JP2006234085A - Vacuum valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a 2-port vacuum valve capable of easily drawing a vacuum to 100 pascal or under by increasing a flow passage in the valve without remarkably increasing the outer size of the valve. <P>SOLUTION: Clearances between the outer periphery of a stop valve 2, the outer periphery of a bellows 7, and the inner wall of a valve body in which the stop valve and the bellows are installed are increased to increase the size of the flow passage in the valve. For this purpose, the stop valve 2 and the bellows 7 are installed at a position deviated from the center of a flow passage chamber in the direction that is apart from a pump connection port 4. Thus, a large space can be secured in the opening part of the pump connection port 4 to easily draw a vacuum. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum valve for connecting a vacuum chamber and a vacuum pump.

  A conventional 2-port vacuum valve forms a flow path by opening a gate valve provided at the center of a flow path chamber that connects a cylindrical chamber connection port and a cylindrical pump connection port. Connect.

  The above flow path is formed by the space between the open gate valve and the valve seat, the inner wall of the flow path chamber and the outer periphery of the gate valve serving as the first flow path, and the pump connection port connected to the vacuum pump is a valve. The vacuum chamber is provided on the side wall of the flow channel chamber, and is provided so as to overlap the first flow channel to become the second flow channel. The vacuum chamber has the second flow channel from the first flow channel. It is evacuated via.

  However, since the inner side wall of the flow channel chamber and the outer periphery of the gate valve are close to each other, and the gap between the inner wall of the flow channel chamber and the outer periphery of the gate valve is limited, the first flow channel is generally open. The range between the gate valve and the valve seat is the first flow path, and the gate valve opening range that opens via the shaft seals the stroke of the spring to close the gate valve and the sliding part of the shaft. Because of the restriction due to the bellows stroke, the pump connection port diameter is about one-third. Therefore, the first and second flow paths overlap in a limited area. .

  Usually, the ability of evacuation is called conductance of the corresponding flow path, and is proportional to the opening area of the flow path and the length of the flow path, however, the first flow path and the cylindrical second flow path. Since the overlaps are in a limited area, the conductance of the flow path inside the valve is smaller than the conductance of the chamber connection port and the pump connection port.

  The evacuation capacity is determined by the vacuum pump capacity and the conductance of the piping connecting the chamber and the vacuum pump. Normally, when the vacuum chamber is evacuated by the vacuum pump, the gas exhausted from the atmospheric pressure to almost 100 Pascal is a viscous flow. However, after that, the influence of molecular flow gradually appears. Therefore, when the vacuum pressure is 100 Pascal or higher, the influence of the conductance of the flow path appears. It is almost the same as the conductance of the part.

  Especially in a vacuum pump equipped with a booster pump in order to increase the exhaust capacity after 100 Pascal, the conductance of the flow path restricts the exhaust performance of the vacuum pump, and it becomes impossible to secure the original target vacuum suction capacity. For the above reason, the conventional vacuum valve has the smallest conductance in the pipe line to be connected. Therefore, the vacuuming ability is limited by the vacuum valve.

  By increasing the stroke of the spring for closing the gate valve and the stroke of the bellows that seals the slide part of the shaft, it is possible to widen the opening range of the gate valve and increase the conductance of the flow path inside the valve. However, in order to secure a double stroke, for example, the same spring and bellows as those provided are required in two stages, and the drive mechanism such as an actuator for operating the same requires double stroke. Moreover, in order to operate twice the stoke, at least twice the operating force must be output. For this reason, increasing the opening range of the gate valve significantly increases the outer shape of the valve, which is a major obstacle to installing the valve.

  Accordingly, an object of the present invention is to provide a two-port vacuum valve that secures the conductance of the flow path equivalent to that of the connection port without significantly increasing the outer shape of the valve.

  In order to solve the above problems, the present invention comprises the chamber connection port and the gate valve at a position eccentric from the center of the valve channel chamber in a direction away from the pump connection port.

  This makes it possible to increase the space between the inner wall of the valve channel chamber on the side where the pump connection port is provided and the outer periphery of the gate valve, without significantly increasing the outer shape of the valve, It is possible to ensure the conductance of the flow path.

  According to the present invention, by providing the chamber connection port and the gate valve at an eccentric position in a direction away from the pump connection port provided on the lateral side wall of the valve channel chamber, A large space can be secured between the bellows for sealing the valve shaft and the pump connection port.

  This makes it possible to increase the conductance of the valve channel chamber to the same conductance as the connection port without increasing the stroke of the gate valve. Vacuuming can be performed without limiting the exhaust capacity.

  FIG. 1 is a sectional view showing an open state of a two-port vacuum valve according to an embodiment of the present invention.

  The two-port vacuum valve shown in FIG. 1 has a substantially cylindrical valve body 1, and a chamber connection for connecting to the vacuum chamber is provided at the tip of the axis b at a position eccentric from the axis a of the valve body 1. A port 3 is formed, a pump connection port 4 is opened to connect to the vacuum pump in a direction perpendicular to the axial direction of the valve body 1 and away from the chamber connection port. A gate valve mechanism for opening and closing the first flow path 11a of the valve flow path chamber connecting the ports 3 and 4 is provided.

  The gate valve mechanism includes a piston 6 that operates by the action of fluid pressure to drive the gate valve 2, and a shaft 5 that connects the gate valve 2 and the piston 6.

  The piston 6 has a piston packing 10 that is airtightly slidably contacted with the inner wall of the piston chamber 9 on the outer periphery, and the pressure action chamber 13a defined between the piston 6 and the piston chamber 9 It communicates with the operation port 12 opened on the side wall. When a pressure fluid such as compressed air is supplied from the operation port 12 to the pressure working chamber 13a, the piston 6 moves to the cover 13 side and the gate valve 2 is opened.

Inside the valve body 1, a spring 8 that biases the gate valve 2 in the closing direction is contracted between a spring receiver 14 mounted on the gate valve 2 and a pedestal 15. A bellows holder 16 sandwiched between the piece and the base 15 and a bellows 7 containing the shaft 5 are provided. In the figure, 17 is a sealing member that keeps the airtightness between the valve body 1 and the bellows holder 16, and 11 is a packing that keeps the airtightness between the shaft 5 and the base 15.
Reference numeral 18 denotes a breathing hole of the bellows 7.

  Since the two-port vacuum valve is configured as described above, the gate valve 2 normally closes the first flow path 11a. In this state, even if the vacuum pump is operated, the gas in the vacuum chamber is not It is not discharged from the chamber connection port 3 to the pump connection port 4.

  Now, when the pressure fluid is supplied from the operation port 12 to the pressure acting chamber 13a while being pressurized, the piston 6 receives the spring force of the spring 8 as the fluid pressure in the pressure acting chamber 13a increases. The gate valve 2 connected to the piston 6 via the shaft 5 is opened, and the gap between the open gate valve 2 and the valve seat evacuates the chamber. It becomes the first flow path 11a of the valve flow path chamber for pulling.

  The exhausted gas passes through the first flow path 11a, and then easily passes through the gap 14a between the inner wall of the valve body 1 and the outer periphery of the gate valve 2, and flows into the space 15a inside the valve body 1.

  The gate valve 2 and the bellows 7 provided inside the valve body 1 are provided orthogonal to the pump connection port 4 established in the valve body 1, so that the opening surface of the pump connection port 4 is provided. Although the shielding valve 2 and the bellows 7 are installed at a position eccentric in the direction away from the pump connection port 4, the space 15 a inside the body 1 is sufficient in the range of the opening surface of the pump connection port 4. And the opening of the pump connection port 4 is not shielded.

As a result, the exhausted gas flowing into the space 15 a is not shielded by the gate valve 2 and the bellows 7, and the entire opening range 12 a of the pump connection port 4 becomes a flow path and can be easily passed through the valve body 1. It is possible to perform evacuation without being restricted by the flow rate by the flow path inside the valve.
"Effect of the embodiment"

  According to this embodiment, since the stroke of the gate valve 2 is not increased, the flow path inside the valve can be expanded without significantly increasing the outer shape of the valve. This can be done easily without being restricted by the flow rate.

"Other embodiments"
In the embodiment of FIG. 1, the flow path chamber of the valve has a cylindrical shape, but may have an oval shape or a rectangular shape.
The drive mechanism for operating the gate valve may be manually operated by a handle in addition to the actuator.
In addition to the bellows, an airtight packing may be used.

1 is a structural sectional view showing an embodiment of the present invention. It is structural sectional drawing which shows a prior art.

Explanation of symbols

1 Valve body
2 Gate valve
3 First connection port
4 Second connection port
5 shaft
6 Piston
7 Bellows
8 Spring
9 Piston chamber
10 Piston packing
11 Packing
12 Operation port
13 Cover
14 Spring holder
15 pedestal
16 Bellows holder
17 Seal
18 Bellows breathing hole
11a First channel
12a Second channel
13a Pressure chamber
14a Clearance between inner wall and gate valve
15a Space inside the valve body

Claims (1)

A cylindrical chamber connection port for connection to the vacuum chamber, a cylindrical pump connection port for connection to the vacuum pump, a flow path chamber connecting the chamber connection port and the pump connection port, and opening and closing the flow path A two-port vacuum valve having a gate valve and a drive mechanism for opening and closing the gate valve, wherein the gate valve is in a position eccentric from the center of the flow path chamber in a direction away from the pump connection port. A two-port vacuum valve is provided.

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