Principle of operation.

Accurate metering of bulk solids is achieved using a spiral helix, screw, rotary valve, rotating agitator, vibrating tray or cylindrical stator. Even in the volumetric mode, the feedrate remains constant under the condition of a repeatable fill level and an even bulk density of the powder which provides a continuous filling degree of the metering helix.
 

Important parameters for a precise dosing:

1. Uniform subsequent flow in the hopper by means of agitator and adapted auger shape
2.  Uniform bulk density and feeding in helix and screw by using intromitters.
3. Correct selection of the auger and metering tube

A linear volumetric feeder is also a prerequisite for a good gravimetric feeding.