US3822977A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for making plastic film
Assignee: Reynolds Metals Co
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Filing: 1973-04-02
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Granted: 1974-07-09
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Expires: 1993-04-02
Abstract
Abstract Plastic film is made using a heat transfer liquid circulated through the film extrusion die to control (by either heating or cooling, as required) the temperature of the plastic melt flowing through such die. A plastic bubble emerging at the outlet of the die is inflated and ventilated by continuously circulated gas which is controlled in temperature as it enters and leaves the bubble so that it does not adversely affect the temperature of the melt in the die.
Inventors
- 👤 D Hinrichs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:32
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/78; B29C48/86; B29C48/87; B29C48/03; B29C48/07; B29C48/08; B29C48/09; B29C48/10; B29C48/30; B29C48/32; B29C48/33; B29C48/80; B29C48/83; B29C48/832; B29C48/865
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
172 words
An apparatus for making plastic film comprising, an extrusion die having an inlet, a plurality of spaced channels in said die communicating with said inlet, an annular outlet communicating with said channels, said die being adapted to receive a plastic melt in said inlet which is separated into spaced strands in said channels and combined prior to exiting said outlet, means providing said plastic melt to said inlet under pressure causing the extrusion of a plastic tube closeable at a position spaced from said outlet, means for supplying a gas through said die to inflate said tube to form a plastic bubble which is used to define said film, heat transfer means in said die comprising a plurality of spaced passages extending adjacent and parallel to said spaced channels, and a system for providing a heat transfer fluid at a controlled temperature and flow through said heat transfer means to control the temperature of said melt by either heating or cooling thereof and thereby more precisely control the flow of said melt.
Claim 2
Independent Claim
172 words
An apparatus for making plastic film comprising, an extrusion die having an inlet, a plurality of spaced channels in said die communicating with said inlet, an annular outlet communicating with said channels, said die being adapted to receive a plastic melt in said inlet which is separated into spaced strands in said channels and combined prior to exiting said outlet, means providing said plastic melt to said inlet under pressure causing the extrusion of a plastic tube closeable at a position spaced from said outlet, means for supplying a gas through said die to inflate said tube to form a plastic bubble which is used to define said film, heat transfer means in said die comprising a plurality of spaced passages extending adjacent and parallel to said spaced channels, and a system for providing a heat transfer fluid at a controlled temperature and flow through said heat transfer means to control the temperature of said melt by either heating or cooling thereof and thereby more precisely control the flow of said melt.
Claim 3
Dependent Claim
24 words
An apparatus as set forth in claim 1 in which said spaced channels comprise a plurality of parallel channels extending axially through said die.
Claim 4
Dependent Claim
36 words
An apparatus as set forth in claim 2 in which said die has an inlet portion, an outlet portion, and a central portion arranged therebetween and said plurality of spaced passages extend through said central portion.
Claim 5
Dependent Claim
29 words
An apparatus as set forth in claim 1 in which said system comprises a system for providing a liquid which is capable of either heating or cooling said melt.
Claim 6
Independent Claim
132 words
An apparatus for making plastic film comprising, an extrusion die having an inlet and an annular outlet, means providing a plastic melt to said inlet under pressure causing the extrusion of a plastic tube closeable at a position spaced from said outlet, means for supplying a gas through said die to inflate said tube to form a thinwalled plastic bubble which is used to define said film, heat transfer means provided as an integral part of said die for controlling the temperature of said gas passing through said die, and a system for providing a heat transfer fluid at a controlled temperature and flow through said heat transfer means to control the temperature of said melt by either heating or cooling thereof and thereby more precisely control the flow of said melt.
Claim 7
Independent Claim
132 words
An apparatus for making plastic film comprising, an extrusion die having an inlet and an annular outlet, means providing a plastic melt to said inlet under pressure causing the extrusion of a plastic tube closeable at a position spaced from said outlet, means for supplying a gas through said die to inflate said tube to form a thinwalled plastic bubble which is used to define said film, heat transfer means provided as an integral part of said die for controlling the temperature of said gas passing through said die, and a system for providing a heat transfer fluid at a controlled temperature and flow through said heat transfer means to control the temperature of said melt by either heating or cooling thereof and thereby more precisely control the flow of said melt.
Claim 8
Dependent Claim
30 words
An apparatus as set forth in claim 5 in which said system comprises a system for providing a liquid which is also capable of either heating or cooling said gas.
Claim 9
Dependent Claim
177 words
In combination: a die for extruding plastic film having an inlet, an annular outlet, and integral heat transfer means comprising a plurality of liquid-coveying passages in said die; means providing a plastic melt under pressure to said inlet causing the extrusion of a plastic tube from said outlet; said tube being closeable at a position spaced from said outlet; means for supplying a gas through said die to inflate said tube to form a plastic bubble which is used to define said film; a plurality of gasconveying passages in said die for receiving gas exiting said bubble, said gas-conveying passages being arranged adjacent and parallel to portions of said liquid-conveying passages; a heat transfer liquid; a system for providing said liquid through said liquid-conveying passages and heat transfer means; and means for controlling the temperature and flow of said liquid to control the temperature and flow of said melt while simultaneously heating said exiting gas to a temperature which prevents cooling of said melt upon flowing said exiting gas adjacent said melt and out of said die.
Claim 10
Dependent Claim
177 words
In combination: a die for extruding plastic film having an inlet, an annular outlet, and integral heat transfer means comprising a plurality of liquid-coveying passages in said die; means providing a plastic melt under pressure to said inlet causing the extrusion of a plastic tube from said outlet; said tube being closeable at a position spaced from said outlet; means for supplying a gas through said die to inflate said tube to form a plastic bubble which is used to define said film; a plurality of gasconveying passages in said die for receiving gas exiting said bubble, said gas-conveying passages being arranged adjacent and parallel to portions of said liquid-conveying passages; a heat transfer liquid; a system for providing said liquid through said liquid-conveying passages and heat transfer means; and means for controlling the temperature and flow of said liquid to control the temperature and flow of said melt while simultaneously heating said exiting gas to a temperature which prevents cooling of said melt upon flowing said exiting gas adjacent said melt and out of said die.
Claim 11
Dependent Claim
159 words
A die for extruding plastic film, comprising an inlet opening for receiving a plastic melt under pressure, a passage communicating with said inlet opening, a plurality of spaced channels having inlet ends communicating with said passage, and an annulus having an inlet end communicating with the outlet ends of said channels and a discharge orifice for extruding the melt in tubular form, a first series of passages through the die extending inwardly between said channels and thence out of a portion of the die surrounded by said annulus, said first series of passages being adapted to supply heated gas continuously to inflate the tubular film emerging from the orifice, and a second series of passages extending through a portion of the die surrounded by said annulus and thence outwardly between said channels, said second series of passages being adapted to withdraw gas continuously from within the inflated tubular film and thereby control the gaseous content of the inflated film.
Claim 12
Dependent Claim
159 words
A die for extruding plastic film, comprising an inlet opening for receiving a plastic melt under pressure, a passage communicating with said inlet opening, a plurality of spaced channels having inlet ends communicating with said passage, and an annulus having an inlet end communicating with the outlet ends of said channels and a discharge orifice for extruding the melt in tubular form, a first series of passages through the die extending inwardly between said channels and thence out of a portion of the die surrounded by said annulus, said first series of passages being adapted to supply heated gas continuously to inflate the tubular film emerging from the orifice, and a second series of passages extending through a portion of the die surrounded by said annulus and thence outwardly between said channels, said second series of passages being adapted to withdraw gas continuously from within the inflated tubular film and thereby control the gaseous content of the inflated film.
Claim 13
Dependent Claim
23 words
The die of claim 8, in which each gas passage is substantially equidistant between the pair of adjacent channels through which it passes.
Claim 14
Dependent Claim
21 words
The die of claim 9, in which the gas inlet passages and gas outlet passages pass between different pairs of channels.
Claim 15
Independent Claim
321 words
An apparatus for making plastic film, comprising; an extrusion die having an inlet; a passage in said die communicating with said inlet; a stranding chamber in said die adjoining the peripheral edge of said passage; a plurality of spaced substantially axially extending channels in said die communicating with said stranding chamber and each having a discharge end; a combining chamber in said die communicating with the discharge end of each spaced channel; each of said chambers having an undulating peripheral surface defined by a plurality of substantially V-shaped surfaces interconnected at their bases by arcuate surfaces with each arcuate surface being aligned with an associated end portion of an associated chaNnel; an annular discharge orifice in said die communicating with said combining chamber; means providing a plastic melt to said inlet under pressure causing the extrusion of a plastic tube from said orifice which is closeable at a position spaced from said outlet; said plastic melt being received in said inlet as a solid column which is spread radially in said passage, separated into spaced strands in said channels, combined in said combining chamber to effectively minimize uneven flow rates in different parts of said die, and extruded from said orifice to define said plastic tube; said V-shaped surfaces in said stranding chamber providing smooth converging flow of plastic melt into said channels and said V-shaped surfaces in said combining chamber providing smooth diverging flow of said melt into an annular passage communicating with said annular discharge orifice; means for supplying a gas through said die to inflate said tube to form a plastic bubble which is used to define said film; heat transfer means in said die comprising a plurality of spaced passages extending adjacent and parallel to said spaced cahnnels; and a system for providing a heat transfer liquid at a controlled temperature and flow through said heat transfer means to control the temperature and flow of said melt.
Claim 16
Independent Claim
321 words
An apparatus for making plastic film, comprising; an extrusion die having an inlet; a passage in said die communicating with said inlet; a stranding chamber in said die adjoining the peripheral edge of said passage; a plurality of spaced substantially axially extending channels in said die communicating with said stranding chamber and each having a discharge end; a combining chamber in said die communicating with the discharge end of each spaced channel; each of said chambers having an undulating peripheral surface defined by a plurality of substantially V-shaped surfaces interconnected at their bases by arcuate surfaces with each arcuate surface being aligned with an associated end portion of an associated chaNnel; an annular discharge orifice in said die communicating with said combining chamber; means providing a plastic melt to said inlet under pressure causing the extrusion of a plastic tube from said orifice which is closeable at a position spaced from said outlet; said plastic melt being received in said inlet as a solid column which is spread radially in said passage, separated into spaced strands in said channels, combined in said combining chamber to effectively minimize uneven flow rates in different parts of said die, and extruded from said orifice to define said plastic tube; said V-shaped surfaces in said stranding chamber providing smooth converging flow of plastic melt into said channels and said V-shaped surfaces in said combining chamber providing smooth diverging flow of said melt into an annular passage communicating with said annular discharge orifice; means for supplying a gas through said die to inflate said tube to form a plastic bubble which is used to define said film; heat transfer means in said die comprising a plurality of spaced passages extending adjacent and parallel to said spaced cahnnels; and a system for providing a heat transfer liquid at a controlled temperature and flow through said heat transfer means to control the temperature and flow of said melt.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |