Abstract: A swivel joint for high pressure fluid capable of preventing the leakage of the high pressure fluid and smoothing the rotation of the rotating one of the shaft member and the receiving member, with a simple and compact structure, which can be manufactured inexpensively. The swivel joint includes a cylindrical cavity formed inside the receiving member and around the shaft member. including: a contacting end, normal to an axial direction along the axis of relative rotation of the shaft member and the receiving member, contacting with the high pressure fluid through the connecting portion connecting the fluid paths of the shaft member and the receiving member; a movable sealing member, movable in the axial direction, contacting with the high pressure fluid through the contacting end; and a hollow chamber, separated from the contacting end by the movable sealing member, confining the fat oil.

Abstract: A device for transmitting torque from a power unit to a drill string or other rotary pipe, and which is constructed upon reverse rotation to preferentially break a threaded connection between the device and a stand of the pipe without disconnecting a plurality of lengths of pipe in the stand from one another. The torque transmitting device includes a tubular structure having a thread adapted to be advanced into engagement with a thread at an end of the pipe, and a shoulder ring carried by and rotatable with the tubular structure and having a shoulder engageable against a shoulder of the pipe to limit advancement of the threads together, with axial forces being transmitted from the tubular structure to the ring by interengageable bearing surfaces which permit limited rotary movement of the structure and its thread relative to the shoulder ring.

Abstract: A restrained pipe joint is provided for affixing the spigot end of a first pipe into the socket end of a second pipe. The pipe joint includes a circular restraining ring and a retainer ring which includes a groove ring and a plurality of locking segments. When the retaining ring is tightened, the retaining ring is forced against the circular restraining ring, thereby engaging the locking segment teeth into the spigot end of the first pipe. The groove ring abuts the circular restraining ring which holds the spigot end of the first pipe within the socket end of the second pipe.

Abstract: A swivel joint for interconnecting two lengths of pipe, comprises an inner annular member adapted, in use, to be connected to a first length of pipe and an outer annular member co-axial with the inner annular member and adapted, in use, to be connected to a second length of pipe, and a bearing arrangement locating the inner and outer members for relative rotary movement with respect to one another. A lubricant reservoir is connected to the bearing arrangement, and a pump drive driven by relative rotary movement between the inner and outer annular members pumps lubricant from the lubricant reservoir to the bearing arrangement. The lubricant reservoir comprises a collapsible hose, and the pump device (42) comprises system for effecting a peristaltic action in the hose as a result of relative rotary movement of the inner and outer annular members, thereby causing lubricant to be displaced from the hose towards the bearing arrangement.

Abstract: A cementing head apparatus includes a container body having a body bore therethrough. Upper and lower releasing mechanisms are associated with the container body. The lower releasing mechanism has a cylindrical plunger extending into a bore of the container body. A spherical releasing ball rests upon the plunger of the lower releasing mechanism. The upper releasing mechanism is identically constructed and is associated with a releasing dart. Upper and lower ends of the container body have complementary male and female straight threads with associated O-ring seals defined therein. A lifting sub is directly connected to the upper thread and has a loading bore defined therethrough. A cap closes an upper end of the loading bore of the lifting sub. A swivel is directly connected to the straight thread at the lower end of the container body.

Abstract: A power thread comprising a tubing or casing connection having a collar threadably connected to a tubular member at each end is disclosed, utilizing a shallow tapered thread with relatively low crest height. The device has a number of closely mated threads adjacent the inserted end of the tubular member and diminishing but still load bearing engagement of the remaining threads. In one example of a five thread buttress according to the invention, the root to crest dimension of the thread profile is about 0.040" and the thread profile has a taper of about 0.040" per inch. The load flank side of the thread on the tubular member and coupling has about a 3.degree. angle and the stab flank side of the thread has about a 10.degree. angle, relative to a plane perpendicular to the central axis. The crest surface of the threads on the collar and tubular member have a taper of about 1.75.degree. from the approximate midregion of the crest surface to the stab flank.

Abstract: A swivelable quick connect assembly for use with tubular conduits is disclosed as comprising a housing having an axial bore for receiving one end of the conduit, an elastomeric ring-like meal is disposed in the bore for providing a fluid tight seal between confronting portions of the conduit and the housing, an annular bushing is disposed in the bore for positioning the seal and for guiding the one end of the conduit into nesting relationship with the bore, and a retainer is detachably secured to the housing and is cooperable with an annular projection on the conduit for securing the conduit in its operative position within the bore, the retainer having resilient deformable portions which are adapted to snap over the locking wall upon insertion of the conduit into the housing bore.

Abstract: The invention relates to a welded pipe joint comprising a sleeve (3) welded (5, 6) at each end thereof to the respective pipe (1, 2). The wall of the sleeve (3) at each pipe provided with a boring in which a nipple (11, 12) for oil is arranged. In connection with each nipple, a peripheral groove (15 16) is arranged to extend around the respective pipe (1, 2). Oil introduced through the nipples (11, 12) prevents pickling acid from entering clearances (9, 10) between the pipes (1, 2) and the sleeve (3), and impurities from gathering in gaps (7, 8) between the end faces of the pipes and a central shoulder (4) formed internally in the sleeve.

Abstract: An oil field tubular connection is provided for joining metallic tubulars at a well site. At least one end of each tubular is provided with a frustoconical external sealing surface for metal-to-metal sealing engagement with a corresponding surface of an adjoining tubular. A plurality of antigalling grooves provided along the external sealing surface each project radially inward thereof and circumferentially encircle the threaded end of the tubular member and seal the groove from fluid communication with the interior of the tubular member. The antigalling grooves are particularly well suited for use with a low angular taper sealing surface of less than approximately 7.degree., and reduce galling between the metal sealing surfaces during makeup of the connection. Each tubular connection may also include an energizing groove spaced axially between the exterior sealing surface and the threads on the tubular member.

Abstract: A coupling device for connecting an end of a hose to an end of a pipe having a circumferentially extending collar includes a tubular coupling element with axially spaced ends. A first end of the coupling element is received in the end of the pipe and the coupling element is provided with elastic hooks which engage the collar in order to fix the coupling element. The device further includes a sleeve having a first section which is received in the coupling element and defines therewith an annular space of width approximately equal to the wall thickness of the hose. The sleeve also has a second section which projects from the annular space into the end of the pipe so as to define an annular gap with the latter. The second section of the sleeve is of greater diameter than the first section and abuts the first end of the coupling element.

Abstract: A pressure balanced coupling device for quick connection and disconnection with at least one mechanism. The device operates to maintain a sealed flow-through connection between two devices which may also contain a pressurized medium such as refrigerants. The preferred device permits non-destructive gripping of tubing while affording readily selectable means for safely releasing pressure from within the device prior to releasing the gripping connection provided by this coupling device.

Abstract: The present invention relates to an oil well pipe joint having improved resistance to galling and to a process for manufacturing the same, which comprises a porous blast-plated layer provided at least on a metal sealing portion by blasting soft metal particles such as of zinc and aluminum, particularly discrete particles each comprising an iron or iron alloy core covered by a zinc or a zinc alloy coating with an iron-zinc alloy layer intervening therebetween.

Abstract: A pipeline of an indeterminate length, having a substantially constant inner diameter throughout its length, is formed by frictionally joining together a plurality of adjacent pipe segments. The ends of each pair of adjacent pipe segments are frictionally joined within an external, cylindrical sleeve member. The sleeve member has a substantially smooth inner bore and a substantially constant inner diameter, and is adapted to receive the adjacent pipe ends which abut within the sleeve.The joint of the disclosed pipeline is so designed that its strength can develop at least the yield stress of the material from which the pipeline is constructed.

Abstract: A lockring tube joint is described where the end portions of a pair of interfitting tubes are joined by a lockring, wherein the lockring can be installed with less force than prior lockrings and, despite lower installation forces, the tubes are securely held together. The lockring has a front section whose internal surface is tapered, a center section with a cylindrical inner surface of the same diameter as the smallest diameter of the front section, and a rear section forming a push surface for receiving forces to push the ring onto the tubes. The center section is relatively long and thin. As the lockring is pushed onto the interfitting tubes, the front section of the lockring encounters resistance to forward movement, while the center section section of the lockring is longitudinally compressed. The longitudinally compressed center section elastically grows in diameter, which avoids high friction contact with the outermost tube.

Abstract: A hollow flexible joint (10) for connecting two pipes (6, 8) in an engine exhaust system, which includes two or more tubular coupling members (12, 14) adapted for connection between the pipes (6, 8), the tubular members (12, 14) each being sealingly and pivotally engaged with another tubular member (12, 14), and two of the tubular members (12, 14) being engageable with a respective adjacent end of each of the pipes (6, 8). The joint includes three or more pairs of part-spherical mated sealing surfaces (11a, 11b, 11c), and can remain gas-tight even when one of the pipes (6, 8) articulates universally relative to the other.

Abstract: An anaerobic sealant composition is employed to seal a pipe joint between pin and box members intended for use in petroleum drilling operations. The composition is applied to one or both of the members. The members are then joined and the composition cured into a solid form which bonds to the members and fills the space between them. The constituents of the composition can be selectively varied to control its lubricity which also affects the make up torque. Additionally, the concentration of the sealant composition can be selectively varied to control the break out torque of the joint to which it is applied, and preferably make the break out torque substantially greater than the make up torque. Excellent seals can be obtained using lower grade pipe, and the pin and box members can be made up with the application of lower torque to the assembly without reducing the sealing capabilty of the connection. The preferred composition also serves as a rust and corrosion inhibitor for the joint.

Abstract: A swivel joint for interconnecting two lengths of pipe, comprising an inner member (1) and an outer member (2), a chamber defined by the inner member (1) and the outer member (2) and accommodating bearing means (15a, 15b) locating the inner member (1) and the outer member (2) for rotary movement relative to one another. Pump means (8) for circulating lubricant within the chamber is provided, which pump means (8) is driven by relative movement between the inner member (1) and the outer member (2).

Abstract: An articulated conduit coupling for attaching two conduits together so that the conduits can move or vibrate in a generally radial direction relative to each other without rupturing the conduits includes a first conduit section which is coaxial to a second conduit section. The second conduit section has one end which is sized to be concentrically received within one end of the first conduit section. The articulated conduit coupling also includes two radially extending pivot pins in diametrical alignment with each other projecting through the walls of the overlapped section conduit section and overlapping first conduit section so that the first and second conduit sections can move relative to each other in a direction 90 degrees to the axis of the pivot pins.

Abstract: A multi-line or multi-path fluid swivel contains a plurality of stacked modules with each module having an internal core and an external housing. Each core includes one integral flow conduit which extends from the bottom of the core and opens through the side of the core into an annular chamber between the core and the housing. An opening in the housing permits flow of fluid out of or into the annular chamber. Seals between adjacent cores and seals between the cores and housing prevent or reduce leakage. The housings are rotatably mounted on the corresponding core with spaces between adjacent housings to permit axial core growth and deflection. Means between housings transmit rotational forces between housings and yet permit relative movement in the axial direction. Means are provided to fasten the adjacent cores to each other which act both as a dowel for transmitting rotational forces and as a bolt for locking cores together in the axial direction.

Abstract: A gas- and oil-field pipe joint comprises a female part formed with a frustoconical internal thread and a male part formed with a complementary frustoconical external thread and screwable into the female part with both parts centered on a common axis. The female part further is formed centered on the axis with a frustoconical inner surface axially inward from the internal screwthread and with a frustoconical shoulder surface extending radially inward from the axially inner end of the inner surface. The male part is formed centered on the axis with a barrel portion having an ellipsoidal barrel surface engageable radially with the inner surface and with a frustoconical end surface engageable axially with the shoulder surface of the female part.

Abstract: The present invention discloses the use of electroless metal coatings, preferrably copper or zinc, on oil country tubular goods to eliminate galling of the threads, provide a tortuous path as a sealing surface, and provide porous lubricant reservoirs.

Abstract: A connection (20) for oilwell tubular joints (8 and 9) to effect a fluid tight conduit wherein one of two cooperating stop shoulders (19) of limited dimension is formed with peaks (22) and valleys (24) such that the peaks contact the other stop shoulder (18) upon full make-up of the connection so as to provide channels (24) for the escape of lubricant from between the shoulders and thereby effect a higher overload torque capacity for the connection, without sacrificing other characteristics of the connection.

Abstract: A tubular connection includes a shallowly tapered conical sealing surface. The areas on the pin member where make up and sealing respectively occur in the various embodiments comprise multiple angles and surface texturing for the purpose of lubricant retention, facilitate burnishing and reduce the propensity for galling in multiple make up and break out situations. The pin taper in each case is slightly less than the box taper. The area on the pin member is textured ahead of the very smooth seal area to retain some thread compound even after repeated makeups of the connection. The area ahead of the sealing area where stabbing contact is made is textured in the 125-250 R.sub.a range while the smooth seal area is textured about 63 R.sub.a to provide a gas tight seal under high pressure and severe conditions of combined loads and thermal shock.

Abstract: In the rotary coupling for feeding a gaseous or liquid pressurized medium from a first to a second machine part, which are rotatable with respect to each other, the first machine part contains at least one feed piston formed as a spring supported hollow piston and a sliding shoe is mounted between the feed piston and the second machine part. In order to make a rotary coupling, particularly a high pressure rotary coupling, in which when no operating medium is supplied during rotation no frictional forces are present between the component parts, the feed piston contains a mechanically driven check valve which opens in the feed direction and at least one piston spring braced between the feed piston and the first machine part is provided whose compression force is directed opposing that force which is exerted by the medium under pressure on the feed piston.

Abstract: A fitting for joining a tube to another axially aligned tube, or to a T-joint, elbow joint, or the like, comprising a sleeve fitted over the end of the tube, and an annular tubular member forced over the sleeve in coaxial relationship with the sleeve and the tube to compress the sleeve around the end of the tube to provide a high-strength fluid-tight joint between the sleeve and the tube. The fitting and the tube are formed of electrically conductive material, and an insulating dry lubricant is interposed between the components of the fitting, and between the fitting and the tube. The fitting is especially constructed to provide conductive paths from the surface of the tube and from the surface of an inner component of the fitting to an outer component so as to avoid arcing across the lubricant layer in the event of a lightning strike, or the like.

Abstract: This is a novel swivel joint for connecting two fluid conveying conduits. It includes an inner cylinder connected to one conduit and an outer cylinder connected to the other conduit. There is a double seal with a pressure chamber therebetween the two cylinders at one end thereof and a second double seal with pressure chamber therebetween at the other end. Four sets of bearing means are located between the inner and outer cylinders between the two double seals.

Abstract: A multi passage swivel assembly provides fluid or gas flow while continuous or intermittent rotation occurs between a fixed inlet port and a rotating outlet port. The assembly contains a clearance control ring that compensates for dimensional change to allow high pressure operation.

Abstract: A gasket for the tight coupling of pipes having an outer face adapted to cooperate with the cylindrical bearing surface of the female end of a pipe, a succession of annular ribs each taking, in cross section, the form of an asymmetrical tooth, two annular housings opening via slots in the inner face and adapted to receive two rigid annular cores, and two mouldings of prismatic cross section and inclined towards the edge of engagement of said gasket in the female end. The invention is more particularly applicable to underground pipes for the circulation of sewage.

Abstract: An oil well pipe joint comprising a metal-to-metal sealing portion without thread is disclosed. A metal-plated or resin-coated layer exhibiting improved resistance to galling is provided on the outer peripheral surface of a thread-free lip portion which constitutes part of the metal-to-metal sealing portion on an externally-threaded member. At the metal sealing portion, satisfactory sealing properties are maintained under severe corrosive conditions, enabling the joint to be connected and disconnected over 10 times, and usually over 25 times.

Abstract: This invention provides a fluid fitting made up of telescoping sleeves providing an annular space therebetween adapted to receive the end of a tube. The outer sleeve is attached to the inner sleeve by being deflected around annular ridges at one end of the inner sleeve. The sleeves are attached to the tube by swaging the outer sleeve so as to grip the tube between the two sleeves. Grooves in the inner sleeve provide corners which dig into the inner surface of the tube and provide seals and retention, while recesses in the outer sleeve receive deflected material of the tube to prevent rotation.

Abstract: An improved ladder base swivel with a through water channel is provided wherein an annular seal preventing passage of liquid from a cylindrical bore to the exterior of a rotatably-received mating bore is provided with a lubricant. A lubricant reservoir channel which communicates with the seal supplies lubricant to the seal to prevent the seal from drying and cracking and to minimize wearing of the seal. The reservoir also communicates with an external opening which is normally plugged, thereby serving as a water escape channel upon seal failure. Continuous hydraulic and electric circuits are provided between the rotating elements of the swivel.

Abstract: For sealing the joint between a pipe end (2) and a pipe or housing (3) into which it is to be inserted, a metal sleeve (1) has a part (a) which is secured, such as by welding, to the pipe end (2), a first annular corrugation (b) and a second annular corrugation (c) which is of greater diameter than the first annular corrugation (b) and resiliently deformable into sealing engagement with the pipe or housing (3).

Abstract: A method of joining two tubular members which comprises inserting an end portion, which forms a spigot, of one of them into an end portion, which forms a socket, of the other to achieve an interference fit. The thickness of the wall of the end portion of at least one of the tubular members so varies in an axial direction that, when the spigot has been fully inserted into the socket, the external diameter of the spigot and the internal diameter of the socket are smaller at a first point on the axis than at a second point on the axis, the first point being nearer to the mouth of the socket than the second point.

Abstract: A duct liner interconnecting device for temporarily interconnecting the ends of sections of duct liner includes a pair of complementary semi-cylindrical elements hinged together along one edge for movement from an open position in which the elements are side by side to a closed position in which the elements form a short tubular member with a longitudinal channel to receive the ends of duct liner sections to be interconnected, a pair of arcuate spring clips pivotally attached to one of the elements releasably latch the elements together in the closed position, and a tapped aperture in one of the elements receives a lubrication fitting to allow the introduction of lubricant into the duct liner to facilitate pulling of lightguide cable through the duct liner.

Abstract: Oppositely facing surfaces have grooves in one of the surfaces and low coefficient of friction inserts in the grooves. The inserts have a thickness greater than the depth of the grooves so as to project from the grooves when seated therein for bearing against a facing surface and maintaining the two surfaces in spaced apart relation. Such inserts provide a reduced friction relation between the two surfaces whereby the two surfaces can be readily rotated between a working condition having a thrust load therebetween and a loosened non-working condition. Preferably, two or more of the grooves and inserts are provided, the inserts being held in the grooves by distorted portions in the walls of the grooves.

Abstract: This disclosure relates to a quick connect coupling including a tubular socket or receptacle part having an internal groove formed therein, a tubular nipple or insert part having an external groove formed thereon, and a snap ring. The nipple is insertable into the socket and when so inserted the two grooves are radially aligned. The snap ring is mounted in and extends between the two grooves to lock the socket and the nipple in assembled relation. Prior to final assembly, the snap ring is positioned in the socket groove, and in the space within the socket groove and around the snap ring is applied a relatively viscous fluid. This fluid, which may be a grease, holds the snap ring in the desired position in the groove prior to and during assembly, and it also serves as a lubricant on the ring which facilitates the assembly of the parts.The disclosure also describes the method of assembly of the coupling.

Abstract: A sliding member is provided which comprises a base body made of a firmly entangled and collapsed metal fine wire, with the voids formed between the metal fine wires constituting the metal mesh being filled compactly with a heat resistant material, the sliding surface of the base body being formed into a smooth surface with either a lubricant that fills a number of small holes formed in the heat resistant material as well as covering the surface thereof or the lubricant and the metal fine wires being exposed.

Abstract: A sliding member is disclosed wherein a sheet-like heat resistant material comprising expanded graphite, mica, etc. singularly or in combination, and a reinforcing material comprising either a combination of a mesh made of metal fine wires with a mesh made by weaving or knitting metal fine wires and fluoroplastic yarns together, or a mesh made by weaving knitting metal fine wires and fluoroplastic yarns together are integrally shaped so that at least on the sliding surface the metal fine wires and the fluoroplastic yarns are exposed, both constituting the reinforcing material, and the heat resistant material held by the metal fine wires and filling the meshes of the mesh as well as the voids formed between the metal fine wires in a mutually intermingled state, exhibiting a smooth surface.

Abstract: A multi-port hydraulic swivel joint (10) in which a high pressure flow channel (34) is located adjacent an enclosed end (15a) of the swivel joint, the pressure in the return line is maintained at a low level to provide low pressure fluid which is transmitted through a flow channel (37) adjacent to an open end of the swivel joint, and the return flow channel (36) is located between the other two. A passageway (43) communicates fluid which has seeped to a cavity between the high pressure flow channel and the enclosed end to the return flow channel (36), a raceway (44) with steel balls (46) resist forces tending to separate the stator (30) and rotor (40) of the swivel joint, and a lip seal (49) with grease packing seals the low pressure flow channel (37) from the open end (15) of the swivel joint.

Abstract: The present invention discloses the use of electroless nickel coatings on oil country tubular goods to eliminate galling of the threads, provide a tortuous path as a sealing surface, and provide porous lubricant reservoirs.

Abstract: In a swivel joint which leads high-pressure liquid in a fixed pipe into a rotatable pipe coupled slidably to said fixed pipe, a lubricating chamber is provided in the neighborhood of sliding area between the fixed and rotatable pipes, and lubricant having at least same pressure as that of said high-pressure liquid is led into said lubricating chamber for smooth rotation and prevention of leakage of the high-pressure liquid and abrasion of the sldiing area.

Abstract: A swivel joint for handling fluids which is used to connect open-ended male and female pipe sections. A retainer in the form of an annular split ring is mounted circumferentially about the male pipe section in a groove formed on its outer surface. The split ring includes thrust and radial transfer surfaces which cooperate with complementary surfaces formed on solid annular bearings which are disposed generally between the split ring and the female pipe section. The complementary surfaces transmit both radial and thrust loads through the split ring and bearing. An assembly nut connects the male and female pipe sections, split ring and bearing together.

Abstract: There are disclosed two embodiments of an apparatus for releasably latching the lower end of a tubing string within the bore of an upstanding well conduit by means of latching parts adapted to be received in latching position beneath a shoulder in the bore of the well conduit. The latching parts are locked in latching position by locking means which is engageable and releasable in response to manipulation of the well string. The latching parts are moved into unlatching position, upon release of the locking means, without necessity of sliding contact between the latching parts and the shoulder. There are also disclosed two embodiments of a seal ring clamped within a groove about a stinger portion of the apparatus for sealably engaging the bore of the well conduit.

Abstract: The present invention in a rotary coupling or swivel is arranged for maintaining together, respectively, stationary and rotating pipes wherethrough a fluid under pressure is passed and involves an outer stationary body with an inner body journaled therein. The two bodies are held together by positioning a number of hardened balls within complimentary grooves formed, respectively, around the stationary body inner circumference and around the inner body outer circumference, the aligned grooves forming a track or race wherein the hardened balls roll freely. The hardened balls are dropped into the grooves through a port formed through the stationary body, holding the bodies together and functioning as a roller bearing to carry high thrust loads beyond the pressure loading.

Abstract: A fluid coupling for interconnecting a liquid-conveying duct in a shaft element to a duct in a hub element, the two elements being rotatable relative to each other. The shaft element has a central passageway subjected to fluid under high pressure and has an enlarged-diameter end communicating with a smaller-diameter portion. The end of the large diameter portion of the shaft element remote from its small diameter portion is subjected to fluid under high pressure in said passageway; while the opposite end of the large diameter shaft portion is subjected to a sealing fluid. The pressure of the sealing fluid is always greater than that of the high-pressure fluid, with the result that the high-pressure fluid will not enter the chamber filled with sealing fluid to decompose it and form an emulsion.

Abstract: An improved flange protector for sealingly engaging spaced flanges and protecting the flange gasket from the environment. A ring-shaped elastomer body preferably includes a grease fitting for injecting the protective fluid through the body and into engagement with the flange gasket. The elastomer body includes a self-centering rib, and is structured for flexing to relieve excessive pressure in the event of flange gasket failure. An improved method of manufacturing flange gaskets according to the present invention is also provided.

Abstract: A sea anchoring system for anchoring floating sea stations to a sea bed floor such as on a foundation or a stay block comprises a tension member connected between a floating station and the sea bed foundation or block with a plurality of tension members connected between the bed foundation and the floating station through universal joints. The universal joints include an assembly comprising an inner spherical body and an outer spherical body arranged over and slightly embracing the inner spherical body. The outer spherical body includes an opening on one side and a pin connected to the inner spherical body and extends through this opening and is connected, for example, to the foundation or to the floating body. The outer spherical body has a connection for example to the tension member. The inner and outer spherical bodies have spherical surfaces facing each other and at least one of these surfaces has a lining of a material which permits sliding interengagement with a minimum friction and wear.

Abstract: A rotary fluid coupling for conveying fluid from a stationary shaft to a hub rotatably mounted on the shaft, or vice versa. The coupling is characterized in having a shaft provided with an axial passageway extending therethrough, one end of the passageway being connected to a source of high pressure fluid and the other being connected to a source of high-viscosity sealing fluid (e.g., a lubricant). A piston in the passageway separates the high-viscosity sealing fluid from the high pressure fluid, the latter being conveyed to the surrounding hub through radial passageways formed in an enlarged diameter portion of the shaft. The high-viscosity sealing fluid is applied to both ends of the enlarged diameter portion of the shaft to form a seal which prevents escape of the high pressure fluid.

Abstract: Thread joints in explosion-proof electrical fixtures for hazardous areas must relieve the momentary pressure from an internal explosion without flame propagation to the exterior. Ordinary paint on the threads cannot be used due to variations in thickness which alter the flow characteristics and the cooling effects. The invention provides a dense, pinhole-free paint layer uniform in thickness within .+-.15% which can be achieved by electrodeposition. Such a coating facilitates assembly and inhibits deterioration of the clearance path through corrosion but has only a minor effect on the venting relief.

Abstract: A rotary fluid coupling for conveying fluid from a stationary shaft to a hub rotatably mounted on the shaft, or vice versa. The coupling is characterized in having an annular piston which surrounds the shaft and which forms a wall of a chamber connecting a duct in the shaft to a duct in the wall of the hub. A seal is disposed around the shaft between the piston and a closed end of a bore in the hub. In the bore between the piston and the seal is a lubricating material such that pressure exerted on the piston by fluid in the aforesaid chamber will be transmitted by the lubricating material to the seal, preferably a labyrinth seal.