US3905588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for plasticating polymers
Assignee: Milacron Inc
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Filing: 1974-02-08
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Granted: 1975-09-16
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Expires: 1994-02-08
Abstract
Abstract A method and apparatus for plasticating highly crystalline polymers include a screw with a core and constant pitch thread with a thread outside diameter profile presenting or having a necked down or least diameter portion in its compression or central section and which when rotated within a constant diameter barrel provides a varying clearance between the screw and barrel whereby melt quality is improved and screw wear is reduced when such a polymer (for example: polypropylene and high density polyethylene) is passed therethrough.
Inventors
- 👤 Lawrence Walter Reinhart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:19
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/58; B29C45/60; B29C48/00; B29C48/03
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
103 words
An extruder screw having a core and a thread thereon defining a feed section, compression section, and metering section wherein the core diameter is larger in the metering section than in the feed section and increases as the screw progresses through the compression section from the feed to the metering section that further comprises a thread having a varying outside diameter with the least such outside diameter being in the compression section and with its greatest outside diameters being substantially equal and at the ends of the thread in the feed and compression sections, whereby the thread has an hourglass outside diameter profile.
Claim 2
Dependent Claim
103 words
An extruder screw having a core and a thread thereon defining a feed section, compression section, and metering section wherein the core diameter is larger in the metering section than in the feed section and increases as the screw progresses through the compression section from the feed to the metering section that further comprises a thread having a varying outside diameter with the least such outside diameter being in the compression section and with its greatest outside diameters being substantially equal and at the ends of the thread in the feed and compression sections, whereby the thread has an hourglass outside diameter profile.
Claim 3
Dependent Claim
14 words
An extruder screw according to claim 1 wherein said thread has a constant pitch.
Claim 4
Dependent Claim
30 words
A single stage screw according to claim 1 that is integral or made from one piece of material adapted for plasticating highly crystalline polymers wherein the flight is flame hardened.
Claim 5
Dependent Claim
28 words
An extruder screw for a single screw extruder according to claim 1, combined with a barrel of substantially constant inside diameter in which said screw is rotatably mounted.
Claim 6
Dependent Claim
157 words
The combination in a single screw extruder foR plasticating highly crystalline polymers of a barrel having a substantially constant inside diameter and threaded screw having feed, compression and metering sections the diameter of the core of which increases as the screw progresses through the compression from the feed to the metering section and which is supported within said barrel for rotation relative thereto, which combination further comprises: said thread having a varying outside diameter with the least such outside diameter being in the compression section and with its greatest outside diameters being substantially equal and at the end flights of the thread in the feed and metering sections, whereby the thread has an hourglass outside diameter profile and the combination is provided with a varying radial clearance between the inside diameter of the barrel and the thread on said screw with the greatest such clearance between the screw compression section and the adjacent portion of said barrel.
Claim 7
Dependent Claim
157 words
The combination in a single screw extruder foR plasticating highly crystalline polymers of a barrel having a substantially constant inside diameter and threaded screw having feed, compression and metering sections the diameter of the core of which increases as the screw progresses through the compression from the feed to the metering section and which is supported within said barrel for rotation relative thereto, which combination further comprises: said thread having a varying outside diameter with the least such outside diameter being in the compression section and with its greatest outside diameters being substantially equal and at the end flights of the thread in the feed and metering sections, whereby the thread has an hourglass outside diameter profile and the combination is provided with a varying radial clearance between the inside diameter of the barrel and the thread on said screw with the greatest such clearance between the screw compression section and the adjacent portion of said barrel.
References Cited (Backward Citations)
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US3317959A
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US3295160A
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US3826477A
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US3727892A
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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) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |