Inventors:
Herman P. Schutten - Eden Prairie MN
Danny M. Wakefield - Eden Prairie MN
Donald R. Zimmerer - Eden Prairie MN
David W. Malaney - West Bloomfield MI
Assignee:
Eaton Corporation - Cleveland OH
International Classification:
F04B 112
F01B 300
Abstract:
A rotary pump (10) is disclosed of the type including a rotating cylinder block (25) defining a plurality of cylinders (27), each defining an imaginary axis (a), which are uniformly spaced about an axis of rotation (A) of the cylinder block. A piston (29) is disposed for reciprocation within each cylinder (27) as the cylinder block rotates. The housing defines a fluid inlet (43) and a fluid outlet (45). In open communication with each cylinder (27) is a cylinder port (47), disposed for serial communication with the fluid inlet and fluid outlet as the cylinder block (25) rotates. Each cylinder port (47) defines a leading edge (L) which are disposed randomly relative to their respective imaginary axis (a). As a result, the timing of communication between the leading edges of the cylinder ports (47) and the fluid inlet and fluid outlet comprise a non-repetitive pattern, thus substantially reducing the sound level at the second fundamental frequency of the piston frequency, also substantially improving the quality of the sound during operation of the pump.