1.  Filter accuracy first, according to the need of hydraulic system to determine the degree of cleanliness of the cleaning grade, and then according to this cleanliness class, according to the character table to select the filter accuracy of the hydraulic oil filter. Construction machinery is the most commonly used hydraulic oil filter element in the name of filter cleaning degree is 10μm.

Nominal filter accuracy, cannot truly reflect the filter capacity of the filter. Therefore, often under the specified test conditions, to filter the maximum hard spherical particle diameter, as its absolute filtration precision, to directly reflect the new filter initial filtration capacity.

The main criteria for evaluating the hydraulic oil filter, is based on ISO4527-1981E (multi pass test) determination of the beta value, that mixed standard test powder oil repeatedly through the filter, the number of particles on both sides of the oil inlet and the oil outlet ratio.

2.  Discharge characteristic: The filter through the oil flow, and pressure drop is an important parameter for the flow characteristics, flow characteristics should be tested in accordance with ISO3968-91 standard, to draw the flow rate pressure drop curve. At rated oil pressure, total pressure (pressure drop and pressure drop of filter shell and a filter) shall be 0.2MPa.

3.  Filter element strength, according to the ISO2941-83 standard for cracking - impact test. The filter element is damaged, the sharp drop in the pressure difference should be greater than the specified value.

4.  Flow fatigue characteristics, according to the ISO3724 - 90 standard for the 100 thousand cycles of the fatigue test.