GB1293880A - Device for discharging and continuously metering quantities of powder onto moving articles - Google Patents

Abstract

1293880 Weighing-apparatus W MÍLLER 17 Nov 1970 54683/70 Heading G1W [Also in Division G3] A device for metering the quantity of powder blown on to moving articles comprises a powder charging and conditioning means 2, a feed and measuring hopper 11 supplied by the means 2 and provided with a filling level limit transmitter 17 which is arranged to provide signals controlling the means 2, a conveyer belt 3 gravity fed by the hopper 11 and means 4, 5, 7 receiving the powder from the conveyer 3 and blowing it on to the articles. The quantity of powder drawn from the hopper 11 is determined continuously by the speed of the conveyer belt 3 (15) which may be driven by an electric motor (16) through a continuously variable gear. The volume rate of flow may be selected by manually setting the speed ratio of the variable speed gear to control the speed of the belt or weighing means (3b, 3c) associated with the conveyer 3 may automatically control the speed of the conveyer 3 and thence the mass flow of powder drawn from the hopper 11. The conveyer 3 (15) dumps the powder in a hopper 4 feeding a pair of turbines 5, 7 operationally connected in tandem to blow the powder through the pipe 9 which may branch into a plurality of tubes terminating in an atomizing chamber. A Venturi jet mounted coaxially in the pipe 9 feeds pressurized air to accelerate the flow of powder. The charging means 2 may be a pneumatically operating suction conveyer or a combination of screws and agitators and its input 2a may comprise conduits through which pressurized air flows or a conveyer screw having an input agitator at its inlet, whereby the powder is homogenized before being metered. A sieve 14 may be provided above the inlet to the hopper 11. Powder for preventing oxidation or scale forming on metallic articles may be applied at rates up to 250 kilogrammes of powder per hour.