Sealing gasket

Abstract

A seal gasket (20) for a vacuum pump includes a first seal member (22) defining a closed shape (preferably a rounded square or a rounded rectangle), having a first surface (30), a second surface (32) opposite the first surface (30), a first inner surface (34), and a first outer surface (36) opposite the first inner surface (34), with the first inner surface (34) and the first outer surface (36) disposed between the first surface (30) and the second surface (32); a second seal member (24) defining a closed shape (preferably a rounded square), having a third surface (40), a fourth surface (42) opposite the third surface (40), a second inner surface (44), and a second outer surface (46) opposite the second inner surface (44), with the second inner surface (44) and the second outer surface (46) disposed between the third surface (40) and the fourth surface (42); a first longitudinal seal member (26) coupled between the first outer surface (36) and the second outer surface (46); and a second longitudinal seal member (28) coupled between the first outer surface (36) and the second outer surface (46).

Description

Technical Field

[0001] The present invention relates to a seal gasket for a vacuum pump and a vacuum pump.

Background Art

[0002] Rotary machines such as compressors or pumps need to be carefully designed and manufactured so that the moving parts cooperate accurately with each other. Providing an effective seal to seal the machine can be problematic, especially when the flow of fluid is facilitated by the pressure difference between the machine and the surrounding environment, as in the case of a vacuum pump. It is desirable to provide an improved seal.

Summary of the Invention

Means for Solving the Problems

[0003] In one aspect, a seal gasket for a vacuum pump is provided. The seal gasket includes a first seal member defining a closed shape (e.g., a circular structure such as an annular body or a rounded square), having a first surface, a second surface opposite the first surface, a first inner surface (which can be a radially inner surface), and a first outer surface opposite the first inner surface (which can be a radially outer surface), the first inner surface and the first outer surface being disposed between the first surface and the second surface; a second seal member defining a closed shape, having a third surface, a fourth surface opposite the third surface, a second inner surface (which can be a radially inner surface), and a second outer surface opposite the second inner surface (which can be a radially outer surface), the second inner surface and the second outer surface being disposed between the third surface and the fourth surface; a first longitudinal seal member coupled between the first outer surface and the second outer surface; and a second longitudinal seal member coupled between the first outer surface and the second outer surface.

[0004] The seal gasket can further include one or more curved surface portions and / or one or more flat surface portions disposed between one or more of the first or second seal members and one or more of the longitudinal seal members, and each of the one or more curved surface portions and / or one or more flat surface portions is positioned at a joint portion between one or more of the first or second seal members and one or more of the longitudinal seal members.

[0005] The seal gasket can further include one or more curved surface portions and / or one or more flat surface portions disposed between one or more outer surfaces and one or more longitudinal seal members and positioned at a joint portion between the one or more outer surfaces and the one or more longitudinal seal members.

[0006] The seal gasket can further include a continuous curved surface portion disposed at a joint portion between an outer surface and a longitudinal seal member coupled thereto so as to provide a smooth continuous transition between the outer surface and the longitudinal seal member coupled thereto.

[0007] The seal gasket can further include a curved surface portion and a discontinuity at a joint portion between an outer surface and a longitudinal seal member coupled thereto, and the curved surface portion and the discontinuity are disposed between the outer surface and the longitudinal seal member coupled thereto.

[0008] The seal gasket can further include one or more discrete flat surface portions disposed at a joint portion between an outer surface and a longitudinal seal member coupled thereto. In some embodiments, there can be only one discrete flat surface portion (e.g., chamfer) disposed between the outer surface and the longitudinal seal member coupled thereto. In some embodiments, there can be a plurality of discrete flat surface portions (i.e., multi-faceted portions) disposed between the outer surface and the longitudinal seal member coupled thereto.

[0009] In a further aspect, a seal gasket for a vacuum pump is provided. The seal gasket comprises: a first seal member defining a closed shape; a second seal member defining a closed shape; a first longitudinal seal member coupled between the first seal member and the second seal member; a second longitudinal seal member coupled between the first seal member and the second seal member; one or more curved portions and / or one or more planar portions disposed between one or more of the seal members and one or more of the longitudinal seal members and positioned at one or more joint portions between one or more of the seal members and one or more of the longitudinal seal members.

[0010] The seal gasket can comprise continuous curved portions arranged to provide a smooth continuous transition between the first or second seal member and the longitudinal seal member coupled thereto at the joint portion between the first or second seal member and the longitudinal seal member coupled thereto.

[0011] In any of the above aspects, the seal gasket can be a one-piece gasket. The seal gasket can be a molded gasket. Part or all of the seal gasket can have a square or rectangular cross-section. The seal gasket can be deformable. The seal gasket can be made of or include an elastomer.

[0012] In any of the above aspects, the closed shape can be, for example, annular, loop-shaped, ring-shaped, or a rounded square (i.e., a square having rounded corners, such as a substantially squircle), or a rounded rectangle.

[0013] In any of the above aspects, the first sealing member can have a rounded square, i.e., a square with rounded corners, for example, can define a substantially squircle. The first surface can be a rounded square surface. The second surface can be a rounded square surface. The first sealing member can include a first curved section, a second curved section, a third curved section, a fourth curved section, a first substantially linear section disposed between the first curved section and the second curved section, a second substantially linear section disposed between the second curved section and the third curved section, a third substantially linear section disposed between the third curved section and the fourth curved section, and a fourth substantially linear section disposed between the fourth curved section and the first curved section. The first longitudinal sealing member can be coupled to the first curved section. The second longitudinal sealing member can be coupled to the third curved section.

[0014] In any of the above aspects, the second sealing member can have a rounded square, i.e., a square with rounded corners, for example, can define a substantially squircle. The third surface can be a rounded square surface. The fourth surface can be a rounded square surface. The second sealing member can include a fifth curved section, a sixth curved section, a seventh curved section, an eighth curved section, a fifth substantially linear section disposed between the fifth curved section and the sixth curved section, a sixth substantially linear section disposed between the sixth curved section and the seventh curved section, a seventh substantially linear section disposed between the seventh curved section and the eighth curved section, and an eighth substantially linear section disposed between the eighth curved section and the fifth curved section. The first longitudinal sealing member can be coupled to the fifth curved section. The second longitudinal sealing member can be coupled to the seventh curved section.

