NC State
I.D. McFarlane and W.D. Hoath. Analog simulation study of an airknife coater. In Papermaking Systems and their Control, Trans. of the IVth Fund. Res. Symp. Oxford, 1969, (F. Bolam, ed.), pp 304–320, FRC, Manchester, 2018.


The response of a flow balance coating weight control system to changes in control settings and transient disturbances has been investigated by means of an electronic analog. A non-linear blow-off characteristic, determined experimentally, is shown to give rise to instability in certain conditions. The effect of pipe lags and valve action times can be demonstrated by use of the model; the validity of analog approximations to pure time delays is discussed and corroborated by results obtained with a digital computer simulation technique. The extension of the model to take account of preferential pick-up of moisture by the paper web is described.

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