Hydril Company

Ipsco Enterprises, Inc.

Interlock Technologies Corporation

Other

Xl Systems

Thomas L Blose

David L Britten

Doyle E Reeves

K Darrel Chelette

Donald J Ortloff

Trent M Kaiser

Kevin J Humphreys

A pipe coupling or connection comprises a female coupling component and a mating male coupling component. Each component is matingly threaded for coupling engagement, and each is provided with an adjacent frusto-conical sealing surface. The sealing surface is provided with a controlled surface roughness, viz. very shallow fine surface variations, preferably formed as microgrooves at a pitch small relative to the pitch of the threads. The slope of the frusto-conical surface of the sealing area of the male component is slightly mismatched with that of the sealing area of the female component to simulate the bearing force vs. axial distance characteristic of shrunk-fit circular cylindrical sealing surfaces. The slight mismatch enables the sealing pressure to be above a design minimum throughout the entire sealing area yet higher at each end of the sealing area. As the coupling is assembled, thread interference in the vicinity of the sealing surface lags the occurrence of interference between the sealing surfaces. Load threads are provided with negatively inclined load flank faces. Load thread interference values and tolerances are selected to enable the shrunk-fit cylindrical sealing surface simulation to be met over the range of tolerances provided. The envelope of the range of curves of interference vs. distance along the effective pin sealing surface area has a positive slope. The effective sealing area is at least about one-third and preferably at least about one-half of the available sealing area.

Pipe coupling

A pipe coupling or connection comprises a female coupling component and a mating male coupling component. Each component is matingly threaded for coupling engagement, and each is provided with an adjacent frusto-conical sealing surface. The sealing surface is provided with a controlled surface roughness, viz. very shallow fine surface variations, preferably formed as microgrooves at a pitch small relative to the pitch of the threads. The slope of the frusto-conical surface of the sealing surface of the male component is slightly mismatched with that of the sealing surface of the female component to simulate the bearing force vs. axial distance characteristic of shrunk-fit circular cylindrical sealing surfaces. The mismatch enables the sealing pressure to be above a design minimum throughout the entire sealing area yet higher at each end of the sealing area. As the coupling is assembled, thread interference in the vicinity of the sealing surface lags the occurrence of interference between the sealing surfaces. Load threads are provided with negatively inclined load flank faces. The slope of the load thread pitch line of the male element is slightly steeper than the slope of the load thread pitch line of the female element. Load thread interference values and tolerances are selected to enable the shrunk-fit cylindrical sealing surface simulation to be met over the range of tolerances provided. The envelope of the range of curves of interference vs. distance along the effective pin sealing surface area has a positive slope. The effective sealing area is at least about one-third and preferably at least about half of the available sealing area.

Metal-to-metal seals for pin and box member tubular joints are disclosed where mating annular surfaces are machined at slightly different angles such that the bearing load from initial contact is entirely on the leading edge of the pin annular surface and the trailing edge of the box annular surface. The mismatch of the sealing surfaces is selected for any particular seal geometry such that at final make-up, the bearing load has a relatively even distribution across the entire sealing surface in contact, thus broadly distributing make-up bearing stresses and minimizing any resulting tendency for galling that may occur, in particular for joints having relatively thick walls for both pin and box members.

Tubular coupling with metal to metal seal

A pipe coupling or connection comprises a female coupling component and a mating male coupling component. Each component is matingly threaded for coupling engagement, and each is provided with an adjacent frusto-conical sealing surface. The sealing surface is provided with a controlled surface roughness, viz. very shallow fine surface variations, preferably formed as microgrooves at a pitch small relative to the pitch of the threads. The slope of the frusto-conical surface of the sealing area of the male component is slightly mismatched with that of the sealing area of the female component to simulate the bearing force vs. axial distance characteristic of shrunk-fit circular cylindrical sealing surfaces. The slight mismatch enables the sealing pressure to be above a design minimum throughout the entire sealing area yet higher at each end of the sealing area. As the coupling is assembled, thread interference in the vicinity of the sealing surface lags the occurrence of interference between the sealing surfaces. Load threads are provided with negatively inclined load flank faces.

A pipe coupling or connection comprises a female coupling component and a mating male coupling component. Each component is matingly threaded for coupling engagement, and each is provided with an adjacent frusto-conical sealing surface. The sealing surface is provided with a controlled surface roughness, viz. very shallow fine surface variations, preferably formed as microgrooves at a pitch small relative to the pitch of the threads. The slope of the frusto-conical surface of the sealing area of the male component is slightly mismatched with that of the sealing area of the female component to simulate the bearing force vs. axial distance characteristic of shrunk-fit circular cylindrical sealing surfaces. The slight mismatch enables the sealing pressure to be above a design minimum throughout the entire sealing area yet higher at each end of the sealing area. As the coupling is assembled, thread interference in the vicinity of the sealing surface lags the occurrence of interference between the sealing surfaces. Load threads are provided with negatively inclined load flank faces. The slope of the load thread pitch line of the male element is slightly steeper than the slope of the load thread pitch line of the female element.

A thread form for a tubular connection between sections of large diameter pipe or casing having a pin member adapted to be made up with a box member, utilizing converging, trapped thread flanks and mating shoulders and end faces with dissimilar angles. The thread crests and roots make contact with each other before the thread flanks are touching. At final make-up, the thread flanks of the pin member are trapped by the thread flanks of the box member. The stab flanks assist the shoulders/end faces in resisting axial compressive loading. The different angles between the mating shoulders and end faces are such that the deformation of the shoulders upon axial compressive loading is less than the preferred maximum yield of the critical area. The amount of load bearing forces on the shoulders and end faces are predictable and can easily be controlled within the preferred axial deformation of the critical area.

Driveable threaded tubular connection

A joint and male and female tubular elements are disclosed where the threads of the female and male members have negative load flanks and have two or more radial steps axially separated one from another by a reverse angle torque shoulder having one or two adjacent conical sealing surfaces. The reverse angle torque shoulder serves as a positive assembly stop. The negative load flank angle of the threads and the reverse torque shoulder angle combine to interlock the male and female members and to prevent differential radial separation of the conical sealing surfaces when the joint is exposed to internal pressure, external pressure or both. Tapered threads and sealing surfaces and interference threads may advantageously be used in joint construction. Tapered conical sealing surfaces where the taper of the member having the thinner wall thickness at the seal surface is inclined at a smaller angle with respect to the axis of the threaded connection than the complementary conical seal surface of the mating member, may advantageously be used so that the bearing load across the entire axial width of the male and female sealing surfaces has a relatively even distribution at final make-up.

Tubular joint with trapped mid-joint metal-to-metal seal having unequal

A thread form for a tubular connection of the type having a pin member adapted to be made up with a box member to form a pipe joint is shown. The pin member has pin threads with thread crests and thread roots which are adapted to be made up with a mating box member having a complimentary thread structure. The pin thread crests are formed between a stab flank and a load flank of the pin thread. The pin thread has a chevron-shaped load flank for engaging a mating chevron-shaped load flank of the complimentary box member to provide a chevron type interfit between the load bearing load flanks of the pin and box threads. The pin and box threads are also helically structured as a wedge. The chevron type interfit serves to limit the radial movement of the pin threads into the mating box member complimentary thread structure to control the radial make up of the pipe joint.

Tubular connection having a chevron wedge thread

A thread form is shown for a tubular connection of the type having a pin member adapted to be made up with a box member to form a pipe joint. The pin member has pin threads with thread crests and thread roots which are adapted to be made up with a mating box member having a complimentary thread structure. The pin thread crests are formed between a stab flank and a load flank of the pin thread. A pin thread has a chevron-shaped load flank for engaging a mating chevron-shaped load flank of the complimentary box member to provide a chevron type interfit between the load bearing flanks. The load flanks of the pin member includes an outer wall portion with a positive slope which provides additional clearance between the complimentary threads on the pin and box members during disassembly to prevent inadvertent hanging-up of the threads.

Tubular connection having a parallel chevron thread

A joint of male and female tubular elements is disclosed where the threads of the female and male members have negative load flanks and have two or more radial steps axially separated one from another by a reverse angle torque shoulder having one or two adjacent conical sealing surfaces. The conical sealing surfaces develop radial positional interference and the reverse angle torque shoulder serves as a positive assembly stop. The negative load flank angle of the threads and the reverse torque shoulder angle combine to interlock the male and female members and to prevent differential radial separation of the engaged conical sealing surfaces when the joint is exposed to internal pressure, external pressure or both. Tapered threads and sealing surfaces and interference threads may advantageously be used in the joint construction.

Tubular joint with trapped mid-joint metal-to-metal seal

A gaging system and method involves sensing longitudinal, lateral and rotatable displacements of a gaging tip or probe, for processing, as via a computer, and readout. One or more base positions of the tip may be selectively established; and corrections for misalignment of the gage relative to the work may be made as via the computer. Means is provided to obtain diameter or radius measurements associated with an annular body surface, at various locations on that surface, and said measurements may be averaged, as via the computer. Also, the measurement signals may be transmitted only after predetermined pressure application to a gaging tip.

Gaging system and method

A cylindrical threaded connector is provided with a small amount of taper to produce a controlled radial interference to prevent inadvertent thread disengagement. The threaded connector is especially suited for use with radial clearance cylindrical threads subjected to tensionload such as tubular goods used in wells. The taper can be used on either or both threads of two step cylindrical threads.

Cylindrical threaded connection

Pipe joint pin and box members have interengageable two-step threads and interengageable annular shoulders for preventing radial and axial separation of the members.

Dovetail connection for pin and box joints

A pipe joint includes pin and box members having interengaged two-step threads and interengaged annular shoulders preventing radial and axial separation of the members.

A pipe joint includes pin and box members having interengaged threads characterized as producing hoop tension in the pin member and hoop compression in the box members.

Growing community of inventors

Houston, TX, United States of America

Thomas L Blose