US3847516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for extruding melted polymeric thermoplastic materials
Assignee: Eastman Kodak Co
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Filing: 1972-11-24
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Granted: 1974-11-12
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Expires: 1992-11-24
Abstract
Abstract A molten polymeric plastic such as a sheet of poly (ethylene terephthalate) is extruded under pressure through an orifice while impinging a blast of clean hot air or other gas against the extruded product at the instant it leaves the orifice. Water vapor is introduced into the gas, as by steam injection or water sprays, so as to maintain its humidity at a level corresponding to a dew point of at least 35*F., and preferably 50*-80*F. When casting a sheet of film onto a wheel, die lines are avoided by this process. The apparatus comprises a humidistat for monitoring the humidity of the air fed to the blast, a valve for controlling the injection of steam into the air, and a control system between the humidistat and valve for automatically maintaining the desired humidity.
Inventors
- 👤 E Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:42
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/911; B29C48/9135; B29C48/915; B29C48/917; B29C48/03; B29C48/07; B29C48/08; B29C48/27; B29C48/272; B29C48/914
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
100 words
An apparatus for preventing the occurrence of random die lines in an extruded thermoplastic product comprising in combination: an extrusion die for a thermoplastic product; means for directing gas heated to a desired temperature against the thermoplastic product as it leaves said die; means for supplying said heated gas to said directing means; means in communication with said supplying means upstream of said directing means for increasing the humidity of said heated gas when it falls below a desired level: means within said supplying means for sensing the humidity of said heated gas and cooperating with said humidity increasing means.
Claim 2
Independent Claim
100 words
An apparatus for preventing the occurrence of random die lines in an extruded thermoplastic product comprising in combination: an extrusion die for a thermoplastic product; means for directing gas heated to a desired temperature against the thermoplastic product as it leaves said die; means for supplying said heated gas to said directing means; means in communication with said supplying means upstream of said directing means for increasing the humidity of said heated gas when it falls below a desired level: means within said supplying means for sensing the humidity of said heated gas and cooperating with said humidity increasing means.
Claim 3
Dependent Claim
33 words
An apparatus in accordance with claim 1 wherein said humidity increasing means comprises a source of water vapor and flow control means for controlling the flow of water vapor into said supplying means.
Claim 4
Dependent Claim
36 words
An apparatus in accordance with claim 2 wherein said flow control means is a valve for controlling the flow of water vapor, and further comprising a servo control connected between said sensing means and said valve.
Claim 5
Independent Claim
66 words
An apparatus in accordance with 3 1 wherein said extrusion die has a long narrow orifice for extruding said product as a sheet, wherein said apparatus also comprises a casting wheel adjacent said die for receiving said sheet, and wherein said directing means is so constructed and arranged as to direct said heated gas against the full width of at least one surface of said sheet.
Claim 6
Independent Claim
66 words
An apparatus in accordance with 3 1 wherein said extrusion die has a long narrow orifice for extruding said product as a sheet, wherein said apparatus also comprises a casting wheel adjacent said die for receiving said sheet, and wherein said directing means is so constructed and arranged as to direct said heated gas against the full width of at least one surface of said sheet.
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |