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US4089651A
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US
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Pyrophosphate-zinc corrosion inhibitor
Assignee: ChampionX LLC
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Filing: 1976-08-04
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Granted: 1978-05-16
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Expires: 1996-08-04
Abstract
Abstract A method for inhibiting metal corrosion in once-through water systems entailing the use of a pyrophosphate-zinc composition.
Inventors
- 👤 James E. Scott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:36
CPC Classifications
C; C23; C23F; C23F11/00; C23F11/08; C23F11/18; C23F11/187; C23F11/188
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
49 words
A method for inhibiting metal corrosion in once-through water systems comprising maintaining a level of 0.1-20 ppm by weight of pyrophosphate and 0.01-10 ppm by weight of zinc in the water passing through the system, said once-through systems being characterized as being at least partially composed of copper alloys.
Claim 2
Independent Claim
49 words
A method for inhibiting metal corrosion in once-through water systems comprising maintaining a level of 0.1-20 ppm by weight of pyrophosphate and 0.01-10 ppm by weight of zinc in the water passing through the system, said once-through systems being characterized as being at least partially composed of copper alloys.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein the pyrophosphate is potassium pyrophosphate.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the pyrophosphate is sodium pyrophosphate.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the pyrophosphate is present at a level of 0.1-0.9 ppm and the zinc is present at a level of 0.04-0.3 ppm.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein the pyrophosphate is ammonium pyrophosphate.
References Cited (Backward Citations)
US3445395A
Cited
US3510436A
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US3580855A
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US3668132A
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US3669616A
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US3887488A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |