Precision Brush Feeders


Terronics' Brush Feeder Technology meters powder and particulate materials in a highly uniform, controllable, and precise manner. Cyclical or instantaneous variation of material feed rates are dramatically reduced compared to other commercial feeders.


Principle of Operation

A flexible soft bristle of diameter roughly approximating the powder particle size is used as the motive means, providing low contact pressure to the particle and the feeder. The brush has a very large number of bristles which provide a very large number of interstitial sites to receive the powder by gravity fill from a bulk reservoir as the brush rotates.


Precision feeding is based on the narrow difference between average-to-peak volumetric fill of the bristles. The very slow rotation of the brush (typically less than 20 RPM) then brings these sites to a "vertical down" position where a combination of gravity and a "flip" mechanism releases and dispenses the powder.


Feed rates are a complex function of several design variables: brush diameter, brush maximum RPM, and bristle type and density, as well as the powder's physical properties. Noteworthy is the linear relationship between RPM and feed rate for most powders, enabling straightforward process control. Specific properties of your powder and desired feed rate ranges can be readily evaluated to produce a suitable design.




A wide range of powders, including fragile surfaces, abrasive-type materials, and heat/pressure reactive powders can be fed and metered with minimal degradation of the powder or the feeder.


Development of the brush feeder was driven by our own internal demand for a precise, controllable method for feeding pressure reactive powder at a very consistent rate. A satisfactory method was not available in other commercial feeding systems. Our brush feeders have been operating since 1994 in various R&D and commercial powder deposition systems.