JP5052155B2 - Check valve and vacuum pump device - Google Patents

Description

  The present invention relates to a check valve and a vacuum pump device including the check valve.

Conventionally, a check valve is provided in a flow path in a pipe or in an apparatus in order to flow a fluid in only one direction and prevent backflow. For example, in a semiconductor manufacturing apparatus, a wafer processing chamber and a vacuum pump are connected by piping, but if the vacuum pump stops unintentionally due to a failure, abnormality, or power failure, the wafer being processed is It becomes a defective product. Even when such a vacuum pump stop occurs, a check valve is incorporated in the piping in order to maintain the vacuum in the processing chamber and protect the wafer.

  Patent Document 1 discloses a technique for preventing the dust in the exhaust pipe from flowing into the processing chamber when the open / close valve is closed during vacuum exhaust in a semiconductor manufacturing apparatus. The semiconductor manufacturing apparatus includes a wafer processing chamber, a vacuum pump connected to the processing chamber via an exhaust pipe, and an open / close valve provided in the exhaust pipe, and an exhaust pipe between the process chamber and the open / close valve. Is provided with a check valve. This check valve is configured by forming a plurality of bars radially with a certain gradient from the processing chamber side to the opening / closing valve side, and the bar is formed by an opening / closing valve. When closed, a gas (purge fluid) is blown out toward the open / close valve side.

  Further, in Patent Document 2, in an oil backflow prevention device for a vacuum pump, an intake port is provided in an intake passage communicating with a pump chamber via an intake check valve, and an intake passage between the check valve and the pump chamber is provided. Discloses a solenoid valve that is electrically connected to a rotor in a pump chamber. Here, as a check valve for intake, a spherical valve body is fixed to a valve seat with a spring, the intake passage is closed with a sphere during non-intake, and the spring is compressed by differential pressure to open during intake. The thing is adopted. This check valve requires a support body (spring and valve seat) that supports the valve body. Similarly, a check valve that requires a support body has a hinge portion and the hinge portion is movable. Some open and close the valve.

  The check valve has a structure that does not require a valve body other than a valve body that is fixed and requires another mechanism such as a purge fluid blowing mechanism or a support that supports the valve body. There is something to have. FIG. 4 shows a cross-sectional view of such a check valve.

  The check valve 6 shown in FIG. 4 includes a flat valve body 60 and a valve chamber that has an inlet 61 and an outlet 62 and accommodates the valve body 60. The valve chamber includes a storage portion that stores the valve body 60 so that the thickness direction of the valve body 60 is in the flow path, and a bypass flow path 64 that allows only the fluid flowing in the forward direction to flow out. The storage unit stores the valve body 60 so as to be movable within a predetermined range (predetermined vertical movable distance) by the inner walls of both the upper movement restriction unit 65 and the lower movement restriction unit 63 in the forward and reverse directions of the flow.

When the fluid is flowing in the forward direction, the valve body 60 is pressed against the lower movement restricting portion 63 by its own weight and flow as shown in FIG. To flow. On the other hand, when the fluid tries to flow in the reverse direction, as shown in FIG. 4B, the valve body 60 is pressed against the upper movement restricting portion 65 by the flow, and the inflow port (forward direction) from the detour channel 64. The flow path to the inlet 61) is blocked, and the fluid is blocked.
JP-A-7-122503 Registered Utility Model No. 3070980

  However, the check valve 60 having the structure shown in FIG. 4 is provided between the vacuum pump and the processing chamber (chamber) for manufacturing the semiconductor, and as a result of the experiment when the vacuum pump is stopped, the check valve 60 is operated. It took 400 msec to stop the backflow (see FIG. 5). The experiment result shown in FIG. 5 is an experiment using a circular aluminum alloy valve body 60 having a weight of 25 g, a thickness of 1 mm, and a diameter of 100 mm, and the vertical movable distance of the valve body 60 being 7 mm. .

  This reaction rate cannot be said to be fast, and in the experimental results of FIG. 5, the pressure in the chamber rises to 64 Pa (1 V = 13.3322 Pa in the figure), and as a result, the wafer cannot be protected. This is because since the valve body is a flat plate, the flow of the fluid that flows backward cannot be effectively received.

  The present invention has been made in view of the circumstances as described above, and provides a check valve that does not require a complicated structure and has a high reaction speed, and a vacuum pump device including the check valve. For that purpose.

In order to solve the above-described problems, a check valve according to the present invention is a check valve having a valve body and a valve chamber that houses the valve body, and the valve body is a central portion of a circular flat plate. in a shape remembering curvature of convex, said valve chamber, said valve body, the inlet side of the fluid flowing in the positive direction on the convex side, and is movably accommodated in the forward and reverse direction of flow by a predetermined range a housing portion, have a positive direction flows bypass flow path for only the outflow fluid, the housing section, the plane of the movement limiting portion provided on the inflow side and the outflow side to abut the flat portion of the valve body The movement of the valve body in the forward and reverse directions of the flow is limited to the predetermined range by a shaped inner wall .

  The vacuum pump device of the present invention is characterized by comprising the above-described check valve and a vacuum pump connected to the check valve.

  The check valve according to the present invention does not require other mechanisms such as a support for supporting the valve body and a purge fluid supply mechanism, and can increase the reaction rate. In addition, according to the vacuum pump device of the present invention, the check valve functions quickly even when the vacuum pump is unexpectedly stopped, thereby preventing a decrease in the degree of vacuum in the container to be sucked. be able to.

FIG. 1 is a cross-sectional view showing a configuration example of a check valve according to the present invention, in which 1 is a check valve.
The check valve 1 shown in FIG. 1 includes a valve body 10 and a valve chamber that has an inflow port 11 and an outflow port 12 and accommodates the valve body 10 therebetween. The valve chamber includes a storage portion that stores the valve body 10 and a bypass channel 14 that allows only the fluid flowing in the forward direction to flow out of the valve chamber.

  Further, the bypass flow path 14 is formed from an inner wall around the valve body 10 (in the state where the valve body 10 is pressed against the upper movement restriction portion 15, an inner wall on the side opposite to the inlet 11 with respect to the valve body 10). It only needs to be formed so as to pass through the lower movement restricting portion 13 and continue to the outlet 12, and the shape thereof is not limited. The bypass flow path 14 allows the fluid to flow while the valve body 10 is in contact with the lower movement restricting portion 13 with respect to the flow path between the inlet 11 and the outlet 12 without the valve body 10 being provided. In order to play a role of flowing from the inflow port 11 to the outflow port 12, it is called a “detour” flow path, but this detour flow path 14 is a regular flow path.

  The valve body 10, which is a main characteristic part of the present invention, has a plate-like shape curved at least in the central part. Although FIG. 1 shows an example in which the bottom 10b of the valve body 10 is a flat plate and the curved portion 10a is provided at the center portion of the valve body 10, the valve body 10 may be entirely curved. Further, as the curved shape, it is preferable that the cross section in the thickness direction is an arc shape or a convex curve similar to the curved shape (including a macroscopically curved curve) because stress concentration due to fluid does not occur. Further, the outer shape of the valve body 10 (the outer shape seen from above) may be a circle or a polygon including a quadrangle.

  And the above-mentioned storage part is the state which made the inflow side of the fluid which flows the valve element 10 into the forward direction (here downward direction) into the convex side, and the upper side movement restriction | limiting part 15 and lower side movement are carried out in the forward / backward direction of a flow. The valve body 10 is accommodated so as to be movable by a predetermined range (predetermined vertical movable distance) by both inner walls of the restricting portion 13. That is, in the valve chamber, the valve body 10 only needs to be in the guide formed by the upper movement restriction portion 15 and the lower movement restriction portion 13, and is floated in a pressure equilibrium state, and supports the valve body 10 in the valve chamber. There is no need for a support.

  With the above-described configuration, when the fluid is flowing in the forward direction, as shown in FIG. 1 (A), the valve body 10 abuts against the lower movement restricting portion 13 due to its own weight and flow (pressure difference). When pressed, the fluid can flow from the bypass channel 14 to the outlet 12. On the other hand, when the fluid tries to flow in the reverse direction, as shown in FIG. 1 (B), the valve body 10 is pressed against the upper movement restricting portion 15 by the flow (pressure difference), and the bypass flow path. The flow path from 14 to the inlet (inlet referred to as a forward flow) 11 is blocked, and fluid flow can be prevented (reverse flow is prevented). In addition, it is preferable to provide a mechanism for sealing, such as providing an O-ring at a location where the upper body movement restricting portion 15 (and the lower side movement restricting portion 13) contacts the valve body 10.

  In addition, it is preferable that the valve body 10 is pressed against the lower movement restricting portion 13 only by its own weight, and therefore, it is preferable that the valve body 10 is disposed so that the thickness direction (strictly, the thickness direction of the bottom portion 10b) is the vertical direction. That is, it is preferable that the convex side of the curved portion 10a of the valve body 10 is disposed in a state in which the convex side faces vertically upward (the flow path in which the valve body 10 is installed faces in the vertical direction). However, the valve body 10 is not necessarily provided horizontally, and can be moved only by a pressure difference if provided vertically in the flow path. In this case, the upper movement restriction unit 15 indicates an upstream movement restriction unit, and the lower movement restriction unit 15 indicates a downstream movement restriction unit.

  Further, the valve body 10 may be replaced at the time of maintenance. In that case, it is preferable to adopt an assembly structure of the valve chamber in which the valve body 10 can be detached from the valve chamber itself. The valve element 10 of the present invention is also referred to as a “diaphragm” because it has a thin film-like structure that separates the inlet 11 and the outlet 12, and since it can quickly move up and down according to the flow (pressure difference), (Flapper) ".

  FIG. 2 is a schematic diagram showing a configuration example of a vacuum system using the check valve of FIG. In the vacuum system illustrated in FIG. 2, a vacuum pump device is connected to a chamber 5 via a pipe (vacuum pipe) 4, and the inside of the chamber 5 is evacuated by suction with the vacuum pump apparatus. The vacuum pump device includes the check valve 1 described above and a vacuum pump 2 connected to the check valve 1 via a pipe (vacuum pipe) 3. As described above, the check valve 1 is preferably connected to the vacuum pump 2 so that the convex side of the valve body 10 faces upward.

  As the chamber 5, various containers that are desired to be evacuated, such as a processing chamber of a semiconductor manufacturing apparatus, can be applied. In addition, a heater may be provided in the valve chamber of the check valve 1 to warm the valve body 10 so that unnecessary products from the chamber 5 do not adhere to the valve body 10. Although not shown, a solenoid valve or the like is provided in the middle of the pipe 3 (or the pipe 4) or between the pipe 3 and the vacuum pump 2 and the valve is closed or the vacuum pump 2 is expected. At the time of unstoppable stop, etc., the check valve 1 can prevent backflow and keep the degree of vacuum in the chamber 5.

  FIG. 3 is a diagram showing experimental results obtained by examining the reaction rate of the check valve shown in FIG. The experimental result shown in FIG. 3 is a valve made of a round aluminum alloy press having a weight of 25 g, a thickness of 1 mm of the bottom portion 10b, a thickness of 0.9 mm of the curved portion 10a, and an outer diameter of 100 mm of the flat bottom portion 10b. A valve body 10 having a height from the top of the valve body 10 to the bottom 10b of 5 mm and a radial length of the bottom 10b of 10 mm (that is, the inner diameter of the bottom 10b is 80 mm) is used. The experiment was conducted using a valve chamber having a vertical movement distance of 10 mm. Although the valve body 10 is made of an aluminum alloy, it may be made of another metal such as titanium or a material such as carbon other than metal.

  The check valve 1 having the structure shown in FIG. 1 is provided between the vacuum pump 2 and the semiconductor manufacturing process chamber (chamber 5), and as a result of an experiment conducted when the vacuum pump was stopped, as shown in FIG. It only took 350 msec for the check valve to operate and stop the reverse flow. This reaction rate is significantly faster than the conventional results described in FIG. Further, in the experimental result of FIG. 3, the pressure in the chamber rises only up to 40 Pa (1 V = 13.3322 Pa), and a pressure increase of 24 Pa can be prevented compared to the conventional case, and as a result, the wafer can be protected. . This can be said to be the result that the valve body 10 is not a conventional flat plate but has a curved shape (dome shape), so that the flow of the backflowing fluid can be effectively received.

  Although the present invention has been described above, the check valve according to the present invention is not limited to the vacuum system described with reference to FIG. 2, but includes various pipes such as being incorporated in place of the oil backflow prevention device of Patent Document 1. It can be incorporated into the flow path in the device, and its use is not limited. The vacuum pump device according to the present invention includes the check valve 1 described above and the vacuum pump 2 directly connected to the check valve 1 without a pipe 3 so as to be substantially configured in one housing. It may be.

It is sectional drawing which shows the structural example of the non-return valve which concerns on this invention. It is the schematic which shows the structural example of the vacuum system using the non-return valve of FIG. It is a figure which shows the experimental result which investigated the reaction rate of the non-return valve of FIG. It is sectional drawing of the non-return valve by a prior art. It is a figure which shows the experimental result which investigated the reaction rate of the non-return valve of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Check valve, 2 ... Vacuum pump, 3, 4 ... Pipe, 5 ... Chamber, 10 ... Valve body, 10a ... Curve part of valve body, 10b ... Bottom part of valve body, 11 ... Inlet, 12 ... Outlet , 13: Lower movement restriction unit, 14: Detour channel, 15 ... Upper movement restriction unit.

Claims (2)

A check valve having a valve body and a valve chamber for housing the valve body,
The valve body has a shape with a convex curved portion at the center of a circular flat plate ,
The valve chamber has a storage portion for storing the valve body in such a manner that the inflow side of the fluid flowing in the forward direction is a convex side and movable within a predetermined range in the forward and reverse directions of the flow, and only the fluid flowing in the forward direction flows out. possess a bypass flow passage through which,
The storage portion moves the valve body in the forward and reverse directions of the flow by the planar inner walls of the movement restricting portions provided on the inflow side and the outflow side in order to contact the flat plate portion of the valve body in the predetermined range. A check valve characterized by being restricted to   A vacuum pump device comprising the check valve according to claim 1 and a vacuum pump connected to the check valve.

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