GB937797A - Improvements in pneumatic tobacco feed systems - Google Patents

Abstract

937,797. Pneumatic conveyers. VOKES Ltd. Jan. 1, 1962, No. 56/62. Class 78 (1). In a pneumatic conveyer system for feeding charges of tobacco &c. from a single source 8, Fig. 1, to a number of hoppers 1a-1c of utilizing machines in which suction is applied selectively to dischargers 2a-2c according to demand, the necessity for repeatedly removing tobacco from the conveyer lines 9, 10 is avoided by an automatic control system which switches the suction directly from one discharger to any other discharger of a machine from which a demand has been signalled during the time that the first discharger is being filled. Solenoid-operated valves 7 in separate suction lines 5 for each discharger are selectively opened through the control system, Fig. 4, according to demand signalled by flap controlled two-way switches 4a- 4c in the hoppers 1a-1c. The signal from the switch 4a in the first hopper operates a clutch 29 and motor 27 for driving a spring return double-arm selector switch 21, 22 through which a holding circuit R20a, C20a for the solenoid L11a of the selected valve 7 is obtained. Application of suction through the valve 7 operates trip switches 15a, 17a in the discharger, operating to release the double arm selector switch 21, 22 to return to its initial position under spring action. In the event of the switch 4b in the second hopper signalling a demand the selector switch 21, 22 rotates to the relevant contacts. Closure of the holding circuit for the relavant solenoid L11b is however prevented until the filling of the first discharger 2a is completed, causing the level indicator switch 15a to be opened whereupon the solenoid L11a is disconnected and the solenoid L11b placed in circuit. The feeder 8 may be mechanical or fed by hand and the delay circuit for cutting-off the mechanical feed after the required time for clearing the conveyer line is not described.