JPH05288285A - Multistep valve actuator - Google Patents

Abstract

PURPOSE:To provide a general-purpose multistep valve actuator which can attain gradual valve body movement with extremely simple constitution, by removing piston drive in pistons. CONSTITUTION:When compressed gas is introduced into the lower part portion of the 2nd piston 8, the 2nd piston 8 is ascended by means of compressed gas until it butts against a stopper 14. At this time, the 1st piston 6 that is positioned at the upper part of the 2nd piston 8, is also pushed up by means of the 2nd piston 8. Accordingly, a main valve body 5 connected to the 1st piston 6 through the 1st stem 4 is moved upward proportionately to the height of the stopper 14, and forms a leak opening portion. Next, compressed gas is also introduced into an opening 7 between the 1st and 2nd pistons 6, 8, then this time only the 1st piston 6 accompanied by the main valve body 5 is moved rapidly upward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-step valve for stepwise driving a vacuum valve interposed between a vacuum chamber and a vacuum pump, particularly when the vacuum chamber is in a vacuum state. Regarding the actuator.

[0002]

2. Description of the Related Art Conventionally, in order to bring a vacuum chamber used for semiconductor manufacturing or the like close to a vacuum state, a vacuum chamber (01) and a vacuum pump (02) are connected by a conduit (03) as shown in FIG. The vacuum chamber (01) was sucked by the vacuum pump (02) by opening the single vacuum valve (04). However, when the single vacuum valve (04) is opened, the vacuum chamber (0
Turbulent flow was generated in 1) and the conduit (03), which caused particles to rise in the vacuum chamber (01).

In order to prevent this, in recent years, as shown in FIG. 3, a bypass passage (06) is provided so as to bypass the large-diameter vacuum valve (04), and the bypass passage (0) is provided.
A vacuum valve (05) with a small diameter is attached to 6), and both vacuum valves are used together to perform vacuuming stepwise. That is, when evacuating the vacuum chamber (01), first, the small-diameter vacuum valve (05) is opened, and the conduit (03) and the vacuum chamber (0) are gradually moved by the vacuum pump (02).
1) is evacuated to about several torr, and then the large-diameter vacuum valve (04) is opened to achieve complete vacuum evacuation.

In a vacuum state of about several torr, there is no molecular weight enough to cause particles to fly up, so even if the large-diameter vacuum valve (04) is fully opened in that state,
Evacuation is stable and stable. However, providing both the small-diameter vacuum valve (05) and the large-diameter vacuum valve (04), which are controlled by the controller (07) over time, not only complicates the structure,
It becomes expensive in terms of cost.

For this reason, the applicant first introduced a vacuum valve having an extremely simple structure which can be operated so as to switch from a slow exhaust gas to a large-diameter exhaust gas stepwise by simply introducing a predetermined compressed gas into a single vacuum valve. Applied for.

As shown in FIG. 4, the first piston (003) connected to the main valve body (001) through the first stem (002) slides inside the cylinder housing (004). It has a so-called double piston structure in which it is slidably accommodated inside the moving second piston (005).

When the compressed gas is introduced into the lower portion of the first piston (003), the compressed gas acts on the pressure receiving surface of the first piston (003) and the first compressed gas is generated inside the second piston (005).
The piston (003) is moved upward, whereby the main valve body (001) moves slightly upward together with the first piston (003) via the first stem (002), and forms a leak opening. The vacuum pump is in operation, first the air in the vacuum chamber is gradually sucked through the leak opening,
After a predetermined time, the pressure in the vacuum chamber reaches a pressure of several torr where particles no longer rise.

After the lapse of the predetermined time, the cylinder housing (00
4) When compressed gas is introduced into the lower part of the second piston (005) in the main valve body (001), the main valve body (001) moves into the first stem (002).
Through the first piston (003) and the second piston (0
Along with 05), it moves upward rapidly.

Therefore, the large-diameter main valve device communicating the vacuum chamber and the vacuum pump is fully opened, and the remaining air in the vacuum chamber is exhausted. The initially formed leak opening is operated by moving the stem guide up and down by operating the handle.
Very easily adjusted.

[0010]

However, in this device, the first piston (003) is the second piston (00).
5) because it is inside, the passage for supplying compressed gas to the first piston (003) inevitably has a cylinder housing (00
4) and the second piston (005) are crossed, the piping is complicated, and both pistons must be lifted together to fully open the main valve device, and therefore high pressure compressed gas is required. There is a problem of having to supply a large amount.

An object of the present invention is to provide a versatile multi-step valve actuator capable of achieving stepwise valve body movement with a very simple structure by eliminating the piston drive in the piston.

[0012]

A multi-step valve actuator of the present invention is a multi-step valve actuator composed of a valve housing and a cylinder housing.
A main valve body is formed on the valve housing side of the first stem penetrating from the valve housing into the cylinder housing, and a first piston is formed on the cylinder housing side.
With a predetermined gap on the main valve body side of the piston, a second piston that is penetrated by the first stem is installed inside,
It is characterized in that a stopper for limiting the upper limit position of the second piston is provided so that the first piston and the second piston can be driven by using the gas that presses them.

[0013]

When the compressing gas is introduced into the lower portion of the second piston, the second piston is raised by the compressing gas until it comes into contact with the stopper. At this time, the first piston located above the second piston is also pushed up by the second piston. Therefore, the main valve body connected to the first piston via the first stem moves upward in accordance with the height of the stopper to form the leak opening. Next, when the gas to be compressed is also introduced into the gap between the first piston and the second piston, only the first piston moves rapidly upward with the main valve body. As a result, the main valve body reaches the fully open position.

[0014]

1 shows an embodiment of the present invention, in which a multi-step valve actuator comprises an upper cylinder housing (1) and a lower valve housing (2).
The partition wall (3) located between the cylinder housing (1) and the valve housing (2) is penetrated by the first stem (4), and the valve housing (1) of the first stem (4) is penetrated. The main valve body (5) is attached to the end on the () side, and the first piston (6) is attached to the end on the cylinder housing (2) side.

On the main valve body (5) side of the first piston (6) in the cylinder housing (2), that is, the first piston (6).
A second piston (8) penetrated by the first stem (4) with a predetermined gap (7) between the first piston (6) and the partition wall (3). In order to form the gap (7), a ridge (9) is provided on the upper surface of the second piston (8) in this embodiment.

Between the first piston (6) and the second piston (8) and the cylinder housing (1), and between the second piston (8) and the partition wall (3) and the first stem (4). Are each provided with a suitable sealing means. Further, in order to make the sealing between the cylinder housing (1) and the valve housing (2) more complete, in this embodiment, the main valve body (5) is used.
And a partition wall (3), a bellows (10) is stretched so as to surround the first stem (4), and the inside of the bellows (10) is provided with a passage ( 11) via a suitable low pressure source (not shown).

A second stem (12) extending upward through the first piston (6) is planted in the second piston (8). The upper end of the second stem (12) is
A guide piece (17) having a recess (16) for receiving a projection (15) of a stopper (14) provided on the upper end wall (13) of the cylinder housing (1) is fixed by a bolt (18). There is.

The stopper (14) is movably held in the vertical direction via a threaded portion (20) of a tubular portion (19) provided on the upper end wall (13). Further, a groove (21) is provided on the peripheral surface of the stopper (14) below the screwing portion (20), and inside the groove (21), the pin (22) penetrating the tubular portion (19) is provided. The end is protruding.

The outer end portion of the pin (22) is in contact with the sleeve (23) which is fitted onto the cylindrical portion (19), so that the pin (22) does not fall out. Pin (2
2) limits the vertical movement of the stopper (14) by contacting the side wall of the groove (21). Further, the adjustment handle (24) is fitted to the stopper (14),
A skirt piece (25) suspended around the periphery of the adjusting handle (24) surrounds the tubular portion (19).

The vertical position of the stopper (14) can be confirmed by engraving the scales on the skirt piece (25) and the tubular portion (19). Furthermore, in order to prevent the stopper (14) from unintentionally moving,
Screw (2) into the screw hole (26) engraved in the upper end wall (13).
The front end surface of the screw (27) can be pressed against the peripheral surface of the stopper (14) by screwing in 7).

The cylinder casing (1) is provided with a passage (28) for supplying gas to press the gap (7) between the first piston (6) and the second piston (8). The partition wall (3) is provided with a passage (29) for supplying gas to the space below the second piston (8). The first piston (6) is urged downward by a spring (30) that is compressed between the upper surface of the first piston (6) and the upper end wall (13), whereby the main valve body (5) is , The valves are closed in the state that the gas for pressing each piston is not working.

In the closed state as shown by the broken line on the right side of FIG. 1, the passage (2) is provided below the second piston (8).
When the compression gas is introduced from an arbitrary pressure source via 9), the compression gas acts on the pressure receiving surface of the second piston (8) and pushes up the second piston (8). The second piston (8) ascends while being guided by the projection (15) of the stopper (14) which is projected into the recess (16) of the guide piece (17) of the second stem (12), and eventually the projection ( 1
The front end surface of 5) and the bottom surface of the concave portion (16) are brought into contact with each other to be stopped. When the second piston (8) rises, the second piston (8) simultaneously pushes up the first piston (6) via the raised portion (9), so that the main valve body (5) ends up becoming the stopper (14). Is pushed up to form the leak opening (the state on the left side of FIG. 1).

For example, when the vacuum pump connected to the downward opening of the valve housing (2) is in operation, this valve housing (2)
The air in the vacuum chamber connected to the sideways opening is gradually sucked through the leak opening, and after a predetermined time, the vacuum chamber reaches an atmospheric pressure of several Torr where particles are no longer worried about.

Then, when the compressing gas is introduced into the gap (7) through the passage (28), the compressing gas acts on the pressure receiving surface of the first piston (6), and this time the first piston (6) Only 6) rises rapidly with the second piston (8) stopped. Therefore, the first piston (6)
The main valve body (5) connected through the stem (4) also rapidly rises accordingly and reaches the fully opened position. This state is shown on the right side of FIG. Thus, the remaining air in the vacuum chamber is completely exhausted by the vacuum pump.

The size of the leak opening initially formed, that is, the lift of the second piston (8), depends on the adjusting handle (24).
Can be arbitrarily adjusted by rotating the to move the protrusion (15) of the stopper (14) up and down, that is, by changing the contact position of the protrusion (15) and the recess (16). it can.

The constitution and use of the present invention are not limited to the above embodiment. This includes embodiments at a level that can be easily conceived by those skilled in the art when embodying the subject matter of the invention. For example, the stopper for the second piston may be provided on the inner peripheral wall of the cylinder housing and directly engage with the second piston. Further, the respective radii of the first piston and the second piston may be the same as or different from each other.

[0027]

According to the structure of the present invention, since the first piston and the second piston are provided adjacent to each other in the common cylinder housing, in order to supply the pressure gas to the pressurizing chamber of each piston. The passages in s1 only extend through one member (e.g., cylinder housing). Therefore, such a passage is very easily formed. In addition, when the main valve body is opened to the fully open position after the leak opening is formed, it is sufficient to raise only the first piston with the gas that presses while keeping the second piston stopped. In addition, the supply amount can be reduced as compared with the conventional one, and thus the pressure gas source can be downsized.

[0028]

[Brief description of drawings]

FIG. 1 is a sectional view for explaining the operation of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a conventional technique.

FIG. 3 is a schematic diagram showing a conventional technique.

FIG. 4 is a schematic diagram showing a conventional technique.

[Explanation of symbols]

 (1) Cylinder housing (2) Valve housing (3) Partition wall (4) First stem (5) Main valve body (6) First piston (7) Gap (8) Second piston (9) Raised part ( 10) Bellows (11) Passage (12) Second stem (13) Upper end wall (14) Stopper (15) Projection (16) Recess (17) Guide piece (18) Bolt (19) Cylindrical part (20) Threaded part (21) Groove (22) Pin (23) Sleeve (24) Adjustment handle (25) Skirt piece (26) Screw hole (27) Screw (28) Passage (29) Passage (30) Spring

Claims (4)

[Claims] 1. A multi-step valve actuator comprising a valve housing and a cylinder housing, wherein a main valve body is provided on the valve housing side of a first stem penetrating from the valve housing into the cylinder housing. A first piston is formed on the cylinder housing side, and a second piston penetrated by the first stem is provided inside the cylinder housing with a predetermined gap on the main valve body side of the first piston. A multi-step valve actuator characterized in that a stopper for limiting the upper limit position of the second piston is provided so that the first piston and the second piston can be driven by using gas that presses them respectively. 2. A second piston is planted with a second stem extending upward through the first piston, the second stem comprising:
The multi-step valve actuator according to claim 1, wherein the multi-step valve actuator contacts the stopper when the second piston moves up. 3. The multi-step valve actuator according to claim 2, wherein the stopper has a guide portion for the second stem. 4. The multi-step valve actuator according to claim 1, wherein the height of the stopper is adjustable.