CN216555325U

CN216555325U - Longitudinal seal and vacuum system

Info

Publication number: CN216555325U
Application number: CN201990001003.3U
Authority: CN
Inventors: P·诺思; N·特纳; M·弗马
Original assignee: Edwards Ltd
Current assignee: Edwards Ltd
Priority date: 2018-09-05
Filing date: 2019-09-04
Publication date: 2022-05-17
Anticipated expiration: 2029-09-04
Also published as: JP3233724U; TW202023837A; GB2576896A; GB2576896B; WO2020049295A1; DE212019000370U1; TWM640001U; GB201814455D0; KR20210001093U

Abstract

A longitudinal seal and vacuum system, the longitudinal seal having a cross-section comprising a wall (10) surrounding an inner section; wherein the wall is formed of a material configured such that a physical property of the material varies by at least 10% along at least one of a length and a cross-section of the seal, the variation in the physical property resulting in a variation in at least one of deformability and elasticity of a corresponding portion of the seal.

Description

Longitudinal seal and vacuum system

Technical Field

The field of the utility model relates to seals, vacuum systems having such seals, and methods of manufacturing seals.

Background

Systems that operate with pressure differentials, such as vacuum systems, require effective seals at the connections between the different components in order to operate efficiently.

An effective seal is one that is resilient and capable of deforming to fill the gap. The seal is typically manufactured using an elastomeric material that is resilient and deformable.

Some vacuum systems operate at high temperatures and/or process aggressive materials. Elastomeric seals may not be sufficiently resistant to high temperatures or aggressive materials to function as an effective seal in such systems.

Materials with higher resistance to such environments include metals. Metal seals are known. Metal seals have the disadvantage that they require high clamping forces and a fine finish on the surfaces between which they attempt to seal in order for them to seal effectively. Higher clamping forces can result in deformation of the clamped components and may require specialized clamping components and tools to loosen and tighten the clamping components. Finer polishing of the surface is expensive.

It would be desirable to provide a seal that is capable of withstanding higher temperature operation and/or at least some aggressive materials, and forming an effective seal at relatively low clamping forces.

SUMMERY OF THE UTILITY MODEL

A first aspect provides a longitudinal seal having a cross-section including a wall surrounding an interior section; wherein the wall is formed of a material configured such that a physical property of the material varies by at least 10% along at least one of a length and the cross-section of the seal, the variation in the physical property resulting in a variation in at least one of deformability and elasticity of a corresponding portion of the seal.

The degree of deformability and elasticity of the seal affect its sealing properties. The inventors of the present invention have realised that both the resilience and deformability are dependent on the physical properties of the material from which the seal is formed, and that varying these properties in different parts of the seal may allow the seal to function more effectively. The physical properties include density and width of the seal wall.

Varying the physical properties along the length or cross-section of the seal changes its sealing properties and these may be selected to improve the sealing effect of the seal. For example, the deformability of a segment configured to cooperate with the surface to be sealed may be increased, and the elasticity of the segment may be correspondingly reduced. However, the overall elasticity of the seal may be maintained by increasing the elasticity of another portion of the seal in which deformability may be less important. In this way, the characteristics of a seal formed from a material that is less elastic or deformable than the elastomer can be adjusted to increase the effectiveness of the seal. This allows for an effective seal to be made from a material with a lower spring force, which may have increased resistance to higher temperatures and aggressive chemicals.

The longitudinal seal is an elongated seal that is longer than its width. The length is the distance along the wall of the seal and the width is the distance across the cross-section. The seal may be a ring, wherein the length is the circumference of the ring. The sealing surface is on the outer periphery of the wall.

In some embodiments, the at least one physical property comprises a thickness of the wall.

Varying the thickness of the wall, i.e. the size of the wall in the cross-section of the seal, varies the elasticity and deformability of the seal; thicker walls provide higher elasticity, while thinner walls provide greater deformability. Knowledge of the effect of wall thickness variation on performance allows the seal to be designed and constructed with increased deformability where appropriate, which is compensated for by increased resilience at other points where deformability is not important.

In some embodiments, the thickness of the wall varies along a length of the seal.

The thickness of the wall may vary along the length of the seal and may be as low as 0.01mm in some embodiments and at some locations along the seal, while rising to higher values, possibly up to 0.5mm, at other locations. In any case, the variation along the length will be at least 10%, and in some embodiments at least 50%, and in other embodiments at least 100%.

In some embodiments, the seal is configured to seal against a surface in a vacuum system, and the wall is configured to be thinner at a portion along a length of the seal away from a clamping element used to clamp the seal between the surfaces, such that the elasticity of the seal away from the clamping element is reduced.

Varying the thickness of the wall along the length of the seal allows the seal to be constructed so that it has greater resilience at the point where the seal will be clamped in use. At these pinch points, there is greater force on the seal, and therefore, greater resilience at these points allows the seal to maintain a more uniform cross-section and a more uniform sealing effect along the length of the seal. In fact, it allows the elasticity of the seal away from the clamping element to be reduced, and allows for reduced clamping forces and more effective sealing.

In some embodiments, the thickness of the wall varies around the cross-section of the seal.

Alternatively and/or additionally, the thickness of the wall may vary around the cross-section of the seal. For example, it may be lower at or near the sealing surface of the seal. In this regard, the seal is configured to have an outer peripheral surface with a sealing surface thereon. These portions of the outer surface are the portions that are used to provide the seal. It is advantageous if the sealing surfaces have a high deformability, and therefore it may be advantageous to limit the wall thickness at these points. Having a greater thickness at other points provides a more resilient and stronger seal while allowing it to be deformable at the point at which it seals.

In some embodiments, the at least one physical property comprises a density of the material forming the wall.

Another physical property that affects the elasticity and deformability of the seal is the density of the material forming the walls of the seal. This change in density can allow the performance of the seal to be varied and the seal to be tailored to its particular use.

In some embodiments, the density of the material at the sealing portion of the outer periphery of the seal is lower than the density of the material at the inner edge of the seal.

The lower density material at the sealing outer surface of the seal allows the seal to be more easily deformed and provides a more effective seal. The increased density away from this portion provides a more resilient seal.

In some embodiments, the portion of the wall at and adjacent to the sealing portion comprises a porous or porous portion. In some embodiments, this may be an additional protrusion extending from the outer wall. The protrusion may also be used to help position the seal in a desired location.

One way to reduce the material density and provide a more deformable surface is to change the structure at and adjacent the sealing surface so that the sealing surface collapses and conforms to the mating surface. A porous or porous structure will provide these properties.

In some embodiments, the density of the material forming the wall varies along the length of the seal.

Instead of and/or in addition to the varying density of the material around the cross-section, the density of the material forming the wall may also vary along the length of the seal. In the case where the walls are formed of a porous or porous substance, such density variation may be achieved by varying the porosity along the length of the walls.

In some embodiments, the density of the material forming the wall is lower at a portion of the seal remote from a clamping element used to clamp the seal between the surfaces, such that the resilience of the seal remote from the clamping element is reduced.

In particular, it may be advantageous to have a high density of material at portions of the seal which are configured to be adjacent to the clamping element in use and a lower density portion of material remote from these regions. This provides a reduced resilience of the seal away from the clamping element, and an increased resilience adjacent the clamping element. Adjacent to the clamping element, the clamping force will be higher and therefore the seal will be under greater compression. By varying the density and reducing the required clamping force in this way, a more uniform compression cross section of the seal can be achieved.

In some embodiments, the wall surrounding the inner section includes a portion having a substantially uniform cross-section and a portion having a spring-like configuration.

One way to provide a difference in sealing performance around the cross-section is to have a portion with a uniform cross-section and a portion with a spring-like configuration. The spring-like configuration will provide resilience and elasticity, while the uniform portion will provide an effective sealing surface.

In some embodiments, the portion having the spring-like configuration includes connecting portions angled to the portion and connecting the portion with a uniform cross-section, the connecting portions having a gap therebetween.

In some embodiments, the configuration of the spring-like portion may vary along the length of the seal such that the gap between the connecting portions or the thickness of the connecting portions may vary to vary the elasticity of the seal along its length.

Although the seal may have a variety of shapes, in some embodiments the wall and the inner section have a circular cross-section.

While the wall may extend at least some length of the seal around only a portion of the interior section, in some embodiments the wall surrounds the interior section.

In some embodiments, the wall extends in a longitudinal direction and has a tubular shape.

In some embodiments. The wall extends longitudinally to form a loop.

In some embodiments, the material forming the wall of the seal is a non-elastomeric material.

A seal configured to provide varying elasticity and deformability, allowing an effective seal to be formed from a material that is not elastomeric. Elastomers have high resilience and generally form good seals, but may not be resilient to high temperature or aggressive chemicals. Thus, forming a seal of a non-elastomeric material allows for the selection of materials with appropriate properties for higher temperatures and aggressive chemicals, and such seals may still provide an effective seal with the configurations according to embodiments.

In some embodiments, the material comprises a metallic material.

In some embodiments, the metallic material comprises at least one of aluminum, aluminum alloy, nickel alloy, noble metal, steel, stainless steel, copper.

In other embodiments, the material comprises a polymeric material comprising one or more thermoplastics.

In some embodiments, the polymer material includes at least one of a fluoropolymer, Polyetheretherketone (PEEK), and polyphenylene sulfide (PPS).

Although the seal may be formed entirely of metal or entirely of a polymeric material, in some embodiments it may be formed of a combination of the two materials.

In some embodiments, the inner section comprises a void.

In other embodiments, the inner section comprises a substance for increasing the elasticity of the seal.

The inventors of the present invention have realized that an outer periphery with increased deformability but reduced elasticity may be used for the seal, wherein an inner structure is provided within the outer periphery to increase the elasticity. In this way, for example, the wall thickness can be reduced, making it more deformable and providing a better sealing surface. In this case, a thickness as low as 0.01mm may be acceptable.

In some embodiments, the substance comprises a continuous solid structure attached to the wall.

In some embodiments, the continuous solid structure is non-uniform along a length of the seal such that the elasticity of the seal varies along the length.

To provide variation in the elasticity of the seal along the length of the seal, which may be desirable as previously described, the structure inside the seal may be made non-uniform along the length of the seal.

While the continuous solid structure may have a variety of forms, in some embodiments it includes at least one inner wall that extends across the interior section.

In some embodiments, the at least one inner wall extends across a diameter of the inner section.

In other embodiments, the substance comprises a porous or porous material.

A porous or porous material, i.e. a material with voids, allows it to be compressed and also provides elasticity.

In some embodiments, the seal is configured to cooperate with a surface to be sealed and the density of the foraminous material remote from a clamping element used to clamp the seal between the surfaces is reduced such that the resilience of the seal remote from the clamping element is reduced.

The change in density of the internal substance can be used to change the elasticity of the seal. Where the seal is used in conjunction with a clamping element to retain the seal, it may be advantageous to increase the resilience at points adjacent the clamping element and have reduced resilience at other points.

A second aspect of the utility model provides a vacuum system comprising at least one seal according to the first aspect of the utility model.

In some embodiments, the vacuum system comprises at least one seal configured to have a portion with reduced elasticity through reduced thickness of the wall and/or reduced elasticity of the internal structure, the vacuum system having a clamping element to retain the at least one seal between two mating surfaces at the portion with increased elasticity of the seal.

A third aspect of the utility model provides a method of manufacturing a seal according to any preceding claim using additive manufacturing techniques.

Conventionally, seals, for example made of metal, are made to form a metal tube or other profile and joined by welding. It is difficult to control the young's modulus and other mechanical properties of sealing elements made by these conventional methods. Using additive manufacturing techniques allows the mechanical properties to vary in the cross-section of the seal and also around the periphery of the seal and along its length. This allows the seal to be designed with variations in these properties appropriate to its environment, allowing lower resilience materials to provide an effective seal. This may allow the vacuum system to use lower clamping forces and still provide high seal integrity.

In some embodiments, the additive manufacturing technique is selected from the group consisting of Stereolithography (SLA), Fused Deposition Modeling (FDM), multi-jet modeling (MJM), 3D printing, and Selective Laser Sintering (SLS).

Further specific and preferred aspects are set forth in the main and preferred embodiments. The features of the preferred embodiments may be combined with those of the main embodiments as appropriate, and may be combined in combinations other than those explicitly set forth in the main and preferred embodiments.

Where an apparatus feature is described as being operable to provide a function, it will be understood that this includes an apparatus feature that provides that function or is adapted or configured to provide that function.

Drawings

Embodiments of the utility model will now be further described with reference to the accompanying drawings, in which:

FIG. 1 shows a cross-section of a seal having a variable wall thickness according to a first embodiment;

FIG. 2 shows a longitudinal cross-section of a seal according to a second embodiment having a variable wall thickness along the length of the seal;

FIG. 3 schematically shows a cross-section of a seal according to a third embodiment, the seal having a variable density across the cross-section;

FIG. 4 schematically illustrates a cross-section of a seal having a variable density across the cross-section according to another embodiment;

FIG. 5 shows a cross-section of a seal with internal structure for increased elasticity;

FIG. 6 shows a longitudinal cross-section of a seal having an internal structure with variable density along the length of the seal;

FIG. 7 shows a longitudinal cross-section of a seal having a spring-like configuration for a portion of the outer wall; and

fig. 8 shows a cross-section of the seal of fig. 7.

Detailed Description

Before discussing the embodiments in any more detail, an overview will first be provided.

Using additive manufacturing techniques to manufacture the seal allows the seal to be manufactured with a targeted variation in spring force, which allows the sealing force to be optimized for the sealing effect against the clamping force. Indeed, the profile, shape, and materials of construction of the seal may be designed to provide the desired seal integrity with reduced clamping forces.

Due to this ability to fine tune the seal design, it can be made of a material with reduced spring properties, such as metal. Such materials may have improved heat and chemical resistance.

Features that allow this improved seal integrity with reduced clamping force include:

a variable thickness of elements of the profile;

complex structures that provide spring force within the seal;

the change in structure or density at the sealing surface, for example, provides an open structure, such as foam, that will collapse and conform to the mating surface.

In some embodiments, additional features may be added, such as features to position or align the seal to the sealing face and coatings on the sealing face to enhance seal integrity.

Fig. 1 shows a cross section of a seal according to an embodiment, wherein the outer wall 10 surrounding the inner section has a variable wall thickness. Providing a variation in wall thickness allows portions of the wall, thicker portions, to provide increased elasticity, while thinner portions have increased deformability. The portions with increased deformability provide more effective sealing surfaces because they are more easily deformed. Thus, the seal is configured to have thinner walls over its sealing area, i.e. over the area of the outer surface that provides the sealing effect when the seal is installed in a vacuum system in use, than other parts remote from these sealing parts. In this way the effective sealing portion is more easily deformed, while the whole seal retains its elasticity due to the thicker portion.

Fig. 2 shows a longitudinal section through a second embodiment of the seal, which has an outer wall 10 of different thickness in a similar manner to the embodiment of fig. 1. In this particular embodiment, the thickness variation occurs along the length of the seal. It should be noted that the variation may occur in the cross-section of the seal and/or around the periphery of the seal and/or along the length of the seal. In this case, the thicker portion of the seal is configured to be located within the vacuum system adjacent to the clamping element such that the clamping force 20 acts on the more resilient portion of the seal, and the portion of the seal remote from the clamping element and having a reduced clamping force acting thereon is formed with a thinner wall and has a lower resilience but greater deformability. In this way, a seal is provided which is suitable for its use and which allows the sealing force to be optimized or at least improved for the sealing effect against the clamping force.

Fig. 3 shows an alternative embodiment in which the physical property for adapting the seal to the forces acting on it during use is the density of the material, which changes the density of the material forming the outer wall 10. In this case, the density may vary over the cross-section of the seal and/or it may vary along the length of the seal. Thus, a density-reduced portion having lower elasticity and a density-increased portion having higher elasticity are provided. The reduced resilience portion may be disposed towards the sealing surface around the periphery and the increased density portion may be disposed away from these portions and at a longitudinal position corresponding to the position of the clamping element when the seal is mounted in use in a vacuum assembly.

Fig. 4 shows another embodiment, in which the outer wall is provided with additional areas 12 protruding from the wall, and in which the material is perforated and therefore has a particularly low density. These are provided at the sealing surface of the seal and will compress and conform to the mating surface. They may also be used to position the seal in a certain orientation within the vacuum system.

Fig. 5 shows a cross section of another embodiment, in which an internal structure is provided in the outer wall 10. In this embodiment, an inner wall 22 is provided which passes through the inner section of the seal and provides resilience to seal deformation. The addition of such an internal structure allows the outer wall to be made thinner than would be the case without the internal structure. This has the advantage of providing improved deformability of the outer structure, which may provide an improved seal and allow the seal to provide an effective seal in a vacuum system with a less fine polishing of the sealing surface.

Although in this embodiment the internal structure is provided by an internal wall extending and attached to the outer wall 10, in other embodiments the internal structure may be different and may for example be formed from a perforated material. Such a perforated material may have different densities across its cross-section and may also have different densities along its length, thereby providing targeted variation in the elasticity of the seal at different points. In a similar manner, the seal of fig. 5 may have a variation in the width of the inner wall 22 along its length to provide a difference in elasticity. In addition to the variation in porosity and thus the density of the internal substance, the wall may also be formed of a porous substance, the porosity of which may also vary along its length.

Fig. 6 shows a longitudinal cross-section through a seal having a perforated interior 24, wherein the density of the perforated interior varies along the length of the seal, allowing the seal to be arranged such that when installed in a vacuum assembly, areas of increased density and increased elasticity are closer to the clamping elements, while areas of reduced density and reduced elasticity are further from these elements. This allows the seal to be held in place with a reduced clamping force without unduly affecting the sealing performance of the seal.

Fig. 7 shows a side view of another embodiment, in which a portion of the periphery of the seal is formed by a strip 30 of material forming the outer wall 10, which provides a spring-like construction and increases the resilience of the seal.

Fig. 8 shows a cross-section of such a seal. It should be noted that the number, thickness and gaps between the strips may vary along the length of the seal to increase or decrease the elasticity of the seal at different portions as desired.

The seal is shown in cross-section, longitudinal section or as a side view. They may have a tubular form and the tubular form may be a ring adapted to seal between e.g. stators of vacuum pumps or around connecting elements in vacuum systems. Due to their ability to not use elastomeric materials for these seals, they are particularly effective for use in abatement systems where aggressive materials may be pumped and high temperatures are used.

The use of additive manufacturing techniques to manufacture the seals allows them to be made of metal, for example, and also have properties that can vary along the length and/or around the perimeter and/or across the cross-section. This allows the seal to be adapted to a specific position and a specific clamping force and improves the sealing effect.

Although illustrative embodiments of the present invention have been disclosed in detail herein with reference to the accompanying drawings, it is to be understood that the utility model is not limited to those precise embodiments, and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the utility model as defined by the appended claims and their equivalents.

List of reference numerals

10 outer wall of sealing element

12 porous structure

20 clamping element

22 inner wall

24 porous internal filling

30 spring-like strips.

Claims

1. A longitudinal seal, wherein the seal is configured to seal against a surface in a vacuum system, the seal having a cross-section comprising a wall surrounding an interior section; wherein

The wall is formed of a material configured such that a physical property of the material varies by at least 10% along at least one of a length and the cross-section of the seal, the variation in the physical property resulting in a variation in at least one of deformability and elasticity of a corresponding portion of the seal.

2. The seal of claim 1, wherein at least one physical property comprises a thickness of the wall, wherein the thickness of the wall varies along a length of the seal.

3. A seal as claimed in claim 2, wherein the wall is configured to be thinner at such a portion along the length of the seal that is configured to be, in use, remote from a clamping element used to clamp the seal between the surfaces, such that the resilience of the seal remote from the clamping element is reduced.

4. A seal as claimed in claim 2 or 3, wherein the thickness of the wall varies around the cross-section of the seal.

5. The seal of claim 4, wherein the thickness of the wall is less at a sealing surface of the seal than at other points on the cross-section of the seal.

6. The seal of any one of claims 1 to 3, wherein at least one physical property comprises a density of the material forming the wall, wherein the density of the material forming the wall varies along a length of the seal.

7. The seal of claim 6, wherein the density of the material at the sealing portion of the outer periphery of the seal is lower than the density of the material at the inner edge of the seal.

8. The seal of claim 6, wherein the density of the wall at the sealing portion of the seal is lower than the density of the wall at a point distal from the sealing portion.

9. The seal of claim 8, wherein a portion of the wall at and adjacent the sealing portion comprises a perforated or porous portion.

10. A seal as claimed in claim 6, wherein the density of the material forming the wall is lower at a portion of the seal which, in use, is configured to be remote from a clamping element used to clamp the seal between surfaces, such that the resilience of the seal remote from the clamping element is reduced.

11. The seal of any one of claims 1 to 3, wherein the wall surrounding the inner section comprises a portion having a uniform cross-section and a portion having a spring-like configuration.

12. The seal of claim 11, wherein the portion having the spring-like configuration includes a connecting portion angled to the portion and connecting the portion with a uniform cross-section, the connecting portion having a gap therebetween.

13. A seal as claimed in any one of claims 1 to 3, wherein the material forming the wall of the seal is a non-elastomeric material.

14. The seal of claim 13, wherein the material comprises:

a metal material; or

A polymeric material comprising a thermoplastic.

15. The seal of claim 14, wherein the metallic material is one of aluminum, aluminum alloy, nickel alloy, precious metal, steel, stainless steel, copper.

16. The seal of claim 14, wherein the polymer material is one of a fluoropolymer, Polyetheretherketone (PEEK), and polyphenylene sulfide (PPS).

17. The seal of any one of claims 1 to 3, wherein the inner section comprises a void.

18. The seal of any one of claims 1 to 3, wherein the inner section comprises a substance for increasing the elasticity of the seal.

19. A seal as claimed in any one of claims 1 to 3, wherein the wall comprises at least one external protrusion formed from a porous or cellular material.

20. A vacuum system, characterized in that it comprises at least one seal according to any of claims 1-19.

21. A vacuum system according to claim 20, wherein the vacuum system comprises at least one seal according to claim 3 or 10, and at least one clamping element for retaining the at least one seal between two mating surfaces, the seal being configured such that the elasticity of the seal is reduced at a portion remote from the at least one clamping element.