CA2432926A1 - Replaceable corrosion seal for threaded connections - Google Patents
Replaceable corrosion seal for threaded connections Download PDFInfo
- Publication number
- CA2432926A1 CA2432926A1 CA002432926A CA2432926A CA2432926A1 CA 2432926 A1 CA2432926 A1 CA 2432926A1 CA 002432926 A CA002432926 A CA 002432926A CA 2432926 A CA2432926 A CA 2432926A CA 2432926 A1 CA2432926 A1 CA 2432926A1
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- CA
- Canada
- Prior art keywords
- pin
- box
- threads
- seal
- tubular body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000007797 corrosion Effects 0.000 title description 5
- 238000005260 corrosion Methods 0.000 title description 5
- 239000002184 metal Substances 0.000 claims abstract description 32
- 239000011324 bead Substances 0.000 claims description 8
- 239000012530 fluid Substances 0.000 abstract description 5
- 230000008439 repair process Effects 0.000 abstract description 4
- 230000008878 coupling Effects 0.000 description 13
- 238000010168 coupling process Methods 0.000 description 13
- 238000005859 coupling reaction Methods 0.000 description 13
- 238000007789 sealing Methods 0.000 description 11
- 238000003754 machining Methods 0.000 description 8
- 238000011068 loading method Methods 0.000 description 7
- 238000003466 welding Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000013011 mating Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Gasket Seals (AREA)
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
Abstract
The threaded connection (10) between the pin (50) and the box (30) ends of t wo pipes (15,20) is sealed externally and internally to protect the threads (40,55) in the connection from exposure to corosive fluids. Seals (60,65) ar e provided at each axial end of the threads. External seals are formed by meta l- to-metal engagement between the pin and box and a third metal body secured circumferentially about the pin. The metal body (90) may be fashioned into a desired annular pin seal surface to mate with and seal with the box at full makeup of the connection. The metal body can be removed and replaced as required to repair or reconstructed the pin seal surface.
Description
REPLACEABLE CORROSION SEAL F(J(~
THREADED CONNECTIONS
Cross Reference to Related Applications This application is a continuation-in-part of U.S. Patent application Serial No. 091679470 assigned to the Assignee of the present application.
This application claims priority from U.S. Provisional Patent Application s Serial No. 60/262,809 filed January 20, 2001 and assigned to the Assignee of the present application.
Field of the Invention The present invention relates to threaded connector's used to secure the ends of tubular bodies together. More particularly, fihe present invention relates t t~ to threaded connections provided with replaceable seals to prGtect the threads in pipe connections from exposure to corrosive fluids.
Back round of the Invention Pipelines that extend through saltwater bodies are employed for multiple purposes, often associated with the drilling of oil and gas wells and the l5 production and distribution of the oil and gas produced by the wells. 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 r~ipelines 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 ~0 concern.
THREADED CONNECTIONS
Cross Reference to Related Applications This application is a continuation-in-part of U.S. Patent application Serial No. 091679470 assigned to the Assignee of the present application.
This application claims priority from U.S. Provisional Patent Application s Serial No. 60/262,809 filed January 20, 2001 and assigned to the Assignee of the present application.
Field of the Invention The present invention relates to threaded connector's used to secure the ends of tubular bodies together. More particularly, fihe present invention relates t t~ to threaded connections provided with replaceable seals to prGtect the threads in pipe connections from exposure to corrosive fluids.
Back round of the Invention Pipelines that extend through saltwater bodies are employed for multiple purposes, often associated with the drilling of oil and gas wells and the l5 production and distribution of the oil and gas produced by the wells. 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 r~ipelines 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 ~0 concern.
Jointed pipelines that are secured together by the fihreaded 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 otloer bottom-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 in surface exerted tension resulting from wind and wave action against a surface support of the riser, and other factors.
I0 The effects of dynamic loading on the connections used in marine applications may be offset, in part, by the use of connectors that have the strength required to withstand the forces imparted by the environment.
Conventional riser connections typically employ heavy tool joint type connections that are welded onto the end of the pipe. These connections are very resistant t; to fatigue damage and often employ a metal-to-metal torque shoulder as an external seal, similarto the design employed in a conventional drill pipe tool joint.
Connections of this type have a very low stress concentration factor (SCF) and provide an environmental seal that prevents the seawater from contacting tire threads in the connection.
?0 The tool joint design is expensive to machine and requires the added step and expense of welding the connector to the pipe. The welding procedure also introduces a potential point of fatigue failure for the dynamically loaded connector. Moreover, as compared with a conventional threarJed and coupled _3_ connection, the tool joint type connection is extremely heavy, requiring additional surface support.
Conventional threaded and coupled connections have been :~,nccessfr.rlly employed, for short periods, as the outer riser in a marine installation. Such s connections cost less than 1/6 the cost of tool joint type connectors. The long-term reliability of ti~ese conventional connections in a saltwater-environment under dynamic loading conditions, however, is not reasonably predictable. The uncertainty stems from the fact that, when used as risers, the threads of conventional threaded and coupled connectors are exposed to salt water that can accelerate corrosion of the threaded area. The dynamic loading of the riser constantly flexes the connections laterally and imposes cyclical tension and compression stresses in the connected components. Any unendaged pin threads that have been machined into the pipe portion of the connection are exposed to the salt water. These exposed threads concentrate the stresses 1 S exerted on the pipe. Adding the effects of corrosion to the cyclical stress concentration unreasonably exposes the connection to a fatigue induced failure that will generally occur in the area of the last full thread 'formed on the body of the pin member of the connection.
The strength of a standard threaded and coupled connection is optimized '_0 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 engacded and covered by threads in the mating coupling. From the point of the last full threaded engagement with the box threads to the last scratch of the pin threads, . the pin threads in a conventional threadecl and coupled connection are exposecJ
to the surrounding environment. The corrosive effects of saltwater in this area s of exposure can accelerate the failure of a connector subjected to cyclical, dynamically induced forces.
U.S. Patent Application Serial No. 9/679470, cited previously, discloses a connector design in which the normally exposed pin runout threads on fully engaged, threaded and coupled connections are sealed fror~n saltwater to prevent corrosion of the threaded area that can accelerate fatigue-induced failure in dynamically loaded pipelines. The seals may be employed with conventional threaded and coupled connectors pemitting the fabrication of pipelines that are inexpensive and lightweight as compared with pipelines constructed with conventional tool joint type connectors.
t 5 The external seal portion of the invention of Application Serial No.
091679470 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 0 sf~oulder may also be provided by enlarging the pin outside diameter. Where an annular, elastomeric seal is provided, the seal may be carried on tl~e 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.
Wf~en the connector is assembled, the pii~ seal surface engryes a frrrstoconic;al 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. During the manufacturing process, if the pin seal surface is not properly machined on the expanded body of the pipe, the entire pipe section can be rendered unusable. Similarly, if a properly machined seal becomes defective through subsequent mishandling or usage, tile 1 t~ remaining expanded wall of the pipe may not be adequate for reconstructing or repairing the damaged seal, resulting in a loss of the complete pipe joint.
Summary of tire Invention 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 ~ metal seal 1 s base that is separately added to the external surface of the metal fonrring 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 seat surface.
In the event the seal formed on the seal base is damaged during construction, handling or use, the separately added seal base may be removed from the pin end and replaced with another seal base to provide the required pin seal surface. The tubular pipe body or joint on which the pin is forr~ned may be -G-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 bocJy about the surface, to form an external pin seal base. The pin seal base is s machined on the welding buildup to form an annular pin sealing surface adjacent the pin thread pullout area of a completed threaded pin connection. Wlaerc: an annular body is used to provide the pin seal base, the annular body rnay 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 IO either method is adapted to engage and seal with a mating box seal surface to protect the engaged pin and box threads of the connector from contact with the corrosive fluids within which the connection is deployed.
If the pin seal is improperly cut during the machining process or damaged during the handling and use of the connector, the welding buildup or annular 1 s 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. By contrast, 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 20 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 wall 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 otloerwise 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 angular metal ring. The metal ring may also be machined with tloe desired sealing surface before being secured to the tubular body.
The pin sealing surface may assume the configuration of a firustroconical 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.
From the foregoing it will be appreciated that a primary object of tire present invention is to provide a tubular pipe member having an external pin seal t s surface that can be repaired or reconstructed if the seal is improperly machined or becomes damaged from handling or use.
It is also an object of the present invention to provide an improved external seal for protecting the engaged threads in a pin and box connection from exposure to corrosive fluids surrounding the connection.
_$_ Brief Description of the Drawings Figure 1 is a quarter section view, partially broken away, illustrating a frustroconical metal-to-metal sealing surface forming an external sc;al betwecr r a coupling box end and a pipe pin end of the preaent invention;
Figure '1A is a detailed cross sectional illustration of the external seal of the connector il~e 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 metal-to-metal seal forming an external seal between the pin and box connection of the present invention;
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;
1, 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 ~0 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.
_9_ Detailed Description of Preferred Embodiments Figure 1 of the Drawings illustrates a coupling and pin connection of the present invention indicated generally at 10. The connection 10 is formed by llne engagement of a coupling 15 and pipe 20. The coupling 15 is provided with s 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.
The connection 10 provides an internal seal 60 and an external seal G5 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 I ~ 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.
As best illustrated in Figure 1A, the external seal 65 is provided by the _'0 engagement of a frustroconical sealing surface 75 formed internally adjacent the open end of tire 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 2~, before the pin threads 55 are machined on the end of tlw pipe 20. ~l~lm seal base 85 may be applied to the pipe 20 as a weld bead with a cross section as s indicated in Figure 4 or it may be applied as a separate metal ring having a cross section as indicated in Figure 5. During the process of machining the threads 55 on to the pin end, the seal base is machined to produce the cross sectional shape illustrated in Figure 1A. It will be appreciated that, in some applications, 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.
Where a line contact external seal is desired, 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. As with the frustroconical seal illustrated in Figure 1, the 1 s seal 90 may be constructed by securing a preformecl metal ring with a hemispherical cross-section to the pipe 95 to eliminate the recluirernent for machining after the pin seal base is secured to the pipe. In the preferred fond of the Invention however, the hemispherical seal is machined with transitions on to the pipe body with radius fillets 96 and 97, as illustrated in I=figure 3A, to prevent stress risers.
When ttie material providing the pin seal base is improperly machined or damaged during handling or use, the mafierial forming the pin seal base may be ground off or otheryvise removed from the external surface of the pipe. The described process for forming a weld bead or adding an annular ring may then be repeated to construct the desired pin seal surface.
Figures 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, s elastomeric seal ring 100. The seal ring is received in an annular groove 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 t , dimensions of the weld bead or of the annular metal ring fon~ing the external pin seal base are selected to accommodate the desired final configuration of the external seal.
While preferred forms of the present invention have been described in detail herein, it will be appreciated that other forms, modifications and variations _'0 of the present invention may be made without departing from the spirit or scope of the invention, which is more fully defined within the tenors of the following Claims.
The dynamic loading of the riser is caused by changing sea currents, changes in surface exerted tension resulting from wind and wave action against a surface support of the riser, and other factors.
I0 The effects of dynamic loading on the connections used in marine applications may be offset, in part, by the use of connectors that have the strength required to withstand the forces imparted by the environment.
Conventional riser connections typically employ heavy tool joint type connections that are welded onto the end of the pipe. These connections are very resistant t; to fatigue damage and often employ a metal-to-metal torque shoulder as an external seal, similarto the design employed in a conventional drill pipe tool joint.
Connections of this type have a very low stress concentration factor (SCF) and provide an environmental seal that prevents the seawater from contacting tire threads in the connection.
?0 The tool joint design is expensive to machine and requires the added step and expense of welding the connector to the pipe. The welding procedure also introduces a potential point of fatigue failure for the dynamically loaded connector. Moreover, as compared with a conventional threarJed and coupled _3_ connection, the tool joint type connection is extremely heavy, requiring additional surface support.
Conventional threaded and coupled connections have been :~,nccessfr.rlly employed, for short periods, as the outer riser in a marine installation. Such s connections cost less than 1/6 the cost of tool joint type connectors. The long-term reliability of ti~ese conventional connections in a saltwater-environment under dynamic loading conditions, however, is not reasonably predictable. The uncertainty stems from the fact that, when used as risers, the threads of conventional threaded and coupled connectors are exposed to salt water that can accelerate corrosion of the threaded area. The dynamic loading of the riser constantly flexes the connections laterally and imposes cyclical tension and compression stresses in the connected components. Any unendaged pin threads that have been machined into the pipe portion of the connection are exposed to the salt water. These exposed threads concentrate the stresses 1 S exerted on the pipe. Adding the effects of corrosion to the cyclical stress concentration unreasonably exposes the connection to a fatigue induced failure that will generally occur in the area of the last full thread 'formed on the body of the pin member of the connection.
The strength of a standard threaded and coupled connection is optimized '_0 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 engacded and covered by threads in the mating coupling. From the point of the last full threaded engagement with the box threads to the last scratch of the pin threads, . the pin threads in a conventional threadecl and coupled connection are exposecJ
to the surrounding environment. The corrosive effects of saltwater in this area s of exposure can accelerate the failure of a connector subjected to cyclical, dynamically induced forces.
U.S. Patent Application Serial No. 9/679470, cited previously, discloses a connector design in which the normally exposed pin runout threads on fully engaged, threaded and coupled connections are sealed fror~n saltwater to prevent corrosion of the threaded area that can accelerate fatigue-induced failure in dynamically loaded pipelines. The seals may be employed with conventional threaded and coupled connectors pemitting the fabrication of pipelines that are inexpensive and lightweight as compared with pipelines constructed with conventional tool joint type connectors.
t 5 The external seal portion of the invention of Application Serial No.
091679470 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 0 sf~oulder may also be provided by enlarging the pin outside diameter. Where an annular, elastomeric seal is provided, the seal may be carried on tl~e 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.
Wf~en the connector is assembled, the pii~ seal surface engryes a frrrstoconic;al 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. During the manufacturing process, if the pin seal surface is not properly machined on the expanded body of the pipe, the entire pipe section can be rendered unusable. Similarly, if a properly machined seal becomes defective through subsequent mishandling or usage, tile 1 t~ remaining expanded wall of the pipe may not be adequate for reconstructing or repairing the damaged seal, resulting in a loss of the complete pipe joint.
Summary of tire Invention 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 ~ metal seal 1 s base that is separately added to the external surface of the metal fonrring 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 seat surface.
In the event the seal formed on the seal base is damaged during construction, handling or use, the separately added seal base may be removed from the pin end and replaced with another seal base to provide the required pin seal surface. The tubular pipe body or joint on which the pin is forr~ned may be -G-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 bocJy about the surface, to form an external pin seal base. The pin seal base is s machined on the welding buildup to form an annular pin sealing surface adjacent the pin thread pullout area of a completed threaded pin connection. Wlaerc: an annular body is used to provide the pin seal base, the annular body rnay 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 IO either method is adapted to engage and seal with a mating box seal surface to protect the engaged pin and box threads of the connector from contact with the corrosive fluids within which the connection is deployed.
If the pin seal is improperly cut during the machining process or damaged during the handling and use of the connector, the welding buildup or annular 1 s 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. By contrast, 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 20 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 wall 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 otloerwise 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 angular metal ring. The metal ring may also be machined with tloe desired sealing surface before being secured to the tubular body.
The pin sealing surface may assume the configuration of a firustroconical 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.
From the foregoing it will be appreciated that a primary object of tire present invention is to provide a tubular pipe member having an external pin seal t s surface that can be repaired or reconstructed if the seal is improperly machined or becomes damaged from handling or use.
It is also an object of the present invention to provide an improved external seal for protecting the engaged threads in a pin and box connection from exposure to corrosive fluids surrounding the connection.
_$_ Brief Description of the Drawings Figure 1 is a quarter section view, partially broken away, illustrating a frustroconical metal-to-metal sealing surface forming an external sc;al betwecr r a coupling box end and a pipe pin end of the preaent invention;
Figure '1A is a detailed cross sectional illustration of the external seal of the connector il~e 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 metal-to-metal seal forming an external seal between the pin and box connection of the present invention;
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;
1, 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 ~0 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.
_9_ Detailed Description of Preferred Embodiments Figure 1 of the Drawings illustrates a coupling and pin connection of the present invention indicated generally at 10. The connection 10 is formed by llne engagement of a coupling 15 and pipe 20. The coupling 15 is provided with s 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.
The connection 10 provides an internal seal 60 and an external seal G5 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 I ~ 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.
As best illustrated in Figure 1A, the external seal 65 is provided by the _'0 engagement of a frustroconical sealing surface 75 formed internally adjacent the open end of tire 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 2~, before the pin threads 55 are machined on the end of tlw pipe 20. ~l~lm seal base 85 may be applied to the pipe 20 as a weld bead with a cross section as s indicated in Figure 4 or it may be applied as a separate metal ring having a cross section as indicated in Figure 5. During the process of machining the threads 55 on to the pin end, the seal base is machined to produce the cross sectional shape illustrated in Figure 1A. It will be appreciated that, in some applications, 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.
Where a line contact external seal is desired, 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. As with the frustroconical seal illustrated in Figure 1, the 1 s seal 90 may be constructed by securing a preformecl metal ring with a hemispherical cross-section to the pipe 95 to eliminate the recluirernent for machining after the pin seal base is secured to the pipe. In the preferred fond of the Invention however, the hemispherical seal is machined with transitions on to the pipe body with radius fillets 96 and 97, as illustrated in I=figure 3A, to prevent stress risers.
When ttie material providing the pin seal base is improperly machined or damaged during handling or use, the mafierial forming the pin seal base may be ground off or otheryvise removed from the external surface of the pipe. The described process for forming a weld bead or adding an annular ring may then be repeated to construct the desired pin seal surface.
Figures 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, s elastomeric seal ring 100. The seal ring is received in an annular groove 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 t , dimensions of the weld bead or of the annular metal ring fon~ing the external pin seal base are selected to accommodate the desired final configuration of the external seal.
While preferred forms of the present invention have been described in detail herein, it will be appreciated that other forms, modifications and variations _'0 of the present invention may be made without departing from the spirit or scope of the invention, which is more fully defined within the tenors of the following Claims.
Claims (9)
1. A connector for connecting together the free pin end and the free box end of two tubular bodies, comprising:
a pin having pin threads formed externally on an end of a first tubular body, said pin threads extending from a starting point on said first tubular body and terminating adjacent the free pin end, a box having box threads formed internally on an end of a second tubular body, said box threads extending from a starting point on said second tubular body and terminating adjacent the free box end, said pin adapted to be received in and threadedly engaged within said box, an external seal between said pin and said box adjacent said pin thread starting point and adjacent said free box end, said external seal comprising a pin seal surface formed externally of said pin on a third tubular body comprising a metal seal base separately added to said first tubular body, and an internal seal adjacent said box threads starting point and said free pin end whereby said pin threads and said box threads are confined between said external and internal seals when said pin and box are engaged.
a pin having pin threads formed externally on an end of a first tubular body, said pin threads extending from a starting point on said first tubular body and terminating adjacent the free pin end, a box having box threads formed internally on an end of a second tubular body, said box threads extending from a starting point on said second tubular body and terminating adjacent the free box end, said pin adapted to be received in and threadedly engaged within said box, an external seal between said pin and said box adjacent said pin thread starting point and adjacent said free box end, said external seal comprising a pin seal surface formed externally of said pin on a third tubular body comprising a metal seal base separately added to said first tubular body, and an internal seal adjacent said box threads starting point and said free pin end whereby said pin threads and said box threads are confined between said external and internal seals when said pin and box are engaged.
2. The connector as defined in Claim 1 wherein said pin threads run out to an outside diameter of said first tubular at said starting point of said pin threads.
3. A connector as defined in Claim 1 wherein said pin seal surface is formed on an annular metal ring secured to said first tubular body.
4. A connector as defined in Claim 1 wherein said pin seal surface is formed on a weld bead secured to said first tubular body.
5. A connector as defined in Claim 1 wherein said pin threads and said box threads are fully confined between said external and internal seals when said pin and box are engaged.
6. A connector for connecting together the free pin end and the free box end of two tubular bodies, comprising:
a pin having pin threads forced externally on an end of a first tubular body, said pin threads extending from a starting point on said first tubular body and terminating adjacent the free pin end, a box having box threads formed internally on an end of a second tubular body, said box threads extending from a starting point on said second tubular body and terminating adjacent the free box end, said pin adapted to be received in and threadedly engaged with said box, an external seal between said pin and said box adjacent said pin thread starting point and adjacent said free box end, said external seal comprising a separately constructed annular body of metal secured on said pin end of a tubular body, and an internal seal adjacent said box threads starting point and said free pin end whereby said pin threads and said box threads are confined between said external and internal seals when said pin and box are engaged.
a pin having pin threads forced externally on an end of a first tubular body, said pin threads extending from a starting point on said first tubular body and terminating adjacent the free pin end, a box having box threads formed internally on an end of a second tubular body, said box threads extending from a starting point on said second tubular body and terminating adjacent the free box end, said pin adapted to be received in and threadedly engaged with said box, an external seal between said pin and said box adjacent said pin thread starting point and adjacent said free box end, said external seal comprising a separately constructed annular body of metal secured on said pin end of a tubular body, and an internal seal adjacent said box threads starting point and said free pin end whereby said pin threads and said box threads are confined between said external and internal seals when said pin and box are engaged.
7. A connector as defined in Claim 6 wherein said body of metal is provided with a frustoconical seal surface adapted to engage a seal surface on said box end of a tubular body.
8. A connector as defined in Claim 6 wherein said body of metal is provided with a hemispherical cross-section to provide a line contact seal surface with said box end of a tubular body.
9. A connector as defined in Claim 6 wherein said external seal includes an annular elastomeric seal ring carried in an annular groove formed on said second tubular body.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US26280901P | 2001-01-20 | 2001-01-20 | |
| US60/262,809 | 2001-01-20 | ||
| PCT/US2002/001380 WO2002068854A1 (en) | 2001-01-20 | 2002-01-18 | Replaceable corrosion seal for threaded connections |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2432926A1 true CA2432926A1 (en) | 2002-09-06 |
Family
ID=22999148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002432926A Abandoned CA2432926A1 (en) | 2001-01-20 | 2002-01-18 | Replaceable corrosion seal for threaded connections |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1377772A4 (en) |
| CA (1) | CA2432926A1 (en) |
| MX (1) | MXPA03005476A (en) |
| WO (1) | WO2002068854A1 (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7585002B2 (en) | 2004-04-21 | 2009-09-08 | Baker Hughes Incorporated | Expandable tubular connection |
| GB2445310B (en) * | 2004-04-21 | 2008-10-29 | Baker Hughes Inc | Tubular connection |
| EP2006589B1 (en) | 2007-06-22 | 2011-08-31 | Tenaris Connections Aktiengesellschaft | Threaded joint with energizable seal |
| EP2017507B1 (en) | 2007-07-16 | 2016-06-01 | Tenaris Connections Limited | Threaded joint with resilient seal ring |
| DE602008001552D1 (en) * | 2008-02-29 | 2010-07-29 | Tenaris Connections Ag | Threaded connector with improved elastic sealing rings |
| EP2243920A1 (en) | 2009-04-22 | 2010-10-27 | Tenaris Connections Aktiengesellschaft | Threaded joint for tubes, pipes and the like |
| EP2325435B2 (en) | 2009-11-24 | 2020-09-30 | Tenaris Connections B.V. | Threaded joint sealed to [ultra high] internal and external pressures |
| EP2372208B1 (en) | 2010-03-25 | 2013-05-29 | Tenaris Connections Limited | Threaded joint with elastomeric seal flange |
| EP2372211B1 (en) | 2010-03-26 | 2015-06-03 | Tenaris Connections Ltd. | Thin-walled pipe joint and method to couple a first pipe to a second pipe |
| US9163296B2 (en) | 2011-01-25 | 2015-10-20 | Tenaris Coiled Tubes, Llc | Coiled tube with varying mechanical properties for superior performance and methods to produce the same by a continuous heat treatment |
| GB2525337B (en) | 2013-01-11 | 2016-06-22 | Tenaris Connections Ltd | Galling resistant drill pipe tool joint and corresponding drill pipe |
| US9803256B2 (en) | 2013-03-14 | 2017-10-31 | Tenaris Coiled Tubes, Llc | High performance material for coiled tubing applications and the method of producing the same |
| EP2789701A1 (en) | 2013-04-08 | 2014-10-15 | DALMINE S.p.A. | High strength medium wall quenched and tempered seamless steel pipes and related method for manufacturing said steel pipes |
| EP2789700A1 (en) | 2013-04-08 | 2014-10-15 | DALMINE S.p.A. | Heavy wall quenched and tempered seamless steel pipes and related method for manufacturing said steel pipes |
| KR102197204B1 (en) | 2013-06-25 | 2021-01-04 | 테나리스 커넥션즈 비.브이. | High-chromium heat-resistant steel |
| US11124852B2 (en) | 2016-08-12 | 2021-09-21 | Tenaris Coiled Tubes, Llc | Method and system for manufacturing coiled tubing |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1590357A (en) * | 1925-01-14 | 1926-06-29 | John F Penrose | Pipe joint |
| US2308066A (en) * | 1940-11-15 | 1943-01-12 | Hughes Tool Co | Tool joint assembly |
| US2539056A (en) * | 1944-09-02 | 1951-01-23 | Chicago Pneumatic Tool Co | Method of assembling tool joints |
| US2825585A (en) * | 1954-07-01 | 1958-03-04 | American Iron & Machine Works | Prestressed shrunk-fitted rotary drill collar and tool joint |
| AT290435B (en) * | 1967-12-29 | 1971-06-11 | Oemv Ag | Riser connection for petroleum and natural gas probes |
| DE3203857C2 (en) * | 1982-02-03 | 1984-08-02 | Mannesmann AG, 4000 Düsseldorf | Oil field pipe connection and method of connecting oil field pipes |
| US4706997A (en) * | 1982-05-19 | 1987-11-17 | Carstensen Kenneth J | Coupling for tubing or casing and method of assembly |
| US4988127A (en) * | 1985-04-24 | 1991-01-29 | Cartensen Kenneth J | Threaded tubing and casing joint |
| DE3542523C1 (en) * | 1985-12-02 | 1987-07-16 | Benteler Werke Ag | Length of pipe |
-
2002
- 2002-01-18 MX MXPA03005476A patent/MXPA03005476A/en unknown
- 2002-01-18 WO PCT/US2002/001380 patent/WO2002068854A1/en not_active Application Discontinuation
- 2002-01-18 CA CA002432926A patent/CA2432926A1/en not_active Abandoned
- 2002-01-18 EP EP02707511A patent/EP1377772A4/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| MXPA03005476A (en) | 2005-07-15 |
| EP1377772A4 (en) | 2004-10-13 |
| EP1377772A1 (en) | 2004-01-07 |
| WO2002068854A1 (en) | 2002-09-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |