Metal seals often use soft metal platings or coatings to enhance sealing performance. The high ductility of soft metals such as silver allows for increased plastic deformation at the interface of the metal seal and the flanges to be sealed, which thereby enhances sealing performance. However, when the seal to be coated is a resilient metal seal, such as an E-seal, U-seal, or V-seal, the resilient metal seal often does not produce enough contact load to plastically deform the soft metal coating, resulting in inconsistent sealing performance. Soft metal coatings also can be difficult to apply to resilient metal seals having relatively complex geometries, such as in the case of E-seals. Moreover, soft metal coatings may not offer the same degree of corrosion protection or chemical inertness as is offered by other materials typically used in metal sealing applications, such as, for example, polytetrafluoroethylene (PTFE) and similar polymers.
Typical spring-energized PTFE seals rely on various spring configurations for resiliency and to provide contact load necessary to effect a seal. These geometries can include helically-wound springs or cantilever (or finger) springs as illustrated in
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary, and the foregoing Background, is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter.
Described herein are embodiments of a resilient metal seal that includes a PTFE jacket or liner capable of improving the sealing performance of the resilient metal seal and providing a near chemically inert surface to protect the seal from coming into contact with potentially damaging media. In some embodiments, the resilient metal seal is an E-, U-, C-, or V-shaped resilient metal seal. A jacket made of PTFE or similar material can be included on the interior or exterior surface of the resilient metal seal. The jacket can include a locking feature to prevent against the jacket becoming dislodged from the resilient metal seal.
These and other aspects of the present system will be apparent after consideration of the Detailed Description and Figures herein. It is to be understood, however, that the scope of the invention shall be determined by the claims as issued and not by whether given subject matter addresses any or all issues noted in the Background or includes any features or aspects recited in this Summary.
Non-limiting and non-exhaustive embodiments of the present invention, including the preferred embodiment, are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense.
The jacketed resilient metal seal generally includes a resilient seal made from a suitable metal material and a jacket or liner shielding an exterior or interior surface of the resilient metal seal. In this application, the interior surface of the seal refers to the surface of the seal facing towards the center of the seal and may define the inner diameter of the seal, while the exterior surface refers to the surface of the seal facing away from the center of the seal and may define the outer diameter of the seal. In other words, the embodiments described herein relate to an internally facing seal where the higher pressure is internal to the seal. However, the technology of the present application is applicable to an externally facing seal as well where the higher pressure is external to the seal.
The resilient metal seal may have any shape known in the art to be suitable for resilient metal seals, including E-, U-, V-, and C-shaped resilient metal seals. The resilient metal seals generally exhibit elasticity in the axial direction such that when the seal is compressed between, e.g., flanges, the surfaces of the seal in contact with the flange surfaces bend towards the center of the seal. The elasticity of the open end of the seal forces the sealing surfaces to form a seal with the flange surfaces. In some configurations, such as with E-shaped resilient metal seals, other portions of the seal not in direct contact with the flanges also bend when the seal is compressed between flanges. The seal preferably experiences no or minimal permanent deformation as a result of the compression between flanges and will revert back to its original position if the compression between flanges is discontinued. The elasticity of the resilient seal helps to enhance sealing performance by virtue of the seal pushing back against the flanges when compressed between the flanges.
The resilient metal seal can be made from any suitable metal material that will exhibit the desired level of elasticity. Typical metals used in the manufacture of resilient metal seals include, but are not limited to, high strength, nickel-based alloys such as Alloy 718 and Alloy X-750. These materials are chosen in part due to ease of fabrication and the ability to strengthen the formed parts through heat treatment.
While the cross-section of the seal is generally as described above (e.g., E-, C-, U, or V-shaped), the overall seal has a generally annular shape so that the seal can form an appropriate radial barrier between flanges. The dimensions of the inner and outer diameter of the seal are generally not limited and can be selected based on the application of the seal. Similarly, the thickness of the seal is not limited and can be adjusted based on the application of the seal.
The resilient metal seal includes a jacket or liner to help improve sealing performance and provide a protective layer. The jacket can be an interior jacket, meaning it protects primarily the interior surface of the seal, or an exterior surface jacket, meaning it protects primarily the exterior surface of the seal. In some embodiments, the seal can include both an interior and an exterior jacket, including a unitary jacket that encapsulates the entire seal and thereby protects both the exterior and interior surface. In addition to providing a barrier layer between potentially damaging media and the resilient metal seal, the jacket also provides improved sealing performance. The jacket is designed to conform to the surface of the mating flanges when compressed between flanges, which thereby helps form a better seal and eliminate any potential leak passageways.
The material of the jacket can generally include any material that will provide chemical inertness and protection against corrosive materials, while also helping to improve the sealing performance of the resilient seal to which it is coupled. In some embodiments, the jacket is made from PTFE. Other materials similar to PTFE which can also be used include, but are not limited to, perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), ultra high molecular weight polyethylene (UHMWPE), and perfluoroelastomers. PTFE and similar materials provide the seal with the desired level of protection against various media while also conforming to the surface of the mating flanges to help create a better seal between flanges.
The jacket will generally have a cross-sectional shape that mirrors the cross-sectional shape of the seal. For example, when the resilient seal has a C-shape, the jacket can also have a C-shape. In the case of an E-shaped resilient seal, the jacket will generally have a C-shape, although E-shapes can also be used. The dimensions of the jacket are generally selected so that the jacket fits closely with the resilient seal when the two elements are coupled. The thickness of the jacket can be varied based on application of the seal.
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Another advantage of the jacketed resilient metal seal described herein relates to the redundant protection against leaks provided by the described configurations when compared to, for example, jacketed spring-energized seals. In extreme conditions, such as fires, the jacket described herein may be consumed. However, the remaining resilient metal seal can withstand the fire and, because it is a continuous body, can continue to prevent leaks and maintain fluid within pipes sealed together by the resilient metal seal. To the contrary, when the jacket used on a spring-energized seal is consumed, the relatively open, non-continuous nature of the spring will allow for leaks. Accordingly, the presently described embodiments provide redundant protection against leaks in extreme conditions.
Unless otherwise indicated, all numbers or expressions, such as those expressing dimensions, physical characteristics, etc. used in the specification are understood as modified in all instances by the term “approximately.” At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter recited in the specification or claims which is modified by the term “approximately” should at least be construed in light of the number of recited significant digits and by applying ordinary rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass and provide support for claims that recite any and all subranges or any and all individual values subsumed therein. For example, a stated range of 1 to 10 should be considered to include and provide support for claims that recite any and all subranges or individual values that are between and/or inclusive of the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1 to 10 (e.g., 3, 5.8, 9.9994, and so forth).
The present application claims priority to U.S. provisional patent application Ser. No. 61/648,460, titled JACKETED RESILIENT METAL SEAL, filed May 17, 2012, the disclosure of which is incorporated by reference as if set out in full.
Filing Document | Filing Date | Country | Kind |
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PCT/US13/41429 | 5/16/2013 | WO | 00 |
Number | Date | Country | |
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61648460 | May 2012 | US |