JP7623085B2 - Flange structure and vacuum pumping system using same - Google Patents

Description

This disclosure relates to a flange structure and a vacuum exhaust system using the same.

A method of assembling a vacuum processing device that prevents damage to the vacuum vessel has been known (see, for example, Patent Document 1). In this method of assembling a vacuum processing device, a bottom flange and a flange member are attached to the reaction tube and the exhaust port, respectively, and the bottom flange and the flange member are fixed to each other by a shaft. Next, the reaction tube is raised to an upper position and the bottom flange is fixed to the housing, and then the flange member and the exhaust pipe are connected to each other.

JP 2012-104755 A

This disclosure provides a flange structure that can tolerate misalignment between flanges when connecting pipes using flanges, and a vacuum exhaust system using the same.

In order to achieve the above object, a flange structure according to one aspect of the present disclosure is a flange structure for connecting a first pipe and a second pipe, comprising:
a first fixing flange provided at a tip of the first pipe;
a second fixing flange provided at a tip of the second pipe;
a seal member provided on one of the first fixed flange and the second fixed flange;
a movable flange having a frame shape surrounding an outer periphery of the second pipe and disposed on a rear side of the second fixed flange and movable in a direction intersecting an extension direction of the second pipe;
a fixing member that fixes the movable flange to the first fixed flange ,
the second fixed flange and the movable flange have groove structures on opposing surfaces that face the extension direction and can face each other,
the opposing surface of the second fixing flange includes a first groove that circumferentially surrounds the second pipe, and a first protrusion that protrudes from a bottom surface of the first groove on an outer side of the first groove,
the opposing surface of the movable flange includes a second groove circumferentially extending on an inner side thereof, and a second protrusion protruding from a bottom surface of the second groove on an outer side thereof,
The groove structure movably engages the movable flange in a direction intersecting the extension direction by the first convex portion entering the second groove with a gap, and the second convex portion entering the first groove with a gap .

According to the present disclosure, piping connections can be made while allowing for misalignment between flanges.

FIG. 2 is a cross-sectional view showing a configuration example of a vertical heat treatment apparatus. FIG. 2 is a cross-sectional view showing a configuration example of a vertical heat treatment apparatus. FIG. 1 illustrates a portion of a vacuum pumping system according to an embodiment of the present disclosure. FIG. 13 is a diagram showing an example of connecting rectangular pipes together. A figure showing an example of connecting a centering pipe having a flange structure according to an embodiment of the present disclosure to a normal pipe 863 consisting of a rectangular pipe. FIG. 2 is a side view of a flange structure according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing in detail a seal structure according to an embodiment of the present disclosure. 1 is a diagram illustrating an example of a fastened state of a flange structure according to an embodiment of the present disclosure. FIG. 13 is a diagram showing a state in which a normal flange and a fastening flange are fixedly connected in a normal position. FIG. FIG. 13 is a diagram showing an example of a fixed connection in a downward and leftward eccentric state. FIG. 13 is a diagram showing an example of a fixed connection in an eccentric state upward and to the right. FIG. 13 is a diagram showing connection and fixation in a state where the shaft is rotated 1.2 degrees in one direction. 1A to 1C are diagrams illustrating an example of a manufacturing method for a flange structure according to an embodiment of the present disclosure. FIG. 1 is a diagram showing a vacuum exhaust system. 13 is a diagram showing an alignment pipe 862 having a flange structure according to this embodiment at the tip of an exhaust passage. FIG. 11A and 11B are diagrams for explaining a method of aligning a core-adjusting pipe and a normal pipe. 13A to 13C are diagrams for explaining a method of fastening a centering piping to a normal piping. FIG. 13 is a diagram showing the final state of fixing the centering piping and the normal piping.

Below, we will explain the form for implementing the present invention with reference to the drawings.

[Vertical heat treatment device]
First, a configuration example of a vertical heat treatment apparatus having a reaction tube unit that can be transported by a transport method according to an embodiment will be described. A vertical heat treatment apparatus having a double-tube structure will be described below, but a vertical heat treatment apparatus having a single-tube structure may also be used. Figures 1 and 2 are cross-sectional views showing a configuration example of the vertical heat treatment apparatus, where Figure 1 shows a vertical cross section and Figure 2 shows a horizontal cross section.

As shown in FIG. 1, the vertical heat treatment apparatus 1 includes a reaction tube 34 that contains semiconductor wafers (hereinafter referred to as "wafers W") as substrates, a lid 36 that airtightly closes the opening at the bottom of the reaction tube 34, a wafer boat 38 that can be contained within the reaction tube 34 and is a substrate holder that holds multiple wafers W at a predetermined interval, a gas supply means 40 that introduces gas into the reaction tube 34, an exhaust means 41 that exhausts gas from within the reaction tube 34, and a heating means 42 that heats the wafers W.

The reaction tube 34 has a cylindrical inner tube 44 with a ceiling that is open at the bottom end, and a cylindrical outer tube 46 with a ceiling that is open at the bottom end and covers the outside of the inner tube 44. The inner tube 44 and the outer tube 46 are made of a heat-resistant material such as quartz, and are arranged coaxially to form a double tube structure.

The ceiling portion 44A of the inner tube 44 is, for example, flat. A nozzle accommodating portion 48 that accommodates a gas supply pipe is formed on one side of the inner tube 44 along its longitudinal direction (vertical direction). For example, as shown in FIG. 2, a part of the side wall of the inner tube 44 protrudes outward to form a convex portion 50, and the inside of the convex portion 50 is formed as the nozzle accommodating portion 48. A rectangular opening 52 of width L1 is formed along its longitudinal direction (vertical direction) on the opposite side wall of the inner tube 44 facing the nozzle accommodating portion 48.

The opening 52 is a gas exhaust port formed so that gas in the inner tube 44 can be exhausted. The length of the opening 52 is the same as the length of the wafer boat 38, or is formed so as to extend vertically longer than the length of the wafer boat 38. That is, the upper end of the opening 52 is positioned at a height that is equal to or higher than the position corresponding to the upper end of the wafer boat 38, and the lower end of the opening 52 is positioned at a height that is lower than the position corresponding to the lower end of the wafer boat 38. Specifically, as shown in FIG. 1, the height-wise distance L2 between the upper end of the wafer boat 38 and the upper end of the opening 52 is within a range of about 0 mm to 5 mm. Also, the height-wise distance L3 between the lower end of the wafer boat 38 and the lower end of the opening 52 is within a range of about 0 mm to 350 mm.

The lower end of the reaction tube 34 is supported by a cylindrical manifold 54 made of, for example, stainless steel. A flange portion 56 is formed at the upper end of the manifold 54, and the lower end of the outer tube 46 is placed on the flange portion 56 to support it. A seal member 58 such as an O-ring is interposed between the flange portion 56 and the lower end of the outer tube 46 to make the inside of the outer tube 46 airtight.

A circular support 60 is provided on the inner wall of the upper part of the manifold 54, and the lower end of the inner tube 44 is placed on the support 60 to support it. A lid 36 is airtightly attached to the opening at the lower end of the manifold 54 via a sealing member 62 such as an O-ring, so as to airtightly close the opening at the lower end of the reaction tube 34, i.e., the opening of the manifold 54. The lid 36 is made of, for example, stainless steel.

A rotating shaft 66 is provided in the center of the lid 36, passing through the magnetic fluid seal 64. The lower part of the rotating shaft 66 is rotatably supported by an arm 68A of a lifting means 68 consisting of a boat elevator.

A rotating plate 70 is provided at the upper end of the rotating shaft 66, and the wafer boat 38 that holds the wafers W is placed on the rotating plate 70 via a quartz heat retention stand 72. Therefore, by raising and lowering the lifting means 68, the lid 36 and the wafer boat 38 move up and down as a unit, allowing the wafer boat 38 to be inserted into and removed from the reaction tube 34.

The gas supply means 40 is provided in the manifold 54 and introduces gases such as film-forming gas, etching gas, and purge gas into the inner tube 44. The gas supply means 40 has a plurality of (e.g., three) quartz gas supply pipes 76, 78, and 80. Each gas supply pipe 76, 78, and 80 is provided in the inner tube 44 along its longitudinal direction, and its base end is bent into an L-shape and supported so as to pass through the manifold 54.

2, the gas supply pipes 76, 78, 80 are installed in a row along the circumferential direction in the nozzle housing portion 48 of the inner pipe 44. A plurality of gas holes 76A, 78A, 80A are formed in each gas supply pipe 76, 78, 80 at a predetermined interval along the longitudinal direction, and each gas can be discharged from each gas hole 76A, 78A, 80A in the horizontal direction. The predetermined interval is set to be the same as the interval between the wafers W supported by the wafer boat 38, for example. In addition, the height direction positions of each gas hole 76A, 78A, 80A are set so that each gas hole 76A, 78A, 80A is located at the middle between the wafers W adjacent to each other in the vertical direction, so that each gas can be efficiently supplied to the space between the wafers W. The types of gas used are film formation gas, etching gas, and purge gas, and each gas can be supplied through each gas supply pipe 76, 78, 80 as necessary while controlling the flow rate of each gas.

A gas outlet 82 is formed on the upper side wall of the manifold 54, above the support portion 60, so that the gas in the inner tube 44 can be exhausted from the opening 52 through the space 84 between the inner tube 44 and the outer tube 46. An exhaust means 41 is provided in the gas outlet 82. The exhaust means 41 has an exhaust passage 86 connected to the gas outlet 82, and a pressure adjustment valve 88 and a vacuum pump 90 are sequentially provided in the exhaust passage 86, so that the reaction tube 34 can be evacuated.

A cylindrical heating means 42 is provided on the outer periphery of the outer tube 46 so as to cover the outer tube 46. The heating means 42 heats the wafer W contained in the reaction tube 34.

The overall operation of the vertical heat treatment device 1 is controlled by a control means 95 such as a computer. In addition, the computer program that controls the overall operation of the vertical heat treatment device 1 is stored in a storage medium 96. The storage medium 96 may be, for example, a flexible disk, a compact disk, a hard disk, a flash memory, a DVD, etc.

[Vacuum exhaust system]
FIG. 3 is a diagram showing a part of a vacuum exhaust system according to an embodiment of the present disclosure. As shown in FIG. 3, the reaction tube 34 is placed on a tube cart 120. The tube cart 120 is a transport jig for transporting the reaction tube 34. A gas outlet 82 is provided at the bottom of the reaction tube 34. The tube cart 120 is moved to the right side of FIG. 3, and the boat elevator is raised with the reaction tube 34 positioned on the lid 36, thereby lifting the reaction tube 34 to a position where the gas outlet 82 and the exhaust passage 86 can be connected. Then, the gas outlet 82 and the exhaust passage 86 are aligned and connected, and the reaction tube 34 is installed above in this state.

As shown in FIG. 3, the exhaust passage 86 extends upward, then horizontally and further extends, and is connected to the reaction tube 34. The lower end of the exhaust passage 86 extending upward is connected to a vacuum pump 90 (not shown) via a pipe (see FIG. 1 for the vacuum pump 90). The exhaust passage 86 has a rectangular cross-sectional shape. The exhaust passage 86 has a bellows 861 in the middle. A pipe that is connected to the vacuum pump 90 is connected to the tip of the exhaust passage 86.

When a circular exhaust passage 86 is used, the bellows 861 can tolerate an error in the connection between the pipes. That is, because the bellows 861 is elastic, even if the connection between the pipes used in the exhaust passage 86 is slightly misaligned, the bellows 861 can absorb that error. However, in the case of a rectangular cross-sectional shape, the bellows 861 hardly moves up, down, left, or right. Because the bellows 861 has a bellows structure, it expands and contracts in the direction along the exhaust passage 86, but has no elasticity in the direction perpendicular to the exhaust passage 861, and is structured so that it hardly moves at all.

Figure 4 shows an example of connecting rectangular pipe 86b to rectangular pipe 86a. Figure 4(a) is a side view, and Figure 4(b) is a front view.

As shown in FIG. 4(a), when rectangular pipe 86b is connected to rectangular pipe 86a, they are fastened together using bolts. As shown in FIG. 4(b), in this case, the bolt holes 86c of rectangular pipe 86a and rectangular pipe 86b must be aligned with a high degree of accuracy. In other words, only an error that allows fastening with bolts is permitted, so the bolt holes 86c of rectangular pipe 86a and rectangular pipe 86b must be aligned with a high degree of accuracy.

However, in the case of rectangular pipes 86a and 86b, which have rectangular cross-sectional shapes, it is difficult to deform them using bellows 861, so the position cannot be adjusted while attaching rectangular pipe 86b to rectangular pipe 86a, and assembly must be performed with considerable precision.

Therefore, in this embodiment, a flange structure is proposed that allows movement in a direction intersecting with the rectangular pipe 86a, for example, in the vertical direction, making it easier to connect the pipes together.

Figure 5 shows an example of connecting a centering pipe 862 having a flange structure according to an embodiment of the present disclosure to a normal pipe 863 consisting of a rectangular pipe.

As shown in FIG. 5, the flange structure according to this embodiment has a normal flange 100 on the normal pipe 863 side, a seal flange 101 on the centering pipe 862 side, and a fastening flange 102.

The normal flange 100 is provided at the tip of the normal pipe 863. On the other hand, the seal flange 101 is provided at the tip of the centering pipe 862. The fastening flange 102 is provided at the back side of the centering pipe 862.

Figure 6 is a side view of a flange structure according to an embodiment of the present disclosure. Figure 6(b) shows the opposing state of the normal flange 100, the seal flange 101, and the fastening flange 102.

As shown in FIG. 6(b), the normal flange 100 and the seal flange 101 face each other, and the fastening flange 102 is located closer to the base than the seal flange 101. As shown in FIG. 6(b), the seal flange 101 has a smaller outer shape than the normal flange 100, and the fastening flange 102 has an outer shape that is the same size as the normal flange 100.

Figure 6 (a) is a front view of the seal flange 101 and the fastening flange 102. As described above, the seal flange 101 has a smaller outer shape than the fastening flange 102, and from the front, the seal flange 101 is contained within the fastening flange 102. Note that the seal flange 101 and the fastening flange 102 are arranged around the periphery of the rectangular pipe, i.e., the outer periphery of the centering pipe 862, so that the center is a rectangular opening and has a frame-like shape.

Figure 6 (c) is a front view of the normal flange 100. The normal flange 100 is also provided at the end of the periphery of a rectangular pipe, and therefore has a frame-like shape surrounding a rectangular opening. The normal flange 100 has a seal groove 100a. A seal member such as an O-ring is provided in the seal groove 100a, and is fixed so as to be in close contact with the seal flange 101, thereby connecting the pipes together in an airtight manner.

The seal groove 100a is located opposite the seal flange 101 and close to the opening.

Figure 7 is a cross-sectional view showing in detail the seal structure according to an embodiment of the present disclosure. As shown in Figure 7, the seal flange 101 has a groove 101a, and the fastening flange 102 also has a groove 102a. The groove 101a of the seal flange 101 and the groove 102a of the fastening flange 102 engage with each other, and the flange 102b of the fastening flange 102 is structured to be slidable within the groove 101a. The distance that the flange 102b can move within the groove 101a is the movable distance in each direction. Such movable distance can be set to any distance depending on the application, but may be set to a movement distance of up, down, left, and right within 10 mm, preferably within 8 mm, for example.

The surface of the fastening flange 102 facing the normal flange 100 and the surface of the seal flange 101 facing the normal flange 100 are configured to be flush with each other. This prevents rattling due to a step when fastening the normal flange 100 and the fastening flange 102 together.

In addition, a seal groove 100a is provided on the surface of the normal flange 100 facing the seal flange 102, and the structure is such that airtightness with the seal flange 102 is maintained. A seal member such as an O-ring is placed in the seal groove 100a.

In addition, in FIG. 7, an example is shown in which the seal groove 100a is provided on the normal flange 100, but it is also possible to provide the seal groove on the seal flange 101. In this case, the surface of the normal flange 100 facing the seal flange 101 is a flat surface. In this case, it is preferable to make the seal flange 101 and the fastening flange 102 thicker to ensure sufficient thickness.

The flange structure according to this embodiment may be configured to accommodate not only the sliding movement of the fastening flange 102, but also the angular misalignment. As shown in FIG. 7, the fastening flange 102 is not a completely fitted engagement rail, but is configured so that the flange portion 102b can move freely, so it can also accommodate inclination. That is, even if the seal flange 101 is not parallel to the normal flange 100 and is slightly inclined, the fastening flange 102 can be adapted to be fixedly connected to the normal flange 100. The inclination angle may be, for example, up to 2 degrees, up to 1.5 degrees, or up to 1.2 degrees. The adjustable angle range can be freely set according to the application.

Figure 8 is a diagram showing an example of the fastening state of the flange structure according to an embodiment of the present disclosure. As shown in Figure 8, the normal flange 100 and the fastening flange 102 are fastened with bolts. As described in Figure 7, the fastening flange 102 has a flange portion 102b that can move within the groove 101a, so its position can be adjusted so that its bolt holes match the bolt holes of the normal flange 100. This allows the rectangular pipes to be properly aligned and easily connected without the bellows 861 being deformed.

In addition, in this embodiment, bolt fastening is used to securely connect the fastening flange 102 and the normal flange 100, but other fastening means such as clamps may also be used. Various fastening connection means can be used to securely connect the fastening flange 102 and the normal flange 100 depending on the application.

Figure 9 shows the normal flange 100 and the fastening flange 102 fixedly connected in the normal position. When fixedly connected in the normal position, the axis coincides with the center.

Figure 10 shows an example of a fixed connection in an eccentric state downward and to the left. In the following example, the movable range is 4 mm in each direction. In Figure 10, the seal groove 100a has moved 4 mm downward and to the left within the seal flange 101. Even in this case, the seal groove 100a and the seal flange 101 face each other, and the fastening flange 102 can be moved to fasten the flanges while maintaining airtightness.

Figure 11 shows an example of a fixed connection in an eccentric state upward and to the right. In Figure 11, the seal groove 100a has moved 4 mm upward and to the right within the seal flange 101. Even in this case, the seal groove 100a and the seal flange 101 face each other, and the fastening flange 102 can be moved to fasten the flanges while maintaining airtightness.

Figure 12 shows the connection and fixation when rotated 1.2 degrees in one direction. In Figure 12, the seal groove 100a moves upward due to the upward forward rotation of the seal flange 102, but since the seal groove 100a and the seal flange 101 face each other, the sealed state can be maintained.

In this way, the seal structure of this embodiment allows for slight misalignment between the seal flange 102 and the seal groove 100a, making it possible to connect rectangular pipes while maintaining a sealed state.

[Method of manufacturing flange structure]
FIG. 13 is a diagram illustrating an example of a method for manufacturing a flange structure according to an embodiment of the present disclosure.

Figures 13(a) and (b) show an example of a normal flange installation process. In the normal flange installation process, the normal flange 100 is welded to the centering pipe 862.

Figure 13(b) is a rear view of Figure 13(a). It has the same configuration as the normal flange 100 described so far.

Figures 13(c) and (d) show an example of the fastening flange installation process. As shown in Figure 13(c), in the fastening flange installation process, the fastening flange 102 is installed around the centering pipe 862.

As shown in FIG. 13(d), it is preferable to provide a regulating member 103 at a position on the surface of the centering pipe 862, which is located further back than the fastening flange 102 on the tip side. The regulating member 103 may be configured, for example, as a protrusion that protrudes from the surface of the centering pipe 862. This makes it possible to regulate the movement of the fastening flange 102 toward the rear side, and to keep the fastening flange 102 close to the seal flange 101.

The restricting member 103 may be provided around the entire circumference of the alignment pipe 862, or may be provided only on a part of the alignment pipe 862, such as only on the top and bottom surfaces, or only on the center of the top, bottom, and both sides. The restricting member 103 may have various configurations as long as it can restrict the movement of the fastening flange 102 toward the back of the alignment pipe 862.

Figure 13 (c) shows an example of the seal flange installation process. In the seal flange installation process, the seal flange 101 is welded to the tip of the centering pipe 862.

Figures 13(e) and (f) show an example of the seal flange installation process. As shown in Figure 13(e), in the seal flange installation process, the seal flange 101 is welded to the tip of the centering pipe 862. This results in the fastening flange 102 being trapped between the seal flange 101 and the regulating member 103. The seal flange 101 is configured to have a size that allows it to face the seal groove 100a of the normal flange 100 and to maintain its facing relationship with the seal groove 100a even if it moves slightly up and down and left and right.

Figure 13(f) is a front view of Figure 13(e), in which the fastening flange 102 surrounds the sealing flange 101.

In addition, the fastening flange 102 is provided with bolt holes 102c for bolt fastening as necessary.

[How to assemble the vacuum exhaust system]
Fig. 14 is a diagram showing a vacuum exhaust system. As shown in Fig. 14, a bellows 861 is provided in the middle of an exhaust passage 86. A bellows 861 is also provided at the tip of the exhaust passage 86.

