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Hydraulic Power Unit – Light Duty

This Mobile Hydraulic Power Unit is designed to provide a source of hydraulic power for aircraft hydraulic system testing.  The unit can provide up to 15 gpm at 4000 psig with open or closed loop operation.  The unit’s instrumentation includes system pressure, flow and temperature gauges.  The unit is completely self-contained.

Fluid cooling is accomplished through air-to-oil heat exchanger with a direct-driven fan.  The boost pump supplies a sufficient supply of fluid to the main pump.  The main pump is a pressure compensated, variable volume piston pump with load sense.  A flow meter in the main pressure line to the aircraft assures accurate flow readings.  A bypass valve permits setting the main pump flow to a known value before supplying flow to the aircraft.  The same valve also permits the operator to reduce system pressure quickly in case of emergency.

The power unit is capable of open or closed-loop operation.  A panel mounted return bypass valve is used to bleed off return pressure when operating in the aircraft reservoir (closed-loop operation) mode.  A return pressure regulator permits the operator to control the aircraft reservoir fluid level when operating in the hydraulic power unit reservoir (open-loop operation) mode.  A thermal relief valve in the return system protects the system from over-pressurization at shutdown due to thermal expansion of fluid.

The power unit is equipped with a primary and secondary remote control allowing the operator to control main system pressure, direct pressurized fluid to the aircraft, fill or drain aircraft reservoir fluid level and shut the unit off in case of an emergency condition.  The primary control allows the operator to be close to the aircraft during testing or seated in the cockpit.  The secondary remote control has an independent system with the capability to fill or drain accumulators, break system, dampers or other low pressure hydraulic devices.

The power unit includes filter electrical indication to warn the operator of a required filter change.  Safety systems include maximum pressure relief, low boost pressure shutdown, water contamination sensor, over-temp and low fluid warnings.