US4224966A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crack arrestor
Assignee: Northern Border Pipeline Co
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Filing: 1978-12-14
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Granted: 1980-09-30
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Expires: 1998-12-14
Abstract
Abstract This invention relates to crack arrestors for arresting longitudinal propagation of a crack in pipelines carrying natural gas or highly volatile normally gaseous liquids or combinations thereof, and to methods for applying said crack arrestor to pipelines.
Inventors
- 👤 Francis S. Somerville
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:52
CPC Classifications
B; B21; B21D; B21D39/00; B21D39/04; B23; B23P; B23P11/00; B23P11/02; F; F16; F16L; F16L57/00; F16L57/02; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49863; Y10T29/49865; Y10T29/49908; Y10T29/49938; Y10T29/4994
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
155 words
A crack arrestor for a large diameter pressurized gas pipepline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor comprising an annular disc having an inside diameter that encircles and fits loosely over a pipeline section in its unexpanded state and that tightly contacts the pipeline section when an ovaling, preceding the advance of the propagating crack, propagates to the location of said disc, said disc having sufficient stiffness to prevent the ovaling in the pipeline from deforming the disc and thereby to retard the velocity of the propagating ductile crack along the pipeline sufficiently to arrest the propagating crack.
Claim 2
Dependent Claim
155 words
A crack arrestor for a large diameter pressurized gas pipepline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor comprising an annular disc having an inside diameter that encircles and fits loosely over a pipeline section in its unexpanded state and that tightly contacts the pipeline section when an ovaling, preceding the advance of the propagating crack, propagates to the location of said disc, said disc having sufficient stiffness to prevent the ovaling in the pipeline from deforming the disc and thereby to retard the velocity of the propagating ductile crack along the pipeline sufficiently to arrest the propagating crack.
Claim 3
Dependent Claim
22 words
A crack arrestor according to claim 1 wherein said disc is in nonwelded contact with the pipeline section in its expanded state.
Claim 4
Dependent Claim
20 words
A crack arrestor according to claim 1 wherein said disc fits loosely over the pipeline section in its expanded state.
Claim 5
Dependent Claim
27 words
A crack arrestor according to claim 1 wherein said disc is in nonwelded contact with a band filling the space between the disc and the pipeline section.
Claim 6
Dependent Claim
21 words
A crack arrestor according to claims 1 through 4 wherein said disc has a radial dimension greater than its thickness dimension.
Claim 7
Dependent Claim
138 words
A crack arrestor for a large diameter pressurized gas pipeline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor comprising means to encircle and fit loosely over a pipeline section and to tightly contact the pipeline section when ovaling, preceding the advance of the propagating crack, propagates to the location of said means, said arrestor acting to restrain the ovaling in the pipeline and thereby to retard the velocity of propagation of the ductile crack along the pipeline sufficiently to arrest its propagation.
Claim 8
Dependent Claim
138 words
A crack arrestor for a large diameter pressurized gas pipeline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor comprising means to encircle and fit loosely over a pipeline section and to tightly contact the pipeline section when ovaling, preceding the advance of the propagating crack, propagates to the location of said means, said arrestor acting to restrain the ovaling in the pipeline and thereby to retard the velocity of propagation of the ductile crack along the pipeline sufficiently to arrest its propagation.
Claim 9
Dependent Claim
167 words
A crack arrestor system for a large diameter pressurized gas pipeline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor system comprising a plurality of annular discs each having an inside diameter that encircles and fits loosely over a pipeline section and that tightly contacts the pipeline section when an ovaling, preceding the advance of the propagating crack, propagates to the location of each said disc, each of said discs having sufficient stiffness to prevent the ovaling in the pipeline from deforming the disc and thereby in combination with other discs of the plurality to retard the velocity of propagation of the ductile crack along the pipeline sufficiently to arrest its propagation.
Claim 10
Dependent Claim
167 words
A crack arrestor system for a large diameter pressurized gas pipeline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor system comprising a plurality of annular discs each having an inside diameter that encircles and fits loosely over a pipeline section and that tightly contacts the pipeline section when an ovaling, preceding the advance of the propagating crack, propagates to the location of each said disc, each of said discs having sufficient stiffness to prevent the ovaling in the pipeline from deforming the disc and thereby in combination with other discs of the plurality to retard the velocity of propagation of the ductile crack along the pipeline sufficiently to arrest its propagation.
Claim 11
Dependent Claim
150 words
A crack arrestor system for a large diameter pressurized gas pipeline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor system comprising a plurality of means to encircle and fit loosely over a pipeline section and to tightly contact the pipeline section when an ovaling, preceding the advance of the propagating crack, propagates to the location of each said means to restrain the ovaling in the pipeline and thereby in combination with other means of the plurality to retard the velocity of propagation of the ductile crack along the pipeline sufficiently to arrest its propagation.
Claim 12
Dependent Claim
150 words
A crack arrestor system for a large diameter pressurized gas pipeline formed from a plurality of tough ductile steel cylindrical pipe sections joined end to end that undergo radial expansion to an expanded state under normal operating conditions in which the gas internal to the pipeline is brought up to operating pressure, the pipe sections in the expanded state being susceptible to propagating ductile cracks driven by the internal pressure in the pipeline, said arrestor system comprising a plurality of means to encircle and fit loosely over a pipeline section and to tightly contact the pipeline section when an ovaling, preceding the advance of the propagating crack, propagates to the location of each said means to restrain the ovaling in the pipeline and thereby in combination with other means of the plurality to retard the velocity of propagation of the ductile crack along the pipeline sufficiently to arrest its propagation.
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) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |