JP7323239B2 - Dry vacuum pump inlet joint - Google Patents

Description

The present invention relates to an inlet joint for connecting an external pipe to the inlet of a dry vacuum pump, and a dry vacuum pump provided with the inlet joint. More specifically, an intake joint with a product recovery function for recovering products such as powdered products and liquefied products that enter the pump from an external pipe through the intake port, and the intake joint. It relates to a dry vacuum pump with.

2. Description of the Related Art In a semiconductor manufacturing process such as a CVD process or an etcher process, a dry vacuum pump is used to evacuate a reaction chamber or the like. The exhaust drawn by the dry vacuum pump contains products such as powdered products, liquefied products and the like. If such products are sucked into the dry vacuum pump in small amounts, there is no problem in driving the pump. However, if a large amount of product enters the dry vacuum pump at once, the pump may become overloaded and unable to start.

In order to prevent such an adverse effect, it is common to install a product recovery device such as an h-shaped pipe for trapping and storing powder, a powder trap, or the like, in front of the dry vacuum pump. For example, Patent Literature 1 proposes a pump-external product recovery device, in which a centrifugal cylinder for trapping powder is attached between the pump inlet and an external pipe. On the other hand, Patent Document 2 proposes a product recovery device with a built-in pump, in which a trap for product recovery is arranged in an intake passage communicating with an intake port inside a casing of a vacuum pump.

Japanese Patent Application Laid-Open No. 2007-205287 JP-A-5-332285

In the case of a product recovery apparatus with a built-in pump, it is necessary to disassemble the pump casing in order to recover the collected product. On the other hand, in the case of an external product recovery device, it can be easily removed from the pump main body, so it is excellent in maintainability.

However, conventional external product recovery devices have the following problems. That is, an intake joint is attached to the intake port in order to connect the intake port of the dry vacuum pump to the external pipe. Product recovery devices such as h-shaped pipes, powder traps, etc., which are larger in size and require more installation space, are attached to the inlet in place of the existing inlet joint. It is necessary to change the layout of the external piping, etc., in order to secure a wide installation space between the intake port and the external piping to which the product recovery device can be attached.

In view of these points, the object of the present invention is to provide a product recovery device that is excellent in maintainability and can be externally attached to the intake port of a dry vacuum pump without requiring a large installation space, and has a product recovery function. To provide an air inlet joint with

The present invention focuses on the inlet joint attached to the inlet of the dry vacuum pump, and by incorporating a product recovery mechanism into the inlet joint itself, the intake of the dry vacuum pump without increasing the installation space. A product recovery device that can be externally attached to the mouth and has excellent maintainability has been realized. As a result, it is possible to collect the product entering the intake port of the dry vacuum pump from the external piping without changing the layout of the external piping (the piping on the equipment side above the pump).

That is, the present invention provides an inlet joint with product recovery that can be treated as a pump accessory attached to the inlet of a dry vacuum pump, comprising:
an outer tube extending in the vertical direction;
a lower flange formed at the lower end of the outer tube and fastened and fixed to the dry vacuum pump;
an upper flange formed on the upper end of the outer tube;
an inner tube coaxially arranged inside the outer tube, the lower end opening being able to communicate with the air inlet through the central opening of the lower flange, and the upper end opening being closed;
an exhaust inlet radially penetrating an outer peripheral wall portion of the inner pipe;
an annular product recovery recess formed between the outer tube and the inner tube, the upper end of which opens upward, and the lower end of which is closed by the lower flange;
It is characterized by having

In the inlet joint of the present invention, a product recovery recess is formed inside the inlet joint attached to the inlet of the dry vacuum pump. An external pipe is connected to the upper flange of the outer pipe of the inlet joint, similar to existing inlet joints. If there is a difference in pipe diameter with the external pipe, a reducer is attached to the upper flange and the external pipe is connected via the reducer. In this case, the inlet joint of the present invention has a reducer as its component. When the external pipe is connected to the inlet joint, the dry vacuum pump is supplied from the external pipe sequentially through the reducer, the product recovery recess, the exhaust inlet formed in the outer peripheral wall of the inner pipe, and the inside of the inner pipe. An exhaust passage leading to an intake port is formed.

The exhaust that is vacuum-sucked from the upper equipment side through the external pipe flows into the product recovery recess that surrounds the outer periphery of the inner pipe whose upper end face is closed inside the inlet joint, and flows into the outer peripheral wall of the inner pipe. The exhaust gas flows into the inner pipe from the exhaust inlet opening to the part, flows inside the inner pipe, and is sucked into the pump from the intake port. When the dry vacuum pump is started or restarted, products such as powdered products and liquefied products that fall from the external piping side into the inlet joint are pushed down by their own weight to the bottom of the product recovery recess. fall down and accumulate. Similarly, any product that flows into the inlet joint with the exhaust is thrown off the exhaust and collects at the bottom of the product recovery recess. After flowing into the product recovery recess, the exhaust gas flows into the inner tube through an exhaust inlet opening in the outer peripheral wall portion of the inner tube, passes through the inner tube, and is sucked into the pump from the intake port.

In the inlet joint of the present invention, the portion of the outer tube with the upper and lower flanges is configured similarly to existing inlet joints. The attachment and detachment work can be performed in the same manner as ordinary pipe connection and detachment work, and no special work is required. The work of recovering the product accumulated inside can be easily performed by simply removing the external pipe from the inlet joint, and it is excellent in maintainability. Moreover, it is sufficient if the same installation space as the existing intake joint can be secured. Therefore, in order to secure a large installation space, it is necessary to change the layout of the external piping (upper equipment side piping) connected to the intake port of the dry vacuum pump, as in the case of attaching a large-sized product recovery device externally. no longer need to do it.

Here, the pumping speed (the amount of gas discharged per unit time), which is the performance of the dry vacuum pump, also depends on the conductance of the upper piping. In order to prevent a decrease in the exhaust speed, it is desirable to secure an opening area equal to or greater than the diameter of the upper pipe as the opening area of the exhaust inlet formed at the upper end portion of the inner pipe placed inside the inlet joint. That is, it is desirable that the opening area of the exhaust inlet of the inner pipe of the inlet joint is equal to or larger than the effective opening area of the external pipe to be connected.

The exhaust inlet formed in the inner tube may be arranged at a position higher than the upper end opening of the outer tube. In this case, for example, the inner tube is longer than the outer tube, and the upper end portion of the inner tube protrudes upward from the upper end opening of the outer tube to form the exhaust inlet at a position higher than the upper end of the outer tube.

It is also possible to removably attach the inner tube to the lower flange. For example, inner tubes with different lengths and exhaust inlets with different open areas may be prepared so that they can be replaced with inner tubes with the required length and open area. .

During operation of the dry vacuum pump, if the product continues to accumulate in the product recovery recess of the inlet joint without evaporating, the sealing material, etc., placed between the upper flange of the outer pipe and the pipe to be connected may become damaged. Corrosion is a concern. An overflow hole may be formed in the outer peripheral wall portion of the inner pipe so as to avoid corrosion of the sealing material due to contact of the product with the sealing material. This hole communicates between the product recovery recess and the interior of the inner tube at a position below the upper end opening of the upper flange of the outer tube. Through this hole, the product accumulated in the product recovery recess can be guided into the inner pipe and dropped toward the intake port.

1 is an explanatory diagram showing an exhaust system provided with an intake joint according to Embodiment 1 of the present invention; FIG. 1B is a longitudinal cross-sectional view of the inlet joint of FIG. 1A; FIG. FIG. 10 is an explanatory diagram showing an exhaust system provided with an intake joint according to Embodiment 2 of the present invention; Figure 2B is a longitudinal cross-sectional view of the inlet joint of Figure 2A; FIG. 4 is a vertical cross-sectional view showing another example of an air inlet joint to which the present invention is applied; FIG. 5 is a longitudinal sectional view showing still another example of an air intake joint to which the present invention is applied;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a dry vacuum pump having an inlet joint to which the present invention is applied will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1A is an explanatory diagram showing a dry vacuum pump provided with an inlet joint according to Embodiment 1. FIG. The dry vacuum pump 1 is in the form of an exhaust device unit, and includes two dry vacuum pumps connected in series inside a rectangular parallelepiped device housing 2 . For example, the dry vacuum pump 1 includes a front-stage mechanical booster pump 3 and a rear-stage dry vacuum pump 4 . As the dry vacuum pump, various dry vacuum pumps such as a screw type vacuum pump, a roots type, a claw type, a scroll type, etc. can be used.

An intake port 6 of the dry vacuum pump 1 opens upward at a horizontal top surface 2 a of the apparatus housing 2 . A portion surrounding the intake port 6 on the upper surface 2a of the housing is a flange mounting portion 2b. An intake joint 10 for external piping connection is vertically attached here. The inlet joint 10 is connected by a coupling 40 to an upstream external pipe 7 indicated by a phantom line in FIG. 1A. The inlet joint 10 has a product recovery function for recovering products such as powdery products and liquefied products that enter from the side of the external pipe 7 .

FIG. 1B is a vertical cross-sectional view showing the inlet joint 10. FIG. The inlet joint 10 includes a vertically extending cylindrical outer tube 21, a lower flange 22 coaxially fixed to the lower end 21a of the outer tube 21, and coaxially integrated with the upper end 21b of the outer tube 21. and a formed upper flange 23 .

The lower flange 22 has a disc shape with a diameter larger than that of the outer tube 21, and a circular opening 22a with a diameter smaller than that of the outer tube 21 is formed in the central portion thereof. The lower flange 22 is fastened and fixed to the flange attachment portion 2b of the upper surface 2a of the housing by fastening bolts 24 or the like via a seal material such as a gasket (not shown). The upper flange 23 is an annular portion projecting outward from the outer peripheral surface of the upper end portion 21 b of the outer tube 21 .

The inlet joint 10 also includes a cylindrical inner tube 26 coaxially arranged inside the outer tube 21 . The inner tube 26 is a cylinder having substantially the same diameter as the circular opening 22 a of the lower flange 22 , and the lower end 26 a of the inner tube 26 is coaxially fixed to the inner peripheral surface of the circular opening 22 a of the lower flange 22 . As a result, the lower end opening 26b of the inner pipe 26 communicates with the lower intake port 6 via the circular opening 22a of the lower flange 22 .

The length of the inner tube 26 is longer than that of the outer tube 21 , and the upper end portion 26 c of the inner tube 26 protrudes upward from the upper end opening 21 c of the outer tube 21 . A top opening of the inner tube 26 is closed by a horizontal circular end plate 27 . An exhaust inlet 26d is formed in the outer peripheral wall portion of the upper end portion 26c of the inner pipe 26. As shown in FIG. The exhaust inlet 26 d penetrates the outer peripheral wall portion in the radial direction and is located higher than the upper end opening 21 c of the outer tube 21 . For example, the exhaust inlets 26d are openings of the same shape formed at equal angular intervals along the circumferential direction.

A gap having an annular cross section formed between the outer tube 21 and the inner tube 26 is closed at the lower end by the lower flange 22 . The inner peripheral surface of the outer tube 21, the outer peripheral surface of the inner tube 26, and the upper end surface 22b of the lower flange 22 define an annular product recovery recess 28. As shown in FIG. The upper end of the product recovery recess 28 is open upward.

Here, an overflow hole 26e is formed in the outer peripheral wall portion of the inner pipe 26 below the exhaust inlet 26d. The hole 26 e is located below the upper end surface of the upper flange 23 of the outer tube 21 . When the product accumulates in the product recovery recess 28 until it reaches the upper flange 23 of the outer pipe 21, the product overflows from the hole 26e into the inner pipe 26 and drops to the inlet port 6 side.

A lower flange 7a of the external pipe 7 is coaxially connected and fixed to the upper flange 23 of the outer tube 21 of the intake joint 10 having this structure by sandwiching a sealing material (not shown) such as a gasket. When the external pipe 7 is connected, the upper end portion of the inner pipe 26 projects into the external pipe 7 . The opening area of the exhaust introduction port 26d formed in the upper end portion 26c of the inner pipe 26 is the same as or larger than the effective opening area of the external pipe 7. As shown in FIG.

Due to the evacuation of the dry vacuum pump 1, the exhaust from the side of the external pipe 7 flows into the product recovery recess 28 between the outer tube 21 and the inner tube 26 of the inlet joint 10, as indicated by the arrow in FIG. 1B. . The upper end of inner tube 26 is closed so that the exhaust flows toward the bottom of product recovery recess 28 . After that, the exhaust gas flows into the inner pipe 26 from the exhaust inlet 26d opened in the outer peripheral wall surface of the inner pipe 26, passes through the inner pipe 26, and is sucked into the dry vacuum pump 1 from the intake port 6. be.

Products such as powdery products and liquefied products carried by the exhaust, or products falling from the external pipe 7 to the inlet joint 10 do not directly enter the pump and are recovered. It collects at the bottom of the recess 28 . Also, during maintenance of the semiconductor manufacturing equipment, etc., a large amount of powder may be discharged from the external pipe 7 in the form of lumps. Also in this case, a large amount of powder lumps temporarily accumulate in the product recovery recess 28 . A part of the product such as powder accumulated in the product recovery recess 28 is sucked by the dry vacuum pump 1 along with the exhaust flow. If it is a small amount of product, even if it is sucked into the dry vacuum pump 1, no problem will occur in practice.

Also, the liquefied product may drop toward the intake port 6 from the external pipe 7 side. Like the powdery product, the liquefied product also temporarily accumulates at the bottom of the product recovery recess 28 and does not enter the dry vacuum pump 1 through the intake port 6 . The liquefied product accumulated in the product recovery recess 28 may be vacuum dried during operation of the dry vacuum pump 1 . Therefore, it is less likely that the accumulated liquefied product will cause problems such as corrosion of the inside of the inlet joint 10 .

Also, when a large amount of product enters at once, the product recovery recess is filled with the product, and a sealing material (not shown) disposed at the joint between the outer pipe 21 and the external pipe 7 is filled with the product. is concerned about corrosion. In this example, an overflow hole 26e is provided in the upper end portion of the inner pipe 26 at a position lower than the position where the sealing material is arranged (position lower than the upper end surface of the upper flange 23). When the product that continues to accumulate in the product recovery recess 28 reaches the position of the hole 26e, it overflows into the inner tube 26 through the hole 26e and drops toward the intake port 6 side. Therefore, it is possible to prevent the product from contacting the sealing material and corroding the sealing material.

Instead of providing the overflow hole 26e, the exhaust inlet 26d may have an overflow function. For example, the position of one of the exhaust inlets 26d may be changed to allow product to overflow from the product recovery recess 28 into the interior of the inner tube 26 via the exhaust inlet 26d. Also, a portion of the exhaust inlet 26d may be extended downward to form an overflow hole.

As described above, in the dry vacuum pump 1 of this embodiment, the inlet joint 10 for connecting the external pipe 7 to the inlet 6 has the product recovery function. Unlike the case where a product recovery device is attached separately, the intake joint 10 having the product recovery function can be attached and detached by ordinary piping connection work and piping removal work. Therefore, it is possible to easily and efficiently collect the product accumulated inside, and the maintenance is excellent. In addition, it is sufficient that an installation space similar to that of the existing intake joint can be secured between the intake port 6 and the external pipe 7 . Therefore, unlike the prior art, there is no need to secure a large installation space for installing a large-sized product recovery device, and there is no need to change the layout of external piping or the like.

(Embodiment 2)
FIG. 2A is an explanatory diagram showing a dry vacuum pump provided with an inlet joint according to Embodiment 2. FIG. Since the dry vacuum pump 100 has the same structure as the dry vacuum pump 1 of Embodiment 1, the description thereof is omitted, and the same reference numerals are given to the corresponding portions in FIG. 2A. It goes without saying that the dry vacuum pump 100 may have a configuration different from that of the dry vacuum pump 1 . The intake port 6 of the dry vacuum pump 100 opens upward on the horizontal housing upper surface 2 a of the apparatus housing 2 . A portion surrounding the intake port 6 on the upper surface 2a of the housing is a flange mounting portion 2b. An intake joint 110 for external piping connection is vertically attached here.

Via the inlet joint 110, the inlet 6 is connected to the upstream external pipe 107 indicated by the phantom line in FIG. 2A. The intake joint 110 of this example includes a pipe joint 120 attached to the intake port 6 and a reducer 130 connecting between the pipe joint 120 and the external pipe 107 having a different pipe diameter. Pipe joint 120 and reducer 130 are coaxially connected by coupling 140 . The pipe joint 120 of the inlet joint 110 has a product recovery function for recovering products such as powdery products and liquefied products that enter from the external pipe 107 side.

FIG. 2B is a perspective cross-sectional view showing the inlet joint 110, with the coupling 140 omitted. As can be seen from this figure, the pipe joint 120 of the intake joint 110 has the same configuration as the intake joint 10 of the first embodiment. Accordingly, the description of the pipe joint 120 is omitted, and in FIG. 2B, the same reference numerals are given to the parts corresponding to the parts of the inlet joint 10. As shown in FIG.

In the inlet joint 110, the reducer 130 coaxially connected and fixed to the pipe joint 120 has a general shape, and consists of a small-diameter pipe portion 131 opening at the upper end and a large-diameter pipe portion 132 opening at the lower end. , a frusto-conical tube section 133 connecting between the small diameter tube section 131 and the large diameter tube section 132 . An annular upper opening flange 134 is formed to surround the upper edge of the small diameter pipe portion 131, and an annular lower opening flange 135 is formed to surround the lower edge of the large diameter pipe portion 132. . An external pipe 107 having a different pipe diameter is connected to the pipe joint 120 via the reducer 130 .

A lower end opening flange 135 on the large diameter side of the reducer 130 is coaxially connected to the upper flange 23 of the pipe joint 120 with a gasket 125 interposed therebetween. An external pipe 107 is coaxially connected to an upper end opening flange 134 on the small diameter side of the reducer 130 .

The upper end portion 26 c of the inner pipe 26 of the pipe joint 120 protrudes upward from the upper end opening of the outer pipe 21 and is positioned inside the large diameter pipe portion 132 of the reducer 130 . The opening area of the exhaust inlet 26d formed in the upper end portion 26c of the inner pipe 26 is equal to or greater than the effective opening area of the small-diameter pipe portion 131 of the reducer 130, and therefore the effective opening area of the external pipe 107. .

Thus, in the dry vacuum pump 100 as well, the inlet joint 110 for connecting the external pipe 107 to the inlet 6 has the product recovery function. Unlike the case where a product recovery device is attached separately, the intake joint 110 having the product recovery function can be attached and detached by ordinary piping connection work and piping removal work. Therefore, it is possible to easily and efficiently collect the product accumulated inside, and the maintenance is excellent. In addition, it is sufficient that an installation space similar to that of the existing intake joint can be secured between the intake port 6 and the external pipe 107 . Therefore, unlike the prior art, there is no need to secure a large installation space for installing a large-sized product recovery device, and there is no need to change the layout of external piping or the like.

(another example of a reducer)
Other shapes of reducer can be used for the reducer 130 in the inlet joint 110 described above. For example, a reducer 230 having the shape shown in FIG. 3A and a reducer 330 having the shape shown in FIG. 3B can be used.

The reducer 230 of the inlet joint 210 shown in FIG. 3A has a shape in which a small diameter pipe portion 232 is coaxially attached to the upper end of a large diameter pipe portion 231 . A lower end opening flange 233 connected to the upper flange 23 of the pipe joint 120 is formed at the lower end opening of the large-diameter pipe portion 231 . An upper end opening flange 234 connected to the external pipe 107 is formed at the upper end opening of the small diameter pipe portion 232 .

The reducer 330 of the inlet joint 310 shown in FIG. and a top opening flange 333 formed at the top opening of tube section 332 . An external pipe 107 is connected to the upper end opening flange 333 .

In the inlet joint 310 having the reducer 330 of this shape, the pipe joint 120 is provided with an outer tube 21 longer than the inner tube 26, and the entire inner tube 26 is located inside the outer tube 21. is stored.

Even when such intake joints 210 and 310 are used, the same effects as when the above intake joint 110 is used can be obtained.

Claims (10)

A dry vacuum pump inlet joint used to connect an external pipe to an upwardly opening inlet of a dry vacuum pump, comprising:
an outer tube extending in the vertical direction;
a lower flange formed at the lower end of the outer tube and fastened and fixed to the dry vacuum pump;
an upper flange formed on the upper end of the outer tube;
an inner tube that is coaxially arranged inside the outer tube, has a lower end opening that can communicate with the intake port through the central opening of the lower flange, and has an upper end opening that is closed;
an exhaust inlet radially penetrating the outer peripheral wall portion of the inner pipe;
an annular product recovery recess formed between the outer tube and the inner tube, the upper end of which opens upward, and the lower end of which is closed by the lower flange;
The inlet joint of a dry vacuum pump with A dry vacuum pump inlet joint according to claim 1, wherein
An inlet joint for a dry vacuum pump, wherein the opening area of the exhaust introduction port is the same as or larger than the effective opening area of the external pipe to be connected. A dry vacuum pump inlet joint according to claim 1, wherein
an overflow hole penetrating the outer peripheral wall portion of the inner tube;
The inlet joint of a dry vacuum pump, wherein the hole communicates between the product recovery recess and the inside of the inner pipe at a position below the upper end opening of the upper flange of the outer pipe. A dry vacuum pump inlet joint according to claim 1, wherein
The upper end portion of the inner tube protrudes upward from the upper end opening of the outer tube,
The air inlet joint of a dry vacuum pump, wherein the exhaust inlet is formed at a position higher than the upper end opening of the outer tube. A dry vacuum pump inlet joint according to claim 1, wherein
An inlet joint of a dry vacuum pump, wherein the inner pipe is removably attached to the lower flange. A dry vacuum pump inlet joint according to claim 1, wherein
The outer pipe is provided with a reducer used for connecting an external pipe having a smaller diameter than the outer pipe,
The reducer is
a small-diameter pipe portion opening at the upper end;
a large-diameter pipe portion opening at the lower end;
a lower end opening flange of the large-diameter tube portion coaxially connected and fixed to the upper flange of the outer tube;
and an upper end opening flange of the small diameter pipe portion connected to the external pipe. In a dry vacuum pump inlet joint according to claim 6,
the upper end portion of the inner tube protrudes upward from the upper end opening of the outer tube and is positioned inside the large diameter tube portion of the reducer;
The exhaust inlet is formed at a position higher than the upper end opening of the outer tube,
An inlet joint of a dry vacuum pump, wherein the opening area of the exhaust inlet of the inner tube is equal to or larger than the effective opening area of the small diameter tube portion of the reducer. In a dry vacuum pump with an inlet joint connecting an external pipe to an upwardly opening inlet,
The inlet joint is
an outer tube extending in the vertical direction;
a lower flange formed at the lower end of the outer pipe and fastened and fixed to a flange mounting portion of the pump housing in which the intake port is formed;
an upper flange formed on the upper end of the outer tube;
an inner tube coaxially arranged inside the outer tube, having a lower end opening communicating with the intake port through the central opening of the lower flange and having an upper end opening closed;
an exhaust inlet radially penetrating the outer peripheral wall portion of the inner pipe;
an annular product recovery recess formed between the outer tube and the inner tube, the upper end of which opens upward, and the lower end of which is closed by the lower flange;
Dry vacuum pump with A dry vacuum pump according to claim 8,
The inlet joint includes a reducer used for connecting an external pipe having a smaller diameter than the outer pipe to the outer pipe,
The reducer is
a small-diameter pipe portion opening at the upper end;
a large-diameter pipe portion opening at the lower end;
a lower end opening flange of the large-diameter tube portion coaxially connected and fixed to the upper flange of the outer tube;
and a top opening flange of the small diameter tube portion connected to the external piping. A dry vacuum pump according to claim 9,
the upper end portion of the inner tube protrudes upward from the upper end opening of the outer tube and is positioned inside the large diameter tube portion of the reducer;
The exhaust inlet is formed at a position higher than the upper end opening of the outer tube,
The dry vacuum pump, wherein the opening area of the exhaust inlet of the inner tube is equal to or larger than the effective opening area of the small diameter tube portion of the reducer.

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