Patent US4478775A successfully refreshed from Google Patents.
US4478775A
Expired / Lapsed
US
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Method of extruding and shaping thermoplastic material
Assignee: Sekisui Chemical Co Ltd
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Filing: 1982-05-07
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Granted: 1984-10-23
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Expires: 2002-05-07
Abstract
Abstract A method of extruding and shaping thermoplastic material in which a constant amount of thermoplastic material is continuously fed from a screw extruder to a die by means of a metering pump. The extruder is arranged to continuously receive a constant amount of the thermoplastic material. The metering pump is adjusted to the correct rotational frequency to maintain the pressure of the molten thermoplastic material between the extruder and the metering pump within a predetermined range.
Inventors
- 👤 Gen Endo
- 👤 Hirokazu Hori
- 👤 Yoshihiro Kawada
- 👤 Junzo Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:48
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/375; B29C48/387; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92019; B29C2948/92323; B29C2948/92361; B29C2948/9238; B29C2948/92504; B29C2948/9258; B29C2948/9259; B29C2948/92819; B29C2948/92857; B29C2948/92876; B29C48/03; B29C48/07; B29C48/08; B29C48/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
123 words
A method of extruding thermoplastic material comprising (A) continuously feeding a substantially constant amount of said thermoplastic material from a constant volume feeder to a twin screw extruder, (B) continuously extruding a substantially constant amount of said thermoplastic material through said twin screw extruder, (C) continuously feeding a substantially constant amount of said thermoplastic material extruded through said twin screw extruder to a die by means of a metering pump, (D) measuring pressure of said thermoplastic material between said twin screw extruder and said metering pump, and (E) adjusting rotational frequency of only said metering pump with a proportional-integral-derivative (PID) system to diminish deviation of said measured pressure from a predetermined pressure value while rotation of said twin screw extruder is maintained constant.
Claim 2
Independent Claim
123 words
A method of extruding thermoplastic material comprising (A) continuously feeding a substantially constant amount of said thermoplastic material from a constant volume feeder to a twin screw extruder, (B) continuously extruding a substantially constant amount of said thermoplastic material through said twin screw extruder, (C) continuously feeding a substantially constant amount of said thermoplastic material extruded through said twin screw extruder to a die by means of a metering pump, (D) measuring pressure of said thermoplastic material between said twin screw extruder and said metering pump, and (E) adjusting rotational frequency of only said metering pump with a proportional-integral-derivative (PID) system to diminish deviation of said measured pressure from a predetermined pressure value while rotation of said twin screw extruder is maintained constant.
Claim 3
Dependent Claim
18 words
The method of claim 1 in which said thermoplastic material is (A) continuously fed from a screw feeder.
Claim 4
Dependent Claim
18 words
The method of claim 1 in which said thermoplastic material is (A) continuously fed from a rotary feeder.
Claim 5
Dependent Claim
27 words
The method of claim 1 additionally comprising the step of (A') continuously feeding a constant amount of liquid from an additional constant volume feeder to said extruder.
Claim 6
Dependent Claim
18 words
The method of claim 4 in which (A') plasticizer is continuously fed from said additional constant volume feeder.
Claim 7
Dependent Claim
31 words
The method of claim 4 in which said additional constant volume feeder (A') is selected from one of a gear pump feeder, a plunger pump feeder, and a diaphragm pump feeder.
Claim 8
Dependent Claim
31 words
The method of claim 1 in which said metering pump (C) is selected from one of a gear rotary pump, a vane pump, a friction screw pump, and a plunger pump.
Claim 9
Dependent Claim
28 words
The method of claim 1 in which (D) pressure is measured by a sensor selected from one of an electric sensor, an hydraulic sensor, and a mechanical sensor.
Claim 10
Dependent Claim
20 words
The method of claim 1 in which (D) said pressure is measured against an upper limit and a lower limit.
Claim 11
Dependent Claim
32 words
The method of claim 1 which produces an extruded thermoplastic material having a volumetric uniformity (3σ/χ) where σ is a standard deviation and χ an average value, of between about ±2 percent.
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) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |