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U.S. Department of Energy
Office of Scientific and Technical Information

Multiple compensating unloading valve circuit

Patent ·
OSTI ID:5689201

A multiple compensating unloading valve circuit including multiple fixed displacement pumps and corresponding compensator unloading valves which are phased so that one pump supplies the fluid demand for the circuit until the demand exceeds that pump's capacity and then another pump adds to the flow to supplier larger flow demands. Thus, a primary pump delivers its output to satisfy low flow requirements while a secondary pump's output is vented to a reservoir. When the primary pump cannot supply the demand, the secondary pump automatically adds to the flow to satisfy larger demands. The compensator unloading valves are closed center and are operated in response to a differential pressure which is created between the primary pump's outlet pressure and the load pressure. The primary pump unloading valve has a differential pressure setting which is greater than the differential pressure setting for the secondary pump unloading valve. This permits phasing of the unloading valves so that the primary pump supplies all of the fluid demand until the demand exceeds that pump's capacity.

Assignee:
J. I. Case Co.
Patent Number(s):
US 4559965
OSTI ID:
5689201
Country of Publication:
United States
Language:
English