Shell stator for vacuum pump

Abstract

A vacuum pump casing stator (12, 14) includes: a seal groove (50, 52) formed in a surface of the casing stator (12, 14), the seal groove (50, 52) defined by a first side wall (60), a second side wall (62) opposite the first side wall (60), and a bottom surface (64) disposed between the first side wall (60) and the second side wall (62), the bottom surface (64) being opposite an opening of the seal groove (50, 52); wherein the sealing groove (50, 52) comprises: a protrusion (68) formed in the first side wall (60) and extending toward the second side wall (62); and a recess (69) formed in the second side wall (62) opposite the protrusion (68).

Description

Technical Field

[0001] The field of the invention relates to a housing stator for a vacuum pump and to a vacuum pump. Background Art

[0002] Rotating machines such as compressors or vacuum pumps require careful design and manufacture in order for the moving parts to cooperate accurately with each other. Providing effective seals to seal the machine is often problematic, particularly when fluid flow is facilitated by a pressure differential between the machine and the surrounding environment. It would be desirable to provide improved seals. Summary of the invention

[0003] In one aspect, a shell stator for a vacuum pump is provided. The shell stator includes: a sealing groove formed in a surface of the shell stator, the sealing groove being defined by a first side wall, a second side wall opposite to the first side wall, and a bottom surface disposed between the first side wall and the second side wall, the bottom surface being opposite to an opening of the sealing groove; wherein the sealing groove includes a biasing device for biasing a sealing gasket in the sealing groove (e.g., biasing to a specific position in the sealing groove). The biasing device includes: a protrusion formed in the first side wall and extending toward the second side wall; and a recess formed in the second side wall opposite to the protrusion.

[0004] The protrusion may be a continuous curved ridge.

[0005] The depression may be a continuous curved depression.

[0006] The sealing groove may include: a plurality of protrusions formed in the first side wall and extending toward the second side wall; and a plurality of recesses formed in the second side wall, each recess of the plurality of recesses being opposite to a corresponding protrusion of the plurality of protrusions.

[0007] The sealing groove may be formed in a mating surface of the case-stator for receiving another case-stator to thereby define at least one pump chamber.

[0008] The sealing groove may be formed in an end surface of the housing stator, the end surface being adapted to receive an end piece.

[0009] The shell stator may further include: another sealing groove formed in the surface of the shell stator, the other sealing groove being defined by a third side wall, a fourth side wall opposite to the third side wall, and another bottom surface disposed between the third side wall and the fourth side wall, the other bottom surface being opposite to the opening of the other sealing groove. The other sealing groove may include: another protrusion formed in the third side wall and extending toward the fourth side wall; and another recess formed in the fourth side wall opposite to the other protrusion. The first side wall and the third side wall may be the outermost walls. The second side wall and the fourth side wall may be the innermost walls. The shell stator may further include a curved sealing groove formed in the end surface of the shell stator, the curved sealing groove being formed between the sealing groove and the other sealing groove.

[0010] On the other hand, a system is provided, comprising: a shell stator as in any of the foregoing aspects; and a sealing gasket disposed in a sealing groove; wherein the protrusion biases at least a portion of the sealing gasket toward or to a specific position within the sealing groove, such as against a second side wall.

[0011] The thickness of the sealing gasket in the direction from the first side wall to the second side wall may be smaller than the dimension of the sealing groove in the direction.

[0012] The sealing gasket may have a substantially uniform thickness.

[0013] On the other hand, a vacuum pump is provided, comprising: a shell stator defining at least one pump chamber, at least one of the shell stators being a shell stator according to any of the aforementioned aspects; an end piece mounted at either end of the shell stator; and a sealing gasket disposed between the shell stator and the end piece, the sealing gasket being disposed in the sealing groove; wherein the protrusion biases at least a portion of the sealing gasket against the second side wall.

[0014] The at least one of the shell stator may also include another sealing groove formed in the surface of the shell stator, the other sealing groove being defined by the third sidewall, the fourth sidewall opposite to the third sidewall, and another bottom surface disposed between the third sidewall and the fourth sidewall, the other bottom surface being opposite to the opening of the other sealing groove. The other sealing groove may include: another protrusion formed in the third sidewall and extending toward the fourth sidewall; and another recess formed in the fourth sidewall opposite to the other protrusion. The first sidewall and the third sidewall may be the outermost wall relative to the at least one pump chamber. The second sidewall and the fourth sidewall may be the innermost wall relative to the at least one pump chamber. The sealing gasket may also be disposed in the other sealing groove. The protrusion and the other protrusion may bias at least a portion of the sealing gasket against the innermost wall.

[0015] The vacuum pump may further include two closed shape sealing grooves, each of which is formed in a corresponding end of the shell stator. The sealing gasket may include two sealing members each defining a closed shape, each of which is disposed in a corresponding one of the closed shape sealing grooves. Each closed shape sealing groove may be defined by an outer wall, an inner wall opposite to the outer wall, and a bottom surface disposed between the outer wall and the inner wall, the bottom surface being opposite to the opening of the closed shape sealing groove. Each closed shape sealing groove may include: a protrusion formed in the outer wall and extending toward the inner wall; and a recess formed in the inner wall opposite to the protrusion; and the protrusion of the closed shape sealing groove biases at least a portion of the sealing member disposed in the closed shape sealing groove against the inner wall of the closed shape sealing groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0017] Figure 1 is a schematic diagram (not drawn to scale) showing a housing of a vacuum pump;

[0018] Figure 2 is a schematic diagram of a sealing gasket (not drawn to scale);

[0019] Figure 3 is another schematic diagram of a sealing gasket (not drawn to scale);

[0020] Figure 4 is a process flow diagram illustrating certain steps of a method of incorporating a sealing gasket into a housing;

[0021] Figure 5 is a schematic diagram (not drawn to scale) showing a sealing gasket located in a housing;

[0022] Figure 6 is a schematic diagram (not drawn to scale) showing a plan view of a first longitudinal seal member positioned in a first longitudinal seal groove; and

[0023] Figure 7 is a schematic diagram (not drawn to scale) showing a first closed shape sealing member positioned in a first closed shape sealing groove. DETAILED DESCRIPTION

[0024] Figure 11 is a schematic diagram (not drawn to scale) showing a housing 10 of a vacuum pump according to one embodiment. The housing 10 includes a pair of housing stators 12, 14 and a pair of end plates 16, 18. The housing stators 12, 14 define recesses that receive components of the vacuum pump. The housing stators 12, 14 are brought together to hold the components in these recesses. The end plates 16, 18 are then placed to hold the housing stators 12, 14. This provides a particularly convenient assembly of the vacuum pump.

[0025] In other words, the housing 10 of the vacuum pump may be formed of multiple components, including shells 12, 14 and end plates 16, 18, which need to be sealed during assembly. Figure 1 In the arrangement shown in FIG. 1 , the stator is formed by bringing together two housing parts or shells 12 , 14 which are then held between the pair of end plates 16 , 18 .

[0026] As will be explained in more detail below, in this embodiment, in order to adequately seal the shell stators 12, 14 together, one or more (e.g., two) longitudinal seals are positioned along the joint surfaces of the shell stators 12, 14. In addition, in order to ensure adequate sealing between the shell stators 12, 14 and the respective end plates 16, 18, a pair of seals (e.g., annular seals in some embodiments) defining a closed shape are positioned between the end plates 16, 18 and the shell stators 12, 14.

[0027] Figure 2 FIG. 2 is a schematic diagram (not drawn to scale) of a sealing gasket 20 for sealing a housing 10 according to one embodiment.

[0028] The sealing gasket 20 includes a first closed shape sealing member 22 (which may be approximately annular), a second closed shape sealing member 24 (which may be approximately annular), a first longitudinal sealing member 26 and a second longitudinal sealing member 28 .

[0029] The first closed shape sealing member 22 includes a first surface 30, a second surface 32 opposite the first surface 30, a first radially inner surface 34, and a first radially outer surface 36 opposite the first radially inner surface 34. The first radially inner surface 34 and the first radially outer surface 36 are disposed between the first surface 30 and the second surface 32.

[0030] The second closed shape sealing member 24 includes a third surface 40, a fourth surface 42 opposite to the third surface 40, a second radially inner surface 44, and a second radially outer surface 46 opposite to the second radially inner surface 44. The second radially inner surface 44 and the second radially outer surface 46 are disposed between the third surface 40 and the fourth surface 42.

[0031] The first longitudinal sealing member 26 is connected or attached between the first radially outer surface 36 (of the first closed shape sealing member 22 ) and the second radially outer surface 46 (of the second closed shape sealing member 24 ).

[0032] The second longitudinal sealing member 28 is connected or attached between the first radially outer surface 36 (of the first closed shape sealing member 22 ) and the second radially outer surface 46 (of the second closed shape sealing member 24 ).

[0033] The second longitudinal sealing member 28 is arranged opposite to the first longitudinal sealing member 26. That is, the second longitudinal sealing member 28 is connected to the first and second closed shape sealing members 22, 24 and is located at a side of the first and second closed shape sealing members 22, 24 opposite to the side where the first longitudinal sealing member 26 is connected to the first and second closed shape sealing members 22, 24.

[0034] The first closed shape sealing member 22 defines a closed shape and may be an annular sealing member. The first closed shape sealing member 22 has a square or rectangular cross-section.

[0035] The second closed shape sealing member 24 defines a closed shape and may be an annular sealing member. The second closed shape sealing member 24 has a square or rectangular cross-section.

[0036] The first longitudinal sealing member 26 may be an O-ring strap, which may have a circular cross-section. The first longitudinal sealing member 26 may have a square or rectangular cross-section.

[0037] The second longitudinal sealing member 28 may be an O-ring strap, which may have a circular cross-section. The second longitudinal sealing member 28 may have a square or rectangular cross-section.

[0038] In this embodiment, the sealing gasket 20 is a continuous, single-piece sealing gasket.

[0039] The sealing gasket 20 is made of a deformable or flexible material, such as an elastomeric material (e.g., fluoroelastomer (FKM / FPM) or perfluoroelastomer (FFKM)) or silicon, so that the sealing gasket 20 is deformable or flexible. Therefore, the sealing gasket 20 can be deformed into a desired shape or configuration suitable for use as a seal of the housing 10.

[0040] Figure 3 is a schematic diagram (not drawn to scale) showing the sealing gasket 20 which has been deformed into a configuration suitable for sealing the housing 10 .

[0041] In this configuration, the first and second closed shape sealing members 22, 24 are square annular members with curved corners. The configuration has main faces (which are the first radial inner surface 34 and the first radial outer surface 36 of the first closed shape sealing member 22, and the second radial inner surface 44 and the second radial outer surface 46 of the second closed shape sealing member 24), which are adjacent to the main faces of the end plates 16, 18 and the adjacent faces of the shell stators 12, 14 in use. In this example, the first and second closed shape sealing members 22, 24 have substantially planar axial outer faces provided by the first radial inner surface 34 and the second radial inner surface 44, respectively. The first and second closed shape sealing members 22, 24 have substantially planar axial inner faces provided by the first radial outer surface 36 and the second radial outer surface 46, respectively. The longitudinal sealing member 26 is connected between the facing axial inner faces of the first and second closed shape sealing members 22, 24 (i.e., between the first radial outer surface 36 and the second radial outer surface 46). The first and second closed shape sealing members 22, 24 have substantially constant thickness.

[0042] Figure 4 is a process flow diagram illustrating certain steps (s40-s48) of a method of assembling, installing or incorporating the sealing gasket 20 into the housing 10.

[0043] Figure 5 is a schematic diagram (not drawn to scale) illustrating the sealing gasket 20 incorporated into the housing 10 .

[0044] At step s40 , a shell-stator 14 is provided into which components of a vacuum pump can be assembled.

[0045] At step s42, the sealing gasket 20 is positioned relative to the shell stator 14 so that the first and second longitudinal sealing members 26, 28 are positioned along the joint surface of the shell stator 14. The longitudinal sealing members 26, 28 are positioned in corresponding longitudinal sealing grooves 50, 52 extending along the joint surface of the shell stator 14, as shown in FIG. Figure 5 As depicted in .

[0046] The longitudinal sealing grooves 50, 52 and the positioning of the longitudinal sealing members 26, 28 therein will be referred to later herein. Figure 6 Describe in more detail.

[0047] At step s44, the case stator 12 is brought into close contact with the longitudinal sealing members 26, 28. Specifically, the case stator 12 is moved onto the longitudinal sealing members 26, 28 toward the joint surface of the case stator 14. Figure 5 The shell stators 12, 14 are shown arranged in this manner.

[0048] At step s46, the case stators 12, 14 are clamped together, which compresses the longitudinal sealing members 26, 28. The case stators 12, 14 are fixed together to form a pump chamber.

[0049] After step s46, the first and second closed shape sealing members 22, 24 tend to extend or protrude axially from the axial ends of the assembled shell stators 12, 14.

[0050] At step s48, the end plates 16, 18 are brought together to compress the first and second closed-shape sealing members 22, 24 in the axial (ie, longitudinal) direction.

[0051] The first and second closed shape sealing members 22 , 24 are positioned in closed shape (eg, annular) sealing grooves 54 , 56 located in the shell stators 12 , 14 and / or the end plates 16 , 18 .

[0052] The closed shape sealing grooves 54, 56 and the positioning of the first and second closed shape sealing members 22, 24 therein will be referred to later below. Figure 7 Describe in more detail.

[0053] refer to Figure 5 , the end plate 18 is shown as having been moved to the first annular sealing member 22 at the first end of the assembled shell stators 12, 14. The end plate 16 can be moved to the second annular sealing member 24 at the second end (opposite the first end) of the assembled shell stators 12, 14, as shown. Figure 5 Indicated by arrow and reference numeral 58 .

[0054] Thus, a method of assembling, installing or incorporating the sealing gasket 20 into the housing 10 is provided.

[0055] Figure 6 is a schematic diagram (not drawn to scale) showing a plan view of the first longitudinal seal member 26 positioned in the first longitudinal seal groove 52. Those skilled in the art will appreciate that the second longitudinal seal member 28 is positioned in the second longitudinal seal groove 50 in a similar manner.

[0056] The first longitudinal sealing groove 52 extends along and is formed in the joint surface of the case-stator 14 .

[0057] The first longitudinal sealing groove 52 includes a first side wall 60, a second side wall 62 opposite to the first side wall 60, and a bottom surface 64 disposed between the first side wall 60 and the second side wall 62. The first side wall 60 is the surface of the first longitudinal sealing groove 52 farthest from the pump chamber. The second side wall 62 is the surface of the first longitudinal sealing groove 52 closest to the pump chamber. The bottom surface 64 is opposite to the opening of the first longitudinal sealing groove 52.

[0058] The first longitudinal seal groove 52 includes a biasing device 66 for biasing the first longitudinal seal groove 52 against the second side wall 62. In this embodiment, there are a plurality of biasing devices 66 arranged along the length of the first longitudinal seal groove 52 in a spaced apart arrangement.

[0059] Each biasing device 66 includes a corresponding protrusion 68 and a corresponding recess 69. The protrusion 68 is formed in the first side wall 60. The protrusion 68 extends from the first side wall 60 toward the second side wall 62. The recess 69 is formed in the second side wall 62 opposite to the protrusion 68.

[0060] Seal grooves such as the first and second longitudinal seal grooves 50, 52 can provide a leakage path for gas between the low vacuum end and the high vacuum end of the pump. In this embodiment, the longitudinal seal members 26, 28 are biased against the pump chamber side (i.e., the innermost side relative to the pump chamber) of the longitudinal seal grooves 50, 52. This advantageously tends to block the leakage path.

[0061] In this embodiment, the first and second longitudinal sealing grooves 50, 52 are wider than the longitudinal sealing members 26, 28 located therein. This tends to provide some freedom of lateral movement and the ability of the sealing gasket 20 to expand, for example due to heating and / or compression of the sealing gasket 20.

[0062] In some embodiments, one or more protrusions are formed in the second sidewall and extend toward the first sidewall, and one or more recesses are formed in the first sidewall opposite to the corresponding protrusions.

[0063] Preferably, the longitudinal sealing grooves 50, 52 each have a constant width and thus tend to be machined in a single pass with one tool. This tends to provide advantages over grooves that, for example, include one or more sections of reduced width for clamping the sealing gasket. Furthermore, the absence of such narrowing sections tends to reduce the chance of pinch points for the gasket as it expands under compression and temperature changes.

[0064] Figure 7 is a schematic diagram (not drawn to scale) showing the first closed shape sealing member 22 positioned in the first closed shape sealing groove 54. Those skilled in the art will appreciate that the second closed shape sealing member 24 is positioned in the second closed shape sealing groove 56 in a similar manner.

[0065] The first closed shape sealing groove 54 may be formed in the end surfaces of the case-stators 12 , 14 and / or the engaging surface of the end plate 18 .

[0066] The closed shape sealing groove 54 includes a first side wall 70, a second side wall 72 opposite to the first side wall 70, and a bottom surface 74 disposed between the first side wall 70 and the second side wall 72. The first side wall 70 is a surface of the first closed shape sealing groove 54 farthest from the center of the closed shape defined by the first closed shape sealing groove 54. The second side wall 72 is a surface of the first closed shape sealing groove 54 closest to the center of the closed shape defined by the first closed shape sealing groove 54. The bottom surface 74 is opposite to the opening of the first closed shape sealing groove 54.

[0067] The first closed shape sealing groove 54 includes a biasing device 76 for biasing the first closed shape sealing groove 54 toward a center portion of the first closed shape sealing groove 54. In this embodiment, there are a plurality of biasing devices 76 arranged in a spaced arrangement around the first closed shape sealing groove 54. For clarity, Figure 7 Only some of the biasing devices 76 are indicated by reference numerals.

[0068] Each biasing device 76 includes a corresponding protrusion 78 and a corresponding recess 79. The protrusion 78 is formed in the first side wall 70 or the second side wall 72 and extends toward the opposite side wall 70, 72. The recess 79 is formed in the other of the second side wall 72 or the first side wall 70 and is opposite to the protrusion 78.

[0069] In this embodiment, the first and second closed shape sealing grooves 54, 56 are wider than the first and second closed shape sealing members 22, 24 located therein. This tends to provide some freedom of lateral / radial movement and the ability of the sealing gasket 20 to expand, such as due to heating and / or compression of the sealing gasket 20. In addition, by biasing the first and second closed shape sealing members 22, 24 toward the center portion of the closed shape sealing grooves 54, 56, it tends to allow expansion of the sealing members 22, 24 in both radially inward and outward directions.

[0070] Preferably, the closed shape sealing grooves 54, 56 each have a constant width and thus tend to be machined in a single pass with one tool. This tends to provide advantages over grooves that, for example, include one or more sections of reduced width for clamping the sealing gasket. Furthermore, the absence of such narrowing sections tends to reduce the chance of pinch points of the gasket existing as the gasket expands under compression and temperature changes.

[0071] In the above embodiments, each protrusion may be a continuous curved ridge or convex portion. Preferably, the protrusions omit discontinuities or sharp corners, that is, they are smooth. This advantageously tends to reduce the possibility of damaging the sealing gasket.

[0072] In the above embodiments, each depression may be a continuous curved depression, cavity or void. Preferably, the depressions omit discontinuities or sharp corners, i.e. they are smooth. This advantageously tends to reduce the possibility of damaging the sealing gasket.

[0073] The use of a biasing or locating device that uses only structural features of the sealing groove to locate the sealing gasket within the sealing groove advantageously tends to allow the use of sealing gaskets with simpler geometries. This tends to facilitate the design, manufacture and cost of the sealing gasket. For example, compared to the shell stator or end plate, the sealing gasket tends to require relatively frequent maintenance or replacement.

[0074] The sealing gasket tends to be easy to install into the housing or vacuum pump.

[0075] It will be appreciated that the straps and spacers may have different shapes or thicknesses to suit the arrangement of the housing.

[0076] In the above-described embodiments, the sealing gasket is a continuous single-piece sealing gasket. However, in other embodiments, the sealing gasket includes a plurality of separate parts joined together. The plurality of parts may be joined together by any joining device or method, such as using an adhesive, fusing or via an interference fit.

[0077] In the above described embodiments, the sealing gasket has a substantially constant cross-section over a portion thereof. However, in other embodiments, the sealing gasket has a non-constant cross-section.

[0078] In the above-mentioned embodiments, the sealing gasket has a square or rectangular cross-section. However, in other embodiments, a part or all of the sealing gasket has an alternative cross-section other than a square or a rectangle, such as a circle, a triangle, an ellipse, etc.

[0079] In the above embodiments, the sealing gasket may be made of an elastomer. In some embodiments, the sealing gasket may be made of different deformable materials, such as metal.

[0080] Although the major faces of the sealing gaskets in the above described embodiments are substantially planar, it will be appreciated that they may be of any shape suitable for engaging with the major faces of the end plates and the adjacent faces of the case stator.

[0081] Although illustrative embodiments of the present invention have been disclosed herein in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the specific embodiments and that various changes and modifications may be implemented therein by those skilled in the art without departing from the scope of the present invention as defined by the appended claims and their equivalents.

[0082] Reference numerals list

[0083] 10- Shell

[0084] 12, 14-shell stator

[0085] 16, 18-End plate

[0086] 20-Sealing gasket

[0087] 22-First closed shape sealing member

[0088] 24-Second closed shape sealing member

[0089] 26-First longitudinal sealing member

[0090] 28-Second longitudinal sealing member

[0091] 30-First surface

[0092] 32- Second surface

[0093] 34-first radial inner surface

[0094] 36- first radial outer surface

[0095] 40-Third surface

[0096] 42-Fourth Surface

[0097] 44- second radial inner surface

[0098] 46- second radial outer surface

[0099] s40-s48-method steps

[0100] 50, 52-longitudinal sealing groove

[0101] 54, 56- Closed shape sealing groove

[0102] 60-first side wall of longitudinal sealing groove

[0103] 62-Second side wall of longitudinal sealing groove

[0104] 64- Bottom surface of longitudinal sealing groove

[0105] 66-Biasing device for longitudinal sealing groove

[0106] 68-protrusion

[0107] 69-Depression

[0108] 70-First side wall of closed shape sealing groove

[0109] 72-Second side wall of closed shape sealing groove

[0110] 74- Bottom surface of closed shape sealing groove

[0111] 76-Biasing device for closed shape seal groove

[0112] 78-protrusion

[0113] 79-Depression

Claims

1. A shell stator for a vacuum pump, the shell stator comprising: A sealing groove is formed in the surface of the shell stator, the sealing groove is defined by a first side wall, a second side wall opposite to the first side wall, and a bottom surface disposed between the first side wall and the second side wall, the bottom surface being opposite to the opening of the sealing groove; wherein, The sealing groove comprises: a protrusion formed in the first side wall and extending toward the second side wall; and A recess is formed in the second side wall opposite to the protrusion.

2. The shell stator according to claim 1, wherein: The protrusion is a continuous curved ridge.

3. A shell stator according to any preceding claim, wherein: The depression is a continuous curved depression.

4. A shell stator according to any preceding claim, wherein: The sealing groove comprises: a plurality of protrusions formed in the first side wall and extending toward the second side wall; and A plurality of recesses are formed in the second sidewall, each of the plurality of recesses being opposite to a corresponding protrusion of the plurality of protrusions.

5. A shell stator according to any preceding claim, wherein: The sealing groove is formed in a joining surface of the case-stator, the joining surface being adapted to receive another case-stator to thereby define at least one pump chamber.

6. A shell stator according to any preceding claim, wherein: The sealing groove is formed in an end surface of the case stator, the end surface being for receiving an end piece.

7. A shell stator according to any preceding claim, further comprising: another sealing groove formed in the surface of the shell stator, the other sealing groove being defined by a third side wall, a fourth side wall opposite to the third side wall, and another bottom surface disposed between the third side wall and the fourth side wall, the other bottom surface being opposite to the opening of the other sealing groove; wherein, The other sealing groove comprises: another protrusion formed in the third side wall and extending toward the fourth side wall; and Another recess is formed in the fourth side wall opposite to the another protrusion.

8. The shell stator according to claim 7, wherein: The first side wall and the third side wall are outermost walls, and the second side wall and the fourth side wall are innermost walls.

9. The case stator according to claim 7 or 8, further comprising a curved sealing groove formed in an end surface of the case stator, the curved sealing groove being formed between the sealing groove and the another sealing groove.

10. A system comprising: A shell stator as claimed in any preceding claim; as well as A sealing gasket is arranged in the sealing groove; wherein, The protrusion biases at least a portion of the sealing gasket against the second side wall.

11. The system according to claim 10, wherein: A thickness of the sealing gasket in a direction from the first side wall to the second side wall is smaller than a dimension of the sealing groove in the direction.

12. The system according to claim 10 or 11, wherein: The sealing gasket has a substantially uniform thickness.

13. A vacuum pump comprising: a shell-stator defining at least one pump chamber, at least one of the shell-stators being a shell-stator according to any one of claims 1 to 9; end pieces mounted at either end of the shell stator; as well as A sealing gasket is arranged between the shell stator and the end piece, and the sealing gasket is arranged in the sealing groove; wherein, The protrusion biases at least a portion of the sealing gasket against the second side wall.

14. The vacuum pump according to claim 13, wherein: The at least one of the case-stators further includes another sealing groove formed in a surface of the case-stator, the other sealing groove being defined by a third side wall, a fourth side wall opposite to the third side wall, and another bottom surface disposed between the third side wall and the fourth side wall, the other bottom surface being opposite to an opening of the other sealing groove; The other sealing groove comprises: another protrusion formed in the third side wall and extending toward the fourth side wall; and another recess formed in the fourth side wall opposite to the another protrusion; The first side wall and the third side wall are outermost walls relative to the at least one pump chamber; The second side wall and the fourth side wall are innermost walls relative to the at least one pump chamber; The sealing gasket is also disposed in the other sealing groove; and The protrusion and the further protrusion bias at least a portion of the sealing gasket against the innermost sidewall.

15. The vacuum pump according to claim 13 or 14, further comprising: two closed shape sealing grooves, each closed shape sealing groove is formed in a respective end of the shell stator; wherein, The sealing gasket includes two sealing members each defining a closed shape, each of the sealing members being disposed in a corresponding one of the closed shape sealing grooves; Each closed shape sealing groove is defined by an outer wall, an inner wall opposite to the outer wall, and a bottom surface disposed between the outer wall and the inner wall, the bottom surface being opposite to the opening of the closed shape sealing groove; wherein, Each closed shape seal groove includes: a protrusion formed in the outer wall and extending toward the inner wall; and a recess formed in the inner wall opposite to the protrusion; and The protrusion of the closed shape sealing groove biases at least a portion of the sealing member disposed in the closed shape sealing groove against the inner wall of the closed shape sealing groove.

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