GB1460015A - Dispensing device and method - Google Patents

Abstract

1460015 Dispensing fluent materials WR GRACE & CO 13 March 1974 [16 March 1973] 12691/73 Heading A4T A device e.g. for applying metered quantities of adhesive cement to can side wall blanks comprises a continuously operable pump having an outlet conduit 1a communicating with an intermittently operable dispensing gun 2 having a needle valve 1, opening of which allows the cement to be dispensed while closing interrupts dispensing. Pelletized or powdered material from a vibratory feeder 8 enters a feed hopper 7 of the pump, which comprises a screw conveyer 1 including a screw 38, slidable axially relative to a driving cog 37 which is driven continuously by a motor 4 during operation, and biased towards the delivery end of a conveyer chamber 39 by a hydraulic ram 40. Heating means 31, (32), (33), Fig. 3b (not shown), is preferably provided around the conveyer chamber 39, controlled by thermocouples 34, (35), (36), and a compression zone of the conveyer 1 leads through a metering zone to an inlet 19 of the gun 2. Blanks are fed continuously along a path 3, and a detector 10 operates to raise a pneumatic piston 25 when a blank reaches the gun 2, thus raising the valve needle 23 and allowing the cement to be dispensed through a nozzle 24 until the end of the blank is sensed. During the closed phases of the gun 2, pressure build-up within the conveyer 1 acts on the ram 40, in opposition to the pressure generated by a pump 41, fluid escape through a relief valve 43 allowing the screw 38 to retract until the gun is once more operated, while a limit switch 46 acts to slow down or interrupt the drive to the screw 38 in the event of full retraction before further dispensing. Alternatively, Fig. 4 (not shown), pressure buildup in the conveyer 1 may be released by a return line (47) from the gun (2<SP>1</SP>) through a gate valve 51 to a decompression zone (48) of the conveyer.