The filter element of the hydraulic oil filter in the manufacturer's product sample, or the nameplate is marked with nominal filtration accuracy, rather than absolute filtration accuracy, and only the beta value determined by the test can indicate the filtration capacity of the filter. The filter element of the hydraulic oil filter should also meet the requirements of pressure loss (the total pressure difference of the high pressure filter is less than 0.1PMa, and the total pressure difference of the return oil filter is less than 0.05MPa) to ensure the optimization of the flow rate and the life of the filter element.

1. Filtration accuracy First, determine the cleanliness level of the stain according to the needs of the hydraulic system, and then select the filtration accuracy of the hydraulic oil filter according to the cleanliness level. The most commonly used hydraulic oil filter element in construction machinery has a nominal filtration clarity of 10μm.

The nominal filtration accuracy cannot truly reflect the filtration capacity of the filter element. Therefore, under the specified test conditions, the filter often takes the diameter of the largest hard spherical particle through as its absolute filtration accuracy, which directly reflects the initial filtration capacity of the newly installed filter element.

The most important criterion for evaluating the filter element of the hydraulic oil filter is the beta value measured according to ISO4527-1981E (multi-pass test), that is, the ratio of the number of particles on both sides of the oil inlet and the oil outlet when the oil mixed with the standard test powder is circulated through the filter several times.

2. Flow characteristics: the flow of the filter element through the oil, and the pressure drop is an important parameter of the flow characteristics, should be carried out according to ISO3968-91 standard flow characteristics test, in order to draw the flow - pressure drop characteristics curve. Under the rated oil supply pressure, the total pressure drop (the sum of the pressure drop of the filter shell and the pressure drop of the filter element) should generally be below 0.2MPa.

3. The filter element strength should be rupture-impact resistance test according to ISO2941-83 standard. When the filter element is damaged, the pressure difference that drops sharply should be greater than the specified value.

4. The flow fatigue characteristics should be tested for 100,000 cycles according to ISO3724-90 standards.

5. For the hydraulic oil adaptability test, the pressure flow bearing capacity test should be carried out according to ISO2943-83 standard to verify the compatibility of the filter filter material to the hydraulic oil.