JPH0474592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for sealing a vacuum valve such as a vacuum gate valve.

[Conventional technology]

Conventionally, as a vacuum gate valve, as shown in FIGS. 5 and 6, a plate-shaped plate having smooth sealing surfaces on both the front and back sides is installed in a valve box 11 having the opening 9 and the rear opening 10. A gate valve 12 is movably arranged, and an inner bellows 5 and an outer bellows are provided between the front and back surfaces of the gate valve 12 and a portion surrounding the front opening 9 and a rear opening 10 in the valve box 11, respectively. A bellows 6 is arranged,
The gate valve side ends of the inner bellows 5 and the outer bellows 6 are arranged in an annular recess 2 facing the gate valve 12.
The other ends of the inner bellows 5 and the outer bellows 6 are fixed to the valve body 11 by welding, and the opening of the annular recess 2 is connected to the annular fitting 3 on the face of the annular fitting 3 facing the gate valve. A mirror-like thin plate 4 that closes the mirror-like thin plate 4 is fixed by welding, and the annular metal fitting 3 has an annular pressurizing chamber 8 formed by the annular recess 2 and the mirror-like thin plate 4, and bellows 5, 6.
A communication hole 13 that communicates with the annular bellows chamber 7 between
The valve box 11 is provided with a fluid supply port 14 that opens into the annular bellows chamber 7. Pressurized fluid is supplied from the fluid supply port 14 to the annular bellows chamber 7, and the pressurized fluid is By supplying water from the communication hole 13 to the annular pressurizing chamber 8, the bellows 5 and 6 are extended to press the specular thin plate 4 against the sealing surface of the gate valve 12, and the specular thin plate is pressed by the fluid pressure of the annular pressurizing chamber 8. 4 is in pressure contact with the sealing surface of the gate valve 12.

In this vacuum gate valve, when pressurized fluid is supplied from the fluid supply port 14, the bellows 5 and 6 first expand and the mirror thin plate 4 is pressed against the sealing surface of the gate valve 12, and then annular pressure is applied. Ideally, the mirror thin plate 4 is pressed against the sealing surface of the gate valve 12 by the fluid pressure in the pressure chamber 8, but in reality, the expansion of each bellows 5, 6 is faster than the bulge deformation speed of the mirror thin plate 4. Since the speed is slow, after the mirror thin plate 4 bulges and deforms as shown in FIG. , the mirror thin plate 4 is compressed and deformed into a flat shape as shown in FIG.

However, when the specular thin plate 4 is bulged and deformed and then compressed, the bulged and deformed specular thin plate 4 is forcibly compressed, so that both sides of the specular thin plate 4 in the width direction are compressed as shown in FIG. It tends to be bent and deformed, generating large bending stress, and when such bending deformation is repeated, eventually both sides of the mirror thin plate 4 in the width direction are bent as shown in FIG. As a result, there is a problem in that the seal portion of the vacuum gate valve is damaged at an early stage.

In addition, as other gate valves, JP-A-57-
A gate valve disclosed in Publication No. 114065 is known.

In the case of this gate valve, the widthwise middle part of the thin plate whose outer and inner edges are fixed to the valve body is pressed against the sealing surface of the intermediate plate or the sealing surface of the valve body, so the thin plate is sealed. If the thin plate is strongly pressed against the surface, an excessive bending force will be applied to the thin plate, and there is a risk that the thin plate will be damaged.

In addition, in the case of the conventional gate valve, the pressurizing chamber for pressing the thin plate formed by the annular recess of the valve body and the thin plate is communicated with the pressurizing chamber for moving the valve body through the introduction hole. There is a problem in that it is not possible to press the thin plate against the sealing surface at an arbitrary pressure by supplying fluid at an arbitrary pressure into the pressing pressurizing chamber regardless of the pressure inside the valve body moving pressurizing chamber.

