Phosphate ester fire-resistant oil is a high-pressure lubricating oil with a working pressure of 14.7MPA and temperature of 35-45 ℃. The main indicators of oil performance include particle size, acid value, moisture content, and electrical resistivity. These indicators need to be within a certain range of values to indicate that the oil quality is qualified. Otherwise, it will need to be dealt with. Generally, the following indicators can be used as a reference:

High pressure EH oil is an artificially synthesized oil composed of phosphate esters with strong polarity. It is easy to absorb moisture in the air and hydrolyzes when interacting with water, producing acidic phosphate diesters, acidic phosphate monoesters, and phenolic substances. The acidic substances produced by hydrolysis have a catalytic effect on the further hydrolysis of the oil, causing a vicious cycle, which will leads to a rapid decrease in its volume resistivity and a rapid increase in its acid value, resulting the deterioration of oil quality.

When the volume resistivity of EH oil exceeds the standard, it will corrode the servo valve core shoulder and spring tube. Corrosion of the valve core shoulder can lead to increased internal leakage in the servo valve, increased system heat generation, and reduced control accuracy. Corrosion of the spring tube can cause oscillation of the servo valve, leading to fatigue damage of the spring tube and oil leakage of the servo valve.

Based on experience, low volume resistivity of high-pressure EH oil is an important condition for corrosion of servo valves. Controlling the resistivity of EH oil plays an important role in preventing corrosion faults of servo valves. Usually, corrosion failure of servo valves occurs simultaneously on multiple servo valves in the entire system. After the servo valve undergoes corrosion, the valve core and valve sleeve must be replaced, resulting in significant losses.

In summary, it is necessary to strictly control the volume resistivity of EH oil to not exceed the standard, and to ensure that the water in the EH oil does not exceed the standard. Yoyik suggests that when a decrease in the resistivity of the EH oil is detected, the bypass regeneration device of the EH oil system should be immediately put into operation. The structure of the bypass regeneration device consists of a particle precision filter element and a diatomite filter or a two-stage parallel anion exchange filter. If the increase in volume resistivity is not significant, a mobile vacuum oil filter can be put into operation to further regenerate the oil quality of the fuel tank. After filtration, promptly test whether all indicators of the EH oil quality have returned to normal.