Patent US4726828A successfully refreshed from Google Patents.
US4726828A
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Method of manufacturing rotationally symmetrical glass bodies
Assignee: US Philips Corp
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Filing: 1986-07-14
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Granted: 1988-02-23
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Expires: 2006-07-14
Abstract
Abstract A method of manufacturing rotationally symmetrical glass bodies. The starting material for the glass body is a thixotropic suspension consisting of powered glass in a liquid dispersing agent. The suspension is introduced into a hollow mold whose geometry corresponds to that of the glass body to be formed. The hollow mold is rotated about its longitudinal axis to deposit the suspension on the inner wall of the hollow mold. The after which the green body thus formed is purified and sintered. The green body is formed by heating the rotating mold and the suspension therein to a temperature below the boiling point of the dispersing liquid until cross-linking and solidification of the starting material is obtained. Thereafter, the green body can be removed from the hollow mold.
Inventors
- 👤 Rolf Clasen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:01
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/12; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/016
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
159 words
A method of manufacturing rotationally symmetric glass bodies, said method comprising the steps of: providing a hollow mold having a longitudinal axis and having an inside with an inner wall; preparing a first liquid having a density; preparing a thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point, said suspension having a density lower than the density of the first liquid; introducing the first liquid into the inside of the mold; introducing the suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the first liquid on the inner wall of the mold to produce an auxiliary layer, and to deposit the suspension on the auxiliary layer; heating the suspension to a temperature below the boiling point of the liquid dispersing agent until the suspension cross-links and solidifies; removing the solidified suspension from the mold; and purifying and sintering the solidified suspension.
Claim 2
Independent Claim
159 words
A method of manufacturing rotationally symmetric glass bodies, said method comprising the steps of: providing a hollow mold having a longitudinal axis and having an inside with an inner wall; preparing a first liquid having a density; preparing a thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point, said suspension having a density lower than the density of the first liquid; introducing the first liquid into the inside of the mold; introducing the suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the first liquid on the inner wall of the mold to produce an auxiliary layer, and to deposit the suspension on the auxiliary layer; heating the suspension to a temperature below the boiling point of the liquid dispersing agent until the suspension cross-links and solidifies; removing the solidified suspension from the mold; and purifying and sintering the solidified suspension.
Claim 3
Dependent Claim
13 words
A method as claimed in claim 1, wherein the first liquid is bromonaphthalene.
Claim 4
Dependent Claim
13 words
A method as claimed in claim 1, wherein the first liquid is diiodomethane.
Claim 5
Dependent Claim
39 words
A method as claimed in claim 1, further comprising the step of providing a separation layer between the auxiliary layer and the suspension, said separation layer comprising a synthetic resin which does not react with the liquid dispersing agent.
Claim 6
Dependent Claim
14 words
A method as claimed in claim 4, wherein the synthetic resin is a polycarbonate.
Claim 7
Dependent Claim
15 words
A method as claimed in claim 4, wherein the synthetic resin is a polyethelene terephthalate.
Claim 8
Dependent Claim
16 words
A method as claimed in claim 4, wherein the synthetic resin is an elastomeric synthetic resin.
Claim 9
Dependent Claim
14 words
A method as claimed in claim 7, wherein the elastomeric synthetic resin is polyurethane.
Claim 10
Dependent Claim
14 words
A method as claimed in claim 8, wherein the separation layer is a sleeve.
Claim 11
Independent Claim
118 words
A method of manufacturing rotationally symmetric glass bodies, said method comprising the steps of: providing a hollow mold having a longitudinal axis and having an inside with an inner wall; preparing a thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point; introducing the suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the suspension on the inner wall of the mold; heating the suspension to a temperature below the boiling point of the liquid dispersing agent while rotating the mold until the suspension cross-links and solidifies; removing the solidified suspension from the mold; and purifying and sintering the solidified suspension.
Claim 12
Independent Claim
118 words
A method of manufacturing rotationally symmetric glass bodies, said method comprising the steps of: providing a hollow mold having a longitudinal axis and having an inside with an inner wall; preparing a thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point; introducing the suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the suspension on the inner wall of the mold; heating the suspension to a temperature below the boiling point of the liquid dispersing agent while rotating the mold until the suspension cross-links and solidifies; removing the solidified suspension from the mold; and purifying and sintering the solidified suspension.
Claim 13
Dependent Claim
26 words
A method as claimed in claim 10, wherein prior to the step of rotating the mold, the method further comprises the step of liquefying the suspension.
Claim 14
Dependent Claim
33 words
A method as claimed in claim 11, wherein the powdered glass material consists essentially of SiO 2 particles having diameters from 10 to 500 nanometers, with an average diameter of approximately 40 nanometers.
Claim 15
Dependent Claim
33 words
A method as claimed in claim 12, wherein: some of the SiO 2 particles are doped to change their refractive index; and the SiO 2 particles have diameters from 10 to 100 nanometers.
Claim 16
Dependent Claim
27 words
A method as claimed in claim 13, wherein the ratio by weight of the powdered glass material to the liquid dispersing agent is from 0.7:1 to 2:1.
Claim 17
Dependent Claim
14 words
A method as claimed in claim 14, wherein the liquid dispersing agent is water.
Claim 18
Dependent Claim
38 words
A method as claimed in claim 15, wherein the suspension further comprises an ionogenic additive for shifting the pH of the suspension into the range from 5 to 8 so as to increase the alkalinity of the suspension.
Claim 19
Dependent Claim
15 words
A method as claimed in claim 16, wherein the ionogenic additive is an ammonium compound.
Claim 20
Dependent Claim
19 words
A method as claimed in claim 16, wherein the ionogenic additive is an aqueous 5% NH 4 F solution.
Claim 21
Dependent Claim
28 words
A method as claimed in claim 18, wherein the ionogenic additive is added in an amount from 0.1 to 5% by weight relative to the powdered glass material.
Claim 22
Dependent Claim
48 words
A method as claimed in claim 19, wherein: the ionogenic additive is added in an amount from 0.75 to 1% by weight relative to the powdered glass material; and the ratio by weight of the powdered glass material to the liquid dispersing agent is from 0.9:1 to 1:1.
Claim 23
Dependent Claim
34 words
A method as claimed in claim 20 further comprising the step of vibrating the suspension at a frequency from 20 to 200 hertz or from 20 to 50 kilohertz prior to rotating the mold.
Claim 24
Dependent Claim
28 words
A method as claimed in claim 21, wherein the step of heating the suspension comprises heating the suspension by microwave radiation having a frequency of approximately 2.45 gigahertz.
Claim 25
Dependent Claim
28 words
A method as claimed in claim 21, wherein the step of heating the suspension comprises heating the suspension by electromagnetic radiation having a frequency of approximately 27 megahertz.
Claim 26
Dependent Claim
18 words
A method as claimed in claim 23, wherein the SiO 2 particles are doped with GeO 2 .
Claim 27
Dependent Claim
107 words
A method as claimed in claim 24, wherein after the suspension is solidified, but before the suspension is removed from the mold, the method further comprises the steps of: preparing a second thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point; introducing the second suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the second suspension on the solidified first suspension; and heating the second suspension to a temperature below the boiling point of the liquid dispersing agent while rotating the mold until the second suspension cross-links and solidifies.
Claim 28
Dependent Claim
27 words
A method as claimed in claim 25, further comprising the step of cooling the suspension to approximately 4° C. prior to introducing the suspension into the mold.
Claim 29
Independent Claim
141 words
A method of manufacturing rotationally symmetric glass bodies, said method comprising the steps of: providing a hollow mold having a longitudinal axis and having an inside with an inner wall; preparing a thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point; cooling the suspension to a temperature at which cross-linking between powdered glass particles in the suspension proceeds slowly; liquefying the suspension; introducing the suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the suspension on the inner wall of the mold; and then heating the suspension to a temperature below the boiling point of the liquid dispersing agent while rotating the mold until the suspension cross-links and solidifies; removing the solidified suspension from the mold; and purifying and sintering the solidified suspension.
Claim 30
Independent Claim
141 words
A method of manufacturing rotationally symmetric glass bodies, said method comprising the steps of: providing a hollow mold having a longitudinal axis and having an inside with an inner wall; preparing a thixotropic suspension comprising a powdered glass material and a liquid dispersing agent, said liquid dispersing agent having a boiling point; cooling the suspension to a temperature at which cross-linking between powdered glass particles in the suspension proceeds slowly; liquefying the suspension; introducing the suspension into the inside of the mold; rotating the mold about its longitudinal axis to deposit the suspension on the inner wall of the mold; and then heating the suspension to a temperature below the boiling point of the liquid dispersing agent while rotating the mold until the suspension cross-links and solidifies; removing the solidified suspension from the mold; and purifying and sintering the solidified suspension.
References Cited (Backward Citations)
GB682580A
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JPS59131538A
Cited
JPS59152235A
Cited
EP0123191A2
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US4541855A
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JPS6054928A
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US4605428A
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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) | 1991-02-22 | 1991-08-24 | 1992-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-22 | 1995-08-24 | 1996-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-22 | 1999-08-24 | 2000-02-23 | $7700.00 | Window Closed / Lapsed |