US3771986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuously skimming viscous glass
Assignee: PPG Industries Inc
•
Filing: 1972-06-01
•
Granted: 1973-11-13
•
Expires: 1992-06-01
Abstract
Abstract A silica-rich, volatiles-deficient surface layer is removed from highly viscous glass, near a forming means (rolls or the like). There is used a weir of less-than-usual depth that contains a platinum member that provides a substantially unchanging weir depth; at the same time, Venturi means control the amount of hot gases removed from the glass-melting furnace, to maintain or control the flow of the highly viscous glass. With the invention, it is possible to drain off the silica-rich surface of a highly viscous glass, losing only about 10 percent of the furnace throughput, rather than accepting the higher losses (about 30 percent) required in accordance with previous practices.
Inventors
- 👤 J Stultz
- 👤 J Capellman
- 👤 L Knavish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:19
CPC Classifications
C; C03; C03B; C03B5/00; C03B5/16; C03B5/26; C03B5/262; C03B5/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
36 words
a sheet-like insert piece positioned within said slot, said insert piece comprising material selected from the group consisting of platinum and platinum-base alloys, and said insert having an edge substantially in the form of said notch.
Claim 2
Dependent Claim
12 words
The apparatus as defined in claim 1 wherein said weir member comprises
Claim 3
Dependent Claim
53 words
Apparatus as defined in claim 2 wherein said opening has a diameter of the order of from 3.5 to 6 inches and bottom of said notch of said weir is located about 0.15 to 0.9 inch below the elevation at which the top surface of molten glass in said container may be maintained.
Claim 4
Dependent Claim
28 words
Apparatus as defined in claim 3, further characterized in that said insert piece is made of a platinum-base alloy containing about 20 to 50 weight percent of rhodium.
Claim 5
Dependent Claim
37 words
Apparatus as defined in claim 3, characterized in that said means for accelerating said headspace gases comprises a high-velocity burner located in a conduit communicating with said opening and serving to aspirate headspace gases through said notch.
Claim 6
Dependent Claim
27 words
Apparatus as defined in claim 5, further characterized in that said insert piece is made of a platinum-base alloy containing about 20 to 50 percent of rhodium.
Claim 7
Independent Claim
125 words
A method for making glass comprising a. melting a glass composition within a container to form molten glass having a silica-rich surface layer, said molten glass having a viscosity of from about 100 to 1,000 poises b. providing headspace gases above the surface of said molten glass in said container c. withdrawing a surface portion of said molten glass and a portion of said headspace gases continuously through an opening in a side of said container over a weir positioned substantially immediately below the surface of said molten glass, and d. accelerating the floW of headspace gases through said opening causing molten glass to flow over said weir and discharging said accelerated headspace gases and said portion of molten glass after flowing from said container.
Claim 8
Dependent Claim
46 words
A method as defined in claim 7, further characterized in that said accelerating is done by blowing gases in a high-velocity jet within a conduit that communicates with headspace gases passing within the vicinity of said notch so as to accelerate said headspace gases by aspiration.
Claim 9
Dependent Claim
42 words
A method as defined in claim 8, characterized by the further feature of regulating the rate of flow of gases in said jet in accordance with the flow of molten glass through said notch so as to maintain the latter substantially constant.
Claim 10
Dependent Claim
87 words
A method as defined in claim 7, characterized in that molten glass is withdrawn through at least one opening in said passage while at the same time other portions of said molten glass having said silica-rich surface layer removed from them are continuously removed from said passage and subjected to roll-forming to obtain a product ribbon of glass, the amount per unit time of said removed from said opening being less than 10 percent of the amount of glass per unit time transformed in said product ribbon.
Claim 11
Dependent Claim
42 words
A method as defined in claim 10, characterized by the further feature of regulating the rate of flow of gases in said jet in accordance with the flow of molten glass through said notch so as to maintain the latter substantially constant.
References Cited (Backward Citations)
US1872477A
Cited
US3206295A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |