US4195982A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for extruding articles
Assignee: AT&T Inc
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Filing: 1978-12-26
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Granted: 1980-04-01
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Expires: 1998-12-26
Abstract
Abstract A gas head extrusion apparatus (10), having upper (12) and lower (13) chambers, is arranged to feed glass particulate (60) into the upper chamber (12). The particulate (60) is heated to consolidate the particulate (60) into a first viscous melt (71) as an elevated gas pressure is simultaneously applied within the chamber (12). The first viscous melt (71) is urged through a narrow opening (16) in the bottom (14) of the upper chamber (12) into the lower chamber (13) to form a second viscous melt (73). The lower chamber (13) is pressurized to a second pressure, P 2 , where P 1 >P 2 . Gas bubbles, having an internal pressure, P 1 , formed during the consolidation process in the upper chamber (12), will expand in the lower chamber (13) to facilitate removal thereof from the melt (73). The lower pressure, P 2 , also causes the melt (73) in the lower chamber (13) to be extruded through an annular opening (29), in the bottom of the lower chamber (13), to form a substantially bubble-free hollow glass tube (74).
Inventors
- 👤 Alexander Coucoulas
- 👤 John R. Nis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:48
CPC Classifications
C; C03; C03B; C03B17/00; C03B17/04; C03B37/00; C03B37/01; C03B37/012; C03B37/01265; C03B37/01274; C03B5/00; C03B5/02; C03B5/021; C03B5/16; C03B5/225
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
83 words
A method of forming a substantially bubble-free viscous melt from a solid particulate material, the method comprising the steps of: simultaneously subjecting the solid particulate material to an elevated temperature and gas pressure to consolidate the particulate into a viscous melt while inducing the elevated pressure in any bubbles formed therein; and lowering the gas pressure to expand the gas bubbles to increase the upward mobility thereof wherein the bubbles will rise to the top of the melt and break through the surface.
Claim 2
Independent Claim
83 words
A method of forming a substantially bubble-free viscous melt from a solid particulate material, the method comprising the steps of: simultaneously subjecting the solid particulate material to an elevated temperature and gas pressure to consolidate the particulate into a viscous melt while inducing the elevated pressure in any bubbles formed therein; and lowering the gas pressure to expand the gas bubbles to increase the upward mobility thereof wherein the bubbles will rise to the top of the melt and break through the surface.
Claim 3
Dependent Claim
12 words
The method of claim 1, wherein: the particulate material is quartz crystal.
Claim 4
Dependent Claim
13 words
The method of claim 1, wherein: the particulate material is fused silica glass.
Claim 5
Independent Claim
144 words
A method of extruding a substantially bubble-free article by applying a gas pressure head to a melt of viscous material to urge the viscous melt through a die, the method comprising the steps of: simultaneously subjecting glass particulate in a first chamber to an elevated temperature and gas pressure to consolidate the particulate into a first viscous melt while inducing the elevated pressure in any bubbles formed therein; urging the first viscous melt through a narrow opening in the first chamber into a second chamber to form a second viscous melt, the second chamber having a lower pressure therein than the first chamber to expand the bubbles in the second melt to increase the upward mobility of the bubbles which break through the surface of the melt; and extruding the substantially bubble-free melt through a die in the second chamber to form the article.
Claim 6
Independent Claim
144 words
A method of extruding a substantially bubble-free article by applying a gas pressure head to a melt of viscous material to urge the viscous melt through a die, the method comprising the steps of: simultaneously subjecting glass particulate in a first chamber to an elevated temperature and gas pressure to consolidate the particulate into a first viscous melt while inducing the elevated pressure in any bubbles formed therein; urging the first viscous melt through a narrow opening in the first chamber into a second chamber to form a second viscous melt, the second chamber having a lower pressure therein than the first chamber to expand the bubbles in the second melt to increase the upward mobility of the bubbles which break through the surface of the melt; and extruding the substantially bubble-free melt through a die in the second chamber to form the article.
Claim 7
Dependent Claim
41 words
The method of claim 4 which is further characterized in that: the first viscous melt urged through the opening forms a narrow stream from which the bubbles readily escape upon expansion when subjected to the lower pressure within the second chamber.
Claim 8
Dependent Claim
12 words
The method of claim 4, wherein: the particulate material is quartz crystal.
Claim 9
Dependent Claim
13 words
The methods of claim 4, wherein: the particulate material is fused silica glass.
Claim 10
Dependent Claim
21 words
The method of claim 4 wherein: the die has an annular opening therein; and the article is a hollow, cylindrical tube.
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) | 1983-04-01 | 1983-10-01 | 1984-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-01 | 1987-10-01 | 1988-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-01 | 1991-10-01 | 1992-04-01 | $7700.00 | Window Closed / Lapsed |