PURPOSE: To prevent stoppage due to the bridge in a hopper, etc. by detecting the time change of hopper weight detection signals, comparing it with two preset time changes, and controlling the drive power of an injector and a discharger to the maximum value or the minimum value based on this result.
CONSTITUTION: The weight of a weighing hopper 1 is detected by a load cell 7 and is fed to a differentiator 16 and a subtracter 9. The subtracter 9 feeds the difference signal with the preset injection quantity 10 to an injector drive circuit 11. In addition, the differentiator 16 calculates the time change of the weight in the hopper based on the detected weight and feeds it to comparators 18, 20, 22, which compare it with the firstWthird change rate preset values 17, 19, 21. If it is larger than the first preset value 17, a signal switching the output of the injector drive circuit 11 to the minimum drive signal is outputted; if it is smaller than the second and third preset values 19, 21, a signal switching that to the maximum drive signal is outputted respectively. Accordingly, the device stoppage due to abnormality in the hopper is prevented.
MURAMATSU HIROSHI
OOKI EIJI
| JPS5552830A | 1980-04-17 |