JP3375444B2 - Vacuum valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve which prevents troubles caused by rapid exhaust of gas in a vacuum chamber.

[0002]

2. Description of the Related Art A pump port connected to a vacuum pump, a chamber port connected to a vacuum chamber, a valve seat in a flow path communicating these ports, a valve body for opening and closing the valve seat, The vacuum valve with the drive of the valve body,
When there is a large amount of air in the vacuum chamber, when the valve body opens the valve seat, a large amount of air is temporarily discharged to the pump port, so that the air in the vacuum chamber is disturbed and the reaction in the chamber is disturbed. Since dust such as products rises up and interferes with the subsequent work, it is necessary to provide means for preventing rapid exhaust of air.

In order to solve this problem, a vacuum valve having a mechanism for preventing rapid exhaust of gas in the vacuum chamber has been proposed in Japanese Patent Application No. 5-73132. This already proposed vacuum valve has the advantage that it can prevent troubles due to rapid exhaust of the gas in the vacuum chamber, and can also cut off the communication between the ports regardless of whether the vacuum pump is operating or not. ing. However, when the vacuum valve is connected to a vacuum source by a line without connecting the vacuum pump directly to the pump port,
The vacuum pressure of the pump port may fluctuate due to the conduit resistance, and therefore the pressure of the chamber port when the flow path is in the fully opened state may fluctuate depending on whether or not the conduit is used.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum valve that accurately responds to the pressure of the chamber port when the flow path is in the fully opened state.

[0005]

In order to solve the above-mentioned problems, the present invention provides a pump port connected to a vacuum source, a chamber port connected to a vacuum chamber, and a valve seat in a flow path communicating these ports. a body having a a valve body for opening and closing the valve seat, a vacuum valve and a drive portion of the valve body, the vacuum valve, a breathing chamber opened to the atmosphere, the pressure acting communicating with the chamber port Room and above
It is installed airtight between the breathing chamber and the pressure chamber and
Atmospheric pressure in the breathing chamber and chamber port pressure in the pressure chamber
Force due to the pressure difference with the force and flow rate adjustment in the opposite direction of the force
Moves according to their magnitude relationship under the biasing force of the spring
A moving member that is coupled to the moving member Ru communicated while squeezing the flow path in the pump port side of the valve seat
A throttling member, and the throttling member is a valve seat of the valve body.
Upon opening is moved from <br/> to the moving member regardless of the movement of the valve body, and the opening adjustment between the flow passage aperture and open states between the chamber port and the pump port ,Up
When the valve seat of the valve element is closed, it is pressed by the valve element and squeezed.
It is characterized by returning to the position .

In order to adjust the pressure for fully opening the flow passage, the pressure acting chamber of the vacuum valve can be provided with a flow rate adjusting mechanism capable of adjusting the biasing force of the flow rate adjusting spring outside.

Further, the driving portion of these vacuum valves includes a pressure receiving body which divides a cylinder chamber into which a pressure fluid is supplied and discharged and a breathing chamber which is open to the atmosphere, and drives the throttle member to control the atmospheric pressure of the breathing chamber. To oppose the chamber port pressure of the pressure chamber.

[0008]

When the valve body closes the valve seat, the communication between the pump port and the chamber port is cut off, so that the gas in the chamber port is not discharged. When the drive part is driven in the opening direction of the valve seat, the valve body opens the valve seat.However, since the pressure of the chamber port is high at the beginning of opening the valve seat, the moving part
As for the force acting on the material, the acting force due to the differential pressure between the chamber port pressure of the pressure acting chamber and the atmospheric pressure of the breathing chamber is opposite to the acting force.
It is smaller than the biasing force of the flow rate adjusting spring. Therefore, move
The member was pressed to the stop position by the urging force of the flow rate adjustment spring .
In the stopped state, the throttle member connected to the moving member maintains the throttle state in which the throttle member is located closer to the pump port than the valve seat. Therefore, the gas in the chamber port is sucked into the pump port with the exhaust amount limited by the throttle member, so that the gas in the chamber port is not discharged extremely rapidly.

When the pressure at the chamber port is reduced to a pressure at which dust does not rise in the vacuum chamber, the acting force due to the differential pressure between the pressure acting chamber and the breathing chamber becomes larger than the urging force of the flow rate adjusting spring. The moving member is
Moving from the stop position against the urging force of the flow rate adjusting spring,
The throttle member connected to the moving member moves from the throttle position to the opening direction of the flow path so that the flow path communicates in the fully open state.
In this case, the pressure in the chamber port is lowered, so that the gas in the vacuum chamber is not rapidly exhausted. Further, unlike the case where the pressure of the pump port and the pressure of the chamber port are opposed to each other, it is not affected by the line resistance between the vacuum source and the pump port. Respond accurately to. When the drive unit is driven in the valve seat closing direction, the valve body closes the valve seat, so that communication between the pump port and the chamber port is cut off.

By adjusting the flow rate adjusting mechanism from outside the valve, the pressure of the chamber port when the throttle member opens the flow path can be adjusted. Further, the cylinder chamber and the breathing chamber are divided by the pressure receiving body, and the throttle member connected to the moving member is driven by the difference between the atmospheric pressure of the breathing chamber and the chamber port pressure of the pressure action chamber. It can be simplified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention, in which a vacuum valve 1 includes a body 2 and a bonnet 3.
And a drive unit (pneumatic cylinder in the illustrated example) 4 incorporated in the hood 3, and a pump port 5 connected to a vacuum source (not shown) such as a vacuum pump in the body 2.
And a chamber port 6 connected to a vacuum chamber (not shown) is formed, and a valve seat 8 facing the drive unit 4 is formed in a flow path 7 that connects these ports 5 and 6 to each other. .

The valve body 10 which opens and closes the valve seat 8 has a valve seat 8
Plate 10 with a valve member 11 for airtightly sealing
a and a hollow shaft 10b, and the outer periphery of the distal end of the hollow shaft 10b penetrating the bottom surface of the bonnet 3 is airtightly attached to the piston 12 that constitutes the pressure receiving body of the drive unit 4. The outer peripheral edge of the metal plate 14 is airtightly attached between the body 2 and the bonnet 3, and both ends of the metal bellows 15 are airtightly fixed to the inner peripheral edge of the metal plate 14 and the seal plate 10a. A return spring 16 of the valve body 10 is compressed in a space defined by the bellows 15.

The throttle member 18 is provided with a throttle plate 18a having a diameter smaller than that of the valve member 11 and a shaft 18b for narrowing the opening area of the flow path 7 on the pump port 5 side of the valve seat 8, and the hollow shaft 10b. the distal end of the shaft 18b that are loosely inserted into, the an annular stop plate 19 attached to the hood 3
A moving member that can stop moving (also called a movable stop plate
20 ) is attached airtightly. The front end opening of the bonnet 3 is hermetically closed by the cover 22 and is transferred.
Both ends of the metal flow rate adjusting bellows 23 are airtightly fixed to the peripheral edge of the moving member 20 and the inner wall of the cover 22.
2, the moving member 20, and the flow rate adjusting bellows 23,
The pressure action chamber 24 is partitioned. This pressure chamber 24
Covers 22, bonnet 3 and metal plate 14
The chamber port 6 is communicated with each other by a communication passage 25 provided in and. Further, in the pressure action chamber 24, a flow rate adjusting plate 26 that is airtightly screwed to the cover 22 and constitutes a flow rate adjusting mechanism is inserted, and the flow rate that is compressed between the flow rate adjusting plate 26 and the moving member 20 is reduced. The biasing force of the adjusting spring 27 can be adjusted from outside the cover 22 by advancing and retracting the flow rate adjusting plate 26 with respect to the cover 22.

[0014] port 31 for supplying and discharging compressed air in the cylinder chamber 29 partitioned by the piston 12, the breathing chamber 30 are opened breathing port 32 that opens to the outside, respectively, the piston 12 and the moving member 20 Convex portion 20
Both ends of a metallic piston bellows 33 that airtightly separates the breathing chamber 30 and the pump port 5 are fixed to a.

FIG. 1 shows a state in which the air in the cylinder chamber 29 is exhausted and the inside of the vacuum chamber is at atmospheric pressure.
0 closes the valve seat 8 by the urging force of the return spring 16, and the diaphragm plate 18a is in a state of being pressed by the seal plate 10a. In this state, the communication between the pump port 5 and the chamber port 6 is blocked by the valve body 10, so that the gas in the chamber port 6 is not discharged even when the vacuum pump is operated.

When compressed air is supplied from the port 31 to the cylinder chamber 29, the piston 12 and the valve body 10 move upward in the figure to open the valve seat 8, and the piston 12 comes into contact with the stop plate 19 so that the above Motion stops. However, since the moving member 20 is biased downward in the drawing by the flow rate adjusting spring 27, the diaphragm member 18 is stopped at the position shown in FIG. Therefore, since the chamber port 6 communicates with the pump port 5 in a throttled state by the diaphragm plate 18a of the throttle member 18, the air in the chamber port 6 is gradually exhausted and lowered, and the chamber port 6 communicates with the chamber port 6 through the communication passage 25. Pressure chamber 24
The pressure also gradually decreases.

When the pressure in the chamber port 6 is lowered by the exhaust from the pump port 5 to reach a pressure (x in FIG. 2) at which dust in the vacuum chamber does not rise, the pressure in the pressure action chamber 24 decreases and the moving member is moved. 20 Pressure on the chamber chamber pressure of the pressure chamber and the atmosphere of the breathing chamber
Since the acting force due to the pressure difference from the pressure becomes larger than the urging force of the flow rate adjusting spring 27, the moving member 20 moves the flow rate adjusting spring 27.
The moving member is moved upward from the stop position shown in FIG. 1 against the biasing force.
The diaphragm member 18 connected to 20 is from the diaphragm position shown in FIG.
The flow path 7 is moved to the opening direction and the flow path 7 is fully opened. In this case, since the pressure of the chamber port 6 has dropped, the air in the vacuum chamber is not rapidly exhausted. Therefore, there is no trouble due to rapid evacuation, and the evacuation time can be shortened as compared with the case where evacuation is performed only in the throttled state, and overload of the vacuum pump can be prevented. Further, by moving the flow rate adjusting plate 26 back and forth with respect to the cover 22 and adjusting the urging force of the flow rate adjusting spring 27, the vacuum pressure when the ports 5 and 6 are communicated in a fully opened state is controlled. Can be changed externally.

When the air in the cylinder chamber 29 is discharged, the valve body 10 moves downward in the figure by the urging force of the return spring 16 to close the valve seat 8 and shut off the communication between the pump port 5 and the chamber port 6. . Further, the throttle member 18 serves as the valve body 10.
The seal plate 10a is pressed to move downward and return to the illustrated state.

FIG. 3 shows a second embodiment of the present invention. A piston 42 in this vacuum valve 41 has a side plate 43 loosely inserted in a convex portion 44a of a moving member 44 which replaces the piston bellows, and the moving member 44 has a flow rate. Side plates 45, which replace the adjusting bellows, are provided, and seal members 46 and 47 are attached to the outer peripheral surfaces of the side plates 43 and 45, which are in airtight sliding contact with the convex portion 44a and the inner surface of the bonnet 3. Since the other structure and operation of the second embodiment are the same as those of the first embodiment,
Detailed description is omitted. Since the piston bellows and the flow rate adjusting bellows can be omitted in the second embodiment,
It is easy to form the partition between the pump port 5 and the breathing chamber 30 and the pressure action chamber 24. Note that the piston 42 and moves
A side plate or a seal member may be provided on only one of the moving members 44 and a bellows may be used on the other.

FIG. 4 shows a third embodiment of the present invention. A valve body 52 of a vacuum valve 51 in the third embodiment is provided with a recess 53 that opens on the pump port 5 side, and the inner surface of the recess 53 and the throttle member 18 are provided. Both ends of a metallic piston bellows 54 that hermetically partitions the pump port 5 and the breathing chamber 30 are airtightly fixed to the shaft 18b. Further, in the third embodiment, the moving member 55 can be a flat plate by incorporating the piston bellows 54 in the recess 53. Third
Since the other structure and operation of the embodiment are the same as those of the first embodiment, the same reference numerals are given to the main parts of the drawing, and the detailed description will be omitted. Although not shown, in the third embodiment as well, the moving member 55 can be provided with a side plate and a seal member instead of the flow rate adjusting bellows, as in the second embodiment.

[0021]

According to the present invention described in detail above, the vacuum chamber
Prevent troubles caused by rapid exhaust of gas in the chamber.
And the influence of the line resistance between the vacuum source and the pump port.
When communicating the flow path to the fully open state,
Providing a vacuum valve that responds accurately to chamber port pressure
Can be offered. By adjusting the flow rate adjusting mechanism from outside the valve, the pressure of the chamber port when the throttle member opens the flow path can be adjusted. Furthermore, the pressure receiving body separates the cylinder chamber and the breathing chamber, and the atmospheric pressure of the breathing chamber and the chamber port of the pressure action chamber are separated.
Drive the throttle member connected to the moving member due to the difference in pressure.
Since it moves, the structure of the diaphragm member can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment.

FIG. 2 is a diagram of a flow path opening degree and a chamber pressure.

FIG. 3 is a vertical cross-sectional view showing the main parts of the second embodiment.

FIG. 4 is a vertical sectional view of a third embodiment.

[Explanation of symbols]

1, 41, 51 Vacuum valve 2 Valve body 4 Drive part 5 Pump port 6 Chamber port 7 Flow path 8 Valve seat 10, 52 Valve body 12, 42 Piston 18 Throttling member 24 Pressure action chamber 26 Flow rate adjusting plate 27 Flow rate adjusting spring 29 Cylinder chamber 30 Breathing chamber

Claims (3)

(57) [Claims] 1. A body having a pump port connected to a vacuum source, a chamber port connected to a vacuum chamber, and a valve seat in a flow path communicating these ports, and a valve body for opening and closing the valve seat. in vacuum interrupter and a driving portion of the valve body, the vacuum valve, a breathing chamber opened to the atmosphere, and the pressure action chamber which communicates with the tea <br/> Nbapoto, the breathing chamber and the pressure
It is installed in an airtight manner between the working chamber and
For the pressure difference between the atmospheric pressure and the chamber port pressure of the pressure chamber
Force and the bias of the flow rate adjusting spring in the opposite direction
A moving member that receives force and moves according to their magnitude relationship
When, and a diaphragm member connected to said moving member Ru communicated while squeezing the flow path in the pump port side of the valve seat, the diaphragm member, at the time of the valve seat opening of the valve body of the valve body
Moved is moved independently by the moving member, and the opening adjustment between the flow passage aperture and open states between said switch <br/> Yanbapoto a pump port, a valve seat of the valve body When closed
Is a vacuum valve that is pressed by the valve body and returns to the throttled position . 2. The vacuum valve according to claim 1, wherein the pressure action chamber is provided with a flow rate adjusting mechanism capable of adjusting the urging force of the flow rate adjusting spring outside. 3. The drive unit includes a pressure receiving body that divides a cylinder chamber into which a pressure fluid is supplied and discharged and a breathing chamber opening to the atmosphere,
The vacuum valve according to claim 1 or 2, wherein the atmospheric pressure of the breathing chamber is opposed to the chamber port pressure of the pressure action chamber for driving the throttle member.