초록 ▼

An interconnection for oil field tubular goods operates in a self sealing manner in response to internal pressures which might otherwise cause leakage through couplings or joints. Each coupling sleeve includes an interior fulcrum ring fitted between the nose ends of the tubing or casing, and central

An interconnection for oil field tubular goods operates in a self sealing manner in response to internal pressures which might otherwise cause leakage through couplings or joints. Each coupling sleeve includes an interior fulcrum ring fitted between the nose ends of the tubing or casing, and centrally engaging a fulcrum seating zone centered in the sleeve. Internal pressures tend to bend the ends of the fulcrum ring outwardly toward clearance or relief spans on each side of the fulcrum zone. This deflection increases the contact force and enhances the metal-to-metal seal between the end faces of the fulcrum ring and the pin end faces.

대표청구항 ▼

The invention claimed is: 1. A self sealing pressure responsive coupling device for joining two oil field tubular elements having male threaded ends terminating in end faces, the coupling device comprising: a coupling sleeve having female threaded end sections for matingly receiving the male thread

The invention claimed is: 1. A self sealing pressure responsive coupling device for joining two oil field tubular elements having male threaded ends terminating in end faces, the coupling device comprising: a coupling sleeve having female threaded end sections for matingly receiving the male threaded ends of the tubular elements and having an interior longitudinal span between the threaded female end sections, the interior longitudinal span including a central interior seating region of a first inner diameter, said female threaded end sections including a pair of spaced clearance regions of a second inner diameter greater than said first inner diameter; and a fulcrum ring having spaced fulcrum ring longitudinal ends, each having a longitudinal end span length and a central length between the spaced fulcrum ring longitudinal ends and corresponding to the interior longitudinal span of the coupling sleeve, the fulcrum ring central length being less than each of said longitudinal span end lengths and having a radial outer surface engaging the central interior seating region of the coupling sleeve, end faces of the fulcrum ring being engaged by the end faces of the two tubular elements inserted in the coupling sleeve, internal pressures within the fulcrum ring and the tubular elements acting to bend the longitudinal ends of the fulcrum ring radially outwardly into the clearance regions of the coupling sleeve, the radial bending of the fulcrum ring longitudinal ends increasing a metal-to-metal contact force between the end faces of the fulcrum ring and the end faces of the two tubular elements. 2. A self sealing coupling device as set forth in claim 1 above, wherein the central interior seating region of the coupling sleeve engages the fulcrum ring with a press fit, wherein the two tubular elements have a selected inner diameter and the fulcrum ring has the selected inner diameter, and wherein the fulcrum ring and the two tubular elements have flat end faces lying in planes perpendicular to a central axis of the tubular elements. 3. A self sealing coupling device as set forth in claim 2 above, wherein the pair of clearance regions of the coupling sleeve comprise regions of truncated female threaded end section threads. 4. A self sealing coupling device as set forth in claim 2 above, wherein the fulcrum ring has a substantially constant outer diameter along its length, and wherein the central interior seating region comprises a central projection extending radially inwardly relative to the clearance regions in the body of the coupling sleeve. 5. A self sealing coupling device as set forth in claim 2 above, wherein the fulcrum ring includes a projecting fulcrum central region on an outer diameter of the central length, said projecting fulcrum central region being adapted for mating with the central interior seating region of the coupling sleeve. 6. A self sealing coupling device as set forth in claim 2 above, wherein the two tubular elements and the coupling sleeve each have thread profiles with 90�� load flanks, large radius stab flanks and low taper angles, and wherein the male and female threaded ends have near mirror images. 7. A self sealing coupling device as set forth in claim 6 above, wherein the two tubular elements have upset ends and the threads have a 0.050 inch per inch taper, 0.050 inch thread heights and about 6 full form threads per inch. 8. A threaded connection for drilled hole tubing and casing for oil and gas field applications, comprising: a pair of oil field tubular elements, each having a central axis and a male threaded end with an end face transverse to the central axis; a coupling sleeve with integral longitudinally spaced threaded interior surfaces each adapted for receiving one of the pair of tubular elements inserted from opposite directions into the coupling sleeve, the coupling sleeve including an integral central interior seating region of a first inner diameter and with the longitudinally spaced threaded interior surfaces having a second inner diameter greater than the first inner diameter, and a central fulcrum ring disposed between, and abutting the end faces of the pair of tubular elements, the fulcrum ring having spaced fulcrum ring longitudinal ends each having a longitudinal end span, and a central length between the spaced fulcrum ring longitudinal ends, said fulcrum ring central length being less than each of said longitudinal end span lengths, the central length of the fulcrum ring being centered about the central interior seating region and circumferentially engaging the central interior seating region of the coupling sleeve, whereby internal pressures within the fulcrum ring and the tubular elements will bend the longitudinal ends of the fulcrum ring radially outwardly relative to the coupling sleeve central interior seating region and toward the adjacent surfaces of the second inner diameter on the coupling sleeve and to bring end faces of the central fulcrum ring into high force line contact engagement with the end faces of the pair of tubular elements. 9. A threaded connection as set forth in claim 8 above, wherein the male threaded ends of the pair of tubular elements, and the coupling sleeve spaced threaded interior surfaces have a near mirror image fit, and wherein the first inner diameter of the central interior seating region of the coupling sleeve adjacent the fulcrum ring mates, with a press fit, with the adjacent exterior region of the fulcrum ring. 10. A threaded connection as set forth in claim 9 above, and wherein the central fulcrum ring has a substantially constant diameter and the central interior seating region comprises a radially inward central projection in the coupling sleeve. 11. A threaded connection as set forth in claim 9 above, wherein the central fulcrum ring has a central outward projection and the central interior seating region of the coupling sleeve has said first inner diameter that is less than said second inner diameter of the longitudinally adjacent inner surfaces. 12. A threaded connection as set forth in claim 9 above, wherein a portion of thread crests on the threaded interior surfaces of the coupling sleeve adjacent each end of the central interior seating region are truncated to provide the longitudinally adjacent inner surfaces of the second inner diameter as a bending clearance for the end sections of the fulcrum ring. 13. A threaded connection as set forth in claim 12 above, wherein the male threaded ends of the pair of tubular elements and the spaced threaded interior surfaces of the coupling sleeve have shot peened surfaces for facilitating retention of lubricants with solid particles and for facilitating threaded engagement of the pair of tubular elements and the coupling sleeve. 14. A threaded connection as set forth in claim 13 above, wherein the male threaded ends of the pair of tubular elements and the spaced threaded interior surfaces of the coupling sleeve are dimensioned to mate to within less than 0.0001" on full makeup of the threaded connection. 15. A threaded connection as set forth in claim 14 above, wherein the threads on the male threaded ends and on the spaced threaded interior surfaces have a 90�� load flank and a radiused stab flank, and wherein the central fulcrum ring end sections have end faces which engage the end faces of the tubular elements, and further wherein the central fulcrum ring end section end faces bend into line contact with the end faces of the pair of tubular elements in response to internal pressure exerted on the central fulcrum ring. 16. The method of assembling a string of tubular elements for drilled hole oil field installations using couplers between pairs of elements comprising the steps of: preparing couplers in the form of cylindrical sleeves having interior female threads tapered oppositely from the ends of the coupler to a central section of predetermined inner diameter bounded at each end by radial clearance sections of larger diameter; preparing threaded pin elements having end sections with male threads mating with the female threads of the sleeves within 0.0005" when fully made up; work hardening the threaded surfaces by bombarding the surfaces to provide micro-indentations therein and puffing the surfaces of the parent material of the threaded coupler and pin element ends in a compressive state; applying lubricant including microparticles on the thread surfaces; threading a first tubular pin element into position to a selected degree of dimensional penetration into the coupler; inserting a fulcrum ring into the coupler against the end of the first tubular pin element, the fulcrum ring mating with the inner diameter of the central section of the coupler xvith a press fit and spanning the relief surfaces on each side with a radial clearance of 0.01" or more, and inserting the second tubular pin element into the coupler into end-to-end engagement with the fulcrum ring.