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US4500481A
Expired / Lapsed
US
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Methods for controlling vinyl plastic extrudate
Assignee: AT&T Inc
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Filing: 1983-04-25
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Granted: 1985-02-19
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Expires: 2003-04-25
Abstract
Abstract In order to control the fusion of a polyvinyl chloride plastic material which is being moved along a screw of an extruder from a feed section (36) through a compression section (37) to a metering section (39) and crosshead (26), the melt pressure is measured in the compression section. The melt pressure, which is indicative of the fusion qualities of the plastic material, is used to control the temperature of the plastic material in the feed section to cause it to be substantially homogenous at the crosshead.
Inventors
- 👤 Morris F. Marx, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:08
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92019; B29C2948/92209; B29C2948/92323; B29C2948/92361; B29C2948/9238; B29C2948/92504; B29C2948/92514; B29C2948/92542; B29C2948/9258; B29C2948/9259; B29C2948/92704; B29C2948/92819; B29C2948/92857; B29C2948/92876; B29C2948/92885; B29C2948/92895; B29C48/03; B29K; B29K2027/00; B29K2027/06; Y; Y10; Y10S; Y10S264/00; Y10S264/65
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
160 words
A method of providing a substantially homogenous extrudate of a plastic material which comprises a polyvinyl chloride composition having a fusion characteristic which may vary between supplies thereof, said method comprising the steps of: feeding pellets of the polyvinyl chloride plastic material into a feed section of an extruder screw and barrel arrangement; rotating the screw to convey the pellets from the feed section through a compression section and a metering section to an extruder crosshead where the plastic material is caused to be extruded into a predetermined cross-sectional shape; while heating the plastic material; measuring the melt pressure of the heated plastic material between the feed section and the metering section of the extruder screw; and in response to the measured melt pressure, adjusting the heat energy which is imparted to the plastic material at least prior to the compression section to cause the plastic material that is moved from the barrel to the crosshead to be substantially homogenous.
Claim 2
Independent Claim
160 words
A method of providing a substantially homogenous extrudate of a plastic material which comprises a polyvinyl chloride composition having a fusion characteristic which may vary between supplies thereof, said method comprising the steps of: feeding pellets of the polyvinyl chloride plastic material into a feed section of an extruder screw and barrel arrangement; rotating the screw to convey the pellets from the feed section through a compression section and a metering section to an extruder crosshead where the plastic material is caused to be extruded into a predetermined cross-sectional shape; while heating the plastic material; measuring the melt pressure of the heated plastic material between the feed section and the metering section of the extruder screw; and in response to the measured melt pressure, adjusting the heat energy which is imparted to the plastic material at least prior to the compression section to cause the plastic material that is moved from the barrel to the crosshead to be substantially homogenous.
Claim 3
Independent Claim
166 words
A method of providing a substantially homogenous extrudate of a plastic material comprising a polyvinyl chloride composition which has a fusion characteristic that may vary between supply lots, during the extrusion covering of a substrate, said method comprising the steps of: feeding pellets of the polyvinyl chloride plastic material into a feed section of an extruder screw and barrel arrangement; rotating the screw to convey the pellets from the feed section through a compression section and a metering section to an extruder crosshead where the plastic material is caused to enclose a substrate which is being moved through the crosshead, while heating the plastic material; measuring the melt pressure of the heated plastic material between the feed section and the metering section; and in response to the measured melt pressure, adjusting the heat energy which is imparted to the plastic material at least prior to the compression section to cause the plastic material that is moved from the barrel into the crosshead to be substantially homogenous.
Claim 4
Independent Claim
166 words
A method of providing a substantially homogenous extrudate of a plastic material comprising a polyvinyl chloride composition which has a fusion characteristic that may vary between supply lots, during the extrusion covering of a substrate, said method comprising the steps of: feeding pellets of the polyvinyl chloride plastic material into a feed section of an extruder screw and barrel arrangement; rotating the screw to convey the pellets from the feed section through a compression section and a metering section to an extruder crosshead where the plastic material is caused to enclose a substrate which is being moved through the crosshead, while heating the plastic material; measuring the melt pressure of the heated plastic material between the feed section and the metering section; and in response to the measured melt pressure, adjusting the heat energy which is imparted to the plastic material at least prior to the compression section to cause the plastic material that is moved from the barrel into the crosshead to be substantially homogenous.
Claim 5
Dependent Claim
19 words
The method of claim 2, wherein the heat energy is adjusted by adjusting the temperature in the feed section.
Claim 6
Dependent Claim
29 words
The method of claim 2, wherein the heat energy is adjusted by directing preheated air having a predetermined temperature into a hopper which is connected to the feed section.
Claim 7
Dependent Claim
25 words
The method of claim 2, wherein the heat energy is adjusted by force-feeding the plastic pellets into a hopper which communicates with the feed section.
Claim 8
Dependent Claim
22 words
The method of claim 2, wherein the heat energy is adjusted by adjusting the rotational velocity of the screw in the barrel.
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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) | 1988-02-19 | 1988-08-20 | 1989-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-19 | 1992-08-20 | 1993-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-19 | 1996-08-20 | 1997-02-19 | $7700.00 | Window Closed / Lapsed |