US3981779A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inhibition of scale on saline water heat exchange surfaces with iminodiacetic acid compounds
Assignee: WR Grace and Co
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Filing: 1974-08-01
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Granted: 1976-09-21
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Expires: 1994-08-01
Abstract
Abstract A method for decreasing fouling of metalliferous surfaces of apparatus wherein water is evaporated from an aqueous system containing components which deposit onto the surfaces as hydrophilic foulants. The method comprises adding to the aqueous system a chelant-surfactant having a hydrophobic moiety and a chelating moiety through which the chelant-surfactant chelates with the metalliferous surfaces and provides a hydrophobic barrier to deposition of hydrophilic foulants.
Inventors
- 👤 Jacob Block
- 👤 Nelson Samuel Marans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:32
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12; C02F1/00; C02F1/02; C02F1/04; C02F1/042; Y; Y10; Y10S; Y10S159/00; Y10S159/13; Y10S203/00; Y10S203/18
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
54 words
A method for inhibiting the deposition of scale on heat exchange surfaces of saline water distillation plants which comprises adding 1 to 25 parts per million of a chelant surfactant selected from the group consisting of salts, N-oleyiminodiacetic acid, its alkali metal and ammonium salts, N-oleoyliminodiacetic acid and its alkali metal and ammonium salts.
Claim 2
Independent Claim
54 words
A method for inhibiting the deposition of scale on heat exchange surfaces of saline water distillation plants which comprises adding 1 to 25 parts per million of a chelant surfactant selected from the group consisting of salts, N-oleyiminodiacetic acid, its alkali metal and ammonium salts, N-oleoyliminodiacetic acid and its alkali metal and ammonium salts.
Claim 3
Independent Claim
71 words
A method for inhibiting the deposition of scale on heat exchange surfaces of saline water distillation plants which comprises adding 1 to 25 parts per million of a compound selected from the group consisting of the magnesium, calcium, barium, iron II, Manganese II, mercury, cobalt II, zinc and nickel chelates of N-oleyliminodiacetic acid; the magnesium calcium, barium, iron II, Manganese II, mercury, cobalt II, zinc and nickel chelates of N-oleoyliminodiacetic acid.
Claim 4
Independent Claim
71 words
A method for inhibiting the deposition of scale on heat exchange surfaces of saline water distillation plants which comprises adding 1 to 25 parts per million of a compound selected from the group consisting of the magnesium, calcium, barium, iron II, Manganese II, mercury, cobalt II, zinc and nickel chelates of N-oleyliminodiacetic acid; the magnesium calcium, barium, iron II, Manganese II, mercury, cobalt II, zinc and nickel chelates of N-oleoyliminodiacetic acid.
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) | 1979-09-21 | 1980-03-22 | 1980-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-21 | 1984-03-22 | 1984-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-21 | 1988-03-22 | 1988-09-21 | $7700.00 | Window Closed / Lapsed |