MAN B&W Controllable pitch propeller. Servo oil unit - Hydra Pack
The servo oil unit – Hydra Pack (fig. 9), consists of an oil tank with all components top mounted, to facilitate installation at yard.
Two electrically driven pumps draw oil from the oil tank through a suction filter and deliver high pressure oil to the proportional valve. One of the 2 pumps is in service during normal operation. A sudden change of manoeuvre will start up the second pump. A servo oil pressure adjusting valve ensures minimum servo oil pressure at any time hereby minimizing the electrical power consumption. Maximum system pressure is set on the safety valve.
The return oil is led back to the tank through a cooler and a paper filter. The servo oil unit is equipped with alarms according to the Classification Society as well as necessary pressure and temperature indication.
Fig. 9. Servo oil unit – Hydra Pack
If the servo oil unit cannot be located with maximum oil level below the oil distribution ring the system must incorporate an extra, small drain tank complete with pump, located at a suitable level, below the oil distribution ring the system must incorporate an extra, small drain tank complete with pump, located at a suitable level, below the oil distributor ring drain lines.