JP3234213U - Vacuum pump system with non-elastomer seals and such seals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal which is resistant to high temperature operation and / or at least a part of aggressive materials and provides an effective seal with a relatively low clamping force. Will be disclosed. The seal has a cross section composed of an outer wall surrounding an inner portion. The inner portion comprises a continuous solid structure attached to the outer wall and is configured to increase the elasticity of the seal by providing elasticity that resists deformation of the seal. [Selection diagram] Fig. 5

Description

The technical fields of the present invention relate to seals, vacuum systems with such seals, and methods of making the seals.

Systems operating at different pressures, such as vacuum systems, require effective sealing of the connections between different components in order to operate efficiently.
An effective seal is one that is elastic and can be deformed to fill the gap. Seals are often made using elastic and deformable elastomeric materials.

Some vacuum systems operate at high temperatures and / or process aggressive materials. Elastomer seals may not be sufficiently resistant to high temperatures or aggressive materials to function as effective seals in this system.

A metal can be mentioned as a material having high resistance to such an environment. Metal seals are known. The disadvantage of metal seals is that they require both high clamping forces and a precision finish on each surface to be sealed in between for effective sealing. High clamping forces can lead to deformation of the components to be clamped and may require specialized clamping parts and tools to release and fasten the clamping parts. Precision finishing of the surface is expensive.

It is desirable to provide a seal that is resistant to high temperature operation and / or at least some aggressive materials and provides an effective seal with a relatively low clamping force.

The first aspect provides a seal formed from a non-elastomer material, the seal having a cross section composed of an outer wall surrounding an inner portion, the inner portion comprising a continuous solid structure attached to the outer wall. It is configured to increase the elasticity of the seal by providing elasticity for the deformation of the seal.

The degree of deformability and elasticity of a seal affects its sealing properties. The present inventors recognize that if some high elasticity can be provided to offset the high deformability, the deformability of the outer surface of the seal can be increased to provide an effective seal. Increasing the elasticity by providing a continuous solid structure that does not form a sealing surface portion in the seal can reduce the deformability of at least a part of the sealing surface and at the same time maintain the overall elasticity of the seal. In practice, the continuous solid structure attached to the outer wall of the seal results in increased elasticity of the seal, resulting in greater freedom in the choice of outer wall properties.

In some embodiments, at least a portion of the continuous solid structure extends across the inner portion and joins the outer walls at at least two points.

High elasticity can be provided by a solid structure that extends across the inner part. In some embodiments, the continuous solid structure comprises at least one inner wall extending across the inner portion, while in some embodiments the continuous solid structure comprises a plurality extending across the inner portion. It has an inner side wall of.

One or more inner sidewalls increase elasticity and provide resistance to forces acting to deform the overall cross-sectional shape of the seal.

The seal can have many shapes, but in some embodiments the walls and inner parts have a circular cross section.

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

In other embodiments, the continuous solid structure consists of a porous or polyfoam material.
Porous or polyfoam structures contain voids that can be compressed and even provide elasticity.

In some embodiments, the continuous solid structure is non-uniform along the length of the seal so that the elasticity of the seal varies along the length, alternative and / or additionally. The continuous solid structure can be non-uniform across the cross section of the seal.

A variation in elasticity along the length of the seal is desirable as it allows the seal to have the proper properties for a particular seal position. In this regard, when used in a vacuum system, there will be a clamping force applied to hold the seal in place. These forces may be higher in some areas near the clamp element than in others. It would be convenient to change the elasticity to bring about these fluctuations. This variation can be obtained by making the structure inside the seal non-uniform along the length of the seal.

In addition, there may be a region forming the sealing surface and another region not forming the sealing surface around the outer periphery of the seal. It is equally convenient to provide high deformability near the sealing surface and high elasticity near other parts to offset this, which can enhance the effectiveness of the sealing.

In some embodiments, the thickness of the inner wall varies by at least 10%, preferably at least 50%, along the length of the seal.
The thickness of the inner wall can vary along the length of the seal to result in elastic changes along that length.

Additional and / or alternative, the thickness of the outer wall can vary along its length. In this regard, the wall thickness of the outer wall can be as small as 0.01 mm in some places in some embodiments and perhaps increased to 0.5 mm in others. In either case, the variation can be at least 10%, and in many embodiments 50% or more, or 100% or more. With the inner structure, the elasticity of the seal is higher and the outer wall can be thinner than without it, so thanks to the inner structure it is possible to achieve dimensions as small as 0.01 mm. Keep in mind that you can.

In some embodiments, the density of the porous or polyfoam material forming the continuous solid structure varies by at least 10%, preferably at least 25%, along the seal.
By changing the density of the porous or polyfoam material along the length of the seal, the elasticity of the seal can be changed along its length, and the seal provides elasticity suitable for that particular part. Can be done.

For example, in some embodiments, the seal is configured to match the surface to be sealed, and the seal, in use, has a density of porous material far away from the clamping element for clamping the seal between the surfaces. Is configured to reduce the elasticity of the seal away from the clamp element.

In particular, it would be advantageous to have the high density material in the sealing portions configured to be close to the clamp element during use and to have the low density material far away from these areas. This results in low elasticity of the seal far from the elastic clamp element and high elasticity near the elastic clamp element. The clamping force will be high near the clamping element, thus leaving the seal in a highly compressed state. A more uniform compressed cross section of the seal can be obtained by thus varying the density. In addition, the reduced elasticity of the seal far from the clamping element allows the use of low clamping forces.

In some embodiments, the density of the porous or polyfoam material varies by at least 10%, preferably at least 25%, along the seal.

In some embodiments, the density of the material in the inner portion can vary over the cross section. For example, the density of the material near the seal portion on the outer periphery of the seal is lower than the density of the material far away from the seal portion on the outer circumference of the seal.

It would be convenient to vary the density of the porous or polyfoam material over the cross section so that the density is reduced adjacent to the seal surface and as a result is more likely to be deformed.

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

In other embodiments, the material consists of a polymeric material consisting of one or more thermoplastics.

In some embodiments, the polymer material consists of at least one of a fluoropolymer, polyetheretherketone (PEEK), and polyphenylether (PPS).

The entire seal can be formed of a metallic or polymeric material, but in some embodiments these materials can be formed in combination.

The outer wall is located around the inner part, and in some embodiments, the outer wall surrounds the inner part.

In some embodiments, the walls extend longitudinally and have a tubular shape.

In some embodiments, the walls extend to form a circular structure.

In some embodiments, the walls and inner portions have a circular cross section.

In some embodiments, the seal is a longitudinal or elongated seal, the length of which is longer than the width across its cross section.

A second aspect of the invention provides a vacuum system with at least one seal according to the first aspect of the invention.

In some embodiments, the vacuum system comprises at least one seal composed of parts having various elasticity by changing the properties of the inner structure, and the vacuum system has two cooperative parts with a highly elastic seal part. It has a clamping element to hold at least one seal between the working surfaces.

A third aspect of the present invention provides a method of making the above seal using an additional manufacturing technique.

Traditionally, metal seals have been made by forming a metal tube or other outer shape and joining by welding. It is difficult to control the Young's modulus and other mechanical properties of the sealing elements made by these conventional methods. By utilizing additional manufacturing techniques, seals with an inner structure can be made and the mechanical properties of the inner structure can be varied along the cross section of the seal and also along the length of the seal. .. This allows the seal to be designed with variations in properties appropriate for the environment, resulting in a low elastic material that results in an effective seal. This makes it possible to use the system with low clamping forces and still provide high sealing integrity.

In some embodiments, the additive manufacturing technique is selected from stereo lithography (SLA), Fused Deposition Modeling (FDM), multi-jet modeling (MJM), 3D printing and additive manufacturing (SLS).

Further specific and preferred embodiments are described in independent and dependent claims. The features of the dependent claim can be combined with the features of the independent claim if desired, and other combinations are clearly stated in the claim.

It should be understood that when a device feature is described as operational to provide a function, it includes a device feature that provides or is adapted or configured to provide that function.
Embodiments of the present invention will be further described below with reference to the accompanying drawings.

A cross-sectional view of a seal having a variable wall thickness according to a related method is shown. A vertical cross-sectional view of a seal having a wall thickness that varies with the length of the seal by a related technique is shown. A cross-sectional view of a seal having a density that fluctuates across a cross section according to a related technique is schematically shown. A cross-sectional view of a seal having a density that fluctuates across a cross section according to a related technique is schematically shown. A cross section of a seal having an internal structure for increasing elasticity according to one embodiment is shown. A vertical cross-sectional view of a seal having an inner structure whose density varies along the length of the seal according to one embodiment is shown.

Before explaining the embodiment in more detail, an outline is first presented.
By adopting additional manufacturing techniques for the fabrication of the seal, it is possible to fabricate a seal with the desired elastic variation, which makes it possible to optimize the seal effectiveness against the clamping force. In addition, a solid material configured to increase the elasticity of the seal can be provided on the inside to allow for seals with a more deformable outer wall, resulting in higher seal safety with less clamping force. can get.

This ability to increase the deformability of the outer wall and fine-tune the seal design allows the seal to be made of a material with low elastic properties such as metal. Such materials can have high heat resistance and chemical resistance.

A feature that enables this high seal integrity with a small clamping force is a composite structure inside the seal to increase elasticity. In some examples, varying thicknesses with respect to contour elements and variations in structure or density at the sealing surface are also provided, for example, open structures such as foams that are crushed to fit the mating surfaces.

FIG. 1 shows a cross section of a seal according to a related technique that can be used with the seal according to embodiments as shown in FIGS. 5 and 6. In this example, the outer wall 10 surrounding the inner portion has a variable wall thickness. When the wall thickness is varied, a part of the wall, the thickest part, gives high elasticity, but the thinnest part can have high deformability. The highly deformable part provides an effective sealing surface as it deforms easily. Therefore, the sealing area of the seal, which is the outer surface area that provides the sealing effect when attached to the vacuum system during use, is configured to have a thinner wall than any other portion away from this sealing portion. Thus, the effective seal part is more deformable, but the whole seal retains its elasticity thanks to the thick part.

FIG. 2 shows a vertical cross-sectional view through a second embodiment of a seal according to a related technique, which has a variable outer wall thickness 10 similar to the example of FIG. 1 and is used with the embodiment of the present invention. be able to. In this particular example, the thickness variation occurs over the length of the seal. Note that variations can occur across the cross section and / or perimeter of the seal and / or over length. In this case, the thicker portion of the seal is configured to be located in the vacuum system adjacent to the clamping element, and the clamping force 20 acts on the more elastic portion of the seal, far away from the clamping element. The seal portion with a small clamping force acting on this is formed of a thinner wall and has low elasticity but high deformability. Thus, there is provided a seal that is adapted to the application and allows the seal force to be optimized or at least improved in order to obtain the seal effectiveness against the clamping force.

FIG. 3 shows another example, the physical property used to adapt the seal to the forces acting during use is the density of the material, which causes a change in the outer wall 10. In this case, the density can vary over the cross section of the seal and / or over the length of the seal. Therefore, a lower density portion with lower elasticity is provided, and a high density portion with higher elasticity is provided. The low elastic part can be provided for the purpose of the sealing surface around the outer circumference, while the high elastic area is far away from these parts and the clamp element is located when the seal is attached to the vacuum assembly during use. It can be provided at a position in the longitudinal direction corresponding to the place where it is to be used. Similar to the examples in FIGS. 1 and 2, this technique can be used with embodiments of the present invention.

FIG. 4 shows another example of a related technique, where the outer wall comprises an additional region 12 protruding from the wall and the material is porous, resulting in a particularly low density. These are provided on the sealing surface of the seal and are pressed against the mating surfaces to conform to this. They can also act to position the seal in a particular orientation within the vacuum system. Similar to the examples in FIGS. 1, 2, and 3, this technique can be used with embodiments of the present invention.

FIG. 5 shows a cross section of one embodiment, and an inner structure is provided in the outer wall 10. In this embodiment, an inner wall 22 is provided that traverses the inner portion of the seal and provides elasticity to the deformation of the seal. By adding such an inner structure, the outer wall can be made thinner than when there is no inner structure. This provides improved deformability of the outer structure and can result in improved seals, allowing poor seal surface finish seals to provide effective seals in vacuum systems. Has the advantage of

In this embodiment, the inner structure is provided by an inner wall that extends to and attached to the outer wall 10, but in other embodiments, the inner structure can vary, eg, a porous material. Can be formed with. The porous material can have different densities over its cross section and can also have different densities over its length, which results in the desired changes in the elasticity of the seal at various points. Similarly, the seal of FIG. 5 can have variations in the width of the inner wall 22 along its length to provide a difference in elasticity.

FIG. 6 shows a vertical cross section through a seal according to another embodiment. In this embodiment, the seal comprises a porous interior 24, the density of the porous interior varies along the length of the seal, and the high density and highly elastic regions are adjacent to the clamp element when attached to a vacuum assembly. It allows the seal to be constructed so that the low density and low elastic regions are far away from the clamping element. As a result, the seal can be held in place with a low clamping force without excessively affecting the seal characteristics.

The seal is shown in cross section, vertical section, or side view. The seal can be in the shape of a tube, which can be a circular structure suitable for sealing, for example, between the stators of the vacuum pump or around the connecting elements of the vacuum pump. Thanks to the ability to use no elastomeric material in this seal, the seal is particularly effective for use in abatement systems where aggressive material is pumped and high temperatures may be used.

Utilizing additional manufacturing techniques to make the seal, the seal can be made of metal, for example, and has the property of being able to vary along the length and / or around the perimeter and / or across the cross section. Can have. This allows the seal to adapt to a particular position and a particular clamping force, improving the sealing effect.

In the present specification, exemplary embodiments of the present invention are disclosed in detail with reference to the accompanying drawings, but the present invention is not limited to the detailed embodiments, and claims by those skilled in the art and their equivalents thereof. It should be understood that various changes and modifications can be made within it without departing from the scope of the present invention as defined by.

10 Seal outer wall 12 Porous structure 20 Clamp element 22 Inner side wall 24 Porous inner filling

Claims (17)

A seal formed from a non-elastomer material
The seal has a cross section consisting of an outer wall surrounding an inner portion.
The inner portion comprises a continuous solid structure attached to the outer wall and is configured to increase the elasticity of the seal by providing elasticity to resist deformation of the seal.
The continuous solid structure is
It comprises at least one inner wall extending across the cross section and / or a porous or polyfoam material.
A seal that features that. At least a portion of the continuous solid structure extends across the inner portion and joins the outer walls at at least two points.
The seal according to claim 1. The continuous solid structure comprises a plurality of inner sidewalls extending across the inner portion.
The seal according to claim 1 or 2. The outer wall and the inner portion have a circular cross section.
The seal according to any one of claims 1 to 3. The at least one inner wall extends across the diameter of the inner portion.
The seal according to claim 4. The continuous solid structure is non-uniform along the length of the seal so that the elasticity of the seal changes along the length.
The seal according to any one of claims 1 to 5. The thickness of the inner wall varies by at least 10%, preferably at least 50%, along the length of the seal.
The seal according to claim 6. The density of the porous or polyfoam material varies by at least 10%, preferably at least 25%, along the seal.
The seal according to claim 6 or 7. The seal is configured to be fitted to the surface to be sealed, the seal being said of the porous or polyfoam material that is far from the clamping element for clamping the seal between the surfaces in use. The density is configured to be reduced so that the elasticity of the seal away from the clamp element is reduced.
The seal according to any one of claims 1 to 8. The density of the material in the vicinity of the seal portion on the outer periphery of the seal is lower than the density of the material far away from the seal portion on the outer periphery of the seal.
The seal according to any one of claims 1 to 9. The non-epolymer material is made of, for example, a metal material, which is made of at least one of aluminum, aluminum alloy, nickel, nickel alloy, noble metal, steel, stainless steel and copper.
The seal according to any one of claims 1 to 10. The non-elastomer material comprises, for example, one or more thermoplastics, the polymer material being at least one of a fluoropolymer, a polyether ether ketone (PEEK), and a polyphenyl ether (PPS). Consists of
The seal according to any one of claims 1 to 11. The outer wall surrounds the inner portion.
The seal according to any one of claims 1 to 12. The wall and the inner portion have a circular cross section, and the wall extends longitudinally and has a tubular shape.
The seal according to any one of claims 1 to 13. The wall extends to form a circular structure,
The seal according to claim 14. A vacuum system comprising at least one seal according to any one of claims 1 to 15. The seal comprises at least one seal according to claim 11 and at least one clamping element for holding the at least one seal between two cooperating surfaces, the seal having at least the elasticity of the seal. Constructed to be reduced far away from one clamp element,
The vacuum system according to claim 16.

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