Stock flow control system for feeding a paper machine headbox
Abstract
Abstract Stock feed to a paper machine headbox is controlled by a stock (fan) pump which is controlled to run at variable speeds, the input of stock to the pump originating from a thick stock containing conduit and a conduit containing mixing water. The speed of the pump motor is controlled by a signal from a control element which is responsive to measurements of the stock level or pressure within the headbox and an adjusted value of the forming wire speed. In addition, a thick stock pump located in the thick stock conduit is adjusted to run at a variable speed by a control device which is responsive to signals indicating the pressure drop across an orifice in the thick stock conduit and a signal based on the web speed. Alternatively, the thick stock pump may run at a constant speed and the control device can be used to control an orifice opening or throttling device located in the thick stock conduit between the pressure-drop determining orifice and the stock (fan) pump.
Inventors
- 👤 D Wahren
Bibliographic Details
Claims Analysis
Total Claims: 3References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-17 | 1977-06-18 | 1977-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-17 | 1981-06-18 | 1981-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-17 | 1985-06-18 | 1985-12-18 | $7700.00 | Window Closed / Lapsed |