Patent US3552404A successfully refreshed from Google Patents.
US3552404A
Expired / Lapsed
US
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Installation for the descaling of metals
Assignee: Evonik Operations GmbH
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Filing: 1968-02-16
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Granted: 1971-01-05
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Expires: 1988-02-16
Abstract
Abstract Metals having metal oxide scales are descaled with molten sodium metal. The descaling can be preceded and followed by treatment of the metal with molten alkali metal hydroxide.
Inventors
- 👤 Rudolf Kuhn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:36
CPC Classifications
C; C23; C23G; C23G3/00; C23G3/02; C23G3/021; C23G1/00; C23G1/28; C23G1/32; C23G5/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
110 words
An apparatus according to claim 1 wherein the cross-sectional area of said housing means is less than the cross-sectional area of the upper surface of said first container and the bottom of said housing means extends into said first container above the bottom thereof whereby when said first container contains a molten alkali metal hydroxide bath, said bath seals said housing means, and the open top of said second container extends above the top of said first container, said housing means providing a space for an inert atmosphere above the area of the open top of said second container and at least the immediately adjacent area above said first container.
Claim 2
Dependent Claim
230 words
A metal object treating apparatus comprising in combination a first container open at the top thereof, a molten alkali metal hydroxide bath in said container suitable for the pretreatment of the surface of said metal object, a second, funnel shaped, container having a wide, open top and a narrow, open bottom positioned within, but out of contact with said first container, a molten sodium metal bath in said second container suitable for the treatment therein of the surface of said metal object after said pretreatment, the opening of said narrow bottom being disposed within the internal cross-sectional area of said first container, the molten alkali metal hydroxide bath being in contact with the molten sodium metal bath and sealing the bottom of said second container, said molten sodium metal bath floating on said molten alkali metal hydroxide bath, heating means for maintaining both baths in a molten state, feeder means for feeding a metal object sequentially through said first bath, then through said second bath and again through said first bath, airtight housing means, an inert atmosphere within said housing means, said opening of said wide top of said second container disposed above the level of the molten alkali metal hydroxide in said first container and extending into said inert atmosphere within the cross-sectional area of said airtight housing means whereby an inert atmosphere is maintained above said sodium metal.
Claim 3
Dependent Claim
26 words
An apparatus as in claim 3 in which all surfaces of said second container which contact sodium metal are made of nickel or are nickel plated.
Claim 4
Dependent Claim
15 words
An apparatus according to claim 3 in which said alkali metal hydroxide is sodium hydroxide.
Claim 5
Independent Claim
198 words
An apparatus suitable for treating a metal object in a plurality of baths, one of said baths being a molten alkali metal hydroxide bath and a second of said baths being a molten sodium metal bath disposed on top of said alkali metal hydroxide bath and covered with an inert atmosphere, said apparatus comprising, in combination, a first lower container open at the top thereof suitable for holding said molten alkali metal hydroxide, a second, funnel shaped container suitable for holding said molten alkali metal, said second container having a wide, open top and a narrow, open bottom, said second container being positioned within, but out of contact with said second container, the opening of said narrow bottom being disposed within the internal cross-sectional area of said first container, heating means suitable for maintaining both of said baths in molten state, feeder means for feeding a metal object sequentially through said first container, then through said second container and then again through said first container, airtight housing means, comprising a top and sidewall, said wide top of said second container being disposed within the cross-sectional area of said housing means and below the top of said housing means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |