GB1148839A - Pneumatic conveying system for cigarette-making machines - Google Patents

Abstract

1,148,839. Pneumatic conveyers. BROWN & WILLIAMSON TOBACCO CORP. 19 April, 1967 [3 May, 1966], No. 18094/67. Heading B8A. A pneumatic conveying system for automatically conveying tobacco from a feeder 10 to any one of a plurality of cigarette-making machines 12a-12j when the tobacco supply at the one machine falls below a pre-determined level, comprises a feed pipe 14 between the feeder 10 and the machines, a suction blower 20 forcing air through the pipe at a predetermined conveying velocity, and a differential pressure switch 18 in the pipe 14 to control the operation of the feeder. A separator 13a-13j associated with each machine 12a- 12j comprises an inlet controlled by a check valve 30a, an outlet having a solenoid operated suction control valve 32a and a screen between the inlet and outlet to separate the tobacco from the conveying air. With an appropriate drop in tobacco level in a machine hopper below the associated separator, a sensing switch 66 is operated to energize an electric circuit which causes the valve 32a to be opened, whereupon the suction then applied to the separator opens the check valve 30a and closes a flap in the base of the separator. Tobacco accumulating on the flap eventually blocks the separating screen and a switch 72 actuated by a pressure differential across the screen operates to de-energize the electric circuit, whereupon the suction and check valves 32a, 30a close and the flap opens to discharge the tobacco to the machine. A time delay switch is energized with energization of the electric circuit, and deenergizes the circuit after a time nterval to prevent overloading of the separator 13a if the pressure differential switch 72 has not been operated during this time interval. The feeder 10 comprises a feed belt which delivers tobacco to a metering belt upon a low level on the metering belt being sensed. A doffer above the metering belt meters the tobacco fed into the pipe 14. A controlled air bleed 34 in the feed pipe 14 adjacent the machine 13d furthest from the feeder 10, allows air to bleed into the system when any of the other machines are being fed, to provide a two directional supply of air into the machine being fed. A dust separator 24 and air bleed 26 are provided adjacent and upstream of the blower 20. A second feeder 10<SP>1</SP> supplying a different brand of tobacco can be coupled into the system to supply any of the machines disconnected from the feeder 10.