Hydraulic Unit

The main pressure pump is a variable volume, axial piston, pressure compensated unit rated at pressures up to 5000 psi. This pump is normally operated at 3000 psi to provide extended bearing life and long-term, reliable service. Pressure ControlsThe system pressure output is primarily controlled by the pressure compensator adjustment on the main pump. An emergency backup relief valve is installed in the pressure control manifold. It acts as a limit to system pressure in the event of failure of the main compensator control. This emergency backup relief valve has a solenoid operated bypass which allows the system pressure to be vented to a low pressure mode. This mode is used for low-pressure startup and to provide a remotely controlled idle condition for the power supply. An accumulator is provided on the pressure output to damp pump pulsation and meet instantaneous flow demands. A special bleed down and relief circuit prevents vent surges and return line fatigue failures. Local ControlsAdditional controls located on the enclosure door, include: Control power / emergency stop switchMain pump stop / start-low / high pressure switchesHour meter to monitor running timeIndicator lights for low oil level and oil over temperature error conditionsOptional indicators include low oil pressure, oil over temperature warning and electrical filter condition indicatorsOptional combination fused disconnectFiltration SystemThe filtration system is designed to achieve ISO 14 / 11 contaminant level consistent with the protection of critical servo components. A full-flow filter with a 3-micron replaceable element is provided on the pump discharge. An optional return line filter with replaceable element provides 3-micron return oil filtration. The pump case drain flow as well as the output flow during the idle loop mode is circulated through this filter to allow polishing of the system oil to achieve low contaminant levels. A 1-micron air filter prevents airborne contamination from entering the enclosed hydraulic system. All filters are oversized for low pressure drop and increased contaminant capacity, which allows extended maintenance cycles. Heat Exchanger Cooling CircuitAn oil-to-water shell-and-tube heat exchanger is sized to dissipate the full hydraulic heat load. Oil temperature is controlled by a water flow modulating valve that monitors the reservoir temperature. Water flow is limited to that required to maintain the set reservoir temperature while dissipating the full heat load provided by system operation. The heat exchanger is oversized with four-pass cooling to minimize water consumption. Optional Acoustic EnclosureAn insulated sheet metal enclosure is available which provides hinged door and panel access to the components. This enclosure includes a cooling fan module and control to provide a self-contained sound enclosure for the hydraulic pump. The free field sound level is less than 75 dB measured 3 feet from the operator station. Installed levels will vary with the acoustical characteristics of the location and the hydraulic load. The fan module is available with ventilation grilles or with duct adapters for connection to an external air source. * all instrument will chose your idea.