US3902832A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of blown film
Assignee: GK SYSTEMS Inc
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Filing: 1974-05-09
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Granted: 1975-09-02
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Expires: 1994-05-09
Abstract
Abstract The disclosure is that of an invention directed to the substantially increased production of blown film in which an annular extrusion die is provided with internal coaxial tubes for admitting inflating and cooling air to the formed bubble and exhausting volatiles-containing heat-expanded air from the bubble. Separate blowers are provided for inflation and exhaust; and the coaxial tubes are bodily adjustable axially with respect to the die and relatively axially adjustable with respect to each other. Optical quality of the film is improved by removal of haze-causing condensible volatiles.
Inventors
- 👤 Robert B Gregory
- 👤 Jr Edgar W Irving
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:42
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/78; B29C48/86; B29C48/87; B29C48/03; B29C48/09; B29C48/10; B29C48/30; B29C48/32
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
225 words
A die assembly for the production of blown film including an extrusion die having an annular extrusion slot and means for supplying hot melt plastic to said extrusion slot whereby to extrude therefrom a continuous tube of unset plastic; independently controlled means mounted within said die for introducing inflating and cooling air to the interior of said extruded tube; and independently controlled means mounted within said die for exhausting heated air from the interior of said extruded tube; said extrusion die being provided with an axial bore at a right angle to the plane containing said annular extrusion slot; said air introducing means including a tube coaxially mounted within said bore and having its upper end arranged for discharge of air into a zone in proximity to the plane of tube extrusion and its lower end arranged for connection to a source of air under pressure; said air exhausting means including a tube coaxially mounted within said air introducing tube and having an outside diameter less than the inside diameter of said air introducing tube whereby to define a void therebetween for the passage of said inflating and cooling air, said air exhausting tube having its upper end terminating in a zone above that of the upper end of said air introducing tube and having its lower end arranged for connection to air withdrawing means.
Claim 2
Dependent Claim
225 words
A die assembly for the production of blown film including an extrusion die having an annular extrusion slot and means for supplying hot melt plastic to said extrusion slot whereby to extrude therefrom a continuous tube of unset plastic; independently controlled means mounted within said die for introducing inflating and cooling air to the interior of said extruded tube; and independently controlled means mounted within said die for exhausting heated air from the interior of said extruded tube; said extrusion die being provided with an axial bore at a right angle to the plane containing said annular extrusion slot; said air introducing means including a tube coaxially mounted within said bore and having its upper end arranged for discharge of air into a zone in proximity to the plane of tube extrusion and its lower end arranged for connection to a source of air under pressure; said air exhausting means including a tube coaxially mounted within said air introducing tube and having an outside diameter less than the inside diameter of said air introducing tube whereby to define a void therebetween for the passage of said inflating and cooling air, said air exhausting tube having its upper end terminating in a zone above that of the upper end of said air introducing tube and having its lower end arranged for connection to air withdrawing means.
Claim 3
Dependent Claim
20 words
The die assembly of claim 1 in which said coaxially mounted tubes are axially adjustable relative to said extrusion die.
Claim 4
Dependent Claim
38 words
The die assembly of claim 1 in which said coaxially mounted tubes are bodily axially adjustable relative to said extrusion die and in which one of said coaxially mounted tubes is axially adjustable relative to the other thereof.
Claim 5
Dependent Claim
43 words
The die assembly of claim 3 additionally including means for effecting the bodily axial adjustment of said coaxially mounted tubes relative to said extrusion die; and means for effecting axial adjustment of one of said coaxially mounted tubes relative to the other thereof.
Claim 6
Dependent Claim
69 words
The die assembly of claim 1 in which the upper end of said air introducing tube is provided with an annular outwardly diverging element and in which the upper end portion of said air exhausting tube is provided with an annular radially extending element in juxtaposition to said outwardly diverging element, said elements together defining a nozzle for the radial and upward distribution of said inflating and cooling air.
Claim 7
Dependent Claim
99 words
The die assembly of claim 3 in which the upper end of said air introducing tube is provided with an annular outwardly diverging element and in which the upper end portion of said air exhausting tube is provided with an annular radially extending element in juxtaposition to said outwardly diverging element, said elements together defining a nozzle for the radial and upward distribution of said inflating and cooling air, the relative axial adjustment between said coaxial tubes being effective to vary the spacing between said elements whereby to increase or decrease the rate of air discharge from said nozzle.
Claim 8
Dependent Claim
43 words
The die assembly of claim 6 additionally including means for effecting the bodily axial adjustment of said coaxially mounted tubes relative to said extrusion die; and means for effecting axial adjustment of one of said coaxially mounted tubes relative to the other thereof.
Claim 9
Dependent Claim
25 words
The die assembly of claim 7 in which both of said adjusting means are arranged for external access while said die assembly is in operation.
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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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |