13 normally causes the support rod 12 to move upward. energized.

An air cylinder 16 is screwed onto the upper side of the spring housing 8, and a projecting end of an operating rod 17 within the air cylinder 16 is arranged so as to be able to approach and separate from the upper end of the support rod 12. When the actuating rod 17 is moved downward by air supply to the air cylinder 16, the diaphragm 9 and the valve seat 6 are joined, and the fluid passage 2 is closed. When the actuating rod 17 moves upward due to air exhaust from the air cylinder 16, the diaphragm 9 and the valve seat 6 are separated, and the fluid passage 2 is opened.

A film 19 of silver, which is a malleable metal, is formed on the surface of the valve seat 6, and a film 20 of silicon oxide is formed on the lower surface of the diaphragm 9. These membranes 19, 20
The formation of the ion cluster beam (ICB) is described below.
) is carried out by vapor deposition method. FIG. 2 shows an ICB deposition apparatus. V is a vacuum chamber, and inside the vacuum chamber V there is a nozzle 2 at the top.
1, a semi-closed crucible 22, a heater 23,
An electron radiation source 24 and an accelerating electrode 25 are housed. When the crucible 22 in a high vacuum is heated by the heater 23, the deposited material evaporates and the internal pressure of the crucible 22 increases. As the pressure inside the crucible 22 increases, the vapor of the deposition material is injected from the nozzle 21 into a high vacuum, and the material vapor is affected by the pressure difference inside and outside the crucible 22 immediately after the injection. Due to this pressure difference, the material vapor expands adiabatically, and
A cluster 26 consisting of about 1,000 atoms is formed. Some of the clusters 26 are ionized by the electron shower emitted from the electron radiation source 24 and become ion clusters 27 . After the ion cluster 27 is given high acceleration energy by the accelerating electrode 25, it reaches the valve seat 6, which is the object to be vaporized. When the ion clusters 27 with high acceleration energy collide with the deposition target, the ion clusters 27 are diffused over a wide range.For example, if the valve seat 6 is the deposition target as shown in FIG. A uniform and highly adhesive film 19 is formed by diffusion. Furthermore, in the case of a structure with a complicated interior like the valve seat 6, it is usually difficult to form a film on the invisible part. However, the inner and outer peripheral surfaces of the valve seat 6 are provided with a taper 18 that is visible from the diaphragm 9 side, so that the film can be formed over a wider area of the inner and outer peripheral surfaces of the valve seat 6. .

The present invention focuses on the fact that the ICB deposition method can form a dense thin film on the object to be deposited. Graphs showing this fact are shown in FIGS. 3 to 5. The graphs in Figures 3, 4, and 5 show the depth of the film and the oxygen content in the film when a thin silver film of approximately 5000 Å was formed on glass using the ICB method, sputtering method, and electron beam (EB) method, respectively. It shows the relationship with the rate (%). Films formed by sputtering and electron beam methods are microscopically porous, so as shown in Figures 4 and 5, the film contains about 10 to 20% oxygen. Put it away. However, in the case of the ICB method, the film formed is non-porous and extremely dense, and as shown in FIG. 3, it can be seen that almost no oxygen is mixed into the film.

As described above, since the non-porous and extremely dense membrane 19 containing no gas can be formed over a wide range, gas release and gas adsorption within the fluid passage 2 hardly occur. Therefore, if you try to achieve an ultra-high vacuum using an ultra-vacuum device using such an on-off valve, you can achieve ultra-high vacuum in a shorter time than before, and after achieving an ultra-high vacuum, open the valve and return to the vacuum state. Even if this is canceled, there is no need to worry about gas being adsorbed to the metal film again.

In the on-off valve in which the silver film 19 containing a malleable metal is formed on the contacting and separating portions of the diaphragm 9 and the valve seat 6, the airtightness of the contact between the two 6 and 9 is improved, and the fluid flow when the valve is closed is improved. Leakage can be reliably prevented. Further, since the membrane 20 on the diaphragm 9 side and the membrane 19 on the valve seat 6 side are made of different materials, the membranes will not adhere to each other and transfer even if the two 6 and 9 are repeatedly brought into contact and separated.

Furthermore, since the joint sealing surface 11 between the diaphragm 9 and the main body 1 is the surface on which the silver film 20 is formed on the diaphragm 9, external sealing can be reliably achieved without using an external sealing material such as a metal O-ring as in the conventional case. can be realized. Since no external seal material is required, no waviness occurs in the external seal or the valve seat 6, and therefore the diaphragm 9 does not twist or tilt. Furthermore, the external seal material and the sealing surface of the valve seat 6 can be inspected at the same time.

The present invention is of course not limited to the above-mentioned embodiments; for example, the ICB film may be formed on the entire surface of the fluid passage 2 by performing ICB vapor deposition from different angles, or by combining different types of vapor deposition materials. It is also possible to form a film by Further, although this embodiment describes the case where the diaphragm 9 is used as the valve body, it is of course possible to apply the present invention to other ordinary valve bodies.

Furthermore, a ductile metal film may be provided on the valve body 9 side, or gold, copper, etc. may be used in place of silver as the ductile metal film.
In addition to silicon oxide, silicon nitride, titanium oxide, etc. may be used as a different material for the malleable metal. The on-off valve of the present invention is suitable for use not only in vacuum equipment but also as a chemical gas switching valve in semiconductor equipment.

[0018]

[Effects of the Invention] According to the on-off valve of the present invention, not only the airtightness between the valve body and the valve seat when the valve is closed is excellent, but also gas adsorption and gas release are suppressed as much as possible. Even when used in a vacuum device, it has the excellent effect of quickly achieving ultra-high vacuum.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an open state of the on-off valve of this embodiment.

FIG. 2 is a schematic diagram of an ion cluster beam (ICB) deposition apparatus.

FIG. 3 is a graph showing the oxygen content in a thin film formed using ICB.

FIG. 4 is a graph showing the oxygen content in a thin film formed using sputtering.

FIG. 5 is a graph showing the oxygen content in a thin film formed using an electron beam (EB).

[Explanation of symbols]

1 Main body, 2 Fluid passage, 6 Valve seat, 9 Diaphragm as a valve body, 11 Joint sealing surface, 18 Taper, 19 Membrane (of ductile metal), 20 Membrane (of foreign material).

Claims (3)

[Claims] Claim 1: A valve seat (6) formed on a fluid passageway (2) in a main body (1), and a valve body (9) disposed opposite to the valve seat (6).
), which closes the fluid passage (2) when the valve body (9) and the valve seat (6) come into contact with each other, and opens the fluid passage (2) when the two (6, 9) separate. , valve body (
9) and the valve seat (6), a ductile metal film (
19) is formed by an ion cluster beam evaporation method, and on the other hand, a film (20) of a different material is formed by an ion cluster beam evaporation method. [Claim 2] The peripheral surface of the valve seat (6) is tapered (18) that is visible from the valve body (9) side, and the membrane (19) on the valve seat (6) side is in contact with the valve body (9). The on-off valve according to claim 1, characterized in that it is formed by projecting an ion cluster beam from a direction perpendicular to the contact surface with the valve seat (6). [Claim 3] The valve body is a diaphragm (9), and the diaphragm (9) and the main body (1) have a joint sealing surface (11).
3. The on-off valve according to claim 1 or 2, wherein the diaphragm (9) is a membrane-forming surface.