Patent US3973056A successfully refreshed from Google Patents.
US3973056A
Expired / Lapsed
US
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Inhibition of stress-corrosion cracking of steel pipeline
Assignee: American Gas Association Inc
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Filing: 1974-06-06
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Granted: 1976-08-03
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Expires: 1994-06-06
Abstract
Abstract A method for inhibiting stress-corrosion cracking of a steel pipeline transmitting gas under elevated pressure provided with an external protective coating and means for cathodic protection, and steep pipe and pipelines so protected are described. The method consists of introducing a composition containing at least one of the inhibitors, calcium monobasic phosphate, sodium monobasic phosphate, sodium tripolyphosphate and potassium silicate, into a buried pipeline environment. The inhibiting composition may be simply introduced to the environment adjacent the pipeline or it may be incorporated in a coating on the pipeline, either in the primer or in a top coating thereover or in an intermediate coating between a conventional primer and topcoating, or in a tape applied to the pipeline.
Inventors
- 👤 Raymond Roy Fessler
- 👤 Warren Elmer Berry
- 👤 Russell Lee Wenk
- 👤 Redvers Nicholson Parkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:46
CPC Classifications
F; F16; F16L; F16L58/00; F16L58/02; F16L58/04; C; C23; C23F; C23F11/00; C23F11/08; C23F11/18; C23F11/182; C23F11/184; C23F13/00; C23F13/02; Y; Y10; Y10S; Y10S138/00; Y10S138/06
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
108 words
A method for inhibiting stress-corrosion cracking of a steel pipeline transmitting gas under elevated pressure provided with an external protective coating and means for cathodic protection, and which is in contact with an environment containing at least one material selected from the group consisting of the alkali metal and alkaline earth metal hydroxides, carbonates and nitrates, which comprises: introducing to the environment in contact with said pipeline a composition comprising at least one inhibitor selected from the group consisting of calcium monobasic phosphate, sodium monobasic phosphate, sodium tripolyphosphate, and potassium silicate; in an amount sufficient to provide an inhibitor concentration effective to inhibit stress-corrosion cracking of said pipeline.
Claim 2
Independent Claim
108 words
A method for inhibiting stress-corrosion cracking of a steel pipeline transmitting gas under elevated pressure provided with an external protective coating and means for cathodic protection, and which is in contact with an environment containing at least one material selected from the group consisting of the alkali metal and alkaline earth metal hydroxides, carbonates and nitrates, which comprises: introducing to the environment in contact with said pipeline a composition comprising at least one inhibitor selected from the group consisting of calcium monobasic phosphate, sodium monobasic phosphate, sodium tripolyphosphate, and potassium silicate; in an amount sufficient to provide an inhibitor concentration effective to inhibit stress-corrosion cracking of said pipeline.
Claim 3
Dependent Claim
35 words
A method according to claim 1 wherein the environment contains at least one material selected from the group consisting of the alkali metal and alkaline earth metal hydroxides and wherein the inhibitor is potassium silicate.
Claim 4
Dependent Claim
50 words
A method according to claim 1 wherein the environment contains at least one material selected from the group consisting of the alkali metal and alkaline earth metal carbonates and nitrates and wherein the inhibitor is selected from the group consisting of calcium monobasic phosphate, sodium monobasic phosphate and sodium tripolyphosphate.
Claim 5
Dependent Claim
13 words
A method according to claim 3 wherein the inhibitor is calcium monobasic phosphate.
Claim 6
Dependent Claim
13 words
A method according to claim 3 wherein the inhibitor is sodium monobasic phosphate.
Claim 7
Dependent Claim
12 words
A method according to claim 3 wherein the inhibitor is sodium tripolyphosphate.
Claim 8
Dependent Claim
78 words
A method according to claim 1 wherein the environment contains at least one material selected from the group consisting of the alkali metal and alkaline earth metal hydroxides and at least one material selected from the group consisting of the alkali metal and alkaline earth metal carbonates, bicarbonates, and nitrates, and wherein the inhibitor comprises potassium silicate and at least one additional inhibitor selected from the group consisting of calcium monobasic phosphate, sodium monobasic phosphate and sodium tripolyphosphate.
Claim 9
Dependent Claim
14 words
A method according to claim 7 wherein the additional inhibitor is calcium monobasic phosphate.
Claim 10
Dependent Claim
14 words
A method according to claim 7 wherein the additional inhibitor is sodium monobasic phosphate.
Claim 11
Dependent Claim
13 words
A method according to claim 7 wherein the additional inhibitor is sodium tripolyphosphate.
Claim 12
Dependent Claim
21 words
A method according to claim 1 wherein the inhibitor is incorporated in a coating applied to the pipeline to be protected.
Claim 13
Dependent Claim
15 words
A method according to claim 11 wherein the coating containing the inhibitor comprises coal tar.
Claim 14
Dependent Claim
16 words
A method according to claim 11 wherein the coating containing the inhibitor comprises an asphalt material.
Claim 15
Dependent Claim
13 words
A method according to claim 11 wherein the coating comprises an epoxy resin.
Claim 16
Dependent Claim
18 words
A method according to claim 11 wherein the inhibitor is incorporated in a prime coating on said pipeline.
Claim 17
Dependent Claim
18 words
A method according to claim 11 wherein the inhibitor is incorporated in an intermediate coating on said pipeline.
Claim 18
Dependent Claim
18 words
A method according to claim 11 wherein the inhibitor is incorporated in a top coating on said pipeline.
Claim 19
Dependent Claim
27 words
A method according to claim 1 wherein the inhibitor is mixed with an inert solid material and mixed with the soil adjacent the pipeline to be protected.
Claim 20
Dependent Claim
27 words
A method according to claim 1 wherein the inhibitor is introduced to the environment adjacent the pipeline to be protected by application thereto in an aqueous solution.
Claim 21
Dependent Claim
21 words
A method according to claim 1 wherein said inhibitor is incorporated in a cement material applied to said pipeline by spraying.
References Cited (Backward Citations)
US2685523A
Cited
US2861892A
Cited
US2883289A
Cited
US3070065A
Cited
US3357927A
Cited
US3468687A
Cited
US3333973A
Cited
US3354169A
Cited
US3689305A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |