US3778205A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for cooling blown polymer films
Assignee: Dow Chemical Co
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Filing: 1970-06-11
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Granted: 1973-12-11
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Expires: 1990-06-11
Abstract
Abstract This invention relates to the cooling of blown polymer film by spraying a relatively low boiling point liquid onto the film, thereby causing cooling and solidification of the heat plastified polymer. The vaporized liquid coolant is condensed on the exterior wall of a cooling chamber which surrounds the blown film and the condensate is collected and re-cycled.
Inventors
- 👤 R Turner
- 👤 E Poli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:56
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/885; B29C48/03; B29C48/09; B29C48/10; B29C48/911; B29C48/9115; B29C48/912
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
141 words
An apparatus for cooling polymer film prepared by the trapped bubble process, wherein a polymer tube is extruded from a die and radially distended to form a blown polymer film in tubular form, the apparatus comprising a closed housing defining a cooling chamber and end openings, said housing adapted to be positioned about the blown polymer film tube with the end openings adapted to be in sliding sealing engagement with said film tube, wherein the film tube itself constitutes an inner wall which further defines the chamber, a liquid coolant spraying means attached to a wall of the housing adjacent an extrusion die orifice, a liquid condensing means, a liquid receiving area in a bottom wall of the housing to receive condensed liquid coolant, and a circulating means adapted to forward coolant from the liquid receiving area to the spraying means.
Claim 2
Independent Claim
141 words
An apparatus for cooling polymer film prepared by the trapped bubble process, wherein a polymer tube is extruded from a die and radially distended to form a blown polymer film in tubular form, the apparatus comprising a closed housing defining a cooling chamber and end openings, said housing adapted to be positioned about the blown polymer film tube with the end openings adapted to be in sliding sealing engagement with said film tube, wherein the film tube itself constitutes an inner wall which further defines the chamber, a liquid coolant spraying means attached to a wall of the housing adjacent an extrusion die orifice, a liquid condensing means, a liquid receiving area in a bottom wall of the housing to receive condensed liquid coolant, and a circulating means adapted to forward coolant from the liquid receiving area to the spraying means.
Claim 3
Dependent Claim
19 words
The apparatus of claim 1 wherein the cooling chamber defined by the closed housing is generally annular in shape.
Claim 4
Dependent Claim
14 words
The apparatus of claim 1 wherein said cooling chamber contains heat exchange conduit members.
Claim 5
Dependent Claim
28 words
The apparatus of claim 1 wherein exterior walls of the housing are in operative combination with a heat exchanger adapted to remove heat from the housing exterior wall.
Claim 6
Independent Claim
193 words
An apparatus for cooling blown polymer film prepared by the trapped bubble process comprising in cooperative combination an extruder having an upwardly extruding annular die for extruding polymeric material in the form of a tube, sets of nip rolls spaced from the die along the axis of the tube for collapsing and closing an end of the tube distal from the die, thereby forming a closed gas space, a film wind-up apparatus spaced from the nip rolls and means for cooling said film comprising a closed housing defining a cooling chamber and end openings, said housing adapted to be positioned about a radially distended polymer film tube with the end openings adapted to be in sliding sealing engagement with said tube, wherein the tube itself constitutes an inner wall which further defines the chamber, a liquid coolant spraying means attached to a wall of the housing adjacent an extrusion die orifice, heat exchange conduit members disposed within the cooling chamber, a liquid receiving area in a bottom wall of the housing to receive condensed liquid coolant and a circulating meand adapted to forward coolant from the liquid receiving area to the spraying means.
Claim 7
Independent Claim
193 words
An apparatus for cooling blown polymer film prepared by the trapped bubble process comprising in cooperative combination an extruder having an upwardly extruding annular die for extruding polymeric material in the form of a tube, sets of nip rolls spaced from the die along the axis of the tube for collapsing and closing an end of the tube distal from the die, thereby forming a closed gas space, a film wind-up apparatus spaced from the nip rolls and means for cooling said film comprising a closed housing defining a cooling chamber and end openings, said housing adapted to be positioned about a radially distended polymer film tube with the end openings adapted to be in sliding sealing engagement with said tube, wherein the tube itself constitutes an inner wall which further defines the chamber, a liquid coolant spraying means attached to a wall of the housing adjacent an extrusion die orifice, heat exchange conduit members disposed within the cooling chamber, a liquid receiving area in a bottom wall of the housing to receive condensed liquid coolant and a circulating meand adapted to forward coolant from the liquid receiving area to the spraying means.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |