Abstract: In a subassembly electrical isolation connector for interconnecting sections of a tubular drill rod, the subassembly having an electrically insulated connector for and between spaced-apart connector sections to transmit drilling forces therethrough, the use of a sealing membrane for sealing an insulated spacing in the electrically insulated connector to prevent ingress of pressurized drilling mud into the connector and shorting out said spaced-apart sections of the connector, the sealing membrane overlapping said connector sections as a continuous sleeve and having at least its sleeve ends sealed to respective portions of the connector sections to thereby activate the sealing membrane.

Abstract: A pipe coupling for coupling together two pipes in a fluid-tight manner includes a tubular casing, a tubular sealing gasket located within the casing, and screws for tensioning the casing around the gasket. The casing includes an inner tubular casing and an outer tubular casing, both of metal. A layer of fire-resistant thermally-insulating material is disposed between the inner and outer casings to form a fire shield.

Abstract: The invention relates to a device reinforcing circumferential welds 8 which join two contiguous pipes 6 and 7 in order to increase the fatigue life of said welds by reducing mechanical stresses in them when being subjected to periodic bending. The device comprises a rigidifying element 10 which is firmly joined to said pipes by a connection means 11, 13, said bush being made of the same material as the pipes. The rigidifying element 10 consists of a bush slipped over the two pipes 6, 7 opposite the weld 8. The connection means is a hardening material 11 such as resin or cement which is injected between bush and pipes and which is confined at this site by shaping, in particular cold-forming, the bush's ends. The application is to offshore hydrocarbon conveyance conduits subjected to periodic loads.

Abstract: The present invention provides an apparatus for pre-conditioned air (PCA) hoses and an assembly for a plurality of PCA hoses. The present invention further provides a method of assembling a plurality of PCA hoses. A hose in the assembly has an outer vinyl layer and further an insulative layer and an inner antibacterial layer. Hook and loop fasteners are employed to provide a way for attaching and securing junctions between hoses in the assembly, where two ends are butted together to form one of the junctions. The two ends each have a first portion of the hook and loop fastener attached substantially about the circumference of the hose. An elongated member having a second portion of the hook and loop fastener is attached at one of the ends where it is effective for wrapping about the circumference of the hoses thereby connecting and covering the butted junction between hoses.

Abstract: The method of forming a field joint around the bare joint of two joined insulation covered pipes includes providing a first angular cut back in the coating to expose the end of a pipe and providing a second cut back in the coating to provide an annular band of the coating of a lesser diameter than the coating on the pipe. A thin coating of polyurethane may then be applied over the first and second cut backs and a recess provided in the band of coating. A mould may then be secured around the lesser diameter band, and polyurethane pumped into the mould in a sufficient amount to form a field joint which extends into the second cut back and lies flush with the coating of the pipes so as to allow for reeling and laying of the pipe without snagging. The field joint can be located around the bare joint and includes a polyurethane infill recessed into the insulated coating of the pipes such that infill lies flush with the surface of the coating on the pipes.

Abstract: Prefabricated insulated pipe sections are constructed of an inner pipe surrounded by a concentrically-positioned outer pipe. End portions of the inner and outer pipes are joined with bellow members so that an annular space is defined. A portion of the inner pipe is wrapped with layers of insulation material with inert insulating granules positioned between the layers. The annular space is partially evacuated to below atmospheric pressure. Multiple pipe sections may be joined by their inner pipes through brazing or other known methods. The joints and neighboring bellow members on abutting pipe sections are covered by clam shells that are sealed and filled with insulation.

Abstract: A fluid conduit system, including silencer systems, including intake and exhaust systems for engines, blowers, compressors, pumps, and the like, includes first (16), second (22), and third (28) pipes, and first (34, 36) and second (38, 40) flex joints each flexibly and sealingly interconnecting respective outlets and inlets of respective pipes. The flex joints include double O-ring sealing gaskets provided by first and second annular meshes (46, 48) received in respective annular grooves (50, 52) separated by a land (54), and a cloth (56) wrapped around the annular meshes and having a central web portion (58) spanning the land.

Abstract: A fixture is disclosed for use in fabricating a connector ferrule for a fiber optic cable which includes a plurality of generally parallel optical fibers. The fixture includes a base, with a receptacle on the base for receiving and properly positioning a ferrule body. A cable locator is provided on the base at one side of the receptacle for positioning the cable inserted in the ferrule body, with exposed end portions of the optical fibers projecting from the ferrule body at an opposite side of the receptacle. A fiber aligner is provided on the base at the opposite side of the receptacle for aligning the exposed end portions of the optical fibers relative to each other and relative to the properly positioned ferrule body.

Abstract: A flexible connection arrangement for connecting a pipe of an exhaust system to an engine is provided at one of its axial ends with a fastening flange and at its other axial end with a connection piece for the end of the pipe to be received. The connection piece and fastening flange are connected with one another via a helical spring. A metallic bellows and a damping insert which extends coaxially to the bellows, encloses the bellows radially externally and contacts the turns of the bellows are provided between the connection piece and the fastening flange. The helical spring is connected at both of its axial end regions with the connection piece and fastening flange, respectively. The connection at the fastening flange is effected via two fastening locations, one of which lies at that end of the helical spring, while the second fastening location is arranged so as to be offset to the first fastening location by an angle of 45.degree. to 53.degree..

Abstract: An insulative threaded connection is provided for metal tubulars to be placed in wells or for other metal pipe. The connection contains a coating of plastic having a selected thickness which is applied to the surface of the threads of a tubular to be mated with another joint of tubular. The plastic contains particles at a selected loading such that the particles support load between the mated threaded joints. Metal is removed from the mating threads, the thickness of the metal removed being about the same as the thickness of the plastic coating. The coating may be applied to the pin end or the box end of connections. The box end may be a coupling or an integral threaded area. The insulative threaded connection is used in tubulars for improved transmission of electromagnetic signals to or from wells.

Abstract: This invention relates to a method for exchanging heat between one fluid and another fluid by using a heat exchanger, and circulating at least the one fluid through a fluid flow channel within a body made of a material which is a good heat conductor as well as a good conductor of electric current, so that the fluids become in heat exchange relationship through the walls of the body. The improvement includes insulating the body from electric current flow therethrough, so that, in use, the tendency for progressive precipitation of solid particles from the fluids onto the wetted surfaces of the body is substantially reduced.

Abstract: A corrosion-resistant connection for use with tubular members having externally threaded ends. The connection includes a stress-bearing sleeve member having an interior surface and an exterior surface; and a fiber-filled polymeric composite shell having at least one internally threaded portion therein, the composite shell molded to the sleeve so as to be coaxially aligned and in close conforming contact with at least a substantial portion of the interior surface of the sleeve member. The composite shell has a thickness of greater than about 0.04 inches.

Abstract: A flexible joint for an exhaust pipe of a motor vehicle which includes: a cylindrical inner layer which consists of a cloth made of ceramic fibers, the inner layer being expansible in an axial direction thereof; an intermediate layer formed of a heat insulating material, for covering an outer circumferential surface of the inner layer; and a cylindrical outer layer disposed radially outwardly of the intermediate layer and formed of an elastic material.

Abstract: A device for connecting pipelines in a flexible gas-tight manner has a bellows provided at each end with a pipe union which can be connected to a pipeline. The device is characterized in that an insulating cassette in the form of a double tube filled with a temperature-resistant material with excellent heat insulating properties is arranged inside the device.

