Reciprocating motor with uni-directional fluid flow

A method of operating a double-acting reciprocating motor with a uni-directional flow path, the motor comprising a movable piston disposed within a cylinder between a cylinder head and a cylinder base with a first variable volume chamber formed between said cylinder base and a first piston pressure surface and a second variable volume chamber formed between said cylinder head and a second piston pressure surface, wherein said second piston pressure surface is larger than said first piston pressure surface, a pass-through valve is operable to allow fluid to flow from said first chamber to said second chamber, and an outlet valve is operable to drain fluid from said second chamber, said method comprising:

• introducing the fluid through an inlet port into said first chamber to cause reciprocating motion of said piston;
• closing said pass-through valve and opening said outlet valve when said piston approaches said cylinder base so that fluid pressure within said first chamber causes said piston to move towards said cylinder head while fluid is drained from said second chamber through said outlet valve;
• opening said pass-through valve and closing said outlet valve when said piston approaches said cylinder head so that fluid pressure within said second chamber causes said piston to move towards said cylinder base.