How to fix mechanical problems with your loss-in-weight feeder — Part II
A loss-in-weight feeder can accurately meter powders, granules, and pellets in several industries, including foods, chemicals, pharmaceuticals, and plastics. But if the feeder hasn't been installed correctly, mechanical problems can create slight upsets or artificial forces that disturb the weight readings and affect the feedrate. In this two-part article, Part I [which appeared in the December 1998 issue] explains how a loss-in-weight feeder operates, how to recognize symptoms of mechanical problems, and how to run feeder tests. Part II explains how to find and fix mechanical problems with the feeder.
If your loss-in-weight [LIW] feeder fails the weight stability, repeatability, or linearity test, you need to diagnose the underlying mechanical problem [or problems] affecting the feeder's operation. Very often, more than one equipment component can be at fault. And two or three small mechanical problems can combine to produce what looks like one large problem.