GB875939A - Improvements in or relating to methods and apparatus for dispensing granular material - Google Patents

Abstract

875,939. Weighing and dispensing apparatus. WAHL, E. A. Jan. 15, 1959 [July 1, 1958], No. 20473/59. Class 143 [Also in Group XXX] A batch of granular or like material is weighed in a de-energized, screw conveyer during one portion of a weighing cycle and discharged therefrom by energizing the screw during another portion of the cycle, the discharged batch entering a continuously running screw conveyer by which it is dispensed over a period of time equal to the duration of the weighing cycle. In the system particularly described an automatically controlled batch weight is discharged into the continuously running screw in each of a series of consecutive weighing cycles and the continuously dispensed material emerges at a uniform rate determined by the weight of each batch and the duration of each cycle. Each batch is weighed in a receptacle 18 whose lower portion incorporates a screw 23, the material being fed from a vibrated hopper 53 via a screw feeder 57. When the required batch weight is attained, beam 11 tilts and breaks switch 74 to de-energize simultaneously the vibrator 62 of the hopper and the motor 61 driving the feed screw 57. The batch is discharged by the subsequent energization of a motor 36 which turns a flexible shaft 33 to rotate the screw 23, an eccentrically mounted transverse member 31 on the shaft of the screw assisting the discharge by vibrating the receptacle 18. The weigh beam 11 is clamped during discharge between a pad 39 and the stem 42 of a solenoid 41 energized at the same time as the motor 36. Each complete weighing cycle comprises the time taken for one revolution of a timing motor 78 which rotates cams 79, 81 acting on switches 76, 77 respectively. In each cycle switch 76 is first closed to initiate feed to the weigher, the switch re-opening after the feed has stopped and remaining open while switch 77 is closed to control the discharge. The screw conveyer 571 into which the weigher discharges is of such length that although fed at one end with discrete batches, the material emerges at the other end at a substantially uniform rate. Specification 815,691 is referred to.