JPS6227309B2 - - Google Patents

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 section of the particle accelerator to atmospheric pressure for repair purposes, and then return it to a vacuum state, the section must be baked at a high temperature. figure,
For this reason, 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 edge as a valve member is pressed against this valve seat. This valve structure maintains a seal between the vacuum section and the atmosphere.

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

(1) The structure for strongly pressing the valve member against a single valve seat is complicated, and furthermore, it lacks reproducibility with 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 large-diameter gate valves.

In addition, a gate valve installed in the middle of a gas transport pipe has a pair of valve members between opposing valve seats,
Some valve bodies have a composite valve body consisting of a bellows integrally provided in the middle (see Japanese Patent Publication No. 51-41691), but the structure is complicated, and especially in particle accelerators that are used as vacuum vessels, charged particle There is a problem in that the wall current that should flow along the inner wall of the particle path is interrupted as the particle advances, causing trouble.

In order to solve these problems, the present inventors
Previously, we developed a gate valve as shown in Japanese Unexamined Patent Publication No. 54-14018, but the present invention aims to improve this even further by using a pair of gate valves provided inside a box-shaped body that can adjust the internal pressure. By providing the ring-shaped bellows to sandwich the opening/closing partition plate between the valve ports facing each other, it is possible to sufficiently improve the sealing performance of the vacuum container, and also to improve the sealing performance of the vacuum container. An object of the present invention is to provide a gate valve for a vacuum vessel which allows wall current to flow without any hindrance.

For this reason, the gate valve for vacuum vessels of the present invention is
A metal box-shaped body having a pair of valve ports formed to face each other on both end walls, and a metal box-shaped body disposed coaxially with the valve ports inside a metal box-shaped body provided with a port that can communicate with the exhaust pump. A pair of ring-shaped bellows having a stretchable double-walled structure made of aluminum, a metal partition plate with an opening and a closing part inserted between these ring-shaped bellows, and the ring-shaped bellows a partition plate drive mechanism capable of driving the partition plate from a state in which the openings of the partition plate are aligned to a state in which the closed portions thereof are aligned; The bellows is provided with a tube, and the end surface of the bellows that is to come into contact with the partition plate is formed with a thin wall portion so as to be press-fitted to the partition plate.

According to the above-mentioned gate valve for a vacuum vessel of the present invention, a pair of ring-shaped bellows that can be expanded and contracted between the valve ports facing each other in the metal box-shaped main body have an opening/closing partition plate between them. Since it has a sandwiching valve structure, it has the advantage of simplifying the sealing part between the opposing valve ports and yet fully exhibiting 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 vacuum vessels 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 ports are closed is located coaxially and axially with each valve port within the box-shaped main body. Since the bellows is arranged to be expandable and retractable, and a fluid inlet and outlet is formed in the bellows, the partition plate sandwiched between the bellows can be evenly pressed, and the end face of the bellows that should be in contact with the partition plate Coupled with the fact that the bellows is formed with a thin wall, the end face of the bellows is crimped to fit the partition plate, which not only improves the sealing performance without difficulty, but also makes it easier to open and close the partition plate. Since there are no parts that cause wear, it has the advantage of being reproducible during repeated use, has a long service life, and can be easily manufactured with large diameters.

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 valve for a vacuum vessel as an embodiment of the present invention will be explained with reference to the drawings.
The figure is a longitudinal sectional view of the same, in which a metal box-like body 1 with a removable lid 1' is provided with a pair of valve ports 1a, 1a facing each other on both end walls, and connected to an exhaust pump (not shown). It is equipped with a port 6 for communication.

Valve seats 2, 2 are provided on the peripheral edge of each valve port 1a, 1a, respectively, facing inward.

Furthermore, inside the box-shaped main body 1, a partition plate 4 attached with a moving rod 5a is arranged between a pair of ring-shaped bellows 3, 3.
The bellows 3 are arranged so as to be inserted between each bellows 3 when the valve is opened.
and a closing portion 4b that is aligned to close the opening of each bellows 3 when the valve is closed. (See Figure 2) A fluid having a piston 5b connected to a moving rod 5a for driving the partition plate 4 from aligning the opening 4a of the partition plate 4 with the bellows 3 to aligning its closing portion 4b. A partition plate drive mechanism 5 as a pressure cylinder is provided, and a relay box 5c inserted between the box-shaped body 1 and the fluid pressure cylinder of the drive mechanism 5 is provided with a partition plate drive mechanism 5 as a pressure cylinder. A sealing bellows 9 is provided between the intermediate flange 5d of the movable rod 5a and the wall of the box-like body 1 to seal the penetrating portion of the rod 5a.

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. 4, and the end surfaces 3a of these bellows 3,
When each valve port 1a is opened, the opening 4a of the partition plate 4
The end surface 3b of the bellows 3 is also pressed against each valve seat 2 by the reaction force thereof. Each end face 3 of bellows 3
a and 3b are formed with thin walls in order to ensure sealing performance, which will be described later.

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 3c for injecting and discharging the fluid 8 into the inside of its double-walled structure, and this injection/discharge pipe 3c communicates with a pump (not shown).

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

Each valve port 1a is connected to each section 7 of the particle accelerator, and the bellows 3 is connected to each valve seat 2.
The end surface 3b may be fixed to the inner wall surface of the box-like main body 1. When fixed in this way, the fixed end surface 3b of the bellows 3 may be formed of a thick wall, but the end surface 3a of the bellows 3 that should be in contact with the partition plate 4 is formed of a thin wall.

In addition, a box-shaped main body 1, a valve seat 2, a partition plate 4, a moving rod 5
a and each bellows 3, 9 are all made of metal to withstand baking.

If necessary, a thin layer made of a soft metal such as aluminum, silver or gold is applied to the end surfaces 3a and 3b of the bellows 3 and the peripheral edges of the opening 4a and closing portion 4b of the valve seat 2 and partition plate 4 that come into contact with these. It can also be formed to provide a better seal upon contact.

Since the gate valve for a vacuum vessel of the present invention is constructed as described above, when the left and right partitions 7, 7 of the particle accelerator are to be made to communicate with each other, the partition plate 4 is driven by its drive mechanism 5. 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 and expanding the bellows 3, the end surfaces 3a, 3b of each bellows 3 are brought into close contact with the peripheral edge of the partition plate opening 4a and the valve seat 2.

The left and right partitions 7, 7 communicated in this way
is used as a particle accelerator while being kept in an ultra-high vacuum.
At the part where b contacts the partition plate 4 and the valve seat 2, the end surfaces 3a and 3b formed by the thin walls of the bellows 3 are crimped to fit the rigid wall surfaces of the partition plate 4 and the valve seat 2, and the contact part Even if a minute foreign object is caught in the bellows 3, the end surfaces 3a and 3b of the bellows 3 are deformed to surround the foreign object, so that a high degree of sealing performance can be maintained.

In addition, wall current (wall current) is generated when the electron beam passes along the central axis inside the particle accelerator.
current) are the left and right partitions 7, 7 of the particle accelerator.
By connecting the inner circumferential wall of the metal ring-shaped bellows 3 and the peripheral edge of the opening 4a of the metal partition plate 4, the liquid can flow without any trouble.

Next, when separating the divided parts 7, 7, each bellows 3 is once contracted by discharging its internal fluid, and then the partition plate 4 is driven so that the closing part 4b connects with the bellows 3. To ensure alignment, each bellows 3 is then expanded again by pressurizing fluid into its interior, thereby blocking the left and right valve ports 1a, 1a from each other.

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

In other words, 4Kg/cm ² of compressed air is applied to each bellows 3.
from the vent 6 as an intermediate exhaust port.
When exhausting at an exhaust speed of 20/sec, and one of the left and right partitions 7, 7 is made into the atmosphere, and the other side is exhausted at an exhaust speed of 250/sec, the amount of leakage from the atmosphere side to the vacuum side is 10 ^-8 It was torr・/sec.

As detailed above, according to the gate valve for vacuum vessels of the present invention, a high degree of sealing performance can be obtained with a simple structure, and the performance does not deteriorate even when used repeatedly. Although there is an advantage that no trouble occurs even if minute dust or the like is present on the sealing surface, further effects and advantages of the gate valve of the present invention are enumerated as follows.

(1) Less susceptible to thermal distortion caused by baking (heating).

(2) The valve opening can be made to have a large diameter, or it can be made into various shapes such as oval or circular.

(3) Since each component is used in an elastic region, the life of the airtight sealing surface is long.

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

(5) The driving mechanism 5 of 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.

(8) End surface 3a of bellows 3 that should be in contact with partition plate 4
However, since it is formed with a thin wall portion that can be press-fitted to fit into the partition plate 4, it is possible to maintain the high sealing performance necessary to maintain an ultra-high vacuum.

[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 - arrow in FIG. DESCRIPTION OF SYMBOLS 1... Box-shaped main body, 1'... Lid, 1a... Valve port, 2... Valve seat, 3... Ring-shaped bellows, 3a, 3b... End surface,
3c... Injection/drainage pipe, 4... Partition plate, 4a... Opening, 4b
... Closing part, 5... Partition plate drive mechanism, 5a... Moving rod,
5b... Piston, 5c... Relay box, 5d... Intermediate flange, 6... Vent as intermediate exhaust port, 7... Particle accelerator partition, 8... Fluid, 9... Sealing bellows.

Claims (1)

[Claims] 1 A pair of valve ports formed to face each other on both end walls and arranged coaxially with the above valve ports inside a metal box-shaped body 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. a partition plate drive mechanism capable of driving the partition plate to a state where the partition plate is in contact with the partition plate, and an injection/drainage pipe for introducing and discharging fluid into the double wall structure of the bellows, and an end face of the bellows that is to be in contact with the partition plate. A gate valve for a vacuum vessel, characterized in that the gate valve is formed of a thin wall portion so as to be press-fitted to fit into the partition plate.