Abstract: A device for controlling the flow of fine powders in a quantising machine includes a pinch valve in combination with a fluidiser maintaining a constant head of fluidised powder. A weigh bucket having a plurality of compartments is rotatably mountable to allow simultaneous filling and discharge. Means for delivering charges of fine powders to receivers rapidly with low change in quantity of the charge, have a power-tight system from the charge measuring means to the receiver, and means for venting the air from the receiver. Accurate net weighing machines for rapidly weighing and delivering charges of fine powders incorporate some or all of the above features in an integrated system.