6.2.4 Jacking-oil pumps and priming pumps
The jacking oil pumps deliver oil at around 300 bar to the individual bearings. The pumps used are motor-driven positive displacement and either multi-plunger pumps or two-shaft gear pumps, see Figs 2.57 and 2.58.
The arrangement utilises either one gear pump per bearing or one motor/pump unit for either one or two bearings. The pumps require a positive suction pressure. The multi-plunger pumps are fed from the lubricating oil manifold and the gear pumps have a motor-driven positive displacement two-shaft gear pump.
On some designs the turning gear is provided with a separate jacking oil pump. This pump is a motor driven, positive displacement, two-shaft gear pump; the discharge pressure is the same as for the other jacking oil pumps.