Abstract: A pipe connection, in particular an electrically insulating pipe connection, formed by interlocking or interpenetration of material between (a) an overlapping, reinforced plastic sleeve which is subdivided into a number of superimposed pipe shells that mutually support each other and which are advantageously separated from each other and can therefore be deformed independently in the axial direction of the sleeve, and b) at least one pipe, preferably overlapped by the pipe shells or layers and made, in particular, of metal. The end of the plastic sleeve is wound, pressed or cast around the end of the overlapped pipe, and the flanges of the innermost pipe shell or layer hooks onto a shoulder at each end of the overlapped pipe. The end region of the outermost pipe shell or layer may be enclosed by a coupling ring. The flanges (1'-10') of the pipe shells (1-10) or pipe layers abut on each other, possibly via an incorporated ring (20) or ring winding preferably perpendicular to the axis of the sleeve.

Abstract: Disclosed herein is a line jointing structure suitable for use in an electrostatic spray painting apparatus. The line jointing structure is used to connect to a device, an insulating line serving as a path for transportation of electrically conductive paint to which a high voltage is applied. The line jointing structure basically comprises a jointing member having a connecting portion capable of being inserted into an end of the insulating line, a sleeve disposed to cover an outer peripheral surface of the line, a nut for pressing the sleeve toward the connecting portion so as to connect the line to the connecting portion, the nut being fixedly mounted on the jointing member, and insulating seals disposed at both ends of the nut.

Abstract: An insulated fitting for a flexible air duct wherein the fitting has a collar for dressing the end of the flexible air duct coupled to the fitting. The fitting can be a tee, wherein the collar is connected to a retaining ring rotatably mounted to the main conduit of the tee so that the angular position of the tee can be varied depending upon the desired direction of the branch conduit of the tee. The retaining ring has a base portion for securing the T-fitting to a supporting surface The fitting can also be a wye and a reducer.

Abstract: The invention relates to a connector for a hydraulic pressure hose, said connector comprising a body (7) which includes a first sleeve member (8), to be fitted inside the end of a hydraulic pressure hose, as well as a connecting member (11). The connecting member (11) preferably includes a gripping means (12) for a tool and a fastening means (13), such as a threaded portion for coupling the connector with a hydraulic system. In addition, the connecting member (11) includes a second sleeve member (9) mounted outside the end of a house in line with said first sleeve member (8), said sleeve members (8,9) being adapted, upon mounting the connector on a hydraulic pressure hose, to squeeze towards each other and to clamp the end of hydraulic pressure hose therebetween. At least a part of at least one of the sleeve members (8,9) is electrically insulated from body (7).

Abstract: A fluid conducting connector for use in water connections particularly water heater connectors. The connector assembly is designed for mating connection to a galvanized nipple for reduction of galvanic corrosion between dissimilar metal connections. An insulator sleeve is seated within the connector to maintain separation between the galvanized nipple and the copper tube of the assembly. The connector assembly includes an internally threaded female connector mounted to the copper tube for connection to the nipple. The insulator sleeve includes a tubular body and a radial flange. The body of the sleeve extends partially into the copper tube while the flange seats within the female connector acting as a washer for the assembly.

Abstract: A flexible coupling for connecting an engine manifold to an exhaust pipe to relieve torque. Concentrically spaced flexible tubes, which have insulation filling the annular space between them, are connected to inlet and outlet tubes having interior ends located between the ends of the flexible tubes. The inlet and outlet tubes have enlarged upstream ends and smaller downstream ends. By overlapping the ends of the inlet and outlet tubes, the tubes are able to have relative angular movement when the flexible tubes bend due to engine torque. One or more separate tubes which also have enlarged and smaller upstream and downstream ends may be provided to overlap with the inlet and outlet tubes to allow bending of longer couplings.

Abstract: An electrically insulated pipe coupling and method is disclosed in which a first sleeve member and a second sleeve member are positioned in axial alignment and include oppositely positioned end portions axially spaced from one another to create an axial space therebetween. A resilient annular seal portion is gradually formed in situ (preferably by applying liquid urethane onto a rotating mandrel) in the axial space. The seal portion is chemically bonding to the oppositely positioned end portions and creates a low pressure coupling seal between said first and second sleeve members. An outer protective layer made from continuous synthetic resin saturated fiberglass strand windings is encircled around at least a portion of the end portions of the first and second sleeve members to enclose the seal portion. Finally, a rigid reinforcing sleeve is embedded in and covered by the fiberglass windings of the outer protective layer.

Abstract: An electrically insulated tube union includes a pair of tube fitting assemblies and an electrically non-conductive connector. Each tube fitting assembly has a fitting body, a fitting nut and a threaded ferrule. The connector has a body with an external radial flange between the ends thereof. The connector body is externally threaded on either side of the flange and the threads are axially spaced from the connector ends. The ferrules threadably engage the connector threads and are captured between their respective fitting nut and body. Each ferrule has a tapered end with an unthreaded portion that seats in a frusto-conical portion of the fitting body so that when the fitting nut and body are threadably engaged the ferrule unthreaded end grips the unthreaded connector ends to provide a fluidtight and electrically insulated coupling between the pair of tube fitting assemblies.

Abstract: A connector member for coupling flexible cylindrical tubular duct to the wall of a fibrous duct is comprised of a pair of parallel metal strips, the opposed marginal edges of which are connected to a flexible central strip. A clamp and a slip joint are provided on the respective strips for maintaining the metal strips in a cylindrical configuration, with the ends of the strips overlapping. One said strip including outwardly facing gaskets disposed at opposite sides of the wall of the fiber duct, the other strip including an inwardly facing gasket clamped about the flexible cylindrical ducting.

Abstract: An improved flexible connector material is comprised of a pair of metal strips between which is mounted a flattened tubular configuration including upper and lower flexible sheets or layers encompassing a compressible glass wool batt. The insulation is bonded preferably to the lower layer of a pair of spaced flexible glue lines whereby the tendency of the insulation to become compressed and change in configuration is overcome.

Abstract: A collar for electrically insulating between upper and lower tubing sections in which load bearing insulating materials in the collar are isolated from fluids both interior and exterior the collar.

Abstract: An electrically insulated pipe joint comprises first and second metal tubular parts each having a flange at one end. The first and second tubular parts are coupled by a metal coupling sleeve surrounding the flanges and narrowing behind the flanges. A metal ring is located between both flanges, the outer diameter of which is greater than that of both flanges and which has its inner periphery in contact with the coupling sleeve. At both sides of the metal ring an electrically insulating seal ring is disposed. Further, an electrical insulation is disposed between the coupling sleeve and the first and second tubular parts.

Abstract: A removable reusable insulating unit for insulating an exposed section of an insulated pipe system is disclosed. The insulating unit has a hollow body portion with insulating walls for enveloping the exposed section of the pipe system. The body portion has a parting line along its length to permit opening thereof so that the unit may be wrapped around the exposed section of the pipe system. The body portion is made of a sufficiently flexible insulating material to permitt such spreading apart of the body portion at its parting line. Fasteners are provided for securing the unit closed with the insulating walls abutting one another along the parting line. Each opening of the unit, through which a pipe or the like of the system may extend, has a substantially more rigid insulating material which snugly envelopes the system to form an insulative blanket for the exposed portion.

Abstract: A sleeve joint for plastic-sheathed insulated pipes, comprising an oversized joint sleeve of plastic material overlapping the ends of the sheaths of connected pipes with a gap provided between the sleeve and said ends. Spacer means are located in the gap at either end. A circumferential groove is provided in the respective sheath outside of the gap. A fillet weld of a plastic material fills up the groove and the gap opening, and covers the sleeve end face.

Abstract: A job site formed double sealed, double wall insulated spa pipe coupling is effected between two axially connected coupling components each having a plastic inner pipe and a concentric plastic outer pipe of considerably larger diameter with the pipes being connected by in situ foam insulation filing the space between the pipes. One component has the outer pipe and the foam insulation severed to expose the bare outer periphery of the inner pipe over a short length. The second component similarly formed includes a radially enlarged section over a short length to define a radially enlarged hub. An annular cylindrical collar of a length equal to the length of the hub is adhesively fixed on its inner periphery to the outer diameter of the outer pipe of the first component.

Abstract: Tube ends are received at opposite ends of a bore passage in a block of an electrically non-conductive material. Ferrules encircling the tube ends are compressed to effect a fluid tight seal of the tube ends and block and effective at pressures of about 650 psi. Plates are mounted to the block ends for applying compression force to the ferrule and the plate mounting involves low reactive force in the block.

Abstract: Bell and spigot pipes are joined coaxially with a compressed gasket and are largely surrounded by a layer of insulation. A sleeve surrounds the joint so made and is sealed to the respective pipes and is filled with a foam insulator.

Abstract: The fuel filling system includes double pipe fuel delivery and tank venting plumbing. Both fuel delivery pipe and tank venting pipe are flexible and communicate with the gas tank through normally closed check valves. An inlet housing defines a vent cut-off chamber which communicates with the tank venting pipe, and also includes an annular nozzle embracing seal for isolating the end of the gas pump nozzle from the vent cut-off chamber. The gas tank is thus fully sealed by the check valves during driving, so that fuel will not spill from the tank should the filling system plumbing become ruptured or should the vehicle become overturned as a result of a collision. Fuel is introduced into the tank under positive pressure provided by the filling station fuel pump. Under pumping pressure, the check valves opens to permit the inflow of fuel and the outflow of air displaced from within the tank.

Abstract: A sleeve, which finds particular application in the environmental sealing of joints between insulated pipes, comprises heat-recoverable polymeric sheet material provided at separate regions of a principle surface thereof with a layer of a heat-activatable adhesive for bonding the sheet to the pipe insulation, and a layer of a sealant to accommodate flexibility in the joint. A layer of a sealing material, having an elongation modulus greater than that of the sealant, overlies at least part of the sealant layer, to improve the pressure retention properties of the sleeve.

Abstract: A process for placing heat-shrinkable polyfluoroolefin polymer sleeves, preferably, FEP resin or PFA resin, over Frasch sulfur well piping and other downhole well piping to protect such piping from corrosion.A heat chamber for heat-shrinking the polyfluoroolefin polymer sleeves onto the piping.

Abstract: A coupler for electrically-isolating two conductive sections of fluid-passing line includes two nonconductively-interconnected pieces of tubing for insertion in the line. The pieces of tubing each have a divergently-flared end, and the flared ends are nonconductively-interconnected within two dielectric wafers. Each wafer has a tapered hole extending through it that matches the flared ends and enlarges to a face on the wafer. The flared ends are each bonded within a separate one of the tapered holes in a position recessed from the face with the flare of the end paralleling the taper of the hole, and the faces are bonded together with the larger ends of the tapered holes aligned and the flared ends sealed in fluid communication with an electrically-nonconductive gap between them.

Abstract: An insulated casing assembly for use in injecting steam into wells or transmitting steam from the generating source to the wellhead is disclosed. A plurality of interconnected casings are used, each casing have outer and inner tubular sections and an annular spacing between the two sections containing thermal insulation. Rigid weld rings connect and prevent relative movement between the corresponding ends of the two sections. A thermal and fluid sealing ring disposed between adjacent inner tubular section prevents ingress of steam into the coupling cavity. A threaded coupling screwed onto threaded ends of outer tubular sections joins adjacent casings together.

Abstract: Two tube systems, each comprised of two or more concentrically arranged metal tubes, are positively and electrically conductive interconnected through a coupler sleeve system composed of a corresponding number of concentrically arranged coupler sleeves of slightly larger diameter such that ends of the sleeves of the coupler sleeves are threaded upon ends of the tubes of the tube systems to be interconnected.

Abstract: The fuel filling system includes double pipe fuel delivery and tank venting plumbing. Both fuel delivery pipe and tank venting pipe are flexible and communicate with the gas tank through normally closed check valves. An inlet housing defines a vent cut-off chamber which communicates with the tank venting pipe, and also includes an annular nozzle embracing seal for isolating the end of the gas pump nozzle from the vent cut-off chamber. The gas tank is thus fully sealed by the check valves during driving, so that fuel will not spill from the tank should the filling system plumbing become ruptured or should the vehicle become overturned as a result of a collision. Fuel is introduced into the tank under positive pressure provided by the filling station fuel pump. Under pumping pressure, the check valves open to permit the inflow of fuel and the outflow of air displaced from within the tank.

Abstract: A fluid transport line comprising coaxial inner and outer metal pipes, the inner pipe of which is intended to transport a thermally insulated fluid, is formed by successive sections, the inner and outer pipe portions of which are connected by means of metal rings interposed between successive sections in junction zones. To reduce the effect of the thermal losses thus created, a closed chamber containing a thermally insulating medium is defined round each junction zone by a metal shell which is welded to the outer pipe portions of the successive sections.

Abstract: A coupler for electrically-isolating two conductive sections of fluid-passing line includes two nonconductively-interconnected pieces of tubing for insertion in the line. The pieces of tubing each have a divergently-flared end, and the flared ends are nonconductively-interconnected within two dielectric wafers. Each wafer has a tapered hole extending through it that matches the flared ends and enlarges to a face on the wafer. The flared ends are each bonded within a separate one of the tapered holes in a position recessed from the face with the flare of the end paralleling the taper of the hole, and the faces are bonded together with the larger ends of the tapered holes aligned and the flared ends sealed in fluid communication with an electrically-nonconductive gap between them.

Abstract: A conduit arrangement for a tilt cylinder of a bulldozer having a track frame and a push arm connected to the track frame for operating the blade of the bulldozer and including a trunnion for pivotally connecting the push arm to the track frame. A pair of spaced fluid passages are provided through the trunnion. A first pair of conduits have one end coupled to the tilt cylinder and the other end connected to the fluid passages. The first pair of conduits pass through an internal bore provided through the push arm. The inboard end of the trunnion extends into the interior of the track frame. The fluid passages extend through the trunnion into the interior of the track frame. A second pair of conduits pass inwardly through the track frame towards the main frame of the bulldozer. One end of each of the second pair of conduits is connected to the fluid passages and the other end extends into the bulldozer main frame. The track frame is spaced from the bulldozer main frame.

Abstract: A coupling is provided for spaced coaxial pipe ends to be connected having a sleeve or middle ring with frusto-conical enlarged ends receiving the pipe ends to be connected coaxially thereof, elastomeric gaskets having a frusto-conical portion fitting the ends of the middle ring, follower members bearing on the gaskets to urge them into the middle ring ends, tightening members drawing the follower members toward each other, an insulating sleeve surrounding at least one pipe end with a depending radially inward spacer member and an insulating member having the shape of the follower member between the follower member and the pipe and middle ring and having a flange coaxial of the pipe extending through said follower member around the pipe. An electrical connector means may be metallurgically bonded to the middle ring.

Abstract: A tubular pipe assembly for hot or cold fluid transfer which assembly includes a plurality of insulated conduit sections joined together, end to end, with male and female couplings. Each conduit section has concentric inner and outer pipes with insulation disposed between the pipes. The outer pipes have threaded ends. A means at both ends of each conduit section seals the cavity between the inner and outer pipes and supports the pipes relative to each other. A male coupling has a first end threaded on the outer pipe of a first conduit section and has a second end which is threaded. A female coupling has a first and a second threaded end. The first threaded end of the female coupling is threaded on the outer pipe of a second conduit section. The second threaded end of the female coupling is threaded on the second end of the male coupling and thusly joins the first and second insulated conduits together.

Abstract: A vacuum insulated conduit exhibiting reduced thermal leakage through a joint area wherein the evacuated space between inner and outer pipes is reduced in the joint area by a plate from the outer pipe to bellows covering the inner pipe which form the major heat transfer pathway.

Abstract: A rigid, molded fiberglass duct having an integral bendable elbow comprised of two sections of cured fiberglass securely bonded to a corrugated metal-foil sleeve. The method of manufacturing the rigid bendable duct is by sliding a corrugated metal-foil sleeve on to a mandrel and then wrapping the ends of the sleeve with uncured fiberglass. The area of the uncured fiberglass overlapping the corrugated, bendable sleeve is compacted by means of a collar which fits around the sleeve and the fiberglass and compresses the fiberglass into the corrugations of the sleeve. In order to enhance the bond, protusions may be provided in the overlapping area of the sleeve, such as by cutting the corrugated sleeve and bending it up to form tabs.

Abstract: An insulated drill collar gap sub assembly for a toroidal coupled telemetry system including a first annular sub member (150) operable to be connected at one end to a drill collar and a second annular sub member (156) operable to form a part of a drill collar sub. The first and second annular sub members have interconnecting structural members (54, 58) operable to structurally interfere. The interconnecting structural members are dimensioned to form a continuous gap (160) between mutually opposing surfaces and a dielectric material (162) fills the gap to electrically isolate the first annular sub member with respect to the second annular sub member. A bearing member (164) is positioned between the first annular member and the second annular member and is coated with a dielectric insulation (166) to facilitate the formation of a drill collar gap sub assembly of structural and electrical integrity.

Abstract: An improved insulated tubing string with insulated coupling formed of concentric tubing members insulated from each other to prevent heat from the inner tubing from being conducted to and through the outer tubing. The coupling joins the outer tubing of successive tubing assemblies to provide additional strength to the string and the inner tubing is insulated within the coupling to prevent heat loss at the coupling. The inner tubing is elongated during fabrication and joined to the outer tubing when elongated to reduce heat stress on the string when in use.

Abstract: An insulator device which couples a metallic gas delivery tube to a line leading to a detector device which requires cooling gas for operation. The insulator device of the present invention comprises a molded dielectric insulator, molded about two separated metallic end components, each of the metallic components including a nut portion to allow the insulator to be connected, on one hand to the detector device line, and on the other hand to the metallic gas delivery tube. The two metallic components are separated by a gap in order to provide the necessary electrical isolation between the two metallic end components. One metallic end component includes a built-in check valve which permits gas to flow only in the desired direction while preventing gas flow in the opposite direction.

Abstract: A connection between two pipes of a pipeline includes a pair of coupling members having externally threaded ends with sealing surfaces projecting from the ends. The threaded ends are advanced into opposite ends of an insulating sleeve fabricated of electrically nonconductive material. Internally threaded end portions of the sleeve are separated by an annular recessed portion. A resilient, nonconductive annular spacer is retained within the annular recessed portion. The spacer includes a pair of inclined inner sealing surfaces positioned in overlying sealing relation with the coupling member sealing surfaces and an outer sealing surface sealingly engaging the insulating sleeve to form a fluid and pressure tight seal around the annular space between the coupling members and the insulating sleeve in addition to electrically insulating the coupling members from each other.

Abstract: An improved prestressed conduit string for conducting heated fluids through a well bore comprised of a plurality of concentric double wall tube conduit sections each including an inner heated fluid conductor tube in tension prestress and a larger diameter outer tube in compression prestress to reduce heat transfer from the conducted fluids and prevent deformation of the conduit string when heated. By the present invention, the outer tubes of the conduit sections are shorter than the conductor tubes thereof whereby the ends of the conductor tubes extend short equal distances beyond the ends of the outer tubes.