Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
  • F16L58/18—Protection of pipes or pipe fittings against corrosion or incrustation specially adapted for pipe fittings
  • F16L58/182—Protection of pipes or pipe fittings against corrosion or incrustation specially adapted for pipe fittings for screw-threaded joints

Definitions

• the present invention relates to threaded connectors used to secure the ends of tubular bodies together. More particularly, the present invention relates to threaded connections provided with replaceable seals to prolecl the threads
• Pipelines that extend through saltwater bodies are employed for multiple purposes, often associated with the drilling of oil and gas wells and Ihe production and distribution of the oil and gas produced by the wells.
• the pipelines When the pipelines are not buried or otherwise solidly anchored within the saltwater body, they are subjected to dynamic loadings that can eventually cause the pipelines to rupture or otherwise fail.
• the stresses induced by dynamic loading in the connections of the individual tubular bodies forming the pipeline are of particular concern.
• Jointed pipelines that are secured together by the threaded engagement of pin and box connectors at the ends of individual pipe sections are employed in marine riser pipes as well as submerged pipelines and other botlom-to-surface supply lines.
• the marine riser pipelines are typically constructed of tubular pipe sections that are secured together at their ends by special connectors designed to withstand the destructive effects of the dynamic loading acting on the riser.
• the dynamic loading of the riser is caused by changing sea currents, changes
• the tool joint type connection is extremely heavy, requiring additional surface support.
• the strength of a standard threaded and coupled connection is optimized by forming the pin threads such that the thread roots "run out” or continue to decrease in depth on the external surface of the pipe until they disappear at a point referred to as the "last scratch.”
• the final turns of the threads do not make a full depth cut into the pipe body and are not normally intended to be engaged and covered by threads in the mating coupling.
• the pin threads in a conventional threaded and coupled connection arc exposed to the surrounding environment. The corrosive effects of saltwater in this area of exposure can accelerate the failure of a connector subjected to cyclical, dynamically induced forces.
• the seals may be employed with conventional threaded and coupled connectors permitting the fabrication of pipelines that are inexpensive and lightweight as compared with pipelines constructed with conventional tool joint type connectors.
• 09/679470 may be provided by metal-to-metal engagement between the pin and box or by an elastomeric annular seal compressed between the pin and box.
• the metal-to-metal external seal may be provided by engagement of the face of the box with a shoulder formed on the pin end of a non-upset pipe. The shoulder may also be provided by enlarging the pin outside diameter.
• an annular, elastomeric seal is provided, the seal may be carried on the outer surface of the pin body or may be disposed in the box of the connector.
• the enlarged outside diameter of the pin portion of the parent application connector is formed by expanding the pipe wall radially outwardly.
• a frustoconical pin seal surface is machined externally on the enlarged radial area.
• the pin seal surface engages a fiusloconical box seal surface internally adjacent the end of the box. Engagement of the two seal surfaces forms an external seal that prevents salt water from entering the threaded area of the connection.
• the pin seal surface is not properly machined on the expanded body of the pipe, the
• a metal-to-metal seal between the pin and box connection of a threaded tubular is formed externally of the pin on a tubular body comprising a metal seal base that is separately added to the external surface of the metal forming the pin end of the connection.
• An important part of the present invention is the provision of a third metal seal element in addition to the pin and box components that is separately added to the pin component to provide the desired pin seal surface.
• the separately added seal base may be removed
• the tubular pipe body or joint on which the pin is formed may be reused multiple times by reconstructing or repairing the pin seal.
• the outer surface of a tubular pin end connector is enlarged by welding a metal buildup onto the surface, or by the placement of an annular metal body about the surface, to form an external pin seal base.
• the pin seal base is machined on the welding buildup to form an annular pin sealing surface adjacent the pin thread pullout area of a completed threaded pin connection.
• the annular body may be pre- machined before being welded to the connector to provide the desired pin seal surface adjacent the pin thread pullout area.
• the pin sealing surface formed by either method is adapted to engage and seal with a mating box seal surface to
• the welding buildup or annular metal body may be removed and replaced to provide a new pin sealing surface. Only the seal area of the pipe joint is reworked so that the pipe joint is conserved during this replacement process.
• repair or reconstruction of a pin sealing surface on a pin connector of a pipe joint formed by radially expanding a tubular body wall so that the radial enlargement is an integral part of the pipe joint may not be possible. Such is the case for example where the enlargement would not have sufficient radial extension to accommodate the required machining to effect the repair or where the tubular wail would be undesirably reduced in thickness by the required machining repair.
• the enlargement of the pin end connector of the present invention may be made by applying a weld bead to the outside diameter of the tubular body or by welding or otherwise securing an annular metal ring to the external circumferential surface of the body. Once the enlargement is in place on the tubular body, the desired pin sealing surface may be machined into the weld bead or the annular metal ring. The metal ring may also bo machined with the desired sealing surface before being secured to the tubular body.
• the pin sealing surface may assume the configuration of a frustroconical surface to provide an expanded area for sealing engagement with a correspondingly shaped box seal surface or may be formed as an annular band with a hemispherical cross-section to provide a line contact seal with the box seal surface.
• a primary object of the present invention is to provide a tubular pipe member having an external pin seal surface that can be repaired or reconstructed if the seal is improperly machined or becomes damaged from handling or use.
• Figure 1 is a quarter section view, partially broken away, illustrating a frustroconical metal-to-metal sealing surface forming an external soul between a coupling box end and a pipe pin end of the present invention
• Figure 1A is a detailed cross sectional illustration of the external seal of the connector the present invention
• Figure 2 is a quarter sectional view of a modified coupling and pipe connection of the present invention illustrating a line-contact, hemispherical
• Figure 3 is a quarter sectional of view of a modified coupling and pipe connection of the present invention illustrating a metal-to-metal line-contact hemispherical seal and an elastomeric seal ring forming an external seal between the pin and box connection of the present invention;
• Figure 3A is a detailed cross sectional illustration of the external seal of the connector of Figure 3 of the present invention;
• Figure 4 is an enlarged to cross sectional view illustrating details in the formation of a weld bead forming a replaceable pin seal base on which a pin seal surface may be machined; and Figure 5 is an enlarged cross sectional view illustrating details in the placement of an annular metal ring about a pin connector forming a replaceable pin seal base on which a pin seal surface may be machined.
• FIG. 1 of the Drawings illustrates a coupling and pin connection of the present invention indicated generally at 10.
• the connection 10 is formed by the engagement of a coupling 15 and pipe 20.
• the coupling 15 is provided with internally threaded boxes 25 and 30 extending axially from either end of a central coupling area 35. Threads 40 are formed internally of the box 25 and threads 45 are formed internally of the box 30.
• the pipe 20 is externally threaded to form a pin indicated generally at 50. Threads 55 formed on the external surface of the pin 50 are illustrated fully engaged with the box threads 40.
• the coupling 15 is dimensioned axially to extend over the entire threaded area occupied by the threads 55.
• connection 10 provides an internal seal 60 and an external seal 65 that protect the threads 40 and 55 from contact with the fluids external and internal to the coupling and pipe.
• the threads 55 preferably runout to the external surface of the pipe 20 and terminate in a "last scratch" before reaching the external seal 65.
• the internal seal 60 is provided by the metal-to-metal engagement of the axial end area of the pin 50 with the surrounding wall of the coupling and an internal coupling shoulder 70.
• the external seal 65 is provided by the engagement of a frustroconical sealing surface 75 formed internally adjacent the open end of the box 25 with a corresponding frustroconical sealing surface 80 formed externally of a replaceable annular pin seal base 85.
• the annular pin seal base 85 is welded or otherwise securely connected to the external surface of the pipe 20.
• the pin seal base 85 preferably is secured to or formed on the pipe 24, before the pin threads 55 are machined on the end of the pipe 20.
• the seal base 85 may be applied to the pipe 20 as a weld bead with a cross section as
• the seal base 85 may be preformed in the cross sectional shape illustrated in Figure 1A and thereafter secured to the pipe 20, eliminating the need for any further machining.
• the pin seal base may be machined into a hemispherical seal 90 secured to a pipe 95 as illustrated in Figures 2, 3 and 3A.
• the seal 90 may be constructed by securing a preformed metal ring with a hemispherical cross-section to the pipe 95 to eliminate the requirement for machining after the pin seal base is secured to the pipe.
• the hemispherical seal is machined with transitions on to the pipe body with radius fillets 96 and 97, as illustrated in Figure 3A, to prevent stress risers.
• the material forming the pin seal base may be
• FIGs 2 and 3 illustrate a modified coupling 15a with a box 30a in which the external metal-to-metal line contact seal is supplemented with an annular, elastomeric seal ring 100.
• the seal ring is received in an annular groove 105 formed internally of the end of the box 30a.
• Figure 4 illustrates a cross section of an annular weld bead 110 provided about the external circumference of a pipe 115.
• a dotted outline cross section 120 illustrates the cross sectional shape of the external pin surface remaining after the machining process.
• Figure 5 illustrates a cross section of an annular metal ring 125 secured circumferentially externally to a pipe 130.
• a dotted outline cross section 135 illustrates the cross sectional shape of the external pin surface remaining after the machining process. It will be appreciated that the beginning cross sectional dimensions of the weld bead or of the annular metal ring forming the external pin seal base are selected to accommodate the desired final configuration of the external seal.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Gasket Seals (AREA)
• Non-Disconnectible Joints And Screw-Threaded Joints (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=22999148

Family Applications (1)

Country Status (4)

Families Citing this family (16)

Citations (5)

Family Cites Families (4)

• 2002
  • 2002-01-18 MX MXPA03005476A patent/MXPA03005476A/es unknown
  • 2002-01-18 WO PCT/US2002/001380 patent/WO2002068854A1/en not_active Application Discontinuation
  • 2002-01-18 EP EP02707511A patent/EP1377772A4/de not_active Withdrawn
  • 2002-01-18 CA CA002432926A patent/CA2432926A1/en not_active Abandoned

Patent Citations (5)

Non-Patent Citations (1)

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