JP5002845B2 - Vacuum valve - Google Patents

Description

  The present invention enhances the responsiveness of a differential pressure type vacuum valve interposed in an exhaust passage connecting the vacuum pump and the vacuum chamber when the vacuum chamber is brought into a vacuum state using a vacuum pump such as a scroll pump or a vane pump. The present invention relates to a vacuum valve capable of reliably preventing gas from flowing back into the vacuum chamber when the vacuum pump is stopped.

  Conventionally, a vacuum apparatus that sucks and discharges air in a vacuum chamber by a vacuum pump is well known. For example, in a vacuum deposition apparatus, for example, when a metal deposition film is formed on the surface of a semiconductor wafer, the atmosphere in the deposition chamber of the apparatus is first evacuated with a vacuum pump to a high vacuum, and deposition is performed in a high vacuum state. In this method, the pressure in the vapor deposition chamber is returned to atmospheric pressure.

  A vacuum valve is interposed between the vacuum chamber and the vacuum pump as means for preventing a backflow generated by the differential pressure between the vacuum chamber and the vacuum pump when the vacuum pump is stopped. As a vacuum valve having an automatic opening / closing function, a direct acting solenoid type or a differential pressure type automatic opening / closing valve is used.

Although the direct acting solenoid type has good responsiveness for opening and closing, there are problems that the exhaust resistance is large because the stroke is not large, and that the solenoid consumes a large amount of power to maintain the opening and closing operation of the valve.
On the other hand, the differential pressure type vacuum valve performs an opening operation or a closing operation by a differential pressure between a force applied to the valve body in the opening operation direction and a force applied in the closing operation direction. In addition, there is an advantage that power consumption can be reduced.

  Japanese Patent Application Laid-Open No. 5-272456 discloses an example of a differential pressure type vacuum valve. This configuration will be described with reference to FIG. In FIG. 2, this differential pressure type vacuum valve includes a body 1 and a bonnet 2. A suction port 3 connected to a vacuum pump (not shown) is formed on the body 1, and is attached to the outer periphery of the body 1 in the radial direction. The port member 4 is formed with a vacuum port 5 connected to a vacuum chamber (not shown).

  A valve seat 7 is formed on the vacuum port 5 side of the main flow path 6 that directly connects the suction port 3 and the vacuum port 5. The body 1 and the bonnet 2 are airtightly partitioned by a plate 9, and the inside of the bonnet 2 is partitioned by a piston 10 which is an example of a pressure receiving body into a vacuum working chamber 11 and an air chamber 12 opened to the outside. . The vacuum working chamber 11 communicates with the suction port 3 and the vacuum port 5 by a bypass passage 13 described later.

A pressure adjusting spring 14 that urges the piston 10 toward the plate 9 is contracted in the vacuum working chamber 11, and the urging force of the pressure adjusting spring 14 is airtightly screwed to the bonnet 2. Can be adjusted by rotating the pressure adjusting screw.
A hollow valve rod 18 whose one end is screwed to the piston 10 has a valve body 19 that opens and closes the valve seat 7 attached to the tip that is airtightly penetrated through the plate 9, and has a large diameter at the tip on the piston 10 side. An orifice 23 is attached.

  The bypass flow path 13 is composed of a flow path 20 formed in the body 1 and the bonnet 2 and a flow path 18a formed in the hollow portion of the valve rod 18. In order to adjust the flow rate of air flowing through the bypass flow path 13, A needle valve as an example of the variable throttle mechanism 21 is installed in the path 20. The opening degree of the needle valve is adjusted by rotating the valve body 22 and moving it forward and backward with respect to the bonnet 2.

  In such a configuration, when the operation of the vacuum pump (not shown) is stopped and the inside of the vacuum chamber is at or near atmospheric pressure, the sum of the atmospheric pressure and the biasing force of the pressure adjusting spring 14 acting on the piston 10 is the atmospheric chamber 12. In order to exceed the internal atmospheric pressure, the valve body 19 descends to close the main flow path 6. On the other hand, the suction port 3 and the vacuum port 5 communicate with each other through the bypass flow path 13. When the vacuum pump is operated in this state, the atmosphere in the vacuum chamber is discharged by the variable throttle mechanism 21 of the bypass flow path 13. It is controlled and gradually sucked into the vacuum pump.

  Accordingly, since the atmosphere in the vacuum chamber is not greatly stirred, troubles such as dust rising can be prevented. Thereafter, when the sum of the acting force of the vacuum pressure in the vacuum working chamber 11 and the biasing force of the pressure adjusting spring 14 becomes smaller than the acting force of the atmospheric pressure in the atmospheric chamber 12 due to the decrease in the gas pressure in the vacuum chamber, the piston 10 The valve body 19 rises to open the main flow path 6. Thereby, the gas in the vacuum chamber is mainly discharged through the main flow path 6. In this case, since the gas density in the vacuum chamber is lowered, the atmosphere in the vacuum chamber is not stirred.

  Further, Patent Document 2 (Japanese Utility Model Publication No. 7-41173) discloses a differential pressure type vacuum valve similar to Patent Document 1. However, the differential pressure type vacuum valve disclosed in Patent Document 2 performs a valve closing operation by a drive unit such as a fluid pressure actuator.

JP-A-5-272456 Japanese Utility Model Publication No. 7-41173

  As illustrated in Patent Document 1, the differential pressure type vacuum valve opens and closes by the differential pressure between the force in the opening operation direction and the force in the closing operation direction acting on the valve body. As compared with the method of forcibly operating the valve body as described above, the response tends to be delayed. Therefore, when the operation of the vacuum pump is stopped, a situation occurs in which the gas on the exhaust side (vacuum pump side) flows backward to the suction side (vacuum chamber side) due to the differential pressure existing between the vacuum port 5 and the suction port 3. This happens in a very short time.

  For this reason, there is a possibility that the vacuum chamber may break due to the backflowed gas, or the wear powder of the vacuum pump may enter the vacuum chamber and contaminate the devices disposed in the vacuum chamber. Further, when the vacuum pump is an oil supply type, the oil of the vacuum pump may enter the vacuum chamber.

  Further, when a plurality of vacuum pumps are arranged in the exhaust passage system and the plurality of vacuum pumps are alternately operated by a pressure sensor or the like, there is a possibility that the control may become unstable due to erroneous recognition of a pressure increase caused by the backflowing gas. Taking Patent Document 1 as an example, the valve opening / closing operation is performed by supplying / discharging gas to / from the vacuum working chamber 11 or the atmospheric chamber 12, so that the responsiveness is poor, and in particular, the closing operation takes time. Therefore, the backflow of gas from the exhaust side to the suction side cannot be completely prevented.

In order to speed up the responsiveness of the valve opening / closing operation, the force acting on the valve body is increased, that is, by taking Patent Document 1 as an example, the diameter of the piston 10 is increased, or the vacuum pump side exhaust passage Although measures such as increasing the volume of the flow path and slowing the propagation speed of the backflow gas can be considered, there is a problem that the vacuum valve or the vacuum device is increased in size.
Further, the differential pressure type vacuum valve disclosed in Patent Document 2 has a problem that the configuration is complicated and expensive because the valve is closed by a drive unit such as a fluid pressure actuator.

  In view of the problems of the prior art, the present invention is to improve the responsiveness of the valve opening / closing operation of the differential pressure type vacuum valve, particularly the responsiveness when the valve is closed, and the reverse flow of gas from the vacuum pump side to the vacuum chamber side. Accordingly, it is an object to prevent vacuum breakage of the vacuum chamber and contamination of equipment disposed in the vacuum chamber.

In order to achieve such an object, the vacuum valve of the present invention comprises:
In a vacuum valve connected to a vacuum pump and a vacuum chamber and interposed in an exhaust path for exhausting the atmosphere in the vacuum chamber and opening and closing the exhaust path,
A valve housing interposed in the exhaust passage, and a valve function body that is slidably housed in the valve housing and opens or closes the exhaust passage by contacting or separating from a valve seat formed in the valve housing; ,
A partition formed integrally with the valve functional body and partitioning the valve housing into two regions;
A spring chamber defined on one side of the partition, and a spring member attached to the spring chamber and energizing a spring force in a direction to close the exhaust path with respect to the valve function body;
An atmospheric pressure chamber that is defined on the other side of the partition and communicates with the atmosphere through a through-hole provided in the housing wall;
A communication path that can selectively connect the spring chamber to the outlet exhaust path of the valve function body or the atmospheric pressure chamber,
Opening and closing the exhaust passage by selectively connecting the spring chamber to the outlet exhaust passage of the valve function body or the atmospheric pressure chamber;
By increasing the flow rate of the air flowing into the spring chamber with respect to the flow rate of air flowing from the through hole, the exhaust passage can be quickly closed.

  In the present invention, when exhausting the vacuum chamber by operating the vacuum valve, the vacuum pump is operated by communicating the spring chamber and the outlet side exhaust passage of the valve function body via the communication path. . Due to the operation of the vacuum valve, the outlet side exhaust passage becomes negative pressure, and the spring chamber communicating with the outlet side exhaust passage becomes negative pressure. The partitioning portion of the valve function body is loaded with the urging force of the spring member and the acting force of the gas pressure in the spring chamber from the spring chamber side, and the acting force due to the atmospheric pressure is loaded from the atmospheric pressure chamber side. Since the negative pressure in the spring chamber causes the action force of the atmospheric pressure in the atmospheric pressure chamber to be greater than the sum of the biasing force of the spring member in the spring chamber and the action force due to the gas pressure in the spring chamber, Moves away from the seat and opens the exhaust passage.

  Thereafter, when the vacuum chamber is evacuated and the exhaust operation is terminated, the operation of the vacuum pump is stopped, and at the same time, the communication passage is switched to connect the spring chamber and the atmospheric pressure chamber. At that time, in order to increase the flow rate of the air flowing into the spring chamber from the flow rate of the air flowing from the through hole of the atmospheric pressure chamber, the pressure in the atmospheric pressure chamber temporarily becomes lower than the atmospheric pressure, and the pressure in the spring chamber is reduced. Get closer. That is, the pressures in the atmospheric pressure chamber and the spring chamber are balanced in a state lower than the atmospheric pressure chamber. For this reason, only the urging force of the spring member is applied to the valve function body, and the valve function body moves in the direction of closing the exhaust passage by the urging force of the spring member. The vacuum valve can be closed in a shorter time than the time required for the spring chamber to return to atmospheric pressure.

  Thus, the timing at which the force in the closing direction by the spring member acts on the valve function body is advanced, and the vacuum valve can be closed in a shorter time than conventional. Therefore, according to the present invention, the backflow prevention performance can be improved without increasing the size of the vacuum valve or the vacuum device. Therefore, there is no possibility that the vacuum gas is broken due to the backflowed gas, or wear powder or lubricating oil of the vacuum pump enters the vacuum chamber to contaminate the devices arranged in the vacuum chamber.

  In the present invention, the communication passage is provided in the valve housing wall and connects the outlet side exhaust passage of the valve function body, the atmospheric pressure chamber, and the spring chamber, and the spring passage is provided in the communication passage. A three-way valve for switching and connecting to the outlet side exhaust passage of the valve function body or the atmospheric pressure chamber, and the cross section of the through-hole is defined as the cross section of the communication path connecting the atmospheric pressure chamber and the spring chamber It is preferable that the flow rate of the air flowing into the spring chamber is larger than the flow rate of the air flowing in from the through hole when the exhaust passage is closed.

  With this configuration, the responsiveness of the valve opening / closing operation of the vacuum valve can be improved with a simple configuration. By adjusting the flow passage area of the through hole, the pressure increase rate of the atmospheric pressure chamber can be adjusted, and the flow passage cross-sectional area of the through hole, the communication passage connecting the atmospheric pressure chamber and the spring chamber can be adjusted. By appropriately adjusting the ratio with the flow path cross-sectional area, the time during which the pressures in the atmospheric pressure chamber and the spring chamber are balanced can be adjusted.

  Further, in the present invention, the valve function body includes a valve body and a valve body that opens or closes the exhaust path by abutting or separating from a valve seat and a valve seat formed on a valve housing provided at an end of the valve path. And a partition portion provided at the other end of the valve stem and partitioning the inside of the housing into a spring chamber and an atmospheric pressure chamber, the valve rod being slidable on a support portion formed integrally with the valve housing. The atmospheric pressure chamber may be configured to be supported and defined between the support portion and the partition portion.

  With this configuration, the configuration of the vacuum valve can be simplified, and the responsiveness of the valve opening / closing operation of the vacuum valve can be improved with this simple configuration.

  According to the present invention, the valve housing interposed in the exhaust passage connecting the vacuum chamber and the vacuum valve, and the valve seat formed in the valve housing so as to be slidably housed in the valve housing. Alternatively, a valve function body that opens and closes the exhaust path at a distance, a partition part that is integrally formed with the valve function body and partitions the inside of the valve housing into two regions, and a spring that is defined on one side of the partition part And a spring member attached to the spring chamber and energizing a spring force in a direction to close the exhaust passage with respect to the valve function body, and is defined on the other side of the partition portion and provided on the housing wall. An atmospheric pressure chamber that communicates with the atmosphere through the through-hole, and a communication passage that can selectively connect the spring chamber to the outlet exhaust passage of the valve function body or the atmospheric pressure chamber. Are selectively connected to the outlet exhaust passage of the valve function body or the atmospheric pressure chamber. By opening and closing the exhaust passage, the structure of the vacuum valve is complicated or enlarged by increasing the air flow rate flowing into the spring chamber with respect to the air flow rate flowing from the through hole. In addition, the responsiveness of the valve opening / closing operation can be improved.

  Therefore, it is possible to prevent the backflow of exhaust gas when the vacuum pump is stopped. Therefore, the backflowed gas causes vacuum breakage of the vacuum chamber, or wear powder or lubricating oil of the vacuum pump enters the vacuum chamber and There is no risk of contamination of equipment placed in

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.
(Embodiment)

  FIG. 1 is a vertical elevation view of a vacuum valve according to an embodiment of the present invention. In FIG. 1, an exhaust path 33 is connected between a vacuum chamber 31 that is evacuated to a vacuum state and the vacuum pump 32, and a vacuum valve 30 that enables opening and closing of the exhaust path is interposed in the exhaust path 33. It is installed. Hereinafter, the configuration of the vacuum valve 30 will be described.

  In the vacuum valve 30, a valve housing 34 is interposed in the exhaust path 33, and the valve housing 34 has a vacuum port 35 communicating with the exhaust path 33 a connected to the vacuum chamber 31 and an exhaust path 33 b connected to the vacuum pump 32. A suction port 36 that communicates with each other is formed. Inside the valve housing 34, a valve function body 40 is accommodated so as to be slidable in the direction of arrow a or b.

  The valve function body 40 includes a valve rod 41 arranged in the longitudinal direction of the valve housing 34, a disc-like valve body 42 attached to the end of the valve rod 41 facing the vacuum port 35, and a valve rod. The disc-shaped piston 43 is attached to the other end of the disc 41. A support portion 37 protruding inward is formed integrally with the valve housing 34 at a substantially central portion of the valve housing 34, and the support portion 37 supports the valve function body 40 so as to be slidable in the longitudinal direction of the valve housing 34. Yes. An O-ring 44 for sealing is interposed between the support portion 37 and the valve function body 40.

  A valve seat 38 is formed in the vicinity of the vacuum port 35 of the valve housing 34, and an inlet side end face 42 a of the valve body 42 is disposed so as to face the valve seat 38. An O-ring 45 is attached to the inlet side end face 42a, and the vacuum port 35 is closed by the inlet side end face 42a coming into contact with the valve seat 38. An O-ring 46 is provided between the valve housing 34 of the piston 10 and seals between the valve housing 34 and the piston 43. Thereby, two sealed spaces are formed on both sides of the piston 43.

  At one side of the piston 43 (on the left side of the piston 43 in FIG. 1 and in the closing operation direction a of the valve function body 40), the atmospheric pressure communicated with the outside air through a through hole 47 provided in the valve housing 34. A chamber 50 is formed. On the other hand, a spring chamber 51 is formed on the other side of the piston 43 (on the right side of the piston 43 in FIG. 1 and in the opening operation direction b of the valve function body 40). A coil spring 52 is provided which is connected to one surface 43 a and has the other end attached to the inner wall of the valve housing 34. As a result, the piston 43 is loaded with the action force due to the atmospheric pressure of the atmospheric pressure chamber 50 from the atmospheric pressure chamber 50 side, and from the spring chamber 51 side, the spring force of the coil spring 52 and the gas pressure in the spring chamber 51 are applied. The sum with the acting force is loaded.

  The valve housing 34 is provided with communication holes 53, 54, and 55 that connect the suction port 36, the atmospheric pressure chamber 50, and the spring chamber 51, and the spring chamber 51 is connected to the suction port 36 or atmospheric pressure. A three-way solenoid valve 56 that selectively communicates with the chamber 50 is provided. The three-way solenoid valve 56 is switched by a controller 57. The flow passage sections of the communication passages 54 and 55 that connect the atmospheric pressure chamber 50 and the spring chamber 51 are formed larger than the flow passage section of the through hole 47.

  In this embodiment having such a configuration, the exhaust operation of the vacuum chamber 31 is started in a state where the vacuum port 35 is closed by the valve function body 40. In this operation procedure, the controller 57 operates the three-way solenoid valve 56 to cause the suction port 36 and the spring chamber 51 to communicate with each other. At the same time, the vacuum pump 32 is operated. By starting the operation of the vacuum pump 32, the suction port 36 rapidly becomes negative pressure, and since the suction port 36 and the spring chamber 51 communicate with each other, the spring chamber 51 also becomes negative pressure.

  When the spring chamber 51 reaches a vacuum pressure, the force in the opening operation direction b applied to the valve function body 40 (the gas pressure of the vacuum port 35 applied to the inlet side end surface 42 a and the one surface 43 a of the piston 43 is applied. Sum of the acting force due to the atmospheric pressure) exceeds the force in the closing operation direction a (the sum of the spring force of the coil spring 52 and the acting force due to the gas pressure in the spring chamber 51) loaded on the valve function body 40. As a result, the valve function body 40 moves to the spring chamber 51 side, so that the vacuum port 35 is opened. In this state, the operation of the vacuum pump 32 is continued, and the air in the vacuum chamber 31 is sucked by the vacuum pump 32 to make the vacuum chamber 31 in a vacuum state.

  After the vacuum chamber 31 is evacuated, the operation of the vacuum pump 32 is stopped. At this time, since the exhaust gas may flow back to the vacuum chamber 31 side, it is necessary to quickly close the vacuum port 35 by the vacuum valve 30. Therefore, in this embodiment, simultaneously with the stop of the vacuum pump 32, the controller 57 activates the three-way solenoid valve 56, shuts off the communication path 53 and the communication path 5, and connects the communication path 54 and the communication path 55. At this time, since the spring chamber 51 is in a vacuum state, the air in the atmospheric pressure chamber 50 flows into the spring chamber 51.

  By connecting the atmospheric pressure chamber 50 and the spring chamber 51, the pressure in the atmospheric pressure chamber 50 and the spring chamber 51 is balanced, and the pressure in the atmospheric pressure chamber 50 is temporarily lowered from the atmospheric pressure chamber. Approaching 51 pressure. In this embodiment, since the cross-sectional area of the through hole 47 is smaller than the cross-sectional area of the communication passages 54 and 55, the differential pressure between the two chambers is reduced in a short time before the spring chamber 51 is increased to the atmospheric pressure, To balance. As a result, the force applied to the piston 43 is only the spring force of the coil spring 52, so that the valve function body 40 moves in a direction to close the vacuum port 35.

