Patent US4924352A successfully refreshed from Google Patents.
Patent US4430282A successfully refreshed from Google Patents.
US4430282A
Expired / Lapsed
US
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Method for the extrusion of tetrafluoroethylene polymer tubes
Assignee: Dow Chemical Co
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Filing: 1982-05-17
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Granted: 1984-02-07
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Expires: 2002-05-17
Abstract
Abstract Tetrafluoroethylene polymer tubes are ram extruded. Desirable quality tubes are obtained by positioning an insert between ram and mandrel to maintain the ram and mandrel concentric.
Inventors
- 👤 Eugene V. Stack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:57
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/475; B29C48/022; B29C48/001; B29C48/0012; B29C48/0018; B29C48/0021; B29C48/03; B29C48/09; B29C48/15; B29C48/151; B29C48/16; B29C48/18; B29C48/21; B29K; B29K2027/00; B29K2027/12; B29K2027/18; Y; Y10; Y10S; Y10S425/00; Y10S425/055
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
187 words
A method for the fabrication of tetrafluoroethylene polymer tubes wherein a tetrafluoroethylene polymer resin is ram extruded in a ram extruder to generally fuse together particles of the tetrafluoroethylene polymer resin to provide a coherent tetrafluoroethylene polymer tube discharging the coherent tetrafluoroethylene polymer tube from the ram extruder, the ram extruder having a hollow cylindrical barrel, the barrel having a resin entrance end and a resin exit end, a hollow cylindrical ram reciprocally movable to a location within and external to the entrance end of the barrel, a generally cylindrical mandrel disposed within and passing through the hollow cylindrical ram, the mandrel extending into the barrel and terminating generally adjacent the discharge end of the barrel, the ram being in operative association with means to reciprocally position the hollow cylindrical ram generally along an axis of the direction of extrusion of the barrel and means to reciprocally position the mandrel along the axis of extrusion of the barrel, the improvement which comprises disposing a generally hollow cylindrical spacer between the hollow cylindrical ram and the mandrel at a location generally adjacent the entrance end of the barrel.
Claim 2
Independent Claim
187 words
A method for the fabrication of tetrafluoroethylene polymer tubes wherein a tetrafluoroethylene polymer resin is ram extruded in a ram extruder to generally fuse together particles of the tetrafluoroethylene polymer resin to provide a coherent tetrafluoroethylene polymer tube discharging the coherent tetrafluoroethylene polymer tube from the ram extruder, the ram extruder having a hollow cylindrical barrel, the barrel having a resin entrance end and a resin exit end, a hollow cylindrical ram reciprocally movable to a location within and external to the entrance end of the barrel, a generally cylindrical mandrel disposed within and passing through the hollow cylindrical ram, the mandrel extending into the barrel and terminating generally adjacent the discharge end of the barrel, the ram being in operative association with means to reciprocally position the hollow cylindrical ram generally along an axis of the direction of extrusion of the barrel and means to reciprocally position the mandrel along the axis of extrusion of the barrel, the improvement which comprises disposing a generally hollow cylindrical spacer between the hollow cylindrical ram and the mandrel at a location generally adjacent the entrance end of the barrel.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the spacer is glass fiber filled polytetrafluoroethylene.
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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) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |