Check of the status of hydraulic accumulator
Once a system has warmed up, a quick check can be made on the status of an hydraulic accumulator with the flat of the hand. There should always be a significant temperature difference between the gas and the hydraulic oil. The oil/gas split can be detected by the temperature change on the body of the accumulator. If the whole body is the same temperature something has gone severely wrong with the gas bladder.
Installation of hydraulic piston motor
I will present the radial piston motor because I know this type of motor. I serviced this kind of motor on board, bench tested and assembled in the workshop. From practical side I am familiar with this type of hydraulic motor.
Radial piston motor is the most used hydraulic motor. A new one installed should be kept in mind that to be filled with oil, meaning that when the motor is assembled the drain connection must be located on top.
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.