A device used to indicate mud flow from the return line of the well. The key element is a paddle that is mounted on the return flow line with a torque indicating system. This system transmits a signal to an instrument on the rig floor, indicating well flow. The indication is independent of level changes in the mud tank.
A flow meter enables the driller to check pump efficiency, check hole fill-up during trips, spot fluids downhole, predetermine the number of strokes required before fluid or gas from bottom appears at the surface, and be certain the hole is full of mud at all times.