Figure 15 shows an alignment pipe 862 having a flange structure according to this embodiment at the tip of the exhaust passage 86. In this way, the use of an alignment pipe 862 that can be aligned makes it easier to connect the pipes.

Figure 16 is a diagram for explaining a method for aligning the centering pipe 862 and the normal pipe 863. As shown in Figure 16, when connecting the normal pipe 863 to the centering pipe 862, the seal flange 101 is aligned with the normal flange 100 provided at the tip of the normal pipe 863.

Figure 17 is a diagram for explaining a method for fastening the centering pipe 862 to the normal pipe 863. As shown in Figure 17, after the seal flange 101 is aligned with the normal flange 100, the position of the fastening flange 102 is aligned with the normal flange 100.

Figure 18 shows the final state of fastening. As shown in Figure 18, after the fastening flange 102 is aligned with the normal flange 100, the two are fastened and fixed together with bolts 110. At this point, the seal flange 101 is no longer visible from the outside.

The normal flange 100 and the fastening flange 102 may be fixedly connected using a connecting and fixing means other than the bolt 110.

In this way, the flange structure and vacuum exhaust system according to this embodiment allows for misalignment in the direction intersecting the pipes when connected, even when rectangular pipes are used, making it easy to connect rectangular pipes together.

The above describes in detail preferred embodiments of the present invention, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention.

34 Reaction tube 44 Inner tube 46 Outer tube 76, 78, 80 Gas supply tube 86 Exhaust passage 100 Normal flange 100a Seal groove 101 Seal flange 102 Fastening flange 110 Bolt 861 Bellows 862 Centering tube 863 Normal tube

Claims (13)

A flange structure for connecting a first pipe and a second pipe,
a first fixing flange provided at a tip of the first pipe;
a second fixing flange provided at a tip of the second pipe;
a seal member provided on one of the first fixed flange and the second fixed flange;
a movable flange having a frame shape surrounding an outer periphery of the second pipe and disposed on a rear side of the second fixed flange and movable in a direction intersecting an extension direction of the second pipe;
a fixing member that fixes the movable flange to the first fixed flange ,
the second fixed flange and the movable flange have groove structures on opposing surfaces that face the extension direction and can face each other,
the opposing surface of the second fixing flange includes a first groove that circumferentially surrounds the second pipe, and a first protrusion that protrudes from a bottom surface of the first groove on an outer side of the first groove,
the opposing surface of the movable flange includes a second groove circumferentially extending on an inner side thereof, and a second protrusion protruding from a bottom surface of the second groove on an outer side thereof,
The groove structure is a flange structure in which the first convex portion enters the second groove with a gap, and the second convex portion enters the first groove with a gap, thereby movably engaging the movable flange in a direction intersecting the extension direction . The flange structure according to claim 1, wherein the direction intersecting the extension direction of the second pipe is perpendicular to z of the second pipe. The flange structure according to claim 1, wherein the first pipe, the second pipe, the first fixed flange, the second fixed flange, and the movable flange have a rectangular outer shape in a direction perpendicular to the extension direction of the first pipe and the second pipe. The flange structure of claim 3, wherein the quadrangle is a rectangle. The flange structure according to any one of claims 1 to 4, wherein the seal member is disposed in a groove provided in the tip plane of the first fixed flange. The flange structure according to any one of claims 1 to 5, wherein the amount of movement of the movable flange in a direction perpendicular to the extension direction of the second pipe is the allowable amount of misalignment between the first fixed flange and the movable flange. The flange structure according to any one of claims 1 to 6 , wherein the second fixing flange has an outer shape smaller than that of the first fixing flange. The flange structure according to any one of claims 1 to 7 , wherein the movable flange has an outer size larger than that of the second fixed flange. The flange structure according to any one of claims 1 to 8 , wherein the movable flange has the same outer shape as the first fixed flange. The flange structure according to any one of claims 1 to 9 , wherein the fixing member is a screw. The flange structure according to any one of claims 1 to 10 , wherein an outer surface of the second pipe is provided with a movement restricting member that restricts movement of the movable flange along the extension direction of the second pipe. The flange structure according to claim 11 , wherein the movement restricting member is a protrusion protruding from an outer surface of the second pipe. The first pipe;
The second pipe;
A flange structure according to any one of claims 1 to 12 , which connects the first pipe and the second pipe;
a vacuum exhaust device connected to one of the first pipe and the second pipe.

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