NC State
B.W. Wells. The design and operation of a computer-controlled flow box. In Papermaking Systems and their Control, Trans. of the IVth Fund. Res. Symp. Oxford, 1969, (F. Bolam, ed.), pp 506–508, FRC, Manchester, 2018.


One of the problems encountered during the computerisation of No. 6 machine at Dartford was the need for α flow box control system to replace the existing Hornbostel hole arrangement. The circumstances were such that we required α control system implemented by the computer program (DDC) and the facilities for bumpless transfer to an analog controller arrangement in the event of computer failure.

To attain reliability and simplicity, we limited our investigations to the manipulation of the stock and air pressure supply valves to effect automatic control. Our control objectives were

  1. The minimisation of level and total head variability.
  2. The maintenance of stable control at all times.
  3. The inclusion of efflux ratio control, in the computer controller, to reduce general variability and aid weight changes.

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