Patent US4525388A successfully refreshed from Google Patents.
US4525388A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for expanding and coating perlite
Assignee: United States Gypsum Co
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Filing: 1983-12-23
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Granted: 1985-06-25
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Expires: 2003-12-23
Abstract
Abstract Expanded perlite is produced while simultaneously or substantially simultaneously coating the expanded perlite with an hydrophobic coating material by passing the expanded perlite and heated expander exhaust gases from the expansion chamber through a cooling and coating chamber provided with spray nozzles to provide a stream of atomized coating material onto the expanded perlite, while upstream thereof an air intake and temperature sensor are situated to control the air flow and temperature in the cooling and coating chamber so as to provide proper curing temperatures for the coating material upon the expanded perlite before it is separated from the exhaust gases.
Inventors
- 👤 Thomas E. Rehder
- 👤 Terrance L. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:49
CPC Classifications
C; C04; C04B; C04B20/00; C04B20/10; C04B20/1051; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2995; Y10T428/2998
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
139 words
A process for manufacturing expanded perlite of the type in which (a) perlite ore and a stream of hot gases at a temperature above the softening point of perlite are fed to an expansion chamber, (b) hot expanded perlite in a stream of hot exhaust gases are withdrawn from the expansion zone and conveyed to a separation zone, and (c) expanded perlite is separated from hot exhaust gases; the improvement characterized by, intermediate step (b) and step (c), coating the expanded perlite with a hydrophobic material comprising the steps of (1) adjusting the temperature of the exhaust gases to between about 90° C. and about 375° C.; (2) spraying about 0.01% to about 4.0% by weight of hydrophobic coating material onto the expanded perlite, and (3) maintaining the coated perlite at such temperatures for at least about 3 seconds.
Claim 2
Dependent Claim
139 words
A process for manufacturing expanded perlite of the type in which (a) perlite ore and a stream of hot gases at a temperature above the softening point of perlite are fed to an expansion chamber, (b) hot expanded perlite in a stream of hot exhaust gases are withdrawn from the expansion zone and conveyed to a separation zone, and (c) expanded perlite is separated from hot exhaust gases; the improvement characterized by, intermediate step (b) and step (c), coating the expanded perlite with a hydrophobic material comprising the steps of (1) adjusting the temperature of the exhaust gases to between about 90° C. and about 375° C.; (2) spraying about 0.01% to about 4.0% by weight of hydrophobic coating material onto the expanded perlite, and (3) maintaining the coated perlite at such temperatures for at least about 3 seconds.
Claim 3
Dependent Claim
16 words
The process of claim 1 in which in step (2) the coating material is polydimethyl siloxane.
Claim 4
Dependent Claim
43 words
The process of claim 1 in which in step (2) the coating material is polydimethyl siloxane sprayed onto perlite that is at a temperature of about 316° C. and in step (3) the coated perlite is conveyed for at least about 5 seconds.
Claim 5
Dependent Claim
43 words
The process of claim 1 in which in step (2) the coating material is polydimethyl siloxane, sprayed onto perlite that is at a temperature of about 260° C. and in step (3) the coated perlite is conveyed for at least about 15 seconds.
Claim 6
Dependent Claim
43 words
The process of claim 1 in which in step (2) the coating material is polydimethyl siloxane, sprayed onto perlite that is at a temperature of about 205° C. and in step (3) the coated perlite is conveyed for at least about 30 seconds.
Claim 7
Dependent Claim
25 words
The process of claim 1 in which in step (2) about 0.1% to about 2% by weight of polydimethyl siloxane is sprayed onto the perlite.
Claim 8
Dependent Claim
24 words
The process of claim 1 in which in step (1) the temperature of the exhaust gases is adjusted by the introduction of ambient air.
Claim 9
Dependent Claim
46 words
The process of claim 1 in which in step (1) sufficient ambient air is introduced to adjust the temperature of the exhaust gases to about 150°-260° C., and in step (2) about 0.1% to about 2% by weight of polydimethyl siloxane is sprayed onto the perlite.
Claim 10
Dependent Claim
46 words
The process of claim 1 in which in step (1) sufficient ambient air is introduced to adjust the temperature of the exhaust gases to about 177° C., and in step (2) about 0.1% to about 2% by weight of polydimethyl siloxane is sprayed onto the perlite.
References Cited (Backward Citations)
US4183980A
Cited
US4255489A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |