There are roughly several differences between the suction filter and the return filter:

1. The position in the system is different (this point need not be repeated).

2. The function is different: the suction filter is dedicated to protect the pump, preventing large particles from entering the pump and causing damage in accidents; the purpose of the oil return filter is to control the oil pollution of the system and keep the oil clean.

3. According to different functions, the selected precision is different: the oil suction filter is generally coