US4423960A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Twin-screw degassing extruder for degassing thermoplastic materials or the like
Assignee: KraussMaffei Extrusion GmbH
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Filing: 1981-07-07
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Granted: 1984-01-03
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Expires: 2001-07-07
Abstract
Abstract The advantages of a twin-screw extruder, especially the good plasticizing and homogenizing effect, are to be retained in the present invention with a simultaneous, above-average degassing output of the extruder. This object is achieved by dividing the twin-screw extruder into two stages (a) the plasticizing and homogenizing stage with a high screw torque and (b) the degassing and discharging stage in which a large, free degassing volume is achieved by a reduction in the screw core, by an enlargement of the screw housing and by adapting the screw diameter to the respective housing diameters in the degassing and discharging stage.
Inventors
- 👤 Dietmar Anders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:44
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/50; B29C48/76; B29C48/765; B29C48/766; B29C48/767; B29B; B29B7/00; B29B7/30; B29B7/34; B29B7/38; B29B7/46; B29B7/48; B29B7/482; B29B7/483; B29B7/488; B29B7/489; B29B7/80; B29B7/84; B29B7/845; B29B7/86; B29C48/395; B29C48/40; B29C48/402; B29C48/405; B29C48/505; B29C48/57; B29C48/03
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
149 words
A twin-screw degassing extruder for removing gases from thermoplastic materials comprising: (a) a housing defining a plasticizing and homogenizing stage, and a degassing and discharging stage, the housing in said degassing and discharging stage having a larger internal diameter when compared with the internal diameter of the housing in said plasticizing and homogenizing stage, (b) screw members extending through said stages, the screw members in said degassing and discharging stage having a core diameter which is smaller than the core diameter of the screw members in said plasticizing and homogenizing stage, and the external diameters of the webs of the screw members in said degassing and discharging stage corresponding substantially to the relatively larger internal diameter of the housing in such region, whereby a relatively large volume is created in the degassing and discharging stage for improved degassing without affecting the desired results in the plasticizing and homogenizing stage.
Claim 2
Dependent Claim
149 words
A twin-screw degassing extruder for removing gases from thermoplastic materials comprising: (a) a housing defining a plasticizing and homogenizing stage, and a degassing and discharging stage, the housing in said degassing and discharging stage having a larger internal diameter when compared with the internal diameter of the housing in said plasticizing and homogenizing stage, (b) screw members extending through said stages, the screw members in said degassing and discharging stage having a core diameter which is smaller than the core diameter of the screw members in said plasticizing and homogenizing stage, and the external diameters of the webs of the screw members in said degassing and discharging stage corresponding substantially to the relatively larger internal diameter of the housing in such region, whereby a relatively large volume is created in the degassing and discharging stage for improved degassing without affecting the desired results in the plasticizing and homogenizing stage.
Claim 3
Dependent Claim
36 words
An extruder according to claim 1, wherein the angle between an imaginary vertical line and webs forming the screw in said degassing and discharging stage is greater than the angle in said plasticizing and homogenizing stage.
Claim 4
Dependent Claim
35 words
An extruder according to claim 1, wherein the individual screw members are located on rods which have a smaller diameter in said degassing and discharging stage than the diameter in said plasticizing and homogenizing stage.
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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) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |