Hydraulic Power Unit (HPU)
Supplies pressurised oil for hydraulic actuation systems
The Hydraulic Power Unit (HPU) provides pressurised oil to the hydraulic actuation system. A redundant pump system charges the bladder accumulator(s) automatically at a high pressure to utilize the ability of the actuators to store energy. A pressure reducing valve system provides the system with a constant stable system pressure. To ensure the oil cleanliness, supervised filters are installed on the pump and return side. Filtration takes place whenever the pump(s) are running. The HPU is provided with analogue transmitters for oil tank level, temperature and pressure.
- Redundant hydraulic pumps- – Two electrically driven high pressure gear pumps, one operational and one standby. Both may run simultaneously if needed. Each pump is connected to a supervised pressure filter. Changing filter elements can be done during full operation.
- Constant output pressure- – A logical element together with a pilot pressure reducing valve controls the outlet pressure. A pressure relief valve is installed to limit the output system pressure. Output pressure is monitored via a pressure transmitter.
- Surface protection- – As standard, carbon steel parts such as frame, roof and oil tray are painted with corrosion protection for coastal environments with optional coating suitable for seawater areas with high salinity.
- Accumulator system – The HPU can be equipped with 1-3 accumulators, each having a volume of 20-50 litres. The accumulator pressure is monitored via a pressure transmitter, and regulated by the Intelligent Pump Control (IPC). By using a proportional valve to create a smooth transition between charging mode and idling mode, pressure peaks in the system are reduced. A sealed pressure relief valve limits the maximum accumulator pressure. Accumulators are also equipped with burst discs to prevent overpressure in case of fire.
- Intelligent Power Control (IPC) – IPC is mounted and fully installed on the HPU. The IPC controls all the functions of the HPU and communicates with the local Distributed Control System DCS. The IPC is also equipped with a display allowing configuration of minor operating parameters, accessing functions on the HPU and showing its status.