Patent US4550937A successfully refreshed from Google Patents.
US4550937A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Joint for steel tubes
Assignee: Vallourec SA
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Filing: 1979-12-10
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Granted: 1985-11-05
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Expires: 1999-12-10
Abstract
Abstract Threaded pipe joint in which tip of the male member engages shoulder within the female member and any excess in the outer diameter of the male member over the corresponding inner diameter of the female member is so small that the hoop stress in the female member does not exceed the axial stress therein.
Inventors
- 👤 Jean Duret
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:09
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/02; E21B17/04; E21B17/042; F; F16; F16L; F16L15/00; F16L15/001; F16L15/006; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/4984; Y10T29/49945
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
291 words
An oil well pipe joint resistant to embrittlement by corrosive oil well fluids comprising a male pipe member and a female pipe member having mating threads of trapezoidal section adapted to be repeatedly assembled and disassembled, said female member having an internal shoulder and an external surface, said male member having a tip and a seal being formed between said shoulder and said tip, said shoulder defining an annular recess having a radially inner side in the shape of a truncated cone the largest diameter of which is at the bottom of the recess, and an outer side having the shape of a truncated cone the smallest diameter of which is at the bottom of said recess, the tip of said male member terminating in surfaces having substantially the same conicity as the inner and outer sides of said recess, and mating frusto-conical threaded sections inside the end of said female member and on the outside of the end of said male member, the nominal radial dimensions of the threads on said sections being such that when said joint is fully made up there is a nominal radial clearance between each threaded part of the male member and the corresponding threaded part of the female member, the said nominal radial dimensions being chosen such that with the applicable tolerances the maximum clearance between the threads on the male member and the corresponding threads on the female member is 0.3 mm per 100 mm of pipe diameter and the instances of interference are sufficiently minimal to avoid substantial hoop stresses in the female member, whereby said external surface of said female member and said internal surface of said male member are highly resistant to corrosion embrittlement in use in an oil well.
Claim 2
Dependent Claim
291 words
An oil well pipe joint resistant to embrittlement by corrosive oil well fluids comprising a male pipe member and a female pipe member having mating threads of trapezoidal section adapted to be repeatedly assembled and disassembled, said female member having an internal shoulder and an external surface, said male member having a tip and a seal being formed between said shoulder and said tip, said shoulder defining an annular recess having a radially inner side in the shape of a truncated cone the largest diameter of which is at the bottom of the recess, and an outer side having the shape of a truncated cone the smallest diameter of which is at the bottom of said recess, the tip of said male member terminating in surfaces having substantially the same conicity as the inner and outer sides of said recess, and mating frusto-conical threaded sections inside the end of said female member and on the outside of the end of said male member, the nominal radial dimensions of the threads on said sections being such that when said joint is fully made up there is a nominal radial clearance between each threaded part of the male member and the corresponding threaded part of the female member, the said nominal radial dimensions being chosen such that with the applicable tolerances the maximum clearance between the threads on the male member and the corresponding threads on the female member is 0.3 mm per 100 mm of pipe diameter and the instances of interference are sufficiently minimal to avoid substantial hoop stresses in the female member, whereby said external surface of said female member and said internal surface of said male member are highly resistant to corrosion embrittlement in use in an oil well.
Claim 3
Dependent Claim
29 words
An oil well pipe joint according to claim 1, wherein the maximum extent of said interference is 0.1 mm for each 100 mm of the diameter of the pipes.
Claim 4
Dependent Claim
31 words
An oil well pipe joint according to claim 1, wherein the maximum extent of said slight interference is 0.12 mm, and the maximum extent of said slight clearance is 0.18 mm.
Claim 5
Dependent Claim
58 words
A joint as claimed in claim 1, in which the threads hold the tip of the male member against the shoulder on the female member with sufficient force for the tip of the male member to remain seated against said shoulder in spite of any axial forces to which the joint is subjected in the course of use.
Claim 6
Dependent Claim
39 words
A joint as claimed in claim 1, in which a slight lateral clearance is provided between an unthreaded portion of the male member located between its tip and its threaded portion, and the corresponding portion of the female member.
Claim 7
Dependent Claim
18 words
A joint as claimed in claim 1, comprising a polymerized sealing lubricant between said male and female member.
Claim 8
Dependent Claim
39 words
A joint as claimed in claim 1, which comprises two pipe sections the tips of which are formed into male members and which are connected together by a single tubular sleeve defining two female members each having a shoulder.
Claim 9
Dependent Claim
33 words
A joint as claimed in claim 7, in which the distance between the two shoulders on the sleeve is at least equal to 2.2 times the thickness of the sleeve between the shoulders.
Claim 10
Dependent Claim
24 words
A joint as claimed in claim 7, in which the distance between the shoulders on the sleeve is at least equal to 30 mm.
Claim 11
Dependent Claim
37 words
A joint as claimed in claim 1, in which at the tip of the male member the right section of the female member has an area about 10 to 20% larger that that of the male member.
Claim 12
Dependent Claim
35 words
A joint as claimed in claim 1, in which the shoulder on the female member has an axial length equal to at least 1.1 times the total thickness of the female member at the shoulder.
Claim 13
Dependent Claim
25 words
A joint as claimed in claim 1, in which the shoulder on the female member has an axial length equal to at least 15 mm.
Claim 14
Dependent Claim
36 words
A joint as claimed in claim 1, wherein the diameter of the outer conical surface of said tip of the male member is slightly greater than the diameter of said outer side of the female member.
Claim 15
Dependent Claim
41 words
A joint as claimed in claim 13, wherein, for a pipe outer diameter of about 100 mm the diameter of said tip is between 95.6 and 95.97 mm and the diameter of said outer side is between 95.4 and 95.25 mm.
Claim 16
Independent Claim
268 words
A method of making a corrosion embrittlement resistant joint for steel oil well pipes comprising a male pipe member and a female pipe member adapted to be repeatedly assembled and disassembled, said female member having an internal shoulder, and an external surface and a seal being formed between siad shoulder and the tip of the male member, said shoulder defining an annular recess having a radially inner side in the shape of a truncated cone the largest diameter of which is at the bottom of the recess, and an outer side having the shape of a truncated cone the smallest diameter of which is at the bottom of said recess, the tip of said male member terminating in surfaces having substantially the same conicity as the inner and outer sides of said recess, and mating frusto-conical threaded sections inside the end of the female member and on the outside of the end of the male member, which method comprises the step of machining said members and threaded sections so that the radial fit between any threaded part of the male member with respect to a corresponding threaded part of the female member is in the range between a slight radial interference and a slight radial clearance, the maximum extent of said slight radial interference not exceeding 0.1 mm for each 100 mm of the pipe diameter and the maximum extent of said radial clearance not exceeding 0.3 mm for each 100 mm of pipe diameter, so that said external surface of said female member and the internal surface of said male member are highly resistant to corrosion embrittlement.
Claim 17
Independent Claim
268 words
A method of making a corrosion embrittlement resistant joint for steel oil well pipes comprising a male pipe member and a female pipe member adapted to be repeatedly assembled and disassembled, said female member having an internal shoulder, and an external surface and a seal being formed between siad shoulder and the tip of the male member, said shoulder defining an annular recess having a radially inner side in the shape of a truncated cone the largest diameter of which is at the bottom of the recess, and an outer side having the shape of a truncated cone the smallest diameter of which is at the bottom of said recess, the tip of said male member terminating in surfaces having substantially the same conicity as the inner and outer sides of said recess, and mating frusto-conical threaded sections inside the end of the female member and on the outside of the end of the male member, which method comprises the step of machining said members and threaded sections so that the radial fit between any threaded part of the male member with respect to a corresponding threaded part of the female member is in the range between a slight radial interference and a slight radial clearance, the maximum extent of said slight radial interference not exceeding 0.1 mm for each 100 mm of the pipe diameter and the maximum extent of said radial clearance not exceeding 0.3 mm for each 100 mm of pipe diameter, so that said external surface of said female member and the internal surface of said male member are highly resistant to corrosion embrittlement.
Claim 18
Dependent Claim
64 words
A method according to claim 15, wherein said step of forming comprises, machining the threaded section of the male member within a tolerance of 0.19 mm and the female member within a tolerance of 0.11 mm for each 100 mm of pipe diameter, so that the maximum extent of said interference is 0.12 mm, and the maximuum extent of said clearance is 0.18 mm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-11-04 | 1989-05-06 | 1989-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-04 | 1993-05-06 | 1993-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-04 | 1997-05-06 | 1997-11-05 | $7700.00 | Window Closed / Lapsed |