[0015] In any of the above aspects, the first seal member can be an annular seal member. In any of the above aspects, the first surface can be an annular surface. In any of the above aspects, the second surface can be an annular surface.

[0016] In any of the above aspects, the second seal member can be an annular seal member. In any of the above aspects, the third surface can be an annular surface. In any of the above aspects, the fourth surface can be an annular surface.

[0017] In a further aspect, a vacuum pump is provided, the vacuum pump comprising: a shell stator defining at least one pump chamber; an end piece attachable to either end of the shell stator; and a seal gasket as described in any of the above aspects.

[0018] The seal gasket can be disposed within one or more seal grooves formed in one or more of the shell stator and / or one or more of the end pieces.

[0019] The first sealing member can be disposed within the first sealing groove. The first sealing groove can define a closed shape selected from the group of closed shapes consisting of an annular shape, a circular shape, an elliptical shape, an oval shape, a stadium shape, a rounded square, a rounded rectangle, a rounded polygon, and a squircle. The first sealing groove can be defined at an end of the shell stator and / or an end piece. The first curved section can be disposed at a first substantially linear portion of the first sealing groove. The second curved section can be disposed at a second substantially linear portion of the first sealing groove. The third curved section can be disposed at a third substantially linear portion of the first sealing groove. The fourth curved section can be disposed at a fourth substantially linear portion of the first sealing groove. The first substantially linear section can be disposed at a first curved portion of the first sealing groove. The second substantially linear section can be disposed at a second curved portion of the first sealing groove. The third substantially linear section can be disposed at a third curved portion of the first sealing groove. The fourth substantially linear section can be disposed at a fourth curved portion of the first sealing groove.

[0020] The second seal member can be disposed within the second seal groove. The second seal groove can define a closed shape selected from the group of closed shapes consisting of an annular shape, a circular shape, an oval shape, an oblong shape, a stadium shape, a rounded square shape, a rounded rectangular shape, a rounded polygonal shape, and a squircle. The second seal groove can be defined at an end of the shell stator and / or an end piece. The fifth curved section can be disposed at a first substantially linear portion of the second seal groove. The sixth curved section can be disposed at a second substantially linear portion of the second seal groove. The seventh curved section can be disposed at a third substantially linear portion of the second seal groove. The eighth curved section can be disposed at a fourth substantially linear portion of the second seal groove. The fifth substantially linear section can be disposed at a first curved portion of the second seal groove. The sixth substantially linear section can be disposed at a second curved portion of the second seal groove. The seventh substantially linear section can be disposed at a third curved portion of the second seal groove. The eighth substantially linear section can be disposed at a fourth curved portion of the second seal groove.

[0021] In a further aspect, a shell stator for a vacuum pump is provided, the shell stator comprising: a first seal groove disposed along a mating surface of the shell stator, the mating surface being for receiving a further shell stator to thereby define at least one pump chamber; and a second seal groove disposed at an end face of the shell stator, the end face being for receiving an end piece, wherein the first and second seal grooves are joined at an end of the shell stator via a transition groove portion comprising one or more curved surface portions and / or one or more flat surface portions.

[0022] The first and second seal grooves can be joined at an end of the shell stator via a polyhedral transition groove portion comprising a plurality of flat surface portions.

[0023] The first and second seal grooves can be joined at the end of the shell stator via a chamfered transition groove portion having only a single planar portion.

[0024] The first and second seal grooves can be joined at the end of the shell stator via a continuous transition groove portion having only continuous curved surface portions.

[0025] The first and second seal grooves can be joined at the end of the shell stator via a transition groove portion having a curved surface portion and a discontinuous portion. The discontinuous portion can be disposed between the curved surface portion and either the first or the second seal groove.

[0026] The first and second seal grooves can be joined at the end of the shell stator via a transition groove portion having a curved surface portion and a planar portion. The planar portion can be disposed between the curved surface portion and either the first or the second seal groove.

[0027] The first and second seal grooves can be joined at the end of the shell stator via a transition groove portion having a curved surface portion and two planar portions. Each planar portion can be disposed between the curved surface portion and each of the first and second seal grooves.

[0028] In a further aspect, a shell stator for a vacuum pump is provided. The shell stator includes a joint surface of the shell stator, the joint surface being for receiving a further shell stator so as to thereby define at least one pump chamber; a seal groove disposed on an end face of the shell stator, the end face being for receiving an end piece; and a transition groove portion disposed between the joint surface and the seal groove at the end of the shell stator, the transition groove portion including a transition groove portion having one or more curved surface portions and / or one or more planar portions.

[0029] The transition groove portion can be a multi-faceted transition groove portion having a plurality of planar portions.

[0030] The transition groove portion can be a chamfered transition groove portion having only a single planar portion.

[0031] The transition groove portion can be a continuous transition groove portion having only a continuous curved surface portion.

[0032] The transition groove portion can include a curved surface portion and a discontinuous portion. The discontinuous portion can be disposed between the curved surface portion and either the seal groove or the joint surface.

[0033] The transition groove portion can include a curved surface portion and a planar portion. The planar portion can be disposed between the curved surface portion and either the seal groove or the joint surface.

[0034] The transition groove portion can include a curved surface portion and two planar portions. Each planar portion can be disposed between the curved surface portion and each of the seal groove and the joint surface.

[0035] In a further aspect, there is provided a vacuum pump including a shell stator defining at least one pump chamber, an end piece attachable to either end of the shell stator, and a seal gasket disposed between the shell stator and the end piece. One or more of the shell stators is a shell stator according to any of the above aspects. For example, both of the shell stators can follow one of the above aspects, for example, different aspects. The seal gasket can follow any of the above aspects.

[0036] Hereinafter, the present invention will be described merely by way of example with reference to the accompanying drawings.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6a

Figure 6b

Figure 6c

Figure 7a

Figure 7b

Figure 8a

Figure 8b

Figure 9a

Figure 9b

Figure 10a

Figure 10b

Figure 11a

Figure 11b

Figure 12a

Figure 12b

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

DETAILED DESCRIPTION OF THE INVENTION

[0038] FIG. 1 is a schematic diagram showing a housing 10 of a vacuum pump according to one embodiment (not to scale). The housing 10 includes a pair of shell stators 12, 14 and a pair of end plates 16, 18. The shell stators 12, 14 define recesses for receiving components of the vacuum pump. The shell stators 12, 14 are combined to hold the components within their recesses. Next, the end plates 16, 18 are provided to hold the shell stators 12, 14. This enables a convenient assembly of the vacuum pump.

[0039] In other words, the housing 10 of the vacuum pump can be formed from a plurality of components including shells 12, 14 and end plates 16, 18 that need to be sealed during assembly. In the configuration shown in FIG. 1, the stator is formed by combining two housing parts or shells 12, 14 held between a pair of end plates 16, 18.

[0040] As will be described in detail below, in this embodiment, in order to properly seal the shell stators 12, 14, one or two or more (for example, two) longitudinal seals are arranged along the joint surfaces of the shell stators 12, 14. Also, in order to ensure proper sealing between the shell stators 12, 14 and their respective end plates 16, 18, a pair of annular seals are arranged between the end plates 16, 18 and the shell stators 12, 14.

[0041] FIG. 2 is a schematic view (not to scale) of a seal gasket 20 for sealing the housing 10 according to one embodiment.

[0042] The seal gasket 20 includes a first substantially annular seal member 22, a second substantially annular seal member 24, a first longitudinal seal member 26, and a second longitudinal seal member 28.

[0043] The first annular seal member 22 includes a first annular surface 30, a second annular surface 32 opposite to the first annular surface 30, a first radially inner surface 34, and a first radially outer surface 36 opposite to the first radially inner surface 34. The first radially inner surface 34 and the first radially outer surface 36 are arranged between the first annular surface 30 and the second annular surface 32.

[0044] The second annular seal member 24 includes a third annular surface 40, a fourth annular surface 42 on the side opposite to the third annular surface 40, a second radially inner surface 44, and a second radially outer surface 46 on the side 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 annular surface 40 and the fourth annular surface 42.

[0045] The first longitudinal seal member 26 is coupled or attached between a first radially outer surface 36 (of the first annular seal member 22) and a second radially outer surface 46 (of the second annular seal member 24).

[0046] The second longitudinal seal member 28 is coupled or attached between a first radially outer surface 36 (of the first annular seal member 22) and a second radially outer surface 46 (of the second annular seal member 24).

[0047] The second longitudinal seal member 28 is disposed on the side opposite to the first longitudinal seal member 26. That is, the second longitudinal seal member 28 is coupled to the first and second annular seal members 22, 24 on the side opposite to the side where the first longitudinal seal member 26 is coupled to the first and second annular seal members 22, 24.

[0048] The first annular seal member 22 is a ring-shaped seal member. The first annular seal member 22 has a square or rectangular cross-section.

[0049] The second annular seal member 24 is a ring-shaped seal member. The second annular seal member 24 has a square or rectangular cross-section.

[0050] The first longitudinal seal member 26 can be an O-ring cord. The first longitudinal seal member 26 has a square or rectangular cross-section.

[0051] The second longitudinal seal member 28 can be an O-ring cord. The second longitudinal seal member 28 has a square or rectangular cross-section.

[0052] In this embodiment, the seal gasket 20 is a continuous one-piece seal gasket.

[0053] In this embodiment, the seal gasket includes curved surface portions 48a-d at the joint portions between the annular seal members 22, 24 and the longitudinal seal members 26, 28. Specifically, at the joint portion between the first annular seal member 22 and the first longitudinal seal member 26, there is a curved surface portion 48a between the first radially outer surface 36 and the first longitudinal seal member 26. Also, at the joint portion between the first annular seal member 22 and the second longitudinal seal member 28, there is a curved surface portion 48b between the first radially outer surface 36 and the second longitudinal seal member 28. Further, at the joint portion between the second annular seal member 24 and the first longitudinal seal member 26, there is a curved surface portion 48c between the second radially outer surface 46 and the first longitudinal seal member 26. Moreover, at the joint portion between the second annular seal member 24 and the second longitudinal seal member 28, there is a curved surface portion 48d between the second radially outer surface 46 and the second longitudinal seal member 28.

[0054] In this embodiment, the curved surface portions 48a-d tend to make the radially outer surfaces 36, 46 of the annular seal members 22, 24 continuous with the surfaces of the longitudinal seal members 26, 28. There are smooth and continuous transition portions between the radially outer surfaces 36, 46 of the annular seal members 22, 24 and the longitudinal seal members 26, 28. The curved surface portions 48a-d smooth the transition between the radially outer surfaces 36, 46 of the annular seal members 22, 24 and the longitudinal seal members 26, 28 and enable a more continuous transition.

[0055] The seal gasket 20 is made of a deformable or flexible material such as an elastomer material (e.g., fluoroelastomer (FKM / FPM) or perfluoroelastomer (FFKM)) or silicon so that the seal gasket 20 is deformable or flexible. Accordingly, the seal gasket 20 can be deformed into a desired shape or configuration suitable for use as a seal for the housing 10.

[0056] FIG. 3 is a schematic view (not to scale) showing the seal gasket 20 deformed into a configuration suitable for sealing the housing 10.

[0057] In this configuration, the annular seal members 22, 24 are square ring-shaped members having curved corners. This configuration has major surfaces (the first radially inner surface 34 and the first radially outer surface 36 of the first annular seal member 22, and the second radially inner surface 44 and the second radially outer surface 46 of the second annular seal member 24), which, in use, abut against the major surfaces of the end plates 16, 18 and the adjacent surfaces of the shell stators 12, 14. In this example, the annular seal members 22, 24 have a substantially planar axial outer surface provided by the first radially inner surface 34 and the second radially inner surface 44, respectively. The annular seal members 22, 24 have a substantially planar axial inner surface provided by the first radially outer surface 36 and the second radially outer surface 46, respectively. The longitudinal seal member 26 is coupled between the opposing axial inner surfaces of the annular seal members 22, 24 (i.e., between the first radially outer surface 36 and the second radially outer surface 46). The annular seal members 22, 24 have a substantially constant thickness.

[0058] FIG. 4 is a process flow chart showing specific steps (s40 - s48) of a method of fitting, attaching, or incorporating the seal gasket 20 to the housing 10.

[0059] FIG. 5 is a schematic view (not to scale) showing the incorporation of the seal gasket 20 into the housing 10, which is useful for understanding the process of FIG. 4.

[0060] In step s40, a shell stator 14 is provided, and components of a vacuum pump (not shown) are incorporated therein.

[0061] In step s42, the seal gasket 20 is positioned relative to the shell stator 14 such that the first and second longitudinal seal members 26, 28 are located in seal grooves that typically extend along the joint surface of the shell stator 14. This can be done as shown in FIG. 5.

[0062] In step s44, the shell stator 12 is brought into intimate contact with the longitudinal seal members 26, 28.

[0063] Referring to FIG. 5, the shell stator 12 can be moved onto the longitudinal seal members 26, 28 toward the joint surface of the shell stator 14 as shown by the arrow and reference numeral 50 in FIG. 5.

[0064] In step s46, the shell stators 12, 14 are clamped together, which compresses the longitudinal seal members 26, 28.

[0065] Accordingly, after step s46, the annular seal members 22, 24 tend to extend or protrude axially from the axial ends of the assembled shell stators 12, 14.

[0066] In step s48, the end plates 16, 18 are combined to compress the annular seals 26, 28 axially (i.e., longitudinally).

[0067] The annular seal members 22, 24 can be positioned in annular seal grooves positioned in the shell stators 12, 14 and / or the end plates 16, 18.

[0068] Referring to FIG. 5, the end plate 18 is shown in a state of being moved onto the first annular seal member 22 at the first end of the assembled shell stators 12, 14. The end plate 16 can be moved onto the second annular seal member 24 at the second end (opposite to the first end) of the assembled shell stators 12, 14, as shown by the arrow and reference numeral 52 in FIG. 5.

[0069] Accordingly, a method of fitting, mounting, or incorporating the seal gasket 20 into the housing 10 is provided.

[0070] A vacuum pump having an axial dividing line along the stator generally requires seals at both ends of the dividing line, which is called a T-joint. Embodiments provide a seal gasket, such as an integrally molded elastomer gasket, for providing a T-joint seal configuration to a metal, plated, or coated claw pump.

[0071] FIGS. 6A-C are schematic views (not to scale) showing further details of the seal gasket 20 incorporated into the housing 10 near the T-joint. Only one of the T-joints is shown in FIGS. 6a-c, but those skilled in the art should understand that corresponding or similar features can exist at the positions of other T-joints of the assembly and at other shell stators 12.

[0072] Specifically, FIG. 6a shows the seal gasket 20 incorporated into the housing 10 near the T-joint. FIG. 6b shows the shell stator 14 near the T-joint (i.e., the same area as FIG. 6a, with the seal gasket 20 omitted). FIG. 6c shows a side view cross section of the portion of the shell stator 14 shown in FIG. 6b.

[0073] In this embodiment, the shell stator 14 includes a first seal groove 60 extending along the (upper) joint surface of the shell stator 14 and a second seal groove 62 extending across the end face of the shell stator 14.

[0074] In this embodiment, the seal gasket 20 is arranged such that the longitudinal seal member (in this case, the first longitudinal seal member 26) is positioned in the first seal groove 60 and the annular seal member (in this case, the second annular seal member 24) is positioned in the second seal groove 62.

[0075] As shown in FIGS. 6b and 6c, in this embodiment, the shell stator 14 includes a curved surface portion 64 at the joint portion between the first seal groove 60 and the second seal groove 62. The curved surface portion 64 of this embodiment can be considered as a groove portion that transitions between the first seal groove 60 and the second seal groove 62.

[0076] In this embodiment, the curved surface portion 64 tends to enable the concave surfaces (for example, flat bottom surfaces) of the seal grooves 60 and 62 to be continuous with each other. There is a smooth and continuous transition portion between the first and second seal grooves 60 and 62. The curved surface portion 64 provides a smooth and continuous transition portion between the seal grooves 60 and 62.

[0077] Preferably, the curved surface portion 64 between the seal grooves 60 and 62 is complementary to or coincides with the respective curved surface portions 48a - d of the seal gasket 20. This tends to provide improved contact between the seal gasket and the housing 10 and, as a result, improve the sealing performance.

[0078] Advantageously, the rounded or curved edge / surface 64 between the gasket groove (i.e., the first seal groove 60) and the annular seal groove (i.e., the second seal groove 62) tends to allow the seal gasket to deform or flow around the edge without losing firm contact with the seal surface. This configuration tends to withstand all compression scenarios. Further, the curved surfaces 64, 48a - d tend to eliminate sharp edges and create a single continuous tool path for the gasket and the annular seal groove. The seal gasket 20 tends to self - align regardless of the depth of the groove.

[0079] The seal gasket tends to facilitate attachment to the housing or the vacuum pump.

[0080] Advantageously, the seal gaskets described herein tend to be relatively easier to manufacture compared to conventional seal assemblies. For example, the seal gasket tends to be relatively easier to manufacture by molding. For example, the seal gasket can be molded in a mold as a substantially planar or flat article (as shown in FIG. 2 and described in more detail above) and then deformed or manipulated into the desired shape or configuration (as shown in FIG. 3 and described in more detail above). The molding can be performed using a mold having a first part with a recess that is the desired shape of the seal gasket, and placing a substantially planar second part over the recess of the first part, thereby defining a mold cavity in which the seal gasket can be formed. Advantageously, the seal gasket thus formed tends not to have a parting line (the part where two different faces of the mold meet). Thus, the likelihood of separation of the seal gasket is significantly reduced. Further, any mould flash present on the molded seal gasket tends to be limited to non - critical areas of the seal gasket, such as areas that extend outwardly from the upper surface of the seal gasket in the orientation of FIG. 2. This tends to improve the robustness and stability of the seal gasket.

[0081] Conventionally, when the compression of gaskets and annular seals becomes unbalanced, separation of the sealing surface of the T-joint may occur. This separation may cause leakage and may occur during assembly or due to thermal expansion of the seal. Also, conventionally, the sharp edges at the ends of the gasket grooves are difficult to manufacture and may cut the annular seal and cause leakage. Further, conventional complex gasket shapes have irregular distortions and may cause leakage. The methods and apparatuses described above advantageously tend to address these problems.

[0082] Advantageously, the cross-section of the seal gasket described above is substantially constant or uniform, so the tendency for distortion is reduced, the T-seal can withstand a wide compression range, and leakage is reduced.

[0083] The seal gasket described above tends to facilitate the use of the T-seal at higher temperatures, for example up to 300°C.

[0084] The seal gasket can be designed to be slightly shorter than the longitudinal groove of the shell stator (i.e., the gasket groove), so that the tension during assembly can be reduced. Thereby, the seal gasket tends to self-align regardless of the depth of the annular groove.

[0085] The width / thickness of the seal gasket can be made constant in the T-seal region, whereby the tendency for distortion is reduced. Thereby, the T-seal can withstand a wide compression range and leakage tends to be reduced. The width / thickness of the seal gasket can also be made a constant width over the entire seal gasket.

[0086] Advantageously, the seal gasket may be shaped with its sides in a plane (i.e., the configuration of FIG. 2). This tends to result in a continuous seal surface without a parting line from the sidewalls of the mold, which ensures a highly reliable seal surface. This integral seal shape can be reconfigured using only bending to fit the seal housing, and the seal does not need to be threaded in any section.

[0087] It should be understood that the cord and gasket can have various shapes or thicknesses according to the configuration of the housing.

[0088] In the above embodiment, the seal gasket is a continuous integral seal gasket. However, in other embodiments, the seal gasket comprises a plurality of separate parts joined to each other. The plurality of parts can be joined together by some joining means or method, such as using an adhesive, using fusion, or using an interference fit.

[0089] In the above embodiment, the seal gasket has a substantially constant cross-section over its parts. However, in other embodiments, the seal gasket has a non-constant cross-section.

[0090] In the above embodiment, the seal gasket has a square or rectangular cross-section. However, in other embodiments, part or all of the seal gasket has an alternative cross-section other than square or rectangular, such as circular, triangular, elliptical, etc.

[0091] In the above embodiment, the seal gasket can be made of an elastomer. In some embodiments, the seal gasket can be made of another deformable material, such as metal, for example.

[0092] It should be understood that the major surfaces of the seal gasket in the above embodiment are substantially planar, but can be of any suitable shape suitable for engaging the major surface of the end plate and the adjacent surface of the shell stator.

[0093] In the above embodiment, the seal gasket includes a curved surface portion at the joint between the annular seal member and the longitudinal seal member. These curved surface portions provide a continuous transition portion between the annular seal member and the longitudinal seal member. Similarly, one or both of the shell stators include a curved surface portion between the longitudinal gasket seal groove and the annular seal groove. However, in other embodiments, the joint between the annular seal member and the longitudinal seal member and / or the joint between the stator seal grooves of the stator portion are not curved and / or not continuous.

[0094] As a first example, FIGS. 7a and 7b show shell stators 12, 14 according to an alternative embodiment.

[0095] In this embodiment, the shell stator 14 includes a curved surface portion 70 at the joint between the first seal groove 60 and the second seal groove 62. The curved surface portion 70 provides a certain degree of continuity between the concave surfaces (e.g., flat bottom surfaces) of the seal grooves 60, 62.

[0096] Also, in this embodiment, the shell stator 12 includes a seal groove 72 for receiving the annular seal member at its end face. When the shell stators 12, 14 are assembled together, the seal grooves 62, 72 form an annular seal groove for receiving the annular seal members 22, 24 of the seal gasket 20. The seal groove 72 includes a curved surface portion 74 at the joint between the seal groove 72 and the joint surface of the shell stator 12 (i.e., the surface of the shell stator 12 that joins / opposes the shell stator 14). In addition, there is a discontinuous portion or edge 76 disposed between the curved surface portion 74 and the joint surface of the shell stator 12. This discontinuous portion or edge 76 tends to facilitate or enable the omission of the seal groove at the joint surface of the shell stator 12. Thus, the manufacture of the shell stator 12 tends to be facilitated.

[0097] The discontinuities or edges 76 tend to provide improved contact between the seal gasket 20 and the housing 10, and thus an improved seal.

[0098] As a second example, FIGS. 8a and 8b show shell stators 12, 14 according to a further alternative embodiment.

[0099] In this embodiment, the shell stator 14 includes a multi-faceted portion 80 at the junction between the first seal groove 60 and the second seal groove 62. In this embodiment, there are a plurality of discrete surfaces disposed between the first seal groove 60 and the second seal groove 62. Thus, the first and second seal grooves 60, 62 are clearly separated from each other and are discrete rather than continuous. In this example, the multi-faceted portion 80 includes three separate surfaces, but those skilled in the art should understand that the multi-faceted portion 80 can include, for example, four or more or less than three different numbers of facets or surfaces.

[0100] This multi-faceted portion 80 tends to be relatively easy to manufacture, for example, by machining.

[0101] An equivalent multi-faceted portion can be provided on the opposing shell stator 12.

[0102] As a third example, FIGS. 9a and 9b show shell stators 12, 14 according to yet another embodiment.

[0103] In this embodiment, the shell stator 14 includes only a single planar portion 90 at the junction between the first seal groove 60 and the second seal groove 62. The single planar portion 90 can be considered as a chamfer or chamfered transition between the first seal groove 60 and the second seal groove 62. The first and second seal grooves 60, 62 are clearly separated from each other and are discrete rather than continuous.

[0104] This single planar portion 90 tends to be relatively easy to manufacture, for example, by machining.

[0105] Equal single planar portions can be provided on the opposing shell stators 12.

[0106] As a fourth embodiment, FIGS. 10a and 10b show shell stators 12, 14 according to a further alternative embodiment.

[0107] In this embodiment, the shell stator 14 includes a polyhedral portion 100 at the junction between the first seal groove 60 and the second seal groove 62. In this embodiment, there are a plurality of discrete surfaces disposed between the first seal groove 60 and the second seal groove 62. Thus, the first and second seal grooves 60, 62 are clearly separated from each other and are discrete rather than continuous. In this example, the polyhedral portion 100 includes four separate surfaces, but those skilled in the art should understand that the polyhedral portion 100 can include, for example, more than five or less than four different numbers of facets or surfaces. By having more facets, the polyhedral portion 100 is easier to manufacture but can approach a curved surface.

[0108] This polyhedral portion 80 tends to be relatively easy to manufacture, for example, by machining.

[0109] Equal polyhedral portions can be provided on the opposing shell stators 12.

[0110] As a fifth embodiment, FIGS. 11a and 11b show shell stators 12, 14 according to an alternative embodiment.

[0111] In this embodiment, the shell stator 14 includes a curved surface portion 110 and a planar portion 112 at the junction between the first seal groove 60 and the second seal groove 62. The curved surface portion 70 provides some continuity between the concave surfaces (e.g., flat bottom surfaces) of the seal grooves 60, 62. The planar portion 112 is disposed between the curved surface portion 110 and the first seal groove 60.

[0112] Also, in this embodiment, the shell stator 12 can be provided with a seal groove for receiving an annular seal member on its end face. This seal groove has a curved surface portion 114 and a flat surface portion 116 at the joint portion between the seal groove and the joint surface of the shell stator 12. The flat surface portion 116 is disposed between the curved surface portion 114 and the joint surface of the shell stator 12.

[0113] Using one or both of the flat surface portions 112, 116 can result in improved contact between the seal gasket 20 and the housing 10, and as a result, improved sealing performance.

[0114] As a sixth embodiment, FIGS. 12a and 12b show shell stators 12, 14 according to an alternative embodiment.

[0115] In this embodiment, the shell stator 14 has a curved surface portion 120 and two flat surface portions 122, 124 at the joint portion between the first seal groove 60 and the second seal groove 62. The curved surface portion 120 provides a certain degree of continuity between the concave surfaces (e.g., flat bottom surfaces) of the seal grooves 60, 62. The first flat surface portion 122 is disposed between the curved surface portion 120 and the first seal groove 60. The second flat surface portion 124 is disposed between the curved surface portion 120 and the second seal groove 62.

[0116] Also, in this embodiment, the shell stator 12 can be provided with a seal groove for receiving an annular seal member on its end face. This seal groove has a curved surface portion 126 and two flat surface portions 127, 128 at the joint portion between the seal groove and the joint surface of the shell stator 12. The flat surface portion 127 is disposed between the curved surface portion 126 and the joint surface of the shell stator 12. The flat surface portion 128 is disposed between the curved surface portion 126 and the seal groove on the end face of the shell stator 12.

[0117] Using one or more of the planar portions 122, 124, 127, 128 can result in improved contact between the seal gasket 20 and the housing 10, and as a result, improved sealing performance.

[0118] In the above embodiment, the seal gasket can be manufactured by molding as an integrally molded article, as a substantially planar or flat article as shown in FIG. 2. However, in other embodiments, the seal gasket can be manufactured in various ways by molding as an integrally molded article, as a substantially planar or flat article, for example, as shown in FIG. 13 (refer to the integrally molded, substantially planar or flat gasket 130) or FIG. 14 (refer to the integrally molded, substantially planar or flat gasket 140).

[0119] In some embodiments, the seal gasket includes an annular seal member that seals the end plate during use. However, these seal members can have a shape other than strictly annular. The seal member defines a closed shape and can define a closed shape other than annular, such as a loop, ring, ellipse, oval, rounded square or rounded rectangle (i.e., a square or rectangle with rounded corners), squircle, or rounded polygon.

[0120] Next, an embodiment will be described in which the seal member that seals the end plate during use defines a rounded square, i.e., a substantially squircle.

[0121] FIGS. 15 and 16 are schematic views (not to scale) of a further seal gasket 150 for sealing the housing 10 according to one embodiment.

[0122] The seal gasket 150 includes a first seal member 151, a second annular seal member 152, a first longitudinal seal member 153, and a second longitudinal seal member 154.

[0123] The first sealing member 151 defines a closed shape. Specifically, in this embodiment, the first sealing member 151 defines a rounded square, i.e., a square with rounded corners, or substantially a squircle.

[0124] The first sealing member 151 includes a first rounded square surface 161, a second rounded square surface 162 on the opposite side of the first rounded square surface 161, a first inner surface 163, and a first outer surface 164 on the opposite side of the first inner surface 163. The first inner surface 163 and the first outer surface 164 are disposed between the first rounded square surface 161 and the second rounded square surface 162.

[0125] The first sealing member 151 includes a first curved section 165a, a second curved section 165b, a third curved section 165c, a fourth curved section 165d, a first substantially straight section 166a disposed between the first curved section 165a and the second curved section 165b, a second substantially straight section 166b disposed between the second curved section 165b and the third curved section 165c, a third substantially straight section 166c disposed between the third curved section 165c and the fourth curved section 165d, and a fourth substantially straight section 166d disposed between the fourth curved section 165d and the first curved section 165a. The first longitudinal sealing member 153 is coupled to the first curved section 165a. The second longitudinal sealing member 154 is coupled to the third curved section 165c.

[0126] The second sealing member 152 defines a closed shape. Specifically, in this embodiment, the second sealing member 152 defines a rounded square, i.e., a square with rounded corners, or substantially a squircle.

[0127] The second seal member 152 includes a third rounded square surface 171, a fourth rounded square surface 172 on the opposite side of the third rounded square surface 171, a second inner surface 173, and a second outer surface 174 on the opposite side of the second inner surface 173. The second inner surface 173 and the second outer surface 174 are disposed between the third rounded square surface 171 and the fourth rounded square surface 172.

[0128] The second seal member 152 includes a fifth curved section 175a, a sixth curved section 175b, a seventh curved section 175c, an eighth curved section 175d, a fifth substantially linear section 176a disposed between the fifth curved section 175a and the sixth curved section 175b, a sixth substantially linear section 176b disposed between the sixth curved section 175b and the seventh curved section 175c, a seventh substantially linear section 176c disposed between the seventh curved section 175c and the eighth curved section 175d, and an eighth substantially linear section 176d disposed between the eighth curved section 175d and the fifth curved section 175a. The first longitudinal seal member 153 is coupled to the fifth curved section 175a. The second longitudinal seal member 154 is coupled to the seventh curved section 175c.

[0129] The first longitudinal seal member 153 is coupled or attached between the first outer surface 164 (of the first seal member 151) and the second outer surface 174 (of the second seal member 152).

[0130] The second longitudinal seal member 154 is coupled or attached between the first outer surface 164 (of the first seal member 151) and the second outer surface 174 (of the second seal member 152).

[0131] The second longitudinal seal member 154 is disposed on the opposite side of the first longitudinal seal member 153. That is, the second longitudinal seal member 154 is on the opposite side of the first and second seal members 151, 152 with respect to the side where the first longitudinal seal member 153 is coupled to the first and second seal members 151, 152, and is coupled to the first and second seal members 151, 152.

[0132] The first seal member 151 has a square or rectangular cross-section. The second seal member 152 has a square or rectangular cross-section.

[0133] The first longitudinal seal member 153 can be an O-ring cord. The first longitudinal seal member 153 can have a square or rectangular cross-section.

[0134] The second longitudinal seal member 154 can be an O-ring cord. The second longitudinal seal member 154 can have a square or rectangular cross-section.

[0135] In this embodiment, the seal gasket 150 is a continuous integral seal gasket.

[0136] In this embodiment, the seal gasket 150 includes curved surface portions 180a-d at the joint portions between the rounded square seal members 151, 152 and the longitudinal seal members 153, 154. These can be the same as or similar to the curved surface portions 48a-d described in detail above with reference to FIG. 2.

[0137] The seal gasket 150 is made of a deformable or flexible material such as an elastomer material (e.g., fluororubber (FKM / FPM) or perfluoroelastomer (FFKM)) or silicon so that the seal gasket 150 is deformable or flexible. Accordingly, the seal gasket 150 can be deformed into a desired shape or configuration suitable for use as a seal for the housing 10.

[0138] The seal gasket 150 can be mounted in the housing 10 as described in detail above with reference to FIG. 4, for example. In this way, the first and second longitudinal seal members 153, 154 can be arranged in a sealing engagement with the shell stators 12, 14, and these shell stators 12, 14 can be clamped together to compress the longitudinal seal members 153, 154. Also, the rounded square seal members 151, 152 can be positioned in a closed-shaped seal groove located in the shell stators 12, 14 and / or the end plates 16, 18. The seal groove can have any suitable closed shape such as annular, circular, elliptical, stadium-shaped, rounded square, squircle, rounded rectangular, rounded polygonal, etc.

[0139] FIG. 17 is a schematic view (not to scale) showing a first seal member 151 fitted in a closed-shaped seal groove 177 positioned in the shell stators 12, 14. In this embodiment, the seal groove 177 defines a rounded square or a rounded rectangle. In this embodiment, the second seal member 152 can be fitted in a seal groove 177 of substantially the same closed shape at the opposite ends of the shell stators 12, 14.

[0140] In this embodiment, the curved sections 165a-d of the first seal member 151 are positioned in the respective substantially linear portions of the seal groove 177. Also, the substantially linear sections 166a-d of the first seal member 151 are positioned in the respective curved portions of the seal groove 177.

[0141] Specifically, the first curved section 165a is disposed in the first substantially linear portion 178a of the seal groove 177, the second curved section 165b is disposed in the second substantially linear portion 178b of the seal groove 177, the third curved section 165c is disposed in the third substantially linear portion 178c of the seal groove 177, the fourth curved section 165d is disposed in the fourth substantially linear portion 178d of the seal groove 177, the first substantially linear section 166a is disposed in the first curved portion 179a of the seal groove 177, the second substantially linear section 166b is disposed in the second curved portion 179b of the seal groove 177, the third substantially linear section 166c is disposed in the third curved portion 179c of the seal groove 177, and the fourth substantially linear section 166d is disposed in the fourth curved portion 179d of the seal groove 177.

[0142] As described above, the substantially rounded square seal member is disposed within the substantially rounded square seal groove, and the curved sections of the substantially rounded square seal member are positioned in the substantially linear portions of the seal groove, while the substantially linear sections of the seal member are positioned in the curved portions of the seal groove 177. This advantageously tends to reduce the stress on the substantially rounded square seal member. Specifically, the combined bending and / or twisting of the seal member when it is installed in the seal groove tends to be reduced compared to seal members of other shapes. This tends to improve the seal life. Further, the retention of the seal member within the seal groove holding portion tends to be improved. For example, the reduction in the twisting and / or combined bending of the seal member tends to reduce the seal member from twisting out of the seal groove.

[0143] Exemplary embodiments of the present invention are disclosed in detail herein with reference to the accompanying drawings, but the present invention is not limited to the exact embodiments, and it should be understood that those skilled in the art can make various changes and modifications without departing from the scope of the present invention defined by the appended claims and their equivalents.

Description of Reference Numerals

[0144] 10 Housing 12, 14 Shell stator 16, 18 End plate 20 Seal gasket 22 First annular seal member 24 Second annular seal member 26 First longitudinal seal member 28 Second longitudinal seal member 30 First annular surface 32 Second annular surface 34 First radially inner surface 36 First radially outer surface 40 Third annular surface 42 Fourth annular surface 44 Second radially inner surface 46 Second radially outer surface 48a - d Curved surface portion s40~s48 Method steps 50, 52 Directions 60 First seal groove 62 Second seal groove 64 Curved surface portion 70 Curved surface portion 72 Seal groove 74 Curved surface portion 76 Discontinuous portion 80 Polyhedral portion 90 Flat surface portion 100 Polyhedral portion 110 Curved surface portion 112 Flat surface portion 114 Curved surface portion 116 Flat surface portion 120 Curved surface portion 122, 124 Flat surface portions 126 Curved surface portion 127, 128 Flat surface portions 130, 140 Seal gaskets 150 Seal gasket 151 First seal member 152 Second sealing member 153 First longitudinal sealing member 154 Second longitudinal sealing member 161 First rounded square surface 162 Second rounded square surface 163 First inner surface 164 First outer surface 165a - d Curved portion 166a - d Straight portion 171 Third rounded square surface 172 Fourth rounded square surface 173 Second inner surface 174 Second outer surface 175a - d Curved portion 176a - d Straight portion 177 Sealing groove 178a - d Straight portion of the sealing groove 179a - d Curved portion of the sealing groove 180a - d Curved surface portion

Claims

1. A seal gasket for a vacuum pump, comprising: A first seal member defining a closed shape, having: A first surface; A second surface opposite to said first surface; A first inner surface; A first outer surface opposite to said first inner surface; wherein said first inner surface and said first outer surface are disposed between said first surface and said second surface; A second seal member defining a closed shape, having: A third surface; A fourth surface opposite to said third annular surface; A second inner surface; A second outer surface opposite to said second inner surface; wherein said second inner surface and said second outer surface are disposed between said third surface and said fourth surface; A first longitudinal seal member coupled between said first outer surface and said second outer surface; A second longitudinal seal member coupled between said first outer surface and said second outer surface; The seal gasket for a vacuum pump.

2. Said first seal member defines a rounded square or a rounded rectangle, Said first surface is a surface in the shape of a rounded square or a rounded rectangle, Said second surface is a surface in the shape of a rounded square or a rounded rectangle. The seal gasket according to claim 1.

3. Said first seal member has: A first curved section; A second curved section; A third curved section; A fourth curved section; A first substantially linear section disposed between said first curved section and said second curved section; A second substantially linear section disposed between said second curved section and said third curved section; A third substantially linear section disposed between said third curved section and said fourth curved section; A fourth substantially linear section disposed between said fourth curved section and said first curved section; Said first longitudinal seal member is coupled to said first curved section, Said second longitudinal seal member is coupled to said third curved section. The seal gasket according to claim 2.

4. Said second seal member defines a rounded square or a rounded rectangle, The third surface is a surface having a rounded square or rounded rectangular shape. The fourth surface is a surface having a rounded square or rounded rectangular shape. The seal gasket according to any one of claims 1 to 3.

5. The second seal member a fifth curved section, a sixth curved section, a seventh curved section, an eighth curved section, a fifth substantially linear section disposed between the fifth curved section and the sixth curved section, a sixth substantially linear section disposed between the sixth curved section and the seventh curved section, a seventh substantially linear section disposed between the seventh curved section and the eighth curved section, an eighth substantially linear section disposed between the eighth curved section and the fifth curved section, and includes: The first longitudinal seal member is coupled to the fifth curved section. The second longitudinal seal member is coupled to the seventh curved section. The seal gasket according to claim 4.

6. The seal gasket is an integral gasket. The seal gasket according to any one of claims 1 to 5.

7. The seal gasket is a molded gasket. The seal gasket according to any one of claims 1 to 6.

8. Part or all of the seal gasket has a square or rectangular cross section. The seal gasket according to any one of claims 1 to 7.

9. The seal gasket is deformable. The seal gasket according to any one of claims 1 to 8.

10. The seal gasket is an elastomer. The seal gasket according to any one of claims 1 to 9.

11. A shell stator that defines at least one pump chamber, An end piece attachable to any end of the shell stator, The seal gasket according to any one of claims 1 to 10, A vacuum pump comprising.

12. The seal gasket is as described in claim 3 or a claim dependent thereon. The first seal member is disposed in a first seal groove. The first curved section is disposed in the first substantially linear portion of the first seal groove. The second curved section is disposed in a second substantially linear portion of the first seal groove, The third curved section is disposed in a third substantially linear portion of the first seal groove, The fourth curved section is disposed in a fourth substantially linear portion of the first seal groove, The first substantially linear section is disposed in a first curved portion of the first seal groove, The second substantially linear section is disposed in a second curved portion of the first seal groove, The third substantially linear section is disposed in a third curved portion of the first seal groove, The fourth substantially linear section is disposed in a fourth curved portion of the first seal groove. The vacuum pump according to claim 11.

13. The seal gasket is as described in claim 5 or a claim dependent thereon, The second seal member is disposed in a second seal groove, The fifth curved section is disposed in a first substantially linear portion of the second seal groove, The sixth curved section is disposed in a second substantially linear portion of the second seal groove, The seventh curved section is disposed in a third substantially linear portion of the second seal groove, The eighth curved section is disposed in a fourth substantially linear portion of the second seal groove, The fifth substantially linear section is disposed in a first curved portion of the second seal groove, The sixth substantially linear section is disposed in a second curved portion of the second seal groove, The seventh substantially linear section is disposed in a third curved portion of the second seal groove, The eighth substantially linear section is disposed in a fourth curved portion of the second seal groove. The vacuum pump according to claim 11 or 12.

Images