JPS5772015A - Flow rate control method for constant feed wares - Google Patents

Abstract

PURPOSE:To prevent accumulation of discharge integrated errors by a method wherein weighted materials are discharged from a weighing hopper at a constant speed under the instantaneous flow rate control, during supply to the hopper the control state is maintained at the just previous state, and immediately after the supply period the flow rate control with an integrated value is performed until an error in the discharge amount will be corrected. CONSTITUTION:A weighted value of a weighing device 1 is monitored by a processing unit 12 to calculate a flow rate Qs. A difference e1 between the flow rate Qs and a preset goal flow rate Qr is calculated by a substractor 13. Then, an adjuster 14 outputs voltage V1 that causes the difference e1 to become zero and this voltage V1 is applied via a selection circuit 15 to a motor 4 which is a control object 16. As a lower limit level detector 6 detects the reduction of the weighed materials, the materials are supplied from the weighing hopper 5 to 4. During supply of the materials the processing unit 12 is maintained at the state just prior to the supply by a signal J. Immediately after the supply period, control is performed via the selection circuit 15 and an adjuster 18 until a difference signal e2 between signal from a goal discharge weight calculating section 23 and an integrated discharge amount signal from a processing unit 24 becomes to zero. This permits to prevent accumulation of discharge integrated errors.