JPH0741173U - Vacuum valve - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a vacuum valve capable of interrupting communication between ports regardless of whether or not the vacuum pump is operating. A main valve body 15 for connecting a pump port 5 and a chamber port 6 to each other through a main flow path 7 and bypass flow paths 19 and 20 to open and close a main valve seat 8 in the main flow path is replaced by a bypass flow path 19 and 20. The spring 2 is connected to the vacuum action chamber by being connected to the piston 10 which is divided into the open vacuum action chamber 11 and the atmosphere chamber 12.
Reduce 1 Further, the shaft 27 of the drive unit 3 drives the bypass valve body 25 that opens and closes the bypass valve seat 24 provided in the bypass flow passage 20. When the drive unit is driven in the opening direction of the main valve seat, when the pressure in the chamber port 6 is high, the ports 5 and 6 are connected by the bypass flow passage, and when the pressure in the chamber port decreases, the main valve body gradually moves to the main valve seat. Is opened to exhaust from the main flow path. When the drive section is driven in the opposite direction, even if the vacuum pump is operating, the valve elements 15 and 25
Closes valve seats 8 and 24, blocking communication between ports 5 and 6.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vacuum valve that prevents troubles caused by rapid exhaust of gas in a vacuum chamber.

[0002]

[Prior art]

 A vacuum valve provided with 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, and a valve body for opening and closing the valve seat, There is a large amount of air in the vacuum chamber At the beginning of operation of the vacuum pump, when the valve body opens the valve seat, a large amount of air is temporarily exhausted. Since dust such as reaction products in the room will rise and interfere with the subsequent work, it is necessary to provide a means to prevent rapid exhaust of air.

In order to solve this problem, a vacuum valve having a mechanism for preventing rapid exhaust of gas in a vacuum chamber is proposed in Japanese Patent Application No. 10676/1992. This vacuum valve can prevent troubles due to rapid exhaust of gas in the vacuum chamber, but there is a lack of consideration for disconnection between ports, and when the vacuum pump operates, the rapid exhaust prevention mechanism always operates. Then, the pump port and chamber port communicate. However, depending on the equipment, the excess powder after film formation is sucked into the vacuum pump through the vacuum valve, so if the vacuum pump operation is stopped to return the chamber to atmospheric pressure, the excess powder will be added to the vacuum pump. There is a problem that the body sticks and cannot restart.

[0004]

[Problems to be solved by the device]

 The problem to be solved by the present invention is to provide a vacuum valve that does not have troubles due to rapid exhaust and that can cut off communication between ports regardless of whether or not the vacuum pump is operating.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a pump port connected to a vacuum pump, a chamber port connected to a vacuum chamber, a main valve seat in a main flow path connecting these ports, A vacuum valve comprising a main valve body for opening and closing a main valve seat, and a drive unit for the main valve body, wherein the vacuum valve includes a vacuum working chamber defined by a pressure receiving body and an atmosphere chamber communicating with the outside. A valve rod connecting the pressure receiving body and the main valve body, a spring for urging the main valve body compressed in the vacuum action chamber toward the closing direction of the main valve seat, a vacuum working chamber as a chamber port and a pump port. A first bypass flow passage and a second bypass flow passage that communicate with each other, a bypass valve seat formed in the second bypass flow passage, and a bypass valve body that opens the bypass valve seat by driving the main valve seat opening direction of the drive unit. Is equipped with To have.

[0006]

[Action]

 When the drive unit is driven in the closing direction of the main valve seat, the main valve body closes the main valve seat by the driving force of the drive unit and the biasing force of the spring, and the bypass valve body closes the bypass valve seat. Therefore, the communication between the pump port and the chamber port is blocked. Therefore, even if the vacuum pump is operated in this state, the gas in the chamber port is not exhausted. When the drive unit is driven in the opening direction of the main valve seat, the bypass valve body opens the bypass valve seat and the chamber port communicates with the pump port via the bypass flow passage and the vacuum action chamber, so that the gas in the chamber port is not discharged. The gas is exhausted through the bypass channel, and its pressure gradually decreases. In this case, since the pressure of the chamber port is high at the beginning of driving the drive unit, the main valve body closes the main valve seat by the urging force of the spring, so that the gas in the chamber port is not rapidly exhausted. Absent.

When the air pressure in the chamber port is gradually reduced to a pressure at which dust does not rise up, the acting force of the differential pressure between the vacuum working chamber and the atmospheric chamber acting against the pressure receiving body is the biasing force of the bed. Therefore, the pressure receiving body is driven against the biasing force of the spring, and the main valve body gradually opens the main valve seat, so that the main flow path is gradually opened. In this case, the pressure in the chamber port has dropped, so the air in the vacuum chamber is not rapidly exhausted. When the drive unit is driven in the closing direction of the main valve seat, the drive force of the drive unit causes the main valve body to close the main valve seat against the biasing force of the spring, and the bypass valve body closes the bypass valve seat. Therefore, the communication between the pump port and the chamber port is cut off.

[0008]

【Example】

 The figure shows an embodiment of the present invention, in which the vacuum valve includes a body 1, a bonnet 2, and a drive unit 3 (a fluid pressure actuator in the illustrated embodiment), and the body 1 has a vacuum pump (as an example, A pump port 5 connected to a mechanical booster) and a chamber port 6 connected to a vacuum chamber are formed, and a main valve 7 facing the drive unit 3 is provided in a main passage 7 that directly connects these ports 5 and 6. A seat 8 is formed. The body 1 and the bonnet 2 are airtightly partitioned by a plate 9, and the inside of the bonnet 2 is formed by a piston 10, which is an example of a pressure receiving body, and an atmosphere chamber 12 communicating with the outside by a vacuum action chamber 11 and an intake passage 13. It is divided into The pressure receiving body is not limited to the piston 10 and may be, for example, a bellows.

The main valve body 15 that opens and closes the main valve seat 8 has a seal member 16 on the side of the main valve seat, and is attached to the piston 10 by a valve rod 17, and is attached to the main valve body 15 and the plate 9. Both ends of a bellows 18 that seals the outer circumference of the valve rod 17 are airtightly fixed. The vacuum working chamber 11 communicates with the chamber port 6 by the first bypass flow passage 19 and the pump port 5 by the second bypass flow passage 20 formed in the valve rod 17, respectively. A spring 21 for urging 15 in the closing direction of the main valve seat 8 is contracted. Further, the first bypass flow passage 19 has an orifice 22 formed at the opening to the vacuum action chamber 11, and the second bypass flow passage 20 having a larger diameter than the orifice 22 bypasses the opening to the vacuum action chamber 11. On the outer peripheral surface of the bypass valve body 25 that has the valve seat 24 and that opens and closes the bypass valve seat 24, a locking projection that locks to a locking portion 28 provided in a recess at the tip of the shaft 27 of the drive unit 3. 26 is formed.

In the above embodiment, when the shaft 27 of the drive unit 3 is moving downward in the figure, the main valve body 15 closes the main valve seat 8 by the biasing force of the spring 21 acting on the piston 10. At the same time, the bypass valve body 25 closes the bypass valve seat 24 (see the left side of FIG. 1). Therefore, since the communication between the pump port 5 and the chamber port 6 is blocked, the pressure in the chamber port 6 does not drop even if the vacuum pump is operated.

When the shaft 27 moves upward in the figure by the drive of the drive unit 3, the locking portion 28 locks on the locking projection 26 of the bypass valve body 25 to move the valve body, so that the bypass valve seat 24 is opened, and the pump port 5 and the chamber port 6 are connected by the vacuum working chamber 11 and the bypass flow paths 19 and 20. Therefore, the gas in the vacuum chamber is sucked into the pump port 5, but the gas in the vacuum chamber is not rapidly exhausted because the bypass passages 19 and 20 have a small diameter. In this case, in the main valve body 15, the resultant force of the urging force of the spring 21, the reaction force of the bellows 18 and the acting force of the differential pressure between the chamber port 6 and the pump port 5 is downward, and the vacuum chamber 12 and the vacuum action are applied. The acting force of the differential pressure between the chambers 11 acts upward.

When the pressure of the chamber port 6 is lowered to a pressure (x in FIG. 2) at which dust in the chamber does not rise due to exhaust, the pressure of the vacuum action chamber 11 is also reduced and acts opposite to the piston 10. Since the acting force of the differential pressure between the atmosphere chamber 12 and the vacuum working chamber 11 becomes larger than the downward force, the main valve body 15 moves in the opening direction of the main valve seat 8 and the main flow path 7 gradually opens. Then, the gas in the chamber port 6 is also exhausted from the main flow path 7, and when the main flow path 7 is fully opened, the gas in the chamber port 6 is mainly exhausted through the main flow path 7 (see the right side of the figure). In this case, the pressure in the chamber port 6 is lowered, so that the gas in the vacuum chamber is not rapidly exhausted. Therefore, there is no trouble due to rapid exhaust, and the exhaust time can be shortened as compared with the case where the gas is exhausted only from the bypass passage, and the overload of the vacuum pump can be prevented.

When the drive unit 3 is driven in the closing direction of the main valve seat 8, the main valve body 15 closes the main valve seat 8 and the bypass valve body 25 closes the bypass valve seat 24, so that the pump port 5 and the chamber are closed. Communication between the ports 6 is cut off.

[0014]

[Effect of device]

 According to the present invention, when the pressure in the chamber is high, the gas is exhausted by the bypass flow passage at the beginning of driving, and when the pressure of the chamber port decreases, the main flow passage is gradually opened and exhausted by the main flow passage, so that the gas turbulence in the vacuum chamber is prevented In addition, the exhaust time can be shortened and the vacuum pump can be prevented from being overloaded. Further, even when the vacuum pump is operating, the communication between the pump port and the chamber port can be cut off, so that the chamber can be brought to the atmospheric pressure.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment.

FIG. 2 is a diagram of an opening degree of a main valve and a chamber pressure.

[Explanation of symbols]

 3 Drive part 5 Pump port 6 Chamber port 7 Main flow passage 8 Main valve seat 10 Piston 11 Vacuum action chamber 12 Atmosphere chamber 15 Main valve body 19,20 Bypass flow passage 21 Spring 24 Bypass valve seat 25 Bypass valve body

Claims (1)

[Scope of utility model registration request] 1. A pump port connected to a vacuum pump, a chamber port connected to a vacuum chamber, and a main valve seat in a main flow path communicating these ports,
In a vacuum valve including a main valve body that opens and closes the main valve seat, and a drive unit of the main valve body, the vacuum valve includes a vacuum action chamber defined by a pressure receiving body and an atmosphere chamber communicating with the outside, A valve rod connecting the pressure receiving body and the main valve body, a spring for urging the main valve body compressed in the vacuum action chamber toward the closing direction of the main valve seat, and the vacuum action chamber as a chamber port and a pump port. A first bypass flow passage and a second bypass flow passage, a bypass valve seat formed in the second bypass flow passage, and a bypass valve body that opens the bypass valve seat by driving the main valve seat opening direction of the drive unit. The vacuum valve is characterized in that: