Patent GB-392010-A (GB)
Title: Weighing apparatus
IPC: G01G13/30
Filed: 1932-07-15
Abstract: 392,010. Automaticfeed weighers. FULLER CO., Catasauqua, Pennsylvania, U.S.A.-(Morrow, J. H. ; Hokendauqua, Pennsylvania, U.S.A.) July 15, 1932, No. 20066. Convention date, Jan. 8. [Class 143.] An apparatus for withdrawing and weighing predetermined batches of bulk material, for example cement, stored in bins, comprises a suspended weigh hopper, means for admitting material from storage into the hopper, the bottom of the hopper being provided with a discharge gate, electrically-operated means for opening the gate, and switches in the circuit of the opening means actuated by an element of the weighing scale, one of which switches maintains the circuit of the opening means open until the predetermined weight of material has been deposited in the hopper and the other switch keeps the same circuit open if material in excess of the predetermined weight is deposited. Cement from a storage bin (not shown) passes to the weigh hopper 3 through a mechanical feeder 1, Fig. 1, comprising a fluted roll 12, Fig. 5, flanked by pivoted plates 17 and vibrated to dislodge adhering cement by the bouncing of an internal ball 26. An electric motor provided with a brake of conventional type drives the feeder. The discharge gate 8 of the hopper 3 comprises a rotary valve 41, Fig. 4, mounted on a shaft 40 and rotated at appropriate times by a motor 47 supported from the valve casing. The valve in the closed position shown in Fig. 4 provides two sealing portions 43, 44, and its shape assists in obtaining a slow discharge of material. The weigh hopper is supported by the usual levers 61 coupled to a tare beam 54 and scale beam 56. Dust is confined by a canvas apron connecting the feeder with the weigh hopper. The operations of the apparatus are controlled by banks of mercury switches, two banks within a housing 53 and another bank on a support 60 rocked by the tare beam 54. Power is supplied through the usual feeders of a three-phase circuit. In starting the apparatus, that is when the weigh hopper 3 is empty and its discharge gate 8 is open, the attendant presses in a "closing" push-button and thus starts the motor 47 at the same time automatically releasing its brake. The motor, operating through a gear wheel 49, turns the rotary discharge valve 41 to the closed position shown in Fig. 4, and is then arrested owing to a stop on the gear wheel displacing the mercury switches in the housing 53. One of the mercury switches opens the circuit of a solenoid (not shown) employed for holding up the end of the scale beam 56 out of contact with a loop 55 carried by the tare beam 54. The released scale beam now falls into the loop and rocks the tare beam which in turn rocks the support 60 carrying its bank of mercury switches. The motor of the feeder 1 is thereby started and cement is delivered to the weigh hopper. Before the charge is completed, the movement of the tare beam resulting from the descent of the weigh hopper causes one of the mercury switches on the support 60 to break the circuit of the feeder motor, and the further feed of cement due to over-running completes the charge, the correct moment of opening of the circuit being obtained by adjusting the inclination of the mercury switch by trial and error methods. The attendant then moves an " opening " push-button switch and if the weight is exact causes a reverse movement of the motor 47 to open the discharge gate 8, the circuits being arranged to ensure a complete opening before the subsequent closure. If an under or an over weight is present one or other of two mercury switches on the support 60 opens the circuit of the " opening " button for the discharge valve and prevents the attendant from discharging the false weighing. When the discharge gate 8 is completely open one of the mercury switches in the housing 53 closes the circuit of a vibrator 113 which is continued in operation by manual pressure on the " opening " button until the attendant observes by a tell-tale 58 that the weigh hopper is completely discharged. A mercury switch operated by the tare beam opens the circuit of the motor 47 until the tare beam returns to equilibrium, that is until the weigh hopper is completely empty. The direction of rotation of the feed roll 12, Fig. 5, may be reversed by manual operation of a three-pole switch.