MXPA06005955A - Corrugated gasket core with profiled surface cross reference to related applications - Google Patents

Abstract

A gasket is provided comprising a gasket core having an outer portion and an inner portion defining an aperture, and opposing first and second faces, wherein at least a portion of the core is corrugated through its thickness and at least one face is at least partially profiled, and a gasketing material disposed upon said at least one partially profiled face. The profiling comprises a series of concentric grooves formed into the core material and the corrugation preferably comprises a sinusoidal-shaped wave comprising concentric rings of peaks and valleys.

Description

CORRUGATED SHUTTER NUCLEUS WITH PROFILE SURFACE CROSS REFERENCE TO RELATED REQUESTS This application claims priority under 35 U.S.C. § 1 19 (e) of the US Provisional Patent Application. UU Serial number 60 / 524,748 filed on November 25, 2003, entitled "Gasket With Serrated Surface and Corrugated Core ", the description of which is incorporated herein by reference.

FIELD OF THE INVENTION The present invention relates to obturators for sealing the union between opposing projections. More particularly, the present invention relates to sealants having a semi-rigid substrate comprising opposite sides that are both profiled and corrugated.

BACKGROUND OF THE INVENTION Corrugated metal seals are comprised of a thin gauge metal substrate that is corrugated, then covered with a soft sealant material. Examples of these seals are illustrated in US Pat. UU Nos. 5,421, 594; 5,785,322; and 6,092.81 1 which are incorporated herein by reference. The corrugated metal design provides greater resilience than the flat, homogeneous obturator material alone. The resilience of the substrate results in a shutter that continues providing compressive forces in the soft sealing material against the coupling projections. This compressive force maintains sealing forces against the projections while the soft sealing material slides or takes the compression assembly. The use of these corrugated metal core seals is common in pressure vessels and tubing systems. A substantial limitation of this design is the inability of the obturator to withstand high internal pressures. These shutters have been shown to fail at internal pressures of approximately 2,000 psi (13.8 MPa). This failure occurs in part because the sealing material does not mechanically bond sufficiently to the metal substrate, and therefore has a limited amount of shear strength to overcome high internal system pressures. An attempt to solve this problem is the shutter Kammprofile, the Kammprofile plug comprises a metal substrate with profiled sides to which the sealing elements meet. This design overcomes the high pressure limitation of the prior art through the use of a serrated surface that is formed in the metal substrate. The metal core is of a thicker caliber than the corrugated obturators, and the forming process results in a more pronounced surface texture. The serrated surface provides significant mechanical resistance to the cutting of the soft sealing material as it deforms in the serrations by the compressive force applied by the projections. As a result, This design has been shown to withstand much higher pressures (above 5,000 psi, 34.5 MPa) compared to those of the corrugated metal design. However, one disadvantage of the profiled design is the lack of resilience observed in corrugated metal shutters. Due to this lack of resilience, the sealing forces on the protrusion connection will degrade over time due to the tendency of the soft obturator material to slip or take the compression assembly. Therefore, it would be desirable to provide a seal with the resilience of a corrugated metal seal and the high pressure performance characteristics of the Kammprofile family of seals.

BRIEF DESCRIPTION OF THE INVENTION In a first aspect of the present invention there is provided a shutter comprising a sealing core having an outer portion and an inner portion defining an opening, and opposite sides, first and second, wherein at least a portion of the core is corrugation through its thickness and at least one side is at least partially profiled, and a sealing material placed on said at least one partially profiled side. In a preferred embodiment of the present invention, both opposite sides are profiled and the profiling comprises a series of concentric grooves formed in the core material. The corrugation preferably comprises a wave of sinusoidal shape comprising concentric rings of peaks and valleys. The sealant material may comprise expanded graphite, fluorocarbon polymer, or a fjuorocarbon polymer with a graphite filler. The sealing material is preferably adhered to the sealing side with an adhesive, such as a pressure sensitive adhesive or spray adhesive. As will be appreciated by those skilled in the art, many different embodiments of a shutter according to the present invention are possible. The additional uses, objects, advantages and new features of the invention are set forth in the detailed description that follows and will be more apparent to those skilled in the art in the examination of the following or by the practice of the invention. In this way, the most important features of the invention have been emphasized, preferably in a broad manner, so that the detailed description that follows can be better understood and so that the present contribution to the subject can be better appreciated. There are, obviously, additional features of the invention that will be described below and that will form the subject matter of the appended claims thereto. In this regard, before explaining various embodiments of the invention in detail, it should be understood that the invention is not limited in its application to the details and construction and installation of the components set forth in the following description or illustrated in the drawings. The invention is capable of other modalities and practiced and carried out in several ways. It should also be understood that the phraseology and I terminology herein are for the purposes of description and should not be considered as limiting in any respect. Those skilled in the art will appreciate the concepts on which this description is based and which can already be readily used as the basis for designating other structures, methods and systems to carry out the various purposes of this development. It is important that the claims be considered as including such equivalent constructions so far as they do not depart from the spirit and scope of the present invention. The manner in which the features cited above, advantages and objects of the invention, as well as others that will be apparent, are obtained and can be understood in detail, a more particular description of the invention briefly summarized above may have been referenced to the embodiment of the same as illustrated in the accompanying drawings, such drawings form a part of the specification and wherein similar reference characters designate similar parts throughout the various views. It should be noted, however, that the appended drawings illustrate only preferred and alternative embodiments of the invention, and therefore, are not considered to be limiting in their scope, since the invention can be admitted to equally effective, additional modalities.

BRIEF DESCRIPTION OF THE DRAWINGS FIG-1 is a side view of a shutter in an embodiment of the present invention. FIG. 2 is a sectional view of the sealing core of FIG. 1 taken along line A-A in one embodiment of the present invention. FIG. 3 is a detailed view of the area designated "B" in FIG. 2 in one embodiment of the present invention. FIG. 4 is an isometric view of a shutter in an embodiment of the present invention.

DETAILED DESCRIPTION In a first aspect of the present invention, a shutter is provided comprising a rigid core having corrugations formed therein and two profiled sides, the core being encapsulated by a sealing material. In a preferred embodiment of the present invention, the profiled sides comprise a series of concentric spikes and grooves formed in the surface of the obturator at a predetermined depth. In a further preferred embodiment of the present invention, the corrugations comprise a sinusoidal pattern of concentric peaks and valleys formed through the total thickness of the core material such that the second side of the obturator has the opposite corrugation pattern (peaks and valleys) of the first. Referring to the figures, a shutter 10 according to one embodiment of the present invention is shown as comprising a I core material 12 which is at least partially encjapsulated with a sealing material 14. Core material 12 is drilled from an inner diameter through a portion of the material. The corrugations form peaks 22 and valleys 24 on each side, with the first side having the opposite pattern of the second, that is, the corrugations extend through the thickness of the material. The I sides, top and bottom, of the obturator are profiled with small grooves formed in the surface of the core material 12. In a preferred embodiment of the present invention, the grooves generally coexist with the corrugations, both starting at the inside diameter of the obturator as extending 'to a point smaller than the outer diameter of the obturator. The core is typically constructed of a metallic material. In a preferred embodiment of the present invention, the core is constructed of a stainless steel, such as stainless steel 304, 309, 310, 316, 321, 347, 410, 430 and 501. The selection of the metal depends on the metallurgy of the projections (or other surfaces) to be sealed, and the desired degree of chemical resistance of the metal sealing core. For example, metal sealing cores can be formed of Alloy 20, aluminum, bronze, copper, Hastelloy® B and C, Inconel® 600, Incolloy® 825, Monel®, nickel, phosphorus bronze, tantalum and titanium. The geometry of the profiled sides can come in many forms. In a preferred embodiment of the present invention, the profiled sides comprise a multitude of "serrations", I slots, or valleys and alternating peaks cut into the surface of the core material. The peaks and grooves form a "V-inverted V" pattern with sharp peaks and similarly sharp grooves. However, in an alternate embodiment of the present invention, the profile i may also be a plurality of "U-inverted U" shapes, or other similar forms or combinations thereof. The geometry of the corrugations can come in many forms. In a preferred embodiment of the present invention, the corrugations comprise smooth curves forming a cross section similar to a sine wave. However, in other embodiments of the present invention, the corrugations may also be a plurality of "V-inverted V" forms, "U-inverted U" forms, or other similar forms or combinations thereof. The corrugated, profiled core is surrounded by a sealing material. In a preferred embodiment of the present invention, the sealant material comprises expanded graphite. The graphite material is typically an expanded graphite, preferably a nuclear grade, at least about 95% pure graphite (carbon), having no binders or resins, and having less than 50 parts per million leachable chloride and / or water content. fluoride. In one embodiment of the present invention, the graphite material is a flexible expanded graphite material sold under the names Grafoil®, Sigraflex®, Flexicarb® or Calgraph®. It is preferred to employ a nuclear grade, at least about 95% pure graphite (carbon), not having binders or resins, and having less I of 50 parts per million leachable chloride and / or fluoride content.