[Purpose and structure of the invention]

It is an object of the present invention to provide a sealing method for a vacuum valve that can advantageously solve the above-mentioned problems. An annular mirror thin plate 4 that closes the annular recess 2 is fixed to an annular metal fitting 3 having a
One end of the inner bellows 5 and the outer bellows 6 are fixed to the bellows support member, and the other end of the inner bellows 5 and the outer bellows 6 are fixed to the bellows support member.
By pressurizing fluid into the annular bellows chamber 7 between them and expanding each bellows 5 and 6, the mirror thin plate 4 is pressed against the sealing surface 1 over its entire surface, and then the annular recess 2 and the mirror thin plate are pressed against the seal surface 1 over the entire surface thereof. A vacuum valve sealing method characterized in that fluid is pressurized from a fluid supply pipe 21 into an annular pressurizing chamber 8 between the vacuum valve 4 and the mirror thin plate 4 against the sealing surface 1 by the fluid pressure. be.

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

Figures 1 to 3 show an embodiment in which the present invention is applied to a vacuum gate valve.
A flange fitting 15 for connecting an exhaust pump is attached to the lower part of the valve box 11 having a front opening 9 and a rear opening 10.
are provided, with a front opening 9 and a rear opening 10
is connected to the piping system of vacuum equipment or vacuum containers by welding.

A plate-shaped gate valve 12 that is moved up and down via an operating rod 16 by a fluid pressure cylinder (not shown).
is arranged in the valve box 11, and a smooth sealing surface 1 with a mirror finish is provided on both the front and back sides of the gate valve 12, and the left and right sides of the gate valve 12 are arranged in the valve box 1
The lower end of a sealing bellows 18 that fits into a guide groove (not shown) provided in 1 and surrounds the lower part of the operating rod 16 is fixed to the valve box 11, and the upper end of the bellows 18 is fixed to a flange (not shown) fixed to the operating rod 16.

A wedge-shaped end 19 is formed at the distal end of the gate valve 12, and a wedge-shaped guide groove 20 is provided at one end in the valve box 11, facing the wedge-shaped end 19 of the gate valve 12. Gate valve 12
the wedge-shaped end 19 of the gate valve 12 into the wedge-shaped guide groove 2 of the valve housing 11.
0, the gate valve 12 is held at the center of the space within the valve box 11.

A cylindrical inner bellows 5 and an outer bellows 6 are arranged between the front and back surfaces of the gate valve 12 and a portion surrounding the front opening 9 and a rear opening 10 in the valve body 11, respectively. The ends of the inner bellows 5 and the outer bellows 6 on the gate valve side are fixed by welding to an annular fitting 3 having a shallow annular recess 2 facing the sealing surface 1 of the gate valve 12, and are made of aluminum having a thickness of 0.1 mm. Thick-walled parts are connected to the inner and outer peripheries of an annular mirror thin plate 4 made of a thin alloy plate, and the mirror thin plate 4 closes the annular recess 2 in the annular fitting 3 and is attached to the sealing surface of the gate valve 12. They are arranged to face each other, and the thick inner and outer peripheral parts of the mirror thin plate 4 are hermetically fixed to the annular metal fitting 3 by welding.
An annular pressurizing chamber 8 is constituted by the annular recess 2 and the mirror thin plate 4.

The other ends of each of the bellows 5 and 6 are hermetically fixed by welding to a valve body 11 which also serves as a bellows support member, and an annular bellows chamber 7 is formed by each of the bellows 5 and 6, the annular fitting 3, and the valve body 11. It is configured. Further, a fluid supply port 14 is provided in the valve box 11, and a metal fluid supply pipe 21 whose one end is inserted through and fixed to the annular fitting 3 passes through the annular bellows chamber 7 and is fixed to the valve box 11 in an airtight manner. Further, the fluid supply pipe 21 is provided with a corrugated portion 22 for allowing expansion and contraction within the annular bellows chamber 7, and the fluid supply port 14 is connected to a pressurized fluid such as air or liquid through a pipe line and an on-off valve. The fluid supply pipe 21 is also connected to a pressurized fluid supply source via an on-off valve.

From the state shown in FIGS. 1 and 2, the mirror thin plate 4
When the bellows 5 and 6 are brought into pressure contact with the gate valve 12 for sealing, first, pressurized fluid such as compressed air or pressurized fluid is supplied from the fluid supply port 14 into the annular bellows chamber 7 to extend each bellows 5 and 6. As shown in FIG. 3, the thin mirror plate 4 is pressed against the sealing surface 1 of the gate valve 12. Next, by supplying pressurized fluid from the fluid supply pipe 21 into the annular pressurizing chamber 8, the pressure of the pressurized fluid forces the mirror thin plate 4 over its entire surface against the sealing surface of the gate valve 12. Apply pressure.

In addition, when releasing the seal between the gate valve 12 and the thin mirror plate 4, the pressure in the annular pressurizing chamber 8 is first released, and then the pressure in the annular bellows chamber 7 is released to shorten each bellows 5 and 6. As a result, the thin mirror plate 4 is moved away from the gate valve 12 to the position shown in FIGS. 1 and 2.

When carrying out the present invention, the fluid supply pipe 21 may be provided with a telescoping helical portion 23, as shown in FIG. Further, the present invention can be applied to a seal portion of a vacuum valve other than a vacuum gate valve.

〔Effect of the invention〕

According to this invention, an annular mirror thin plate 4 that closes the annular metal fitting 2 is fixed to an annular metal fitting 3 having an annular recess 2 opening toward the sealing surface 1, and one end is fixed to the annular metal fitting 3. The other ends of the inner bellows 5 and the outer bellows 6 are fixed to a bellows support member, and a fluid is pressurized into the annular bellows chamber 7 between the inner bellows 5 and the outer bellows 6 to separate the bellows 5 and 6. By stretching, the mirror thin plate 4 is pressed against the sealing surface 1 over its entire surface, and then fluid is pressurized into the annular pressurizing chamber 8 between the annular recess 2 and the mirror thin plate 4, and the fluid is Since the specular thin plate 4 is strongly pressed against the sealing surface 1 by pressure, even if high-pressure fluid is injected into the annular pressurizing chamber 8, excessive bending stress acts on the specular thin plate 4, causing damage to the specular thin plate 4. Furthermore, since the fluid is pressurized into the annular pressurizing chamber 8 from the fluid supply pipe 21, high-pressure fluid is supplied into the annular pressurizing chamber 8 regardless of the fluid pressure in the annular bellows chamber 7. , the mirror-finished thin plate 4 can be brought into strong pressure contact with the sealing surface 1, so that the effect of reliably sealing can be obtained.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional side view of a vacuum gate valve with the seal portion open, and FIG. 2 is a seal of the vacuum gate valve in FIG. 1. FIG. 3 is a vertical side view showing the sealed portion in a sealed state. FIG. 4 is a longitudinal sectional side view showing a state in which a spiral portion for expansion and contraction is formed in the fluid supply pipe. FIG. 5 is a vertical side view showing a conventional vacuum gate valve, FIG. 6 is an enlarged vertical side view of the sealing part of the gate valve, and FIGS.
The figure is a longitudinal side view showing the order in which the thin mirror plate in a conventional gate valve is pressed against the gate valve, and FIG. 9 is a longitudinal side view showing the state in which the thin mirror plate in the conventional gate valve is bent and deformed. In the figure, 1 is a sealing surface, 2 is an annular recess, and 3
is an annular metal fitting, 4 is a mirror thin plate, 5 is an inner bellows,
6 is an outer bellows, 7 is an annular bellows chamber, 8 is an annular pressurization chamber, 9 is a front opening, 10 is a rear opening,
11 is a valve box, 12 is a gate valve, 14 is a fluid supply port,
21 is a fluid supply pipe, and 22 is a corrugated portion.

Claims (1)

[Claims] 1. An annular mirrored thin plate 4 that closes the annular recess 2 is fixed to an annular metal fitting 3 having an annular recess 2 that opens toward the sealing surface 1, and the annular metal fitting 3
One end of the inner bellows 5 and the outer bellows 6 are fixed to the bellows support member, and the other end of the inner bellows 5 and the outer bellows 6 are fixed to the bellows support member.
By pressurizing fluid into the annular bellows chamber 7 between them and expanding each bellows 5 and 6, the mirror thin plate 4 is pressed against the sealing surface 1 over its entire surface, and then the annular recess 2 and the mirror thin plate are pressed against the seal surface 1 over the entire surface thereof. 4. A vacuum valve sealing method characterized in that fluid is pressurized from a fluid supply pipe 21 into an annular pressurizing chamber 8 between the vacuum valve 4 and the mirror thin plate 4 against the sealing surface 1 by the pressure of the fluid.