US4414014A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a bubble-free vitreous material
Assignee: Heraeus Quarzglas GmbH and Co KG
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Filing: 1981-10-19
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Granted: 1983-11-08
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Expires: 2001-10-19
Abstract
Abstract For the production of a bubble-free vitreous material, and in particular bubble-free vitreous silica, bubbles-containing vitreous material is exposed in a furnace, at a temperature which reduces its viscosity to a value between 10 13 .5 and 10 8 Pa.sec, to the omnidirectional pressure ranging from 100 to 3000 bars of a gas which is insoluble in the vitreous material for a period of not less than 10 minutes and is then cooled.
Inventors
- 👤 Rolf Bruning
- 👤 Poul-Erik Breidenbach
- 👤 Norbert Cibis
- 👤 Fritz Aldinger
- 👤 Waltraud Werdecker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:36
CPC Classifications
C; C03; C03B; C03B32/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
162 words
A method for the production of a shaped article of a bubble free vitreous material, and in particular bubble free vitreous silica, formed a shaped article of bubbles-containing vitreous material, and in particular vitreous silica, which comprises heating said material in the form of a shaped article while said shaped article is disposed on a support in a furnace and while heating said shaped article applying an omnidirectional gas pressure thereagainst which pressure is applied by a gas which is insoluble in said material, said gas being at an omnidirectional pressure of 100 to 3,000 bars, said material being heated to a temperature which reduces the viscosity of said material to a value between 10 13 .5 and 10 8 Pa.sec, said material in the form of a shaped article being heated at said temperature and pressure for a period of not less than 10 minutes and thereafter cooling said material to room temperature over a period of less than 10 hours.
Claim 2
Independent Claim
162 words
A method for the production of a shaped article of a bubble free vitreous material, and in particular bubble free vitreous silica, formed a shaped article of bubbles-containing vitreous material, and in particular vitreous silica, which comprises heating said material in the form of a shaped article while said shaped article is disposed on a support in a furnace and while heating said shaped article applying an omnidirectional gas pressure thereagainst which pressure is applied by a gas which is insoluble in said material, said gas being at an omnidirectional pressure of 100 to 3,000 bars, said material being heated to a temperature which reduces the viscosity of said material to a value between 10 13 .5 and 10 8 Pa.sec, said material in the form of a shaped article being heated at said temperature and pressure for a period of not less than 10 minutes and thereafter cooling said material to room temperature over a period of less than 10 hours.
Claim 3
Dependent Claim
29 words
A method according to claim 1, wherein the vitreous material is treated at a temperature which reduces its viscosity to a value between 10 11 and 10 9 Pa.sec.
Claim 4
Dependent Claim
18 words
A method according to claim 1, wherein a gas pressure ranging from 200 to 1000 bars is employed.
Claim 5
Dependent Claim
12 words
A method according to claim 1, wherein the gas used is argon.
Claim 6
Dependent Claim
27 words
A method according to claim 1, wherein the vitreous material treated is cooled to a temperature of 373° K. over a period of less than 3 hours.
Claim 7
Dependent Claim
13 words
A method according to claim 1, wherein a flame-melted vitreous material is used.
Claim 8
Dependent Claim
18 words
A method according to claim 6, wherein vitreous silica melted by means of a hydrogen-oxygen flame is used.
Claim 9
Dependent Claim
58 words
A method according to claim 1, wherein vitreous silica is subjected at a temperature ranging from 1550° to 1770° K. to an omnidirectionally gas atmosphere of a pressure ranging from 300 to 1000 bars for a period of from 30 to 90 minutes and then is cooled in less than 1 hour to a temperature below 1200° K.
Claim 10
Dependent Claim
32 words
A method according to claim 1, wherein a thin surface of the treated, cooled vitreous material is removed to a depth of not more than 2 mm prior to further hot working.
Claim 11
Dependent Claim
24 words
A method according to claim 9, wherein the outer layer of a treated vitreous silica article is removed by etching with aqueous hydrofluoric acid.
Claim 12
Dependent Claim
11 words
A method according to claim 8, wherein said gas is argon.
Claim 13
Dependent Claim
17 words
A method according to claim 1, wherein said shaped article is a shaped article of vitreous silica.
References Cited (Backward Citations)
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US3228760A
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US3459565A
Cited
US3813276A
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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) | 1986-11-07 | 1987-05-09 | 1987-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-07 | 1991-05-09 | 1991-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-07 | 1995-05-09 | 1995-11-08 | $7700.00 | Window Closed / Lapsed |