JPS58152977A - Gate valve for vacuum receptacle - Google Patents

Abstract

PURPOSE:To heighten sealing tightness retaining performance of a vacuum receptacle by clamping an opening by means of closing partition plate between mutually opposed valve ports, by means of a pair of ring-shaped bellows mounted in a box-shaped main body. CONSTITUTION:In a box-shaped main body, a partition plate 4 is interposed between a pair of ring-shaped bellows 3, 3. The partition plate 4 is provided with an opening portion 4a matching with openings of respective bellows 3 when a valve is opened, and a closing portion matching in such a manner as to close the openings of the respective bellows 3. A fluid is pressed into each bellow 3 to expand it, so that the end surface of each bellow 3 closely adheres to a valve seat 2 and the partition plate 4. At the close contact portion of the bellow 3, the thin wall portion of the bellows 3 is brought into pressure contact with the rigid wall surfaces of the partition plate 4 and the valve seat 2 in such a manner as to fit therewith, so as to keep a good sealing property.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gate valve for sealing and shutting off between containers, and in particular to a gate valve for a vacuum container suitable for sealing a vacuum container such as a particle accelerator to maintain airtightness. Regarding.

Generally, large-scale vacuum vessels such as particle accelerators are constructed so that they can be divided into several sections, each section having its own pressure even if the pressure in an adjacent section is brought to atmospheric pressure. A sufficient degree of vacuum must be maintained, and gate valves are often used to maintain a tight seal between these sections.

In addition, for example, if it becomes necessary to bring a certain section of the particle accelerator to atmospheric pressure for repair purposes, and then return it to a vacuum state, that section must be baked at a high temperature. Therefore, the gate valve must be made of metal.

Therefore, in conventional gate valves of this type, a stainless steel surface coated with a thin layer of soft metal such as gold is used as the valve seat, and a metal knife as a valve member is pressed onto this valve seat. This valve structure maintains a seal between the vacuum section and the atmosphere.

However, in such conventional gate valves, their sealing performance is maintained by a single valve structure in which a ring-shaped knife formed in the valve member is pressed against a single valve seat. There is a problem.

(1) The structure of the reservoir that strongly presses the valve member against a single valve seat is complicated, and furthermore, it lacks reproducibility in repeated use and has a short lifespan.

(2) High processing precision is required for the joint surface between the valve member and the valve seat, making it difficult to manufacture a large-diameter gate valve.

In addition, gate valves installed in the middle of gas transport pipes have a composite valve body consisting of a pair of valve members between opposing valve seats and a bellows integrally provided in the middle. There is also a method (see Japanese Publication No. 51-41691), but the structure is complicated, and there is a problem in that the wall current is interrupted, especially in a particle accelerator as a vacuum container, which causes problems.

In order to solve these problems, the inventor of the present invention previously developed a gate valve as shown in JP-A-54-14018, but the present invention is an attempt to further improve this. A pair of ring-shaped bellows provided in the adjustable box-shaped main body are provided to sandwich the opening/closing partition plate between the opposing valve ports, thereby improving the performance of keeping the vacuum container airtight. It is an object of the present invention to provide a gate valve for a vacuum vessel, which is capable of increasing the voltage sufficiently, and also allows a wall current to flow without problems even in the case of a particle accelerator.

For this reason, the gate valve for a vacuum vessel of the present invention is provided with a pair of valve ports formed on both end walls so as to face each other, and a metal box-shaped body with a vent through which seven exhaust cylinders can communicate. , a pair of ring-shaped bellows made of a stretchable double-walled metal structure arranged coaxially with the valve port, and an opening and a closing part inserted between these ring-shaped bellows. a partition plate drive mechanism capable of driving the partition plate from a state in which the opening of the partition plate is aligned with the ring-shaped bellows to a state in which the closed portion thereof is aligned; According to the above-mentioned gate valve for a vacuum container of the present invention, the gate valve is provided with an inlet and an outlet for allowing fluid to enter and exit the double-walled structure. The valve structure has a pair of ring-shaped bellows that can be expanded and contracted between the valve openings, and an opening/closing partition plate is sandwiched between them.
While simplifying the sealing part between the opposing valve ports,
Moreover, it has the advantage of being able to fully demonstrate its sealing performance.

In addition, in the gate valve for a vacuum vessel of the present invention, the internal pressure of the box-shaped body is adjusted through the port that can communicate with the exhaust pump, so that the intermediate pressure between the two areas partitioned by the gate valve is adjusted to the internal pressure of the box-shaped body. There is an advantage that the sealing between the two regions can be efficiently performed step by step.

Furthermore, in the gate valve for a vacuum vessel of the present invention, a pair of ring-shaped bellows with a stretchable double wall structure that clamps and presses the partition plate between the valve ports when the valve port is closed is installed inside the box-shaped main body. Since the bellows are disposed coaxially with each valve port and extendable in the axial direction, and a fluid inlet/outlet is formed in the bellows, the partition plate held between the bellows can be pressed uniformly. In addition to reasonably improving the sealing performance, there is no part that causes wear when opening and closing the partition plate, so it is reproducible during repeated use, extends its life, and can easily be used for large diameter ones. There are advantages to making it.

Since the above-mentioned box-shaped body, partition plate, and bellows are all made of metal, they can withstand baking as a pretreatment for keeping the inside of the vacuum container at an ultra-high vacuum. The bellows is extended between the periphery of the opening of the plate and the valve port, which has the advantage of being electrically connected to allow wall current to pass through without any hindrance.

Hereinafter, a gate pulp for a vacuum container as an embodiment of the present invention will be explained with reference to the drawings. FIG. However, a pair of valve ports 1a+1 facing each other are provided on both end walls.
In addition, it is provided with a port 6 that can communicate with an exhaust pump (not shown).

Then, on the periphery of each valve port lal la, a valve seat 2,
2 are provided facing inward, respectively.

Further, inside the box-shaped main body l, a partition plate 4 to which a movable rod 5a is attached is arranged so as to be inserted between the pair of ring-shaped bellows 3, 3. teeth,
Opening 4a that should align with the opening of each bellows 3 when the valve is opened
and a closing portion 4b that is aligned so as to close the opening of each bellows 3 when the valve is closed. (See Figure 2) A piston 5bl is connected to a movable rod 5a to drive the partition plate 4 between the state in which the opening 4a of the partition plate 4 is aligned with the bellows 3 and the state in which the opening 4a of the partition plate 4 is aligned with the bellows 3. A partition plate drive mechanism 5 as a fluid pressure cylinder is provided,
The relay box 5C inserted between the box-like main body 1 and the fluid pressure cylinder of the drive mechanism 5 has a moving rod 4 in order to seal the penetration part of the moving rod 4 that penetrates the wall of the box-like main body 1. A sealing bellows 9 is provided between the intermediate flange 4a and the wall of the box-like body 1.

Each ring-shaped bellows 3 has a stretchable double wall structure made of metal such as stainless steel, and is extendable and retractable coaxially and axially with each valve port 1a within the box-shaped main body 1. These bellows 3
Therefore, when each valve port 1a is opened, the opening 4 of the partition plate 4
The end face of the bellows 3 is also pressed against each valve seat 2 by the reaction force of the peripheral edge of the valve seat 3 which is pressed from both sides.

Each ring-shaped bellows 3 has the property of automatically contracting, but if necessary, a plurality of tension springs are interposed therein.

Further, each ring-shaped bellows 3 is provided with an injection/discharge pipe 3a for injecting and discharging a fluid 8'fr into the inside of its double wall structure, and this injection/discharge pipe 3a communicates with a pump (not shown).

Furthermore, each bellows 3 is supported at its outer periphery by a suitable holder (not shown).

Although each valve port 1a is connected to each section 7 of the particle accelerator, the end surface of the bellows 3 may be fixed to the inner wall surface of the box-shaped main body 1 at each valve seat 2.

Also, the box-shaped body 1. Valve seat 2. Partition plate 4. The bellows 3 and 9 of the moving rod 5a are all made of metal to withstand baking.

A thin layer made of a soft metal such as aluminum, silver or gold may be formed on the end face of the bellows 3 and the peripheral edges of the opening 4a and closing part 4b of the valve seat 2 and partition plate 4 that come into contact with the end face, as necessary. , it is also possible to improve the sealing performance during contact.

Since the gate pulp for vacuum vessels of the present invention is constructed as described above, when the left and right partitions 7.7 of the particle accelerator are to be communicated, the partition plate 4 is
Driven by.

As shown in FIG. 1, the opening 4a of the partition plate 4 is aligned with the left and right ring-shaped bellows 3.3.

Then, by injecting fluid into each bellows 3 to expand the bellows 3, the end surface of each bellows 3 comes into close contact with the valve seat 2 and the periphery of the partition plate opening 4a.

The left and right divided sections 7゜7 communicated in this way are used as particle accelerators while being kept in an ultra-high vacuum, but each end face of the pair of bellows 3 comes into contact with the partition plate 4 and the valve seat 2. The thin walls of the bellows 3 are pressed against the rigid walls of the partition plate 4 and the valve seat, and even if a minute foreign object is caught in the contact area, the area around the foreign object should be Since the end face of the bellows 3 is deformed so as to surround it, a high degree of sealing performance can be maintained.
t) can flow without any problem by connecting the left and right partitions 7.7 of the particle accelerator with the inner circumferential wall of the metal ring-shaped bellows 3 and the opening of the metal partition plate. When separating the split parts 7.7, first contract each bellows 3 by discharging the internal fluid, and then drive the partition plate 4 so that the closing part 4b is aligned with the bellows 3. Then, each bellows 3 is expanded again by pressurizing fluid into the inside thereof, and the left and right valve ports 1a and 1 are opened.
It is sufficient to disconnect Kl between a.

As a result of conducting experiments on the gate valve for vacuum vessels of the present invention, the following data were obtained.

That is, compressed air of 4 kg/cm" is injected into the inside of each bellows 3, and is
After exhausting at an exhaust speed of 0.01/sec, the left and right divided sections 7,
When one side of 7 is the atmosphere and the other side is exhausted at a pumping speed of 250t/see, the amount of leakage from the atmosphere side to the vacuum side is ] Q-atorr a t/sec 0 As detailed above, one According to the gate valve for vacuum vessels of the invention, it is possible to obtain a high degree of sealing performance with a simple structure, and there is no deterioration in performance even when used repeatedly, and there is no possibility that minute dust etc. will get on the sealing surface. Although the advantage that the gate pulp of the present invention does not cause any trouble even when it is present is obtained, the effects and advantages of the gate pulp of the present invention are enumerated as follows.

(1) Less susceptible to thermal distortion due to baking (heating).

(2) The valve opening can be made large in diameter, or can be made into an oval or other various shapes in addition to a circular one.

(3) Each component is used in an elastic region.

Airtight seal surface has a long life.

(4) Maintenance and inspection of the inside of the box-shaped main body 1 is easy.

Parts compatibility is achieved.

(5) The drive mechanism 5 for the partition plate 4 does not require a high degree of precision.

(6) Wall current is not disturbed when the valve is opened.

(7) By selecting the intermediate exhaust pump connected to the vent 6, the overall airtight conductance can be adjusted.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a gate valve for a vacuum vessel as an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line -■ in FIG. 1...Box-shaped body + 1'...Lid, 1a...Valve opening. 2e: Valve seat, 3: Ring-shaped bellows, 3a: Inlet/outlet pipe, 4@fist partition plate, 4a: Opening. 4b...Closing part 15...Partition plate drive mechanism t5a...Moving rod, 5b...Piston, 5c...Relay box, 6...Through as intermediate exhaust port 0.7...Divided part of particle accelerator, 8...
Fluid, 9... Bellows for sealing. Agent Patent Attorney Yoshihiko Iinuma Figure 1 Figure 2

Claims (1)

[Scope of Claims] A metal box-like body is provided with a pair of valve ports formed to face each other on both end walls, and a port that is coaxial with the valve ports and is provided inside the metal box-shaped body and provided with a port that can communicate with the exhaust pump. A pair of ring-shaped bellows made of a stretchable double wall structure made of metal. A metal partition plate with an opening and a closing part is inserted between these ring-shaped bellows, and the closing part is aligned from the state in which the opening of the partition plate is aligned with the ring-shaped bellows. The bellows is characterized in that it is provided with a partition plate drive mechanism capable of driving the partition plate to a state where the bellows is in a state where the partition plate is in a state where the bellows is closed, and an inlet and outlet port for allowing fluid to enter and exit the double wall structure of the bellows. Gate valve for vacuum containers.