Ship Crane slewing bearing
A sign for me if the slewing bearing of a ship crane is maintained and the maintenance chart is followed is when looking from outside the crane pedestal has spots of grease.
When I was troubleshooting a ship crane before climbing up into the crane house I was looking on the outside crane pedestal to see any dirt of grease. It was the first step in evaluating the maintenance condition of the crane.
Installation of hydraulic pump of a Ship Crane
I will talk about a high pressure hydraulic pump Rexroth A4V of ship cranes. The pump is a straight-type axial piston pump with variable displacement which is controlled by a servo valve mounted on the pump housing.
According to procedure I worked when new pump is installed on the crane an adjustment has to be done. The pumps are controlled by valves which are sealed and should be adjusted by qualified personnel.
Entrapped air in hydraulic systems leads to the phenomenon of cavitation in pumps.
The phenomenon of cavitation is the formation of gaps or voids in a fluid flow creating high local fluid velocity which causes damage on the surface of components such as gear teeth, vanes, and pistons leading to premature pump failure. Because of entrapped air in the pump, the oil tends to get covered with foam.