KR102173561B1 - Slide type vaccum gate valve - Google Patents

Abstract

The vacuum gate valve of the slide type according to the present disclosure includes a valve body having an inlet and an outlet, a shut-off plate moving forward and backward in a vertical direction with a flow path between the inlet and the outlet to open and close the flow path, and the valve. A cylinder located inside the body to drive the blocking plate, a double seal provided on a flange disposed up and down of the valve body to block flow paths and foreign substances, and a double seal disposed on one side of the valve body, and between the inlet and the outlet It characterized in that it comprises a bypass valve to adjust the air pressure.

Description

Slide type vacuum gate valve {SLIDE TYPE VACCUM GATE VALVE}

The present disclosure relates to a gate valve, and more particularly, to a vacuum gate valve of a slide type for extending the use time of the vacuum gate valve used in a semiconductor manufacturing facility.

The process of manufacturing a semiconductor device is largely classified into three types: exposure and development fixing (Lithography) for pattern formation, a deposition process of depositing a thin film, and an etching process of etching the deposited film in a pattern. Among them, the deposition process uses a lot of harmful gases, and many by-products are generated inside the exhaust line.

), 실리콘나이트라이드(

) 등의 절연막과 금속(Metal) 배선 공정에 해당한다. 절연막에 있어서는 실란(

)을 비롯한 실리콘계 가스들 및 암모니아(

) 등을 사용하게 되며, 증착되는 막은 반도체 웨이퍼만이 아니라 반응기, 진공배관, 진공펌프 등에 쌓이게 된다.The deposition process is mainly silicon oxide (

), silicon nitride (

), etc., and metal wiring processes. In the insulating film, silane (

) Including silicon-based gases and ammonia (

), etc., and the deposited film is accumulated not only on the semiconductor wafer, but also on the reactor, vacuum pipe, and vacuum pump.

,

막을 만드는 공정에서 발생되는 부산물은 가루형태로 진공배관 내부에 쌓이게 되며, 이러한 환경에서 사용되는 진공게이트 밸브는 개,폐 동작을 할 때마다 구동부위로 가루형태의 부산물이 유입되어 동작을 방해하는 요인이 되므로 이를 방지할 기술이 요구되고 있다.During the deposition process

,

By-products generated in the process of making the membrane are accumulated in the vacuum pipe in the form of powder, and the vacuum gate valve used in this environment is a factor that interferes with the operation of the by-product in the form of powder flowing into the driving part whenever the opening or closing operation is performed. Therefore, technology to prevent this is required.

In addition, conventional valves use complex mechanisms (multi-joints, gears, links, double cylinders, etc.), so their lifespan is short, and if the aforementioned powder penetrates, there may be a problem that the operation is not performed smoothly.

Korean Patent Registration No. 10-0539691

The present disclosure uses a vacuum gate valve by securing a technology to limit the amount of powder brought into the valve as much as possible when the vacuum gate valve used in the semiconductor manufacturing process in which the process by-product is in the form of powder performs an opening or closing operation. The purpose is to significantly extend the time.

In addition, the purpose of this is to reduce the impact during opening/closing and extend the life of the vacuum valve and further the controller, piping, and pump.

In addition, the purpose of this purpose is to minimize damage to the valve itself and adjacent peripheral devices by relatively reducing the impact in opening and closing the vacuum gate valve, which ends with one stroke before and after the cut-off plate.

A gate valve according to the present disclosure includes a valve body having an inlet and an outlet, a shut-off plate for opening and closing the flow path by moving forward and backward in a vertical direction with a flow path between the inlet and the outlet, and an inside of the valve body. A first cylinder positioned to drive the blocking plate, a double seal provided on a flange disposed up and down of the valve body to block flow paths and foreign substances, and a double seal disposed at one side of the valve body to control the air pressure between the inlet and the outlet. It characterized in that it comprises a bypass valve to match.

According to a preferred feature of the present disclosure, the double seal includes a gasket and a mounting ring, and a plurality of fixing holes are formed on one surface of the flange to be uniformly spaced apart, and the gasket is seated on one surface of the flange. At one side, a first through hole corresponding to the fixing hole and a groove recessed inward are formed, and the mounting ring includes a second through hole corresponding to the first through hole, and is pressed into the groove of the gasket to be fitted. It is characterized by being combined.

According to a preferred feature of the present disclosure, a fastener is inserted into the fixing hole, the first through hole and the second through hole of the gasket so that the flange, the gasket and the mounting ring are integrally fixed, and the gasket and the mounting ring are combined. The lower end of the gasket is characterized in that the lower end of the gasket protrudes from the horizontal cross section of the mounting ring, and V-shaped grooves are formed on both sides of the gasket based on the mounting ring coupled to the gasket.

According to a preferred feature of the present disclosure, the mounting ring is formed of a hard material to block foreign substances.

According to a preferred feature of the present disclosure, the double seal is characterized in that it is formed of a material such as NBR, SILICON, FKM, FFKM, TEFLON.

According to a preferred feature of the present disclosure, the inclination of the double seal groove shape is set to 30° or more and 60° or less.

According to a preferred feature of the present disclosure, the distance between the lowermost surface of the double seal and the upper surface of the blocking plate is set to -0.35 ~ 0.5mm.

According to a preferred feature of the present disclosure, a space of a certain interval is formed between the double seal and the flange, and when the blocking plate is moved forward or backward, the double seal and the blocking plate are separated, and the double seal is the blocking plate. When in close contact with the plate, it is characterized in that the double seal is pushed up into the space between the double seal and the flange.

According to a preferred feature of the present disclosure, the blocking plate is characterized in that it is in close contact with the double seal at the same time, upper and lower.

According to a preferred feature of the present disclosure, the reverse operation time of the valve body is adjusted to 0.5 or more and 5 seconds or less.

According to a preferred feature of the present disclosure, the bypass valve includes a body formed on one side of the valve body and having a third through hole formed on an upper surface thereof, a second cylinder disposed inside the body, and the second cylinder A bypass flow path connected to one side of and extending toward the valve flow path, a plurality of discharge holes connected to the other side of the second cylinder, and a groove recessed in the upper side are formed, and through the third through hole at the lower side, the And a control plate including a coupling part inserted into the body and a fourth through hole formed through a side of the coupling part and connected to the bypass flow path, wherein a cover is disposed on the upper surface of the control plate, and And a control pin is formed inside the control plate groove to control the rotational movement of the control plate, and accordingly, the open state of the fourth through hole is controlled by driving the control pin. It is characterized in that it is possible to adjust the amount of air sucked into the bypass valve.

5이상 10이하로 설정되는 것을 특징으로 한다. According to a preferred feature of the present disclosure, the bypass flow path has a diameter

It is characterized in that it is set to 5 or more and 10 or less.

According to a preferred feature of the present disclosure, it is characterized in that it further comprises a controller for entirely controlling the operation of the valve body.

According to an embodiment of the present disclosure, the vacuum gate valve is disposed between the semiconductor manufacturing reactor and the exhaust pump, and is used as an autonomous government to open and close the flow path of the semiconductor manufacturing reactor and the exhaust pump.

The slide type vacuum gate valve opens and closes the valve with only the linear motion of the cylinder, thus reducing the risk of malfunction, suppressing the inflow of powder that causes the valve to malfunction to the maximum, increasing the number of valve operations, and significantly extending valve usage time. There is an effect that can be extended by.

1 is an overall perspective view of a sliding type vacuum gate valve according to the present disclosure,
2 is a cross-sectional view showing an open state of a gate valve according to the present disclosure;
3 is a cross-sectional view showing a closed state of a gate valve according to the present disclosure;
4A and 4B are enlarged views of a double seal of a gate valve according to the present disclosure;
5A and 5B are enlarged and exploded perspective views of a bypass valve according to the present disclosure,
6 is a flow chart of an open state of a gate valve according to the present disclosure;
7A to 7D are operational state diagrams showing a process of opening a gate valve according to an embodiment of the present disclosure;
8 is a flowchart of a closed state of a gate valve according to the present disclosure;
9A and 9B are operational state diagrams showing a process of closing a gate valve according to an embodiment of the present disclosure.

The embodiments of the present disclosure are illustrated for the purpose of describing the technical idea of the present disclosure, and the scope of the rights according to the present disclosure is limited to the embodiments disclosed below or specific descriptions of these embodiments. no.

All technical terms and scientific terms used in the present disclosure, unless otherwise defined, have meanings generally understood by those of ordinary skill in the art to which the present disclosure belongs. All terms used in the present disclosure are selected for the purpose of more clearly explaining the present disclosure, and are not selected to limit the scope of the rights according to the present disclosure.

Expressions such as "comprising", "consisting of", "formed", "having" and the like used in the present disclosure include other embodiments, unless otherwise stated in the phrase or sentence in which the expression is included. It should be understood as open-ended terms that imply possibilities.

Expressions such as "first" and "second" used in the present disclosure are used to distinguish a plurality of components from each other, and do not limit the order or importance of the components.

Hereinafter, with reference to the accompanying drawings, looks at the configuration, operation, and effects of the slide type vacuum gate valve according to a preferred embodiment of the present disclosure. In the accompanying drawings, the same or corresponding components may be omitted or schematically illustrated for convenience. However, even if description of a component is omitted, it is not intended that the component is not included in any embodiment.

1 is an overall perspective view of a vacuum gate valve of a slide type according to the present disclosure, FIG. 2 is a cross-sectional view illustrating an open state of a gate valve according to the present disclosure, and FIG. 3 is a closed state of a gate valve according to the present disclosure. 4A and 4B are an enlarged view of a double seal of a gate valve according to the present disclosure, FIGS. 5A and 5B are an enlarged and exploded perspective view of a bypass valve according to the present disclosure, and FIG. 6 is A flow chart of an open state of a gate valve, FIGS. 7A to 7D are operational state diagrams showing a process of opening a gate valve according to an embodiment of the present disclosure, and FIG. 8 is a flowchart of a closed state of a gate valve according to the present disclosure. 9A and 9B are operational state diagrams showing a process of closing a gate valve according to an embodiment of the present disclosure.

1 to 3, the gate valve 100 is a device used in a semiconductor manufacturing facility, a valve body 10 in which an inlet 20 and an outlet 30 are formed, an inlet 20, and A blocking plate 40 that opens and closes the flow path by moving forward and backward in a vertical direction with the flow path between the outlets 30, and a first cylinder 50 located inside the valve body 10 to drive the blocking plate And, a double seal (70) provided on the flange (60) arranged up and down of the valve body (10) to block the flow path and foreign substances, and the inlet (20) and the outlet (30) arranged on one side of the valve body (10) It may include a bypass valve 80 to match the air pressure between.

The valve body 10 has an inlet 20 connected to the semiconductor manufacturing reactor and an outlet 30 connected to an exhaust pump, respectively. The inlet 20 and the outlet 30 may be installed in various positions of the valve body 10, but are symmetrically installed on the upper and lower portions of the valve body 10 to facilitate the movement of the blocking plate 40. It is desirable.

On the other hand, between the inlet 20 and the outlet 30, a flow path passing through the top and bottom of the valve body 10 is formed, and in the vertical direction of the flow path, the blocking plate 40 is formed by the first cylinder 50. It moves forward and backward and opens and closes the flow path.

The first cylinder 50 is a portion located inside the valve body 10 to drive the blocking plate 40 and includes a piston to enable forward and backward movement by pneumatic or hydraulic pressure.

In general valves, the valve is closed by pushing the shutoff plate into the flow path and then pushing it vertically upward. When opening, the valve is opened and closed in a two-step stroke that pulls down the shutoff plate and pulls it outside the flow path. Since the two-stage stroke has to be performed quickly within a limited time, a tremendous impact occurs when the shutoff plate is completed forward and backward, and as a result, shocks are applied to not only the valve but also the controller, piping, and pump, which can shorten the lifespan.

In the case of the present disclosure, the reverse operation time of the shutoff plate 40 of the valve body 10 is adjusted from 0.5 seconds to 5 seconds, and within that time, the shutoff plate 40 is completed in one step forward and backward, so a two-step stroke Compared to that, the impact on the valve body 10 and adjacent peripheral devices can be minimized when the flow path is opened and closed by relatively reducing the impact.

4A and 4B, an enlarged view of the double seal 70 coupled to one side of the flange 60 is disclosed.

The double seal 70 may be bent inward or restored to its original position when the blocking plate 40 is moved forward or backward to receive frictional force or the like.

For this purpose, it is desirable to be made of a flexible material, for example, acrylonitrile-butadiene rubber, silicon, fluorine rubber (FKM), perblue aurocarbon rubber (FFKM), Teflon, and the like. Also, although not shown, it may be composed of a stainless corrugated pipe.

When the blocking plate 40 is opened and closed, the double seal 70 disposed above and below the flange 60 is in close contact with the blocking plate 40 at the same time, and blocks the lowermost surface of the double seal 70. The spacing of the upper surface of the plate may be preferably set to -0.35mm to 0.5mm.

Meanwhile, as shown in FIGS. 4A and 4B, the double seal 70 includes a gasket 72 and a mounting ring 73.

On one surface of the flange 60, a plurality of fixing holes 74 are formed to be uniformly spaced in the circumferential direction.

A groove is formed into the gasket 72 to a certain depth, and protrusions protruding from both sides of the groove are formed (see FIG. 4A ).

In the groove of the gasket 72, a first through hole 75 corresponding to the fixing hole 74 of the flange 60 is formed to be uniformly spaced apart in the circumferential direction.

Accordingly, the first through hole 75 of the gasket 72 is in close contact with the fixing hole 74 of the flange 60 to be seated on one surface of the flange 60.

A mounting ring 73 including a second through hole 76 corresponding to the first through hole 75 is disposed on the gasket 72, and the second through hole 76 covers one surface of the mounting ring 73. Accordingly, the mounting ring 73 is formed to be uniformly spaced apart in the circumferential direction, and the first through hole 75 and the second through hole 76 are in close contact with each other and are pressed into the groove of the gasket 72 to be fitted. In addition, the mounting ring 73 is formed of a hard material to block foreign substances.

In addition, a fastener 71 is inserted into the fixing hole 74, the first through hole 75, and the second through hole 76 so that the flange 60, the gasket 72, and the mounting ring 73 are integrated. Combine.

When the gasket 72 and the mounting ring 73 are combined, the lower end of the gasket 72 protrudes from the horizontal cross-section of the mounting ring 73. Through this structure, the lower end of the gasket 72 can directly contact the blocking plate 40, so that two seals are disposed as one seal.

As mentioned above, the configurations of the double seal 70 are coupled to the lower flange as well as the upper flange in the same manner.

On the other hand, when the valve flow path is closed, the powdery by-products accumulated in the vacuum pipe above the valve fall onto the blocking plate 40 due to vibration generated according to the operating speed of the valve body 10, and the valve flow path is opened again. When doing so, by-products may be introduced into the valve body 10 in proportion to the gap between the blocking plate 40 and the double seal 70.

Specifically, when the operation of opening the valve flow path is performed, the bypass valve 80 is opened to adjust the pressures of the inlet 20 and the outlet 30 of the valve to a certain degree, and the inlet 20 and the outlet 30 When the pressure difference between) increases, when the bypass valve 80 is opened, a strong turbulent air flow is formed in the upper and lower portions of the valve body 10, and by-products in the form of powder accumulated on the upper part of the valve by the turbulence fall onto the blocking plate 40.

At this time, as mentioned above, since the double seal 70 is formed in the form of a double seal in which the gasket 72 is formed on an outer and inner circumferential surface, it has a remarkable by-product blocking effect compared to a structure consisting of one O-ring or seal that blocks by-products. There are, and by combining the mounting ring 73 made of a hard material to the groove portion of the gasket 72, it is possible to block foreign substances in three layers.

Therefore, the double seal 70 can maximize the airtightness inside the flange 60 by preventing the introduction of by-products in the form of powder that can be introduced as the valve flow path is opened and closed while the blocking plate 40 moves horizontally to the left and right. have.

Looking at the overall cross section of the double seal 70 as shown in FIG. 4A, V-shaped grooves are formed on the other side of the gasket 72 on both sides of the mounting ring 73 coupled to the gasket 72. The gasket 72 may have a slope of the V-shaped groove shape set to 30° or more and 60° or less, which can be seen as an escape space (S). Therefore, a space with a certain interval is formed between the double seal 70 and the flange 60, and when the double seal 70 is in close contact with the blocking plate 40, the space between the double seal 70 and the flange 60, That is, as the double seal 70 is pushed up into the escape space S, frictional force when the blocking plate 40 and the double seal 70 are in close contact can be reduced, and the life of the double seal 70 can be increased. .

1 and 5A, the bypass valve 80 is disposed on one side of the valve body 10 to adjust the pressure difference between the upper and lower portions of the blocking plate 40 before opening the valve flow path. In general, before opening the gate valve 100 with a vacuum, the inlet 20 side of the upper part of the blocking plate 40 is 760 torr of atmospheric pressure, and the outlet 30 side of the lower part of the blocking plate 40 is in a vacuum state. Therefore, if the gate valve 100 is opened in this state, damage to the vacuum pump may be caused due to the difference in pressure on the disk and the bottom.

Therefore, the bypass valve 80 functions to match the air pressure between the inlet 20 and the outlet 30 in order to prevent the above problems,

The bypass valve 80 includes a body 81 formed on one side of the valve body 10 and having a third through hole 85 formed on the upper surface thereof, and a second cylinder 82 disposed inside the body 81 , A bypass flow path 83 connected to one side of the second cylinder 82 and extending toward the valve flow path, a plurality of discharge holes 84 connected to the other side of the second cylinder 82, and

An inwardly recessed groove is formed on the upper side and formed through the side of the coupling portion 86 and the coupling portion 86 inserted into the body 81 through the third through hole 85 on the lower side, and the bypass flow path ( It includes a control plate 88 including a fourth through hole 87 connected to 83.

5이상 10이하로 설정될 수 있으며, 바디(81) 내부에 배치된 제 2 실린더(82)는 바이패스 유로(83)로부터 공기가 유입되면 수평운동을 하면서 복수 개의 배출공(84)을 통해 공기를 배출하게 된다.Preferably, the diameter of the bypass flow path 83 is

It may be set to 5 or more and 10 or less, and the second cylinder 82 disposed inside the body 81 performs a horizontal motion when air is introduced from the bypass flow path 83, and air through the plurality of discharge holes 84 Will be discharged.

The control plate 88 has a cover disposed on the upper surface and is coupled to the upper side of the body 81, and an adjustment pin 89 is formed in the groove of the control plate 88 to be coupled with the central axis of one end of the control plate 88. 88) When the upper cover is opened and the adjustment pin 89 is turned with a hexagon wrench, the rotational motion of the entire adjustment plate 88 is controlled.

Accordingly, when the control pin 89 is rotated according to steps 1 to 5 of the instrument panel indicating the degree of air intake located on the upper surface of the control panel 88, the coupling part 86 connected to the control pin 89 rotates and passes through the fourth. By controlling the open state of the hole 87, the amount of air sucked into the bypass valve 80 may be adjusted.

Through this, the pressure of the inlet port 20 and the outlet port 30 is adjusted to the intermediate range of 1 torr to 100 torr, and the bypass valve 80 is automatically closed when it reaches this pressure range.

Hereinafter, a process of opening the gate valve according to the present disclosure will be described according to FIGS. 6 and 7A to 7D.

When the first valve flow path is closed, as described above, a pressure difference between the inlet 20 and the outlet 30 between the upper and lower portions of the blocking plate 40 occurs, and when the flow path is immediately opened, the upper and lower portions of the blocking plate 40 , The vacuum pump may be damaged due to the lower pressure difference.

Accordingly, as shown in FIG. 7, the bypass valve 80 is opened to adjust the upper and lower pressures of the blocking plate 40 through the bypass flow path 83. In the process of opening the bypass flow path 83, turbulence occurs in the vacuum pipe, and powdery by-products in the vacuum pipe are accumulated on the upper surface of the blocking plate 40 by this turbulence.

When the upper and lower pressures of the blocking plate 40 are adjusted through the bypass valve 80, the bypass valve 80 is closed, and the piston on the first cylinder 50 moves backward, and the blocking plate 40 moves backward. . At this time, by-products accumulated on the upper surface of the blocking plate 40 are caught by the double seal 70 and are not introduced into the flange 60.

As can be seen in the flow chart of FIG. 6, when an error occurs when the blocking plate 40 is retracted, an alarm signal is transmitted, and after the blocking plate 40 is normally moved, the closed valve flow path is opened again.

Hereinafter, a process of closing the gate valve according to the present disclosure according to FIGS. 8 and 9A to 9B will be described.

When the semiconductor process is in progress, since the semiconductor process chamber must maintain a vacuum state, the valve flow path is opened as shown in FIG. 8. At this time, since the lower end of the double seal 70 and the blocking plate 40 are in close contact with each other, airtightness of the inside of the flange 60 may be maintained.

In this state, while the piston on the first cylinder 50 advances, the shutoff plate 40 advances and blocks the valve flow path.

As can be seen in the flow chart of FIG. 8, when an error occurs when the blocking plate 40 moves backward, an alarm signal is transmitted. In this case, the blocking plate 40 and the double seal 70 ) Maintains the contacted state, it is possible to block by-products in the form of powder from entering into the flange 60. On the other hand, on the upper surface of the blocking plate 40, powder in the vacuum pipe accumulates due to vibration caused by the movement of the blocking plate 40.

Although not shown, the overall operation of the gate valve 100 may be controlled by further including a controller that controls the operation of the valve body 10 as a whole.

According to an embodiment of the present disclosure, the vacuum gate valve is disposed between the semiconductor manufacturing reactor and the exhaust pump, and is used as an autonomous government to open and close the flow path of the semiconductor manufacturing reactor and the exhaust pump.

The slide type vacuum gate valve opens and closes the valve with only the linear motion of the cylinder, thus reducing the risk of malfunction, suppressing the inflow of powder that causes the valve to malfunction to the maximum, increasing the number of valve operations, and significantly extending valve usage time. There is an effect that can be extended by.

The present disclosure described above is not limited by the above-described embodiments and the accompanying drawings. It will be apparent to those of ordinary skill in the art that various substitutions, modifications and changes are possible within the scope of the technical spirit of the present disclosure.

100: gate valve 10: valve body
20: inlet 30: outlet
40: blocking plate 50: first cylinder
60: flange 70: double seal
71: fastener 72: gasket
73: mounting ring 74: fixing hole
75: first through hole 76: second through hole 80: bypass valve 81: body 82: second cylinder 83: bypass flow path 84: discharge hole 85: third through hole 86: coupling portion 87: fourth through hole 88: control plate 89: control pin S: escape space

Claims (13)

A valve body in which an inlet port and an outlet port are formed;
A blocking plate moving forward and backward in a vertical direction with a flow path between the inlet and the outlet and opening and closing the flow path;
A first cylinder located inside the valve body to drive the blocking plate;
A double seal provided on a flange disposed above and below the valve body to block a flow path and foreign substances; And
Includes; a bypass valve disposed on one side of the valve body and adjusting the air pressure between the inlet and the outlet,
The double seal includes a gasket and a mounting ring,
On one surface of the flange, a plurality of fixing holes are formed uniformly spaced apart,
The gasket is seated on one side of the flange, and a first through hole corresponding to the fixing hole and a groove recessed into the inside are formed on one side of the gasket,
Wherein the mounting ring includes a second through hole corresponding to the first through hole, and is pressed and fitted into a groove of the gasket. delete The method of claim 1,
A fastener is inserted into the fixing hole, the first through hole, and the second through hole of the gasket so that the flange, the gasket, and the mounting ring are integrally fixed, and when the gasket and the mounting ring are coupled, the lower end of the gasket is Protrudes from the horizontal section,
Gate valve, characterized in that V-shaped grooves are formed on both sides of the other side of the gasket based on the mounting ring coupled to the gasket. delete delete delete delete The method of claim 1,
A space of a predetermined interval is formed between the double seal and the flange,
When the barrier plate moves forward and backward, the double seal and the barrier plate are separated,
When the double seal is in close contact with the blocking plate, the double seal is pushed up into the space between the double seal and the flange.
The method of claim 8,
The blocking plate is a gate valve, characterized in that in close contact with the double seal at the same time upper and lower.
delete The method of claim 1,
The bypass valve,
A body formed on one side of the valve body and having a third through hole formed on an upper surface thereof;
A second cylinder disposed inside the body;
A bypass flow path connected to one side of the second cylinder and extending toward the valve flow path;
A plurality of discharge holes connected to the other side of the second cylinder; And
A groove is formed on the upper side and includes a coupling portion inserted into the body through the third through hole on the lower side, and a fourth through hole formed through the side of the coupling portion and connected to the bypass flow path. Including;
The control plate has a cover disposed on the upper surface and is coupled to the upper side of the body, and a control pin coupled with one end central axis of the control plate is formed inside the control plate groove to control the rotational motion of the control plate, and accordingly the control pin The gate valve, characterized in that it is possible to control an open state of the fourth through hole by driving of to control an amount of air sucked into the bypass valve.
delete delete

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