US3744770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Screw extruder
Assignee: Werner and Pfleiderer GmbH
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Filing: 1971-08-25
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Granted: 1973-07-10
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Expires: 1991-08-25
Abstract
Abstract A screw extruder for processing melts of synthetic plastic materials or synthetic plastic material in powder or granulated form to effect mixing, kneading and homogenizing of the material and causing chemical reactions thereof comprises a long main conveyor screw and a short auxiliary screw parallel thereto and disposed in the feed zone of the casing of the extruder. The screws are unidirectionally rotated in tight engagement with each other.
Inventors
- 👤 H Ocker
- 👤 D Buchheit
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:48
CPC Classifications
B; B29; B29B; B29B7/00; B29B7/80; B29B7/82; B29B7/826; B29B7/30; B29B7/34; B29B7/38; B29B7/46; B29B7/48; B29B7/482; B29B7/483; B29B7/484; B29B7/58; B29B7/60; B29C; B29C48/00; B29C48/25; B29C48/285; B29C48/288; B29C48/36; B29C48/395; B29C48/40; B29C48/402; B29C48/425; B29C48/435; B29C48/50; B29C48/505; B29C48/625; B29C48/03
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
A single screw extruder for processing melts of synthetic plastic material and synthetic plastic materials in powder or granulated form, said screw extruder comprising in combination: an elongate casing having at one end a feed zone including a feed port and at the other end a discharge port; a long main conveyor screw rotatably mounted in said casing and extending through substantially the length thereof, said screw and casing defining adjacent to the feed port a feed-in zone, the remaining lengths of the casing and the screw constituting a treatment zone; a short auxiliary screw rotatably mounted in said casing and terminating at the end of the feed-in zone as defined by the screw and the casing, said screws being in parallel and the turns thereof in tight engagement with each other; and drive means for unidirectionally rotating said screws.
Claim 2
Dependent Claim
140 words
A single screw extruder for processing melts of synthetic plastic material and synthetic plastic materials in powder or granulated form, said screw extruder comprising in combination: an elongate casing having at one end a feed zone including a feed port and at the other end a discharge port; a long main conveyor screw rotatably mounted in said casing and extending through substantially the length thereof, said screw and casing defining adjacent to the feed port a feed-in zone, the remaining lengths of the casing and the screw constituting a treatment zone; a short auxiliary screw rotatably mounted in said casing and terminating at the end of the feed-in zone as defined by the screw and the casing, said screws being in parallel and the turns thereof in tight engagement with each other; and drive means for unidirectionally rotating said screws.
Claim 3
Dependent Claim
38 words
The screw extruder according to claim 1 wherein the auxiliary screw along its entire length and the main screw at least along its portion in tight engagement with the auxiliary screw have screw turns with a round profile.
Claim 4
Dependent Claim
28 words
The screw extruder according to claim 1 wherein the lengths of the main screw and of the auxiliary screw in tight engagement with each other have multiple threads.
Claim 5
Dependent Claim
28 words
The screw extruder according to claim 1 wherein the length of the auxiliary screw is about three to five times the diameter of the circumference of the same.
Claim 6
Dependent Claim
35 words
The screw extruder according to claim 1 wherein the main screw includes a plurality of kneading discs intermediate said ports in the casing, and the casing includes a degasing opening downstream of said kneading discs.
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) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |