Patent US3607339A successfully refreshed from Google Patents.
US3607339A
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US
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Sintered aggregates
Assignee: John G Stein and Co Ltd
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Filing: 1968-03-04
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Granted: 1971-09-21
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Expires: 1988-03-04
Abstract
Abstract A synthetic aggregate suitable for use in a road surface is prepared by sintering together particles of hard mineral or ceramic material, a flux, and at least sufficient combustible material to complete the endothermic changes occurring in the sintering. The sintered product is in the form of hard particles linked in a cellular structure by strong crystalline ceramic bonds.
Inventors
- 👤 William Davies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 04:02
CPC Classifications
E; E01; E01C; E01C7/00; E01C7/08; E01C7/085; C; C04; C04B; C04B18/00; C04B18/02; C04B18/027
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
24 words
A process according to claim 1 in which the temperature in the combustion stage of the sintering is maintained between 1100* and 1400* C.
Claim 2
Dependent Claim
81 words
A process according to claim 1 in which the raw materials are employed in such proportions that the final product contains by weight from 70 to 90 percent of the hard particles, and the remainder of the final product is derived from 2 to 10 percent of clay, and from 0.5 to 1.5 percent of fluorspar and contains from 5 to 25 percent in all of at least one member selected from the group consisting of calcium oxide and magnesium oxide.
Claim 3
Dependent Claim
68 words
A process according to claim 1 in which the charge is sintered as a gas-permeable bed on a grate through which air is drawn either upwards or downwards, the combustion proceeding in a zone that moves vertically through the bed, the surface of the bed is ignited by a flame and thereafter the air that is drawn through the ignited bed is preheated to a progressively less extent.
Claim 4
Dependent Claim
36 words
A process according to claim 1, in which the particles of materials are selected from the group consisting of sand, sandstone and gritstone and in which the flux is contained in the sand, sandstone as gritstone.
Claim 5
Dependent Claim
25 words
A process according to claim 1 in which the flux includes a member selected from the group consisting of a glass and a calcined material.
Claim 6
Dependent Claim
16 words
A process according to claim 1 in which the sintering is effected in a shaft kiln.
Claim 7
Dependent Claim
16 words
A process according to claim 1 in which the sintering is effected in a rotary kiln.
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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) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |