Abstract: A spiral-wound gasket includes a plurality of tightly wound metal windings to form a core. The windings each have a Chervon cross-section, wherein V-notched undulations of each winding registers with an adjacent winding at said notches. The edges of the windings are welded to form a pre-assembled integral composite that is installed into a J-shaped outer wrap or cover. Finally, the cover is closed about the core so as to entirely cover and encapsulate the core. In a preferred form, both the core and outer cover are formed of stainless steel materials.

Abstract: The invention concerns a new seal system for resolving the problem of the contamination of special fluids carried in pumps and moreover providing improved sealing by virtue of its special geometry and design. According to the invention, one of the elements to be connected can replace the seal owing to the fact that the seal system includes a combination of two elements to be connected with a fine film ring, one of the elements to be connected having a geometry able to effect a double indentation on the film ring. The invention may be used in pumps and circuits for fluids of the semiconductor industry. The three elements of the seal system, including the pump body, tube, and film ring, may be made of PFA.

Abstract: For manufacturing a seal between two machine parts (10, 11) which together enclose a space (14) in which, at least at times, high pressure and/or high temperature prevail, sealing means which contain a curable composition (30) are arranged between the two machine parts (10, 11). The curable composition (30) is applied directly onto one or both machine parts (10, 11) in liquid form at least in the area which does not directly adjoin the space (14) in which, at least at times, high temperature and/or high pressure prevails. The two machine parts are built in before the curing of composition (30). A sealing ring can be inserted between the two machine parts (10, 11) directly around the edge of the high pressure and high temperature space (14) or that edge can be slightly raised and the curable composition (30) can be used for sealing outside this area.

Abstract: A high pressure seal consists of a minimal convex excess which induces a plastic-elastic deformation on the flat opposing surface. The excess can also be formed by means of a ring with a circular cross section which after tightening of the screw coupling likewise forms a small convex excess. Removal of the ring without damage is accomplished by application of pressure by means of a smaller additional groove and a pressure feeding bore discharging into the additional groove.

Abstract: A seal structure for use in a compressor has a first member, a second member, an O-ring and a gasket. The first member and the second member constitute a housing of the compressor. The first member and the second member are joined to each other at a joint. The O-ring and the gasket are interposed at the joint in a predetermined manner.

Abstract: An axial seal assembly is provided at the interface between adjacent wheels and spacers of a gas turbine rotor and disposed about tubes passing through openings in the rotor adjacent the rotor rim and carrying a thermal medium. Each seal assembly includes a support bushing for supporting a land of the thermal medium carrying tube, an axially registering seat bushing disposed in the opposed opening and a frustoconical seal between the seal bushing and seat. The seal bushing includes a radial flange having an annular recess for retaining the outer diameter edge of the seal, while the seat bushing has an axially facing annular surface forming a seat for engagement by the inner diameter edge of the seal.

Abstract: A sealing member having an elongate body formed of an elastomeric material has a generally planar sealing surface adapted to provide an outward sealing force in a direction generally perpendicular to the sealing surface. The seal further includes a plurality of longitudinally extending hollow regions formed within the sealing member which are bounded at least in part by longitudinally extending and transversely spaced apart structural partitions. A layer of elastomeric material on a side opposite the sealing surface spans the structural partitions thus enclosing the hollow regions. The seals are useful in constructing segmented tunnels, ducts, and the like, and are particularly adapted to withstand high pressures.

Abstract: The gasket makes it possible to maintain a high level of tightness, in spite of the low forces involved, through the use of a sheet of ductile material as outer envelope.

Abstract: A pipe gasket and a method of forming a pipe joint between a metal spigot pipe and metal belled pipe. The gasket has three regions to facilitate a seal. A seal region forms the primary seal within the groove of the belled pipe. A sleeve region extending from the seal region forms a sleeve around the end of an inserted spigot pipe to protect the pipe from contact with fluids flowing there through. A retainer region coupled to the sleeve region covers the end of the spigot pipe and also acts as a stop to prevent over-insertion of the spigot pipe into the belled pipe. The three regions cooperate to form a sleeve around the spigot pipe end and to prevent over-insertion of the spigot pipe into the belled pipe.

Abstract: A sealing system for a gap-free seal for a product chamber has a first structural part having a first flange surface and a first sealing surface. It further has a second structural part having a second flange surface and a second sealing surface. The first and second structural parts are connected to one another via the first and second flange surfaces and form a component of the product chamber. At least one sealing element is inserted between the first structural part and the second structural part and rests against the first and second sealing surfaces without a gap remaining between first and second structural parts. The first and second sealing surfaces are turned so as to be swirl-free. The first and second flange surfaces have a burr-free transition into the first and second sealing surfaces, respectively, and the burr-free transitions provide a sealing line.

Abstract: A buoyancy system for a deep water floating platform includes at least one buoyancy module coupled to the a riser. The module may be coupled to a ring structure of an end cap coupled to the riser, or two modules may be coupled to a ring structure to couple them together. The modules have an interior flange extending into the interior cavity and abutting the ring structure. Fasteners couple the interior flange of the module to the ring structure to form an interior attachment. A seal may be formed between the flange of the buoyancy module and the ring structure, and may include a seal member disposed in a groove. A test port extends to the groove to allow testing of the seal. The module may include a material and may have a thickness that together allow a wall of the buoyancy module to expand outwardly under an internal pressure and force the flange against the ring structure to enhance sealing between the flange and ring structure.

Abstract: This invention relates to a more serviceable seal assembly of the above type, particularly adapted for applications in the cooling systems of internal combustion engines. The seal assembly of this invention comprises an annular ferrule, an elastomeric seal circunferentially disposed thereabout, a pair of annular mounting rings and a clamping device. Tightening of the clamp expands the elastomeric seal outward against the annular mounting rings which are statically sealed within the members of the engine. Selective sizing of the annular mounting rings can be used to control coolant flow. The use of this seal assembly does not require the removal and replacement of members of the engine for installation or servicing.

Abstract: A metallic seal is provided that concentrates the available load over a narrow band to produce a sealing dam over a sufficient width to minimize leakage on a molecular level. The metallic seal has a first annular beam section, a second annular beam section, and inner and outer surfaces extending between the first and second annular beam sections. One of the inner and outer surfaces has an annular recess that at least partially defines an annular column section of material extending substantially perpendicular between said first and second annular beam sections thereto. The first annular beam section has a first non-sealing surface and a first raised portion with a first annular sealing surface facing in a first axial direction to contact a first member for creating a first annular sealing dam therebetween.

Abstract: Methods and apparatus are provided for obtaining a secure mechanical connection and a pressure-tight seal in the overlapping area of two telescoping tubular bodies. The two bodies, including the overlapping area, are radially expanded to increase the inside diameter of the bodies. The expansion forces an annular seal in the overlapping area into a pressure-sealing engagement between the bodies. A string of pipe assembled from joints secured to each other by telescoping, threadedly engaged expanded pin and box connections may be radially expanded into a surrounding well bore to provide a cased well having an internal diameter greater than the original internal diameter of the pipe string. The seal in the connection comprises an annular elastomeric seal ring and an annular Teflon spacer ring carried in a specially dimensioned groove formed in either the box or the pin, or both members of the connection.

Abstract: A brake mechanism which permits adjustment of the outer reach or extent of an elastomeric ring about the periphery of the brake. The adjustment is effected by engaging and bending the elastomeric ring seal to a greater or lesser extent depending upon the axial relationship of the component parts forming the brake.

Abstract: A dielectric gasket (10) includes an outer annular disk (50) and an inner annular disk (56) both formed, at least in part, from electrically non-conducting materials. A seal (54) is disposed between an inside diameter (58) of the outer annular disk (50) and an outside diameter (62) of the inner annular disk (56). The outer annular disk (50), the inner annular disk (56), and the seal (54) operate to form an insulating barrier of electrically non-conducting material between adjacent pipe flanges (12, 14).

Abstract: A system for coupling ultra-high vacuum components specifically where a component is inserted between two standard thickness flanges. This system will minimize the length that is added onto a vacuum system when a component is added. The invention is a relatively thin flange including two sealing surfaces separated by a thin web. The thin flange of the present invention may be configured to mount a variety of equipment within a vacuum system, and/or provide connection between the interior of the vacuum system and the outside environment, such as electrical connection or fluid connection.

Abstract: The invention provides a sealing element for spinning systems used for spinning polymer melts, wherein the sealing element seals the transition between a polymer melt conducting melt channel of a permanently mounted component and a melt channel of a removable, interchangeable component. The sealing element consists of a cylindrical and externally smooth hollow object with an axial bore for passage of the melt, which hollow object is inserted into a fitting socket hole in the interchangeable component and is made of a material with a higher thermal expansion coefficient than that of the surrounding material of the interchangeable component.

Abstract: In order to achieve constantly stable, high seal performance without requiring high machining accuracy, and in order to provide a reusable jacket seal, the present invention discloses a jacket seal, wherein a projection is formed at a position of a metal jacket in opposite relationship with a seal surface of a member being sealed, a flat portion is formed in an elastic member within the metal jacket so as to be brought into surface-to-surface contact with a flange portion interior surface, and the vertex portion of the projection is formed flat.

Abstract: The improved ring seal includes an annularly shaped body element having a radial inner surface, a radial outer surface, a first axial end surface and a second axial end surface. The ring seal also includes a plurality of bores which project radially inward from the radial outer surface toward the radial inner surface. The projection of the bores through the ring seal form sidewalls which project between the axial end surfaces and radially from the ring seal's radial outer surface towards the ring seal's radial inner surface. The addition of the bores to the ring seal increases the ring seal's deformation during sealing compression, while the sidewalls provide elastic recovery of the ring seal during repeated cycles of compression and decompression. The ring seal also includes a circular ridge axially projecting from both axial end surfaces. The axial ridges separate the end surfaces into inner axial end surfaces and outer axial end surfaces.

Abstract: The invention relates to a segment for a sealing arrangement, wherein a plurality of such segments can be attached to the circumference of a sealing ring for centering the sealing arrangement while the latter is installed between two flanges. Each segment comprises a curved centering flank, a further flank serving as a point of attack for a rotating mechanism, and a third flank for attachment of the segment to the sealing ring. The segment is provided as a one-pieced unit of a relatively small size. The segments can be mounted irrespective of the nominal pressure and the nominal diameter. This allows for an inexpensive manufacture of the sealing arrangement. Various embodiments of segments are described.

Abstract: According to this invention, this objective is met by a gasket (1) which is made from a soft plastic and has a central sleeve (8), the diameter of which is tightly fitted to the ascension pipe (5), as well as an outer, bell-shaped flange (9) with a shoulder (7), a skirt (10), a bead (11), and a flat part (12) linking the shoulder (7) of the bell-shaped flange (9) with the central sleeve (8), and where the bead (11) has been manufactured with internal fastening devices (3b), which have been designed to hook into corresponding fastening devices (3a) on the funnel (2), fastening the gasket (1) on the funnel (2), where the shoulder (7) of the bell-shaped flange (9) has a diameter greater than that of the skirt (10) of the bell-shaped flange (9), but smaller than the diameter of the bead (11).

Abstract: Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

Abstract: A wellhead housing includes a metal seal with a ring portion and a rib portion. The ring portion includes two frustoconical surfaces for mating with tapered surfaces of a wellhead connector and the wellhead housing. Two conical, metal-to-metal seals are created where the ring portions of the seal engage the tapered surfaces of the wellhead connector and housing. These metal-to-metal seals contain internal pressure within the wellhead. Two legs extend outward from the rib portion. An upward-facing foot surface at the end of the top leg engages the wellhead connector, while a downward-facing foot surface at the end of the bottom leg engages the wellhead housing. A metal-to-metal seal created between each foot surface and the corresponding tubular member resists external pressure to prevent water ingress into the joint.

Abstract: In a seal structure of a compressor according to the present invention, two O-rings 6 and 7 are disposed at a joint portion between a front housing 2 and a cylinder block 3 constituting a housing of a compressor 1. The inner O-ring 6 uses a material excellent in mechanical and chemical properties (nitrile rubber), and the outer O-ring 7 uses a material excellent in gas permeation resistance (butyl rubber). The inner O-ring 6 has a greater diameter and the outer O-ring 7 has a smaller diameter.

Abstract: A sealing ring is provided that can be used at low load conditions. The sealing ring basically has an annular center section, a first annular end section and second annular end section. The center section has a first end, a second end and a curved bight portion located between the first and second ends of the center section. The first annular end section extends from the first end of the center section. The first end section has a first axially extending leg portion and a first sealing surface facing in a first direction substantially parallel to a main central axis of the sealing ring. The second annular end section extends from the second end of the center section. The second end section has a second axially extending leg portion and a second sealing surface facing in a second direction substantially parallel to the main central axis of the sealing ring. In certain applications, the sealing ring can be provided with a coating of soft material or a second ply of soft material.

Abstract: A seal joint for an arrangement for separating a gas and liquid mixture, the arrangement having a vessel with an inlet for entry of the gas and liquid mixture and an outlet for exit of a separated gas, and a centrifugal separation cyclone in the vessel for centrifugally separating the gas from the mixture. The vessel includes an internal tubular member having an open end and an inlet tube having an open end extending toward the open end of the internal tubular member. A seal joint ring is fixed to the open end of the internal tubular member. The ring has an annular trough which is open toward the open end of the inlet tube and a gasket is provided in the trough and is engaged by the open end of the inlet tube for sealing the open end of the inlet tube to the open end of the internal tubular member.

Abstract: A watertight connector includes male and female housings (10, 20). The male housing (10) has an engaging end surface (10A) with a mounting recess (15) in which a seal (40) is mountable. The seal (40) has sealing portions (45) to be fitted around outer surfaces of pillars (16) that surround male terminal fittings (13). A lattice-shaped array of press-in grooves (46) is provided between the sealing portions (45), and a peripheral press-in groove (47) is formed between the sealing portions (45) and the mounting recess (15). A peripheral rib (32) and a lattice-shaped array of ribs (33) project from an engaging end surface (20A) of the female housing (20). The ribs (32, 33) enter the press-in grooves (46, 47) as the housings (10, 20) are connected and come into sealing contact with the outer circumferential surfaces of the sealing portions (45).

Abstract: A gate valve box adaptor structure, the present invention provides a permanent support for the key box bonnet that is unaffected by the surrounding environment. The adaptor is supported on the gate valve to a positive location for the key box bonnet at a level which prevents infiltration of soil and moisture into the bonnet. The adaptor is provided with a resilient gasket of a unique design to provide a cushion and to create a seal for the bonnet on the gate valve.

Abstract: A gasket for a demountable joint of an hygienic food processing system, the gasket comprising a surface for providing a smooth transition from a first joint part to a second joint part at a joint. The sides of a preferred embodiment gasket each define a plateau adjacent the surface for abutting the joint parts which, in use, produce a hygienic seal. The gasket of the present invention in preferably made from a plastics material having sufficient structural strength(i.e. engineering plastics) which, even when not fully supported to withstand pressures and/or temperatures, during use maintain the hygienic performance of the joint.

Abstract: A clamped flange pipe or tube fitting assembly includes a resilient seal ring compressed in a chamber formed by cooperating recesses in opposed flanges. The chamber and seal ring are dimensionally related in a manner to produce circumferentially continuous, radially spaced primary and secondary seal areas and to assure a continuous interior surface between the connected pipes or tubes with no recesses to entrap process fluids.

Abstract: A seal ring mountable to a rotating member for rotation therewith, the seal ring including a gap or other feature providing controlled leakage therethrough, a radial inner circumferential face, an opposite radial outer circumferential face, and at least one axial end face extending between the inner circumferential face and the outer circumferential face, wherein at least one face includes elements for receiving and holding a lubricant for providing lubrication between the face and a surface located in opposing relation thereto during rotation of the seal ring relative to the surface.

Abstract: A composite gasket for forming a seal between a pipe bell and a spigot comprises a first axially disposed portion formed of an elastomeric material and has a first leading edge and a first trailing edge, and a second axially disposed portion, adjacent the first axially disposed portion, formed of a generally non-elastomeric substantially rigid plastic, which comprises multiple, axially extending, laterally spaced apart, ramp-like projections separated by circumferential valleys, which expose elastomeric material. Fluid entering the valleys during a high pressure surge force the composite gasket into a tighter seal.

Abstract: A sealing gasket for sealing a flange face, especially a flange face that may be sensitive to uneven application of pressure or that cannot be provided with any sort of flange retaining means comprising a sharp angle in the flange surface. The gasket includes at least a metal ring, a reinforced fluoropolymer sheet, an O ring and a fluoropolymer protective shield. The metal ring is defined by inside and outside circumferences, by widely separated outwardly directed parallel surfaces that in turn define maximum thickness of the ring, by narrowly separated parallel surfaces defining opposing depressed portions in the ring and by opposing shoulders. Each of the widely separated parallel surfaces is covered by at least one reinforced fluoropolymer sheet having inside and outside surfaces positioned so that the inside surface of the sheet faces and covers at least one of the widely separated parallel surfaces and so that the outside surface faces outwardly. The gasket includes at least two O rings.

Abstract: A conduit seal is provided for sealing a passageway in an automotive transmission. The transmission has an oil passageway and a member covering the passageway. The passageway is in fluid communication with a clutch. A bore communicates oil from the passageway to a passageway provided in the clutch. An annular seal is sealingly engaged with the bore of the case and the clutch to provide a fluid conduit therebetween. A compliant member is provided between the annular seal and the cover member to axially urge the seal into sealing engagement with the outer surface of the clutch.

Abstract: The present invention provides a seal for use in a modular flow device and is utilized for joining and aligning a first mating surface and second mating surface having axial flow passageways. The seal comprises a protruding annular radiused edge about the axial passageway of the first mating surface and an annular groove about the axial passageway of the second mating surface. The groove has an inner angled wall for engaging with the annular radiused edge when the mating surfaces are compressively joined. Thus, a leak proof seal is formed around the fluid passageway and the passageways are aligned with respect to each other. The invention also relates to check valves for use with modular surface mount systems in which the check valve can be used as a surface mounted component or as part of a substrate that is mounted to or between other substrates and components.

Abstract: A pipe sealing gasket is shown which is designed to be received within a groove provided within a socket end of a thermoplastic pipe. The gasket includes a ring shaped body which, when viewed in cross-section includes a leading nose region and a lower compression region. The leading nose region is joined to the lower compression region by a leading curved surface region which defines an angle .alpha. with respect to a horizontal axis drawn parallel to the central axis of the pipe. The lower compression region is joined to a secondary seal surface by a trailing curved surface region which defines a second angle .beta. with respect to the horizontal axis drawn parallel to the central axis of the pipe. The angles .alpha. and .beta. are selected to minimize the insertion force required when inserting the male spigot end within the female socket end of the pipe joint while guiding the spigot end and maintaining a compression seal between the pipe sections.

Abstract: A sealing element (2) consisting of elastic material is adapted to be molded into for example a concrete pipe socket. In order to improve the binding between the sealing element and the material of the concrete pipe socket the sealing element is at least partially provided with fiber flock (14) at the surface portion which at the molding is adapted to be enclosed by the concrete material of the socket. (FIG.

Abstract: A gate valve box adaptor structure, the present invention provides a permanent support for the key box bonnet that is unaffected by the surrounding environment. The adaptor is supported on the gate valve to a positive location for the key box bonnet at a level which prevents infiltration of soil and moisture into the bonnet. The adaptor is provided with a resilient gasket of a unique design to provide a cushion and to create a seal for the bonnet on the gate valve. A plurality of liquid infiltration prevention structures for preventing liquid infiltration into manhole assemblies.

Abstract: A seal assembly includes a first plate or member having a recess with a bottom mating surface which receives sealing ring therein and a second plate or member having a sealing surface for contacting a metallic sealing ring. First and second plates or members are coupled together by a plurality of fasteners or bolts. By tightening the fasteners the sealing ring is loaded, and thus, compressed to plastically deform and create an annular seal between the first and second members. Metallic sealing ring has a first annular sealing surface, a second annular sealing surface, an annular inner surface and an annular outer surface. The first annular sealing surface faces in a first axial direction to contact sealing surface of first member for creating a first annular sealing dam therebetween.

Abstract: A sealing ring, for use in establishing a fluid-tight connection between the facing ends of tubular members which are to be braced axially with respect to one another, comprises a thin sheet-metal ring provided with a corrugation which defines an effective sealing ring thickness greatly in excess of the thickness of the sheet-metal. The sealing ring is provided with a non-metallic coating on both sides, the coating on at least one side being a layer which functions to achieve microsealing.

Abstract: Sealing assemblies are illustrated for heaters, pumps, conduits, and the like for handling process fluids used in the semiconductor-processing industry. Clean, particle-free, nonreactive, non-trapping, ultra-pure, thermally tolerant, sealed systems are required to maintain process fluids with contaminant levels below parts per billion, or even trillion. A lip seal connects a tube, having a lip at each end, to a face of a creeping material. A creeping fluorocarbon sealing material may form the interface for reducing stress concentrations on the tube, and for providing a consistent reliable seal between the lip and the creeping face. A face seal between creeping faces may be effected by a creeping sealant there between. The faces may be loaded entirely by their own creeping structural materials. No flanges are required. In certain embodiments, retaining rings may be provided for preventing unrestrained creep of sealing assemblies.

Abstract: A split dove-tail gasket channel structure includes a fir structure having a first external surface and a first edge plane substantially parallel to the first external surface, a first surface substantially perpendicular to the first edge plane, a second surface adjacent to the first surface and at an acute angle to the first edge plane, and a third surface adjacent to the second surface and at an acute angle to the first edge plane. A second structure has a second external surface and a second edge plane substantially parallel to the second external surface, a fourth surface substantially perpendicular to the second edge plane, a fifth surface adjacent to the fourth surface and at an acute angle to the second edge plane, and a sixth surface adjacent to the fifth surface and at an acute angle to the second edge plane.

Abstract: A sealing ring for sealing a space between two substantially cylindrical space surfaces (36, 44) axially introducable one into the other comprises two annular sealing portions (2, 4) concentrically connected with each other. The sealing portions have one sealing surface (14, 16) each adapted to engage one space surface (44, 36) each. In its relaxed condition the sealing ring forms a recess (22) between the sealing portions (2, 4) and when this recess (22) is closed substantially without a compression of the sealing ring, the sealing surfaces (14, 16) take a substantially parallel position in relation to the space surfaces (44, 36), respectively. This provides that the sealing ring will at the compression between the space surfaces (44, 36) be subjected to a substantially uniform compression over the main part of its section.

Abstract: A sealing arrangement for a subsea wellhead component is provided which comprises a primary seal to prevent leakage of internal pressure from within the wellhead component and a secondary seal surrounding the primary seal to prevent entry of ambient pressure into the wellhead component. The secondary seal is adapted to permit pressure which leaks past the primary seal to also leak past the secondary seal and vent to the atmosphere to provide an indication during testing of the primary seal that the primary seal has failed.

Abstract: A sealing ring containing an electrode for sensing electrochemical conditions within a fluid handling system, in particular, the occurrence of crevice corrosion, has a body formed of a continuous loop of an electrically insulating fluid-impervious material having a surface which can form a fluid-tight seal with elements of a fluid handling apparatus, an electrode embedded within the body and electrically insulated from electronic conductive contact with those portions of the surface of the body that contact the fluid handling apparatus, and channels extending between the electrode and the surface of the body of the sealing ring to permit electrochemical contact between the electrode and the fluid within the system. The sealing ring also includes electronically conductive wires to connect the embedded electrode to external electrical devices, e.g., electronic measuring equipment.

Abstract: An improved sealable connector has a geometry which effects reliable sealing upon assembly. The connector is useful, for example, for connecting a pressure sensor to a fuel pump accumulator in a fuel injection system. The connector includes a male member, a female member, and an annular seal disc which compressibly seats between the male and female members. The male member has a tip with a flat annulus at an innermost radius surrounding a fluid-delivery bore. A frustoconical section of the tip extends radially outwardly from the annulus, sloping away from the plane of the annulus at about 5.degree.-15.degree., for example. The female member has a cavity shaped to receive the male member, the cavity having a bottom defined by a flat annular seat surrounding another fluid-delivery bore. The seal disc is compressed between the flat seat of the female cavity and the planar/frustoconical tip of the male member.

Abstract: A tubular joint has a pair of tubular members (10, 12) with end hubs (14, 16) in opposed relation and secured by a clamp (22). A primary seal ring (40) has external tapered sealing surfaces (42, 44) engaging internal tapered sealing surfaces (28, 30) on the hubs (14, 16) to provide a primary seal. Secondary sealing surfaces (32, 36) on the hubs (14, 16) are engaged by O-rings (62, 64) as shown in FIG. 4 to seal against external fluid flow to the seal ring (40). O-rings (62, 64) permit internal fluid flow outwardly from the seal ring (40) as shown in FIG. 3.

Abstract: A screened gasket for sealing a junction and filtering fluid flowing through the junction includes a sandwich-type structure with first and second gasket members holding a central screen securely therebetween. An inner seal annularly surrounds the screen and prevents radial fluid leakage between the two gasket members. Outer seals are provided which engage the surfaces of the flanges of the junction.

Abstract: A gasket for use in sealing sanitary piping comprises an annular plate of porous polytetrafluoroethylene, the inner surface layer of the gasket being heat treated to form a pore-free fused solidified layer for directly contacting a fluid to be sealed. The fused solidified layer prevents osmotic leakage of sealed fluid. Since the solidified layer is formed only in the surface layer the intrinsic properties of porous polytetrafluoroethylene, such as flexibility and affinity, are retained. The gasket is made by inserting a tubular member with an internal heater into a porous polytetrafluoroethylene gasket so that the tubular member directly contacts the inner surface layer of the gasket. The tubular member is operated at a temperature of 420.degree. to 460.degree. C. and contacts a gasket for 10 to 30 seconds to form the fused and pore-free layer.