US Patent 7404705 Blending pump assembly

A blending pump assembly for accurately maintaining the proper ratio of two fluid components. Flow of a first fluid is utilized to drive a fluid motor, which in turn drives a pumping mechanism to inject a proportional amount of a second fluid into the flow of the first fluid. The fluid motor and pump are sized so that a predetermined ratio between the two fluids is maintained regardless of changes in pressure and flow rate of such first fluid.