Patent US3873474A successfully refreshed from Google Patents.
US3873474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Regeneration of polymeric material
Assignee: Individual
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Filing: 1972-04-17
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Granted: 1975-03-25
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Expires: 1992-04-17
Abstract
Abstract Polymeric scrap material, such as rubber from used vehicular tires, is reclaimed by comminuting the scrap and then advancing it under substantially atmospheric pressure through a heating chamber with the aid of two or more heated feed screws having interleaved threads, one screw rotating at half the speed of its neighbor and having a double thread with twice the pitch of the single thread of the latter. Residence time in the heating chamber may range between 3 and 30 minutes, at operating temperatures of 140* to 300*C. By relatively accelerating or retarding one of two adjoining screws, their interleaved threads are moved into a nearly contacting relationship in which they scrape adhering incrustations from each other.
Inventors
- 👤 Stefan Ficker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:46
CPC Classifications
B; B29; B29B; B29B17/00; B29B17/0026; B29K; B29K2021/00; B29L; B29L2030/00; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
128 words
A METHOD OF CONTINUOUSLY REGENERATING PREVIOUSLY VULCANIZED RUBBER SCRAP, COMPRISING THE STEPS OF: A. COMMINUTING THE SCRAP TO BE REGENERATED; B. INTRODUCING THE COMMINUTED SCRAP INTO AN ELONGATE HEATING CHAMBER; C. MAINTAINING SAID CHAMBER AT AN OPERATING TEMPERATURE OF 140* TO 300*C; D. ADVANCING SAID SCRAP MATERIAL THROUGH SAID CHAMBER ROTATING FEED SCREWS WITH SPACEDLY INTERLEAVED THREADS AT SUBSTANTIALLY ATMOSPHERIC PRESSURE FOR A RESIDENCE TIME OF 3 TO 30 MINUTES, SAID INTERLEAVED THREADS DIFFERING IN PITCH AND SAID SCREWS ARE BEING ROTATED WITH A COMPENSATORY DIFFERENCE IN SPEED; E. INTERMITTENTLY VARYING THE RELATIVE SPEED OF SAID SCREWS FOR SCRAPING ADHERING INCRUSTATIONS OFF THE THREADS THEREOF; F. CONTINUOUSLY DISCHARGING SAID SCRAP FROM SAID CHAMBER THROUGH A NONRESTRICTIVE OUTLET; AND G. HOMOGENIZING AND CONSOLIDATING THE MATERIAL ISSUING FROM SAID OUTLET.
Claim 2
Independent Claim
128 words
A METHOD OF CONTINUOUSLY REGENERATING PREVIOUSLY VULCANIZED RUBBER SCRAP, COMPRISING THE STEPS OF: A. COMMINUTING THE SCRAP TO BE REGENERATED; B. INTRODUCING THE COMMINUTED SCRAP INTO AN ELONGATE HEATING CHAMBER; C. MAINTAINING SAID CHAMBER AT AN OPERATING TEMPERATURE OF 140* TO 300*C; D. ADVANCING SAID SCRAP MATERIAL THROUGH SAID CHAMBER ROTATING FEED SCREWS WITH SPACEDLY INTERLEAVED THREADS AT SUBSTANTIALLY ATMOSPHERIC PRESSURE FOR A RESIDENCE TIME OF 3 TO 30 MINUTES, SAID INTERLEAVED THREADS DIFFERING IN PITCH AND SAID SCREWS ARE BEING ROTATED WITH A COMPENSATORY DIFFERENCE IN SPEED; E. INTERMITTENTLY VARYING THE RELATIVE SPEED OF SAID SCREWS FOR SCRAPING ADHERING INCRUSTATIONS OFF THE THREADS THEREOF; F. CONTINUOUSLY DISCHARGING SAID SCRAP FROM SAID CHAMBER THROUGH A NONRESTRICTIVE OUTLET; AND G. HOMOGENIZING AND CONSOLIDATING THE MATERIAL ISSUING FROM SAID OUTLET.
Claim 3
Dependent Claim
17 words
A method as defined in claim 1 wherein said operating temperature ranges between substantially 240* and 280*C.
Claim 4
Dependent Claim
30 words
A method as defined in claIm 1, further comprising the step of admixing a plasticizer and a vulcanization promoter with said scrap material prior to introduction thereof into said chamber.
Claim 5
Dependent Claim
38 words
A method as defined in claim 1 wherein said chamber is heated at least in part by passing through said screws a heating liquid having substantially no vapor pressure at an operating temperature of about 180* to 300*C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |