Abstract: A fluid flow meter comprising a shallow rectangular block with first and second faces parallel to each other, a circular opening of selected radius through the block, perpendicular to the faces, an impeller with multiple radial vanes inserted into the central opening, an entrance conduit longitudinally drilled through the block approximately midway between the first and second faces which intersects the circular opening approximately tangentially, a portion of the first face adjacent the circular opening depressed a selected small depth forming a first channel for outflow of fluid. Second conduit means connected to the first channel, and means to cover the first and second faces of the block to seal all openings.