Dual capacity fluid pump

摘要

A dual capacity pump having at least two gear pump stages with a common fluid inlet passage, each pump stage having a discharge port, the discharge port for one stage communicating with a fluid pressure load through a flow delivery passage and the discharge port for the other stage communicating with the flow delivery passage through a one-way flow valve, and flow control valve means responsive to an operating variable for connecting the discharge side of the other stage to the common fluid inlet passage during operation in a first operating range of low driving speeds for the pump and to said flow delivery passage through the one-way flow valve during operation in a calibrated range of values for the operating variable.