US4069292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure control in tubular thermoplastic extrusion
Assignee: Mobil Oil AS
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Filing: 1975-10-17
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Granted: 1978-01-17
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Expires: 1995-10-17
Abstract
Abstract A method for continuously controlling the internal bubble pressure in a tubular thermoplastic film extrusion process which comprises a pressure sensor device which feeds a signal to a pressure controller. In response to the signal the pressure controller feeds a proportional signal to an air valve member which, dependent upon the signal, either increases or decreases air flow into the bubble. A poppet valve, in direct communication with the air pressure inside the bubble, opens to rapidly exhaust air to the atmosphere when the pressure inside the bubble exceeds a set maximum.
Inventors
- 👤 F. John Herrington
- 👤 Gordon P. Hungerford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:30
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/885; B29C48/03; B29C48/09; B29C48/10; B29C48/89; B29C48/911; B29C48/9115; B29C48/912; B29C48/92; G; G05; G05D; G05D16/00; G05D16/14; G05D16/18; G05D16/185; G05D16/20; G05D16/2006; G05D16/2013; G05D16/2026; G05D16/204; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92019; B29C2948/92323; B29C2948/92476; B29C2948/92504; B29C2948/92514; B29C2948/92609; B29C2948/92619; B29C2948/92657; B29C2948/92819; B29C2948/92942; B29C2948/92971; B29C48/001; B29C48/0018; B29C48/0019; Y; Y10; Y10T; Y10T137/00; Y10T137/3584; Y10T137/36; Y10T137/7722; Y10T137/7758; Y10T137/7761
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
163 words
A method for controlling internal air pressure within a tubular thermoplastic film bubble which comprises initially inflating said bubble with air under pressure until a desired internal pressure is achieved, continuously sensing and monitoring said internal pressure by means of a pressure sensor device in communication with the interior of said bubble, said pressure sensor device continuously sending a signal to a pressure control device, and when said pressure falls below a preselected level actuating an air pressure input valve, said valve being in communication with said control device, a source of air under pressure and the interior of said bubble, whereby makeup air pressure is added to said bubble, and when said air pressure within said bubble is above a pre-selected level, said air pressure is immediately reduced through an exhaust valve in direct communication with said bubble, said exhaust valve being pressure-actuated; and said exhaust valve being responsive to small incremental pressure variations as well as sudden surges of high pressure.
Claim 2
Independent Claim
163 words
A method for controlling internal air pressure within a tubular thermoplastic film bubble which comprises initially inflating said bubble with air under pressure until a desired internal pressure is achieved, continuously sensing and monitoring said internal pressure by means of a pressure sensor device in communication with the interior of said bubble, said pressure sensor device continuously sending a signal to a pressure control device, and when said pressure falls below a preselected level actuating an air pressure input valve, said valve being in communication with said control device, a source of air under pressure and the interior of said bubble, whereby makeup air pressure is added to said bubble, and when said air pressure within said bubble is above a pre-selected level, said air pressure is immediately reduced through an exhaust valve in direct communication with said bubble, said exhaust valve being pressure-actuated; and said exhaust valve being responsive to small incremental pressure variations as well as sudden surges of high pressure.
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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) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |