US4249877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-speed direct-drive extruder
Assignee: Individual
•
Filing: 1979-03-26
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Granted: 1981-02-10
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Expires: 1999-03-26
Abstract
Abstract An extruder for thermoplastics having a directly motor-driven high-speed feed screw which mechanically force-feeds raw plastic pellets, pushing them forward under high pressure into a heat-transfer zone for melting, and finally through a static mixer, to deliver a pressurized homogeneous melt to an extrusion die. Melt pressurization results entirely from the mechanical force-feeding action of the screw rather than through the viscous shear action found in conventional screw extruders.
Inventors
- 👤 James F. Machen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:57
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/78; B29C48/80; B29C48/83; B29C48/834; B29C48/36; B29C48/362; B29C48/395; B29C48/50; B29C48/505; B29C48/56; B29C48/68; B29C48/685; B29C48/686; B29C48/86; B29C48/865; B29C48/03
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
123 words
A plastic extruder of the type described comprising: a cool bore; a raw material inlet for said bore; a non-plasticating feed screw in said cool bore; said screw rotatable in said cool bore such that the maximum screw RPM times the square root of the screw diameter in inches equals at least 500; the length to diameter ratio of said screw being less than 16 to 1; said cool bore communicating with a heated-wall melting chamber; means in said melting chamber for conducting heat from said heated walls into a variety of portions of the material flow stream through said melting chamber; mixing means also in said melting chamber downstream from said heat conducting means; and, an extrudate outlet for said melting chamber.
Claim 2
Dependent Claim
123 words
A plastic extruder of the type described comprising: a cool bore; a raw material inlet for said bore; a non-plasticating feed screw in said cool bore; said screw rotatable in said cool bore such that the maximum screw RPM times the square root of the screw diameter in inches equals at least 500; the length to diameter ratio of said screw being less than 16 to 1; said cool bore communicating with a heated-wall melting chamber; means in said melting chamber for conducting heat from said heated walls into a variety of portions of the material flow stream through said melting chamber; mixing means also in said melting chamber downstream from said heat conducting means; and, an extrudate outlet for said melting chamber.
Claim 3
Dependent Claim
27 words
A plastic extruder according to claim 1 wherein said cool bore has grooved rifling of the opposite hand to that of the threads of said feed screw.
Claim 4
Dependent Claim
42 words
A plastic extruder according to claim 1 wherein said means for conducting heat from said heated walls into said material flow stream comprises a plurality of fins extending in an internal direction from said heated walls and into said material flow stream.
Claim 5
Dependent Claim
47 words
A plastic extruder according to claim 1 wherein said means for conducting heat from said heated walls into said material flow stream comprises a plurality of hollow passages in said heated walls each providing a separate flow path through at least a portion of said melting chamber.
Claim 6
Dependent Claim
19 words
A plastic extruder according to claim 1 wherein said mixing means comprises a series of fixed, curved vane elements.
Claim 7
Dependent Claim
19 words
A plastic extruder according to claim 1 wherein said mixing means incorporates a plurality of fixed, non-parallel flow channels.
Claim 8
Dependent Claim
24 words
A plastic extruder according to claim 1 wherein elements of said mixing means are also adapted to conduct heat into said material flow stream.
Claim 9
Dependent Claim
17 words
A plastic extruder according to claim 1 wherein auxiliary cooling means are provided for said cool bore.
Claim 10
Dependent Claim
20 words
A plastic extruder according to claim 1 wherein said feed screw extends for a substantial distance into said melting chamber.
Claim 11
Dependent Claim
19 words
A plastic extruder according to claim 1 wherein the maximum permissible RPM of said screw is at least 750.
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) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |