| 摘要 |
PCT No. PCT/FI90/00315 Sec. 371 Date Aug. 25, 1992 Sec. 102(e) Date Aug. 25, 1992 PCT Filed Dec. 28, 1990 PCT Pub. No. WO91/10177 PCT Pub. Date Jul. 11, 1991.The control method is directed to a quality characteristic of the process material, typically to its outlet concentration. In control of the actuator which is a part of feedforward or feedback control of outlet concentration, one takes account of changes of the material volume and flow, in addition to the inlet concentration or control deviation. With this object, at least two of the quantities of inlet flow, outlet flow and material volume are measured or determined and by means of them a variable is further determined with regard to which the control method is invariant. Two alternative variables are presented, one being typically applicable to control of a process with finite distribution of the flow velocity and the other to control of a process with vigorous mixing. By means of a time-variable control method, the controls can also be implemented with time as the independent variable. The invention also relates to devices which implement the control methods presented.
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