Methods of extruding plastic material
Abstract
Abstract The rate of plastic material into a screw extruder is controlled in accordance with the internal pressure at least one point along the extruder barrel by sampling the pressure measurement at one point, in or at each of several spaced points along, the extruder barrel at intervals under the control of a timing device driven by the extruder screw in such a way that each sample is taken from the same part of the pressure cycle. Pressure samples are compared with a reference signal to produce an error signal when the value of one or more pressure samples deviates from a desired value. These error signals, which may themselves be sampled under the control of the timing device to avoid hunting, are caused to adjust the rate of feed to material to the extruder, e.g. from a second screw extruder, to restore the pressure to the desired value.
Inventors
- 👤 Z Bonikowski
- 👤 B Keen
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |