The Effect of Cavitation Corrosion on the Service Life of Volvo Generators

Today, we will briefly introduce the content that pitting corrosion is an important factor affecting the service life and reliability of Volvo generators.

Insufficient oil output from the oil pump: There are two types of oil pumps for diesel generating sets: gear pump and rotor pump. Some gear pumps have a low roughness of the joint surface between the pump cover and the pump body, and the original design did not add a gasket. If a paper gasket is added during maintenance, it will increase the end clearance of the gear and instead reduce the pump's oil output. But there is a gasket at the interface between the pump and the cylinder block. If it is not installed, the pressure oil from the oil pump will leak outward, causing a decrease in oil pressure. Some rotor pumps have chamfers on one side of the outer rotor and no chamfers on the other side. If installed upside down, the oil output can be reduced by 40-60%.

In addition, excessive radial and end face clearance of gears or rotors due to wear can lead to adverse consequences such as reduced oil volume and oil pressure in the diesel generator set of the pump. The repaired oil pump should be tested on a test bench to adjust the opening pressure of the pressure limiting valve to maintain it between 0.5 and 0.7MPa. If the pressure is too high, it will accelerate the wear of the oil pump; If the pressure is too low, it will cause a decrease in the main oil passage pressure. When installing the oil pump, it is necessary to first fill it with engine oil to avoid air in the pump and prevent oil from being sucked in. The connection between the oil pump and the oil suction plate must be sealed, and if there is air leakage, it will also reduce the oil output of the oil pump.

The oil filter of the diesel generator set is blocked: When the oil filter is blocked and the oil cannot pass smoothly, the safety valve located on the filter base will be pushed open, allowing the oil to enter the main oil passage without filtering. But if the opening pressure of the safety valve is too high and cannot be opened in a timely manner, it will increase the internal leakage of the oil pump and reduce the supply of oil to the main oil channel, resulting in a decrease in oil pressure. The oil filter should be maintained on time and the opening pressure of the safety valve should be adjusted correctly to 0.35-0.45MPa.

In addition, if the safety valve spring is aging and the valve seat and steel ball are not tightly sealed, the oil will also leak a lot and cause foam of oil in the oil pan. At this time, the oil stained with foam can be seen by pulling out the dipstick.

Damaged return valve: If the spring of the return valve in the main oil duct is fatigued, softened or improperly adjusted, the mating surface between the valve seat and the steel ball is worn or jammed by dirt, resulting in loose closure, the return oil volume will significantly increase, and the oil pressure in the main oil duct will also decrease.

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