Measurement of powder flow in a screw feeder by x-ray penetration image analysis

A method for visualizing powder flow in a screw feeder is proposed using x-ray penetration image analysis. With this method, metal minute particle tracers with high absorption ratios are injected into the powder flow, and the motion of tracers is observed using x-ray penetration. This method yields a time series of powder flow images. It is confirmed for powder flow in a screw feeder that the tracer movement ratio agrees well with that of the powder, and a relative density difference of less than 20 times does not cause any distinct problems with tracer response. The visualization method clarified that the powder inside the feeder travels at about one-third the velocity of the screw movement rate along the transmission direction and the powder flow is highly turbulent and loses speed in the region around the screw blade edge.