  Thus, according to the present embodiment, when the vacuum pump 32 is stopped, the timing for working in the direction of closing the vacuum port 35 is advanced, and the exhaust passage 33 can be closed in a shorter time than the conventional vacuum valve. . In addition, the responsiveness can be improved with a simple valve configuration, and the apparatus does not become large. As a result, it is possible to prevent the backflow of the exhaust gas to the vacuum chamber 31 side when the vacuum pump is stopped, so that vacuum breakage in the vacuum chamber 31, wear powder and lubricating oil of the vacuum pump 32 enter the vacuum chamber 31. As a result, it is possible to prevent the devices provided in the vacuum chamber 31 from being contaminated.

  The pressure increase rate of the atmospheric pressure chamber 50 can be adjusted by adjusting the cross-sectional area of the through-hole 47 as appropriate, and the ratio of the cross-sectional areas of the communication passages 54 and 55 to the cross-sectional area of the through-hole 47 is appropriately set. By adjusting, the timing which the valve function body 40 moves to a valve closing direction can be adjusted suitably.

  According to the present invention, since the responsiveness of the vacuum valve can be improved, the backflow of the exhaust gas to the vacuum chamber can be prevented when the vacuum valve is stopped, and vacuum breakdown of the vacuum chamber and contamination of equipment disposed in the vacuum chamber can be prevented. Can be prevented.

It is a vertical elevation view of a vacuum valve according to an embodiment of the present invention. It is a vertical sectional elevation view of a conventional vacuum valve.

Explanation of symbols

30 Vacuum valve 31 Vacuum chamber 32 Vacuum pump 33a, 33b Exhaust path 34 Valve housing 36 Suction port (exit side exhaust path)
37 Supporting part 38 Valve seat 40 Valve functional body 41 Valve rod 42 Valve body 43 Piston (partition part)
47 Through-hole 50 Atmospheric pressure chamber 51 Spring chamber 52 Coil spring (spring member)
53, 54, 55 Communication passage 56 Three-way solenoid valve

Claims (3)

In a vacuum valve connected to a vacuum pump and a vacuum chamber and interposed in an exhaust path for exhausting the atmosphere in the vacuum chamber and opening and closing the exhaust path,
A valve housing interposed in the exhaust passage, and a valve function body that is slidably housed in the valve housing and opens or closes the exhaust passage by contacting or separating from a valve seat formed in the valve housing; ,
A partition formed integrally with the valve functional body and partitioning the valve housing into two regions;
A spring chamber defined on one side of the partition, and a spring member attached to the spring chamber and energizing a spring force in a direction to close the exhaust path with respect to the valve function body;
An atmospheric pressure chamber that is defined on the other side of the partition portion and communicates with the atmosphere through a through hole provided in the valve housing wall;
A communication path that can selectively connect the spring chamber to the outlet exhaust path of the valve function body or the atmospheric pressure chamber,
Opening and closing the exhaust passage by selectively connecting the spring chamber to the outlet exhaust passage of the valve function body or the atmospheric pressure chamber;
A vacuum valve characterized in that the exhaust passage can be quickly closed by increasing the air flow rate flowing into the spring chamber with respect to the air flow rate flowing from the through hole. The communication path is
An exhaust passage on the outlet side of the valve function body provided on the valve housing wall, a communication path connecting the atmospheric pressure chamber and the spring chamber, and an exhaust side exhaust on the outlet side of the valve function body provided in the communication path. A three-way valve connected to the road or the atmospheric pressure chamber,
By forming a flow passage cross section of the communication path connecting the atmospheric pressure chamber and the spring chamber larger than the cross section of the through hole, the spring chamber can be obtained from the flow rate of the air flowing from the through hole when the exhaust passage is closed. The vacuum valve according to claim 1, wherein the flow rate of the atmosphere flowing into the chamber is increased. The valve function body is
A valve body, a valve body that is provided at an end of the valve shaft on the exhaust path side and contacts or separates from a valve seat formed on the valve housing, and is provided at the other end of the valve shaft. The partition portion that partitions the inside of the valve housing into the spring chamber and the atmospheric pressure chamber,
The valve rod is slidably supported by a support portion formed integrally with the valve housing, and the atmospheric pressure chamber is defined between the support portion and the partition portion. Item 3. The vacuum valve according to Item 1 or 2.

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