In a preferred embodiment of the present invention, the graphite is adhered to a sealing core with a spray adhesive;, such as the Super 77 ™ spray adhesive sold by 3M Corporation. In another embodiment of the present invention, the graphite is adhesively fixed to a Mylar material having a two-sided coating i of a pressure-sensitive adhesive material. The graphite / Mylar laminate is fixed to the outside of the corrugated sealing core. The graphite material preferably conforms to, and maintains the corrugation contour, and extends beyond; the outer edges of the annular core plug to partially encapsulate the core plug in the graphite material. In another embodiment of the present invention, the sealant material can be a chemically resistant polymer material such as a fluorocarbon polymer, preferably polytetrafluoroethylene (PTFE). The graphite and / or chemically resistant materials are typically applied as a cover having a sufficient thickness to coat the corrugations of the core, while maintaining the corrugated contour of the plug. . In still a further embodiment of the present invention, other sealant materials may be employed. The choice of sealing material may depend on the composition, chemical fluids (ie, liquids and / or gases, with or without solids) that may be contacted by the seal, and the temperature, pressure, or other operating conditions at which the Shutter can be exposed. Without However, materials that are both resilient and chemically resistant are preferred. In one embodiment of the present invention, the sealant material is a fluorocarbon polymer that is adhesively attached to a Mylar material having a two-sided coating of pressure-sensitive adhesive material. Fluorocarbon polymers are characterized by their thermoplastic properties, resistance to chemicals, moisture, solvents, and oxidation, without combustion capacity, and wide useful temperature range (ie, up to 316 ° C). The structure of fluorocarbon polymers comprises a straight structure of carbon atoms symmetrically surrounded by fluoro atoms. Expanded fluorocarbon polymers such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride, hexafluoropropylene, fluorinated ethylene-propylene polymers, and chlorotrifluoroethylene polymers are preferred because of their resilience, chemical resistance, low torsional seal, and limited cold flow or slippage . These expanded fluorocarbon polymers can be sold under the names Teflon®, Halon®, Viton®, Gylon®, Intertex® and Gore-Tex®. The limited cold flow characteristic is particularly desirable in a shutter used in conditions where the seat tension of a projection may decrease with time. In one embodiment of the present invention, (shutter I is used to seal a pair of parallel protrusions at the junction of two tubes.) The protrusions are typically secured together with bolts or screws. threaded handles or nuts to create a multi sealed, safe connection to failure in a pipe used in, for example, the petrochemical industry. In a preferred embodiment of the present invention, the bolts extend through the retainer ring of the obturator thus ensuring proper positioning and alignment of the obturator within the projection assembly. In one embodiment of the present invention, the obturator with profiled surface and corrugated core is manufactured according to the following method. (1) A 304 stainless steel 1/16 inch (1.59mm) thick (not corrugated) is cut to a square size with one side at least equal to the desired obturator O. D.; in this way, the diagonal length was at least 41/8 inches (10.5 cm). (2) The 1/16 inch (1 .59mm) steel square is drilled in the center. (3) The square is then cut in a circle to cut a circle having a diameter equal to the desired obturator O. D., in this way, the diameter of this circle was 41/8 inches (10.5 cm). (4) The 1/16 inch (1.59mm) thick, 41/8 inch (10.5cm) diameter circle is then profiled, to cut 10/1000 inch slots (0.254mm) depth on both surfaces of the circle having a peak-to-peak width of 20/1000 inches (0.508mm) resulting in approximately 50 slots / cm across the surface. The slots are preferably designed to form a plurality of parallel, circular, concentric rings defined by ridges, peaks or apices and the recesses, channels or valleys, which in the case of a pipe protrusion seal, are concentric with the outer edge and inner circumferential edges of the obturator core. (5) The 1/16 inch (1.59mm) thick, 41/8 inch (10.5cm) diameter circle of profiled steel is then corrugated, using a rotating roller system having nozzles, male and female, of the pattern Undulating arch to create the corrugations in sinusoidal form having a corrugation width of peak to peak of 1/4 inch (6.35mm). In this embodiment, the corrugations are designed to form a plurality of concentric, circular, parallel rings defined by the ridges, peaks or apices and the recesses, channels or valleys, which in the case of a pipe overhang obturator, are concentric with the outer edge and circumferential inner edge of the sealing core. (6) The corrugated, 41/8 inch (10.5cm) diameter corrugated circle is again cut in a circle to cut an inner circle, thus leaving a ring having an outer diameter of 41/8 inches (10.5cm), and an inside diameter of 23/4 inches (6.98cm) in diameter. (7) Expanded graphite sheet material (eg, 0.020 inch (0.508mm) thick Calgraph® or Flexicarb® expanded graphite sheet) is obtained, and a pressure sensitive two-sided adhesive (having Mylar backing) , 0.002 inches (0.0508mm) thick) is applied to the expanded graphite material. The two-sided adhesive is typically available in sheets containing peel layers, quick release on both sides to protect the adhesive until use. (8) The graphite compound / expanded adhesive is then cut into a die stamp with a Steel Rule nozzle having the desired dimensions (here, 41/8 inches (10.5cm) OD x 23/4 inches (6.98cm) ID) to create two graphite / adhesive laminates in the form of a coupling ring. (9) The corrugated metal core is encapsulated then from the outer edge to the innermost channel with the expanded graphite to the laminar and to mold both sides of the core material with the laminated layers of expanded graphite with adhesive backing and 0.022 inches (0.559mm) thick.

A first layer of ring-shaped laminate is aligned symmetrically and proportionally with the metal core. Sufficient pressure is applied to the first layer of laminate to adhere it to the core and maintain such alignment with the core until the second layer of laminate is applied. The second layer of laminate is applied in a manner similar to the opposite side of the metal core. (10) The laminated obturator is then placed between two foam / cloth cushions. The compression is applied to the rollers, and the plug is rotated around the rollers in a circular fashion to mold and compress the graphite laminates with adhesive backing into the individual corrugations (i.e., the area defined by the ridges, spikes, or apices and gaps, channels or valleys), so that the graphite layers adhere to the core and maintain the contour of the corrugation. (11) As a further step to the method described above, it may be desirable to apply heat to the surface of the plug sufficient to carbonize Mylar and other suitable backing of the expanded graphite layers. It will be apparent to those skilled in the art that other suitable mechanical means may be employed to create the profiled sides and corrugations in the sealing core. For example, in addition to the described rotary roller method, grinding, molding, stamping and other techniques can be used to create the desired geometry. It will likewise be apparent to those skilled in the art that other suitable shapes for profile grooves and corrugations can be employed to create the corrugation of the shutters. In addition, the circumferential shape of the obturator and the shape of the opening of the obturator of this invention are not limited to circles. For example, the shutters having a projection and / or aperture defining any shape, eg, oval, square, rectangular, triangular, elliptical, oblong, epicycloid, and / or any combination thereof, can be used. Although a circular ring shape is the desired obturator shape for use in a tube projection, other forms of obturator may be manufactured depending on the shape of the surfaces to be sealed. Further, although discussion of the various embodiments of a shutter in accordance with the present invention suggests use in a raised projecting pipe connection, other variations of this shutter are possible to accommodate different outgoing connection scenarios. For example, a pipe overhang obturator of the invention may be employed where the protrusion connection requires the obturator to extend diametrically beyond the bolt holes of the protrusion. Other graphite products can also be used, such as the 0.020-inch (0.508mm) thick Graforil® product that is available with a layer of 0.002-inch (0.0508mm) Mylar adhesive on one side. Other means are available to adhere the graphite and / or fluorocarbon polymer to the corrugated core, such as by compression molding techniques, or other adhesive techniques. Although a Mylar material with pressure sensitive adhesive on both sides is useful for its temperature stability and carbonization characteristics, other adhesives could be used. As described above, the thickness of the non-corrugated core metal can be 1/16 inch (1.59mm), the width of the corrugation peak can be 1/4 inch (6.35mm) and the slot angle can be of 90 °. However, a wide variety of thickness of combined core material, corrugation peak widths, and obturator material thicknesses are within the scope and spirit of this invention. For example, the shutters may include a core material thickness of 1 / 100-1 / 10 inches (0.254-2.54mm); corrugation peak widths of 1 / 16-1 / 2 inches (1 .59-12.7mm); sealing material layer with thickness of 0. 01-0.075 inches (0.254-1.91 mm) (with an additional adhesive of 0.002 inches (0.0508mm).) For example, in pipe protrusion connections having protruding sides of 1/4 inch to 1/2 inch (6.35-12.7) mm) of width or ID of protrusion from 1/2 inch to 31/2 inches (6.35-88.9mm), it is preferred that the corrugation width is 3/32 inch (2.38mm). 9/16 inch (14.3mm) wide or greater projection side or 4 inch projection ID or greater, the preferred corrugation width is 5/32 inches (3.97cm) .In addition, the relative and absolute widths of layers of sealing material may be varied depending on the expected operational conditions and the particular material used The beneficial seal multiple sealing features encapsulated in fluorocarbon and / or graphite, corrugated, profiled polymer of this invention also has application in irregularly shaped configurations , such as those requ for heat exchanger shutters, or other shape requirements, such as obturators in oval, square, rectangular, triangular, elliptical, oblong and / or epicycloid form, and / or any combination thereof. For example, heat exchanger shutters typically have a circular outer diameter and inner diameter, similar to a tube protrusion plug, but additionally contain divided chambers within the confines of the inner diameter area of the shutter. Although the present invention has been described with reference to particular embodiments, it should be recognized that these embodiments are merely illustrative of the principles of the present invention. Those of ordinary skill in the art will appreciate that the apparatus and methods of the present invention can be constructed and implemented in other ways and modalities. According to the foregoing, the description herein should not be read as limiting the present invention, since other embodiments also fall within the scope of the present invention.

Claims (10)

1. CLAIMS 1. An obturator, comprising: a sealing core having an outer portion and an inner portion defining an opening, and opposite sides, first and second, wherein at least a portion of the core is corrugated through its thickness and at least one side is at less partially profiled; and a sealing material placed on said at least one partially profiled side.
2. 2. The obturator according to claim 1, characterized in that both opposite sides are profiled. The obturator according to claim 1, characterized in that said profiling comprises a series of concentric grooves formed in the core material. The obturator according to claim 1, characterized in that said corrugation comprises a wave in sinusoidal form comprising concentric rings of peaks and valleys. The obturator according to claim 1, characterized in that said sealing material comprises expanded graphite. The obturator according to claim 1, characterized in that said sealing material comprises a fluorocarbon polymer. The obturator according to claim 1, characterized in that said sealing material comprises a polymer of fluorocarbon with a graphite filler. The obturator according to claim 1, characterized in that said sealing material is adhered to the sealing side with an adhesive. The obturator according to claim 8, characterized in that said adhesive comprises a pressure sensitive adhesive. The obturator according to claim 8, characterized in that said adhesive comprises a spray adhesive.