Patent attributes
A pressure pump in a primary liquid flow is combined with a pressure exchanger for energy recovery from a secondary liquid flow. A motor-driven rotor portion, including two (primary and secondary) rotatable drum-type cylinder assemblies, is disposed between end blocks configured with input/output ports and cavities forming sliding synchronous reversing valves. Interconnected piston assemblies, including at least one primary piston and one secondary piston, are reciprocated axially by a central angled swash-plate in a progressive sequential manner by rotation of the rotor portion. The combination machine can be optimized for beneficial deployment in a reverse osmosis seawater desalination system to provide unusual simplicity, high efficiency energy recovery from the brine discharge flow and low overall operating cost.