Patent US4578973A successfully refreshed from Google Patents.
US4578973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing hollow aluminum extrudates for use in a high vacuum environment
Assignee: Resonac Holdings Corp
•
Filing: 1983-06-16
•
Granted: 1986-04-01
•
Expires: 2003-06-16
Abstract
Abstract A process for producing a hollow aluminum extrudate for use in a vacuum comprising the steps of hermetically closing the forward open end of a hollow shaped material immediately after extrusion, subsequently extruding a predetermined length of shaped material, cutting off the predetermined length of extruded material and hermetically closing the cut end thereof at the same time, and cutting off the closed ends. During extrusion, the inner surface of the hollow portion of the shaped material is substantially held out of contact with the atmosphere to inhibit a hydrous oxide on the inner surface while permitting formation of a compact oxide film thereon.
Inventors
- 👤 Hajime Ishimaru
- 👤 Shigeru Nishizaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:05
CPC Classifications
H; H05; H05H; H05H7/00; B; B21; B21C; B21C23/00; B21C23/002; B21C23/009; B21C23/02; B21C23/04; B21C23/08; B21C23/085; B21C23/14; B21C37/00; B21C37/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
129 words
A process for producing a hollow aluminum extrudate for use in a high vacuum environment comprising the steps of: hermetically closing the forward open end of a hollow shaped material immediately after extrusion; cutting the shaped material after a predetermined length thereof has been subsequently extruded and hermetically closing the cut end at the same time; cutting off the closed ends; and supplying a mixture of oxygen and an inert gas to the hollow portion of the shaped material from the start of extrusion to maintain the inner surface of the hollow portion of the shaped material substantially out of contact with the atmosphere during extrusion to effect the formation of only a compact and thin oxide film which is less likely to absorb or occlude vacuum reducing substances.
Claim 2
Dependent Claim
129 words
A process for producing a hollow aluminum extrudate for use in a high vacuum environment comprising the steps of: hermetically closing the forward open end of a hollow shaped material immediately after extrusion; cutting the shaped material after a predetermined length thereof has been subsequently extruded and hermetically closing the cut end at the same time; cutting off the closed ends; and supplying a mixture of oxygen and an inert gas to the hollow portion of the shaped material from the start of extrusion to maintain the inner surface of the hollow portion of the shaped material substantially out of contact with the atmosphere during extrusion to effect the formation of only a compact and thin oxide film which is less likely to absorb or occlude vacuum reducing substances.
Claim 3
Dependent Claim
24 words
A process as defined in claim 1 wherein the mixture comprises 0.5 to 30 vol. % of oxygen and the balance an inert gas.
Claim 4
Dependent Claim
24 words
A process as defined in claim 1 wherein the mixture comprises 1 to 10 vol. % of oxygen and the balance an inert gas.
References Cited (Backward Citations)
US3243984A
Cited
US3808865A
Cited
JPS533341A
Cited
US4165625A
Cited
US4165627A
Cited
US4316373A
Cited
JPS5791822A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-31 | 1989-09-30 | 1990-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-31 | 1993-09-30 | 1994-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-31 | 1997-09-30 | 1998-04-01 | $7700.00 | Window Closed / Lapsed |