Patent US3768269A successfully refreshed from Google Patents.
US3768269A
Expired / Lapsed
US
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Mitigation of propagating collapse failures in pipelines due to external load
Assignee: Shell USA Inc
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Filing: 1972-04-07
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Granted: 1973-10-30
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Expires: 1992-04-07
Abstract
Abstract By increasing the section modulus of an underwater pipeline intermittently and for relatively short distances to a substantially higher level, a barrier is provided preventing propagation of a collapse of the pipe caused by external pressure exerted on the outside diameter of the pipe.
Inventors
- 👤 D Broussard
- 👤 R Ayers
- 👤 G Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:36
CPC Classifications
F; F16; F16L; F16L57/00; F16L57/02; F16L1/00; F16L1/12; F16L1/123; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49828
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
84 words
A method for preventing a collapse from propagating along an underwater pipeline, said method comprising the step of: providing means at intermittent intervals along the length of the pipeline to increase the section modulus of the pipeline; said underwater pipeline having a D/t ratio exceeding the value of the expression (C/H)1/2 wherein D is the outside diameter Of the pipeline, t is the wall thickness of the pipeline, C is an empirical constant equalling 180,000 feet, and H is the water depth in feet.
Claim 2
Independent Claim
84 words
A method for preventing a collapse from propagating along an underwater pipeline, said method comprising the step of: providing means at intermittent intervals along the length of the pipeline to increase the section modulus of the pipeline; said underwater pipeline having a D/t ratio exceeding the value of the expression (C/H)1/2 wherein D is the outside diameter Of the pipeline, t is the wall thickness of the pipeline, C is an empirical constant equalling 180,000 feet, and H is the water depth in feet.
Claim 3
Dependent Claim
46 words
The method of claim 1 wherein the means comprises a collar having an inside diameter slightly larger than the outside diameter of said pipeline and having a minimum length equal to one-half the wall thickness of the pipeline, the collar being weldably attached to said pipeline.
Claim 4
Dependent Claim
54 words
The method of claim 1 wherein the means comprises a section of pipe having a minimum length equal to one-half the wall thickness of the pipeline, and having a greater wall thickness than said pipeline, said pipe section being weldably secured at its ends to said pipeline to form a part of said pipeline.
Claim 5
Dependent Claim
34 words
The method of claim 1 wherein the means comprises a metallic pig inserted in the inner bore of said pipeline and having an outside diameter slightly smaller than the inside diameter of said pipeline.
Claim 6
Dependent Claim
20 words
The method of claim 4 wherein said pig is displaced to the desired position in said pipeline by pump means.
Claim 7
Dependent Claim
20 words
The method of claim 4 wherein said pig is installed in said pipeline and held in place by shearable means.
Claim 8
Dependent Claim
31 words
The method of claim 1 wherein the means increasing the section modulus of said pipeline are spaced apart along said pipeline at a distance ranging from 40 feet to 10 miles.
Claim 9
Dependent Claim
33 words
The method of claim 1 wherein the means to increase the section modulus has a minimum section modulus (I/c) per inch of length that at least equals the value of the expression t2/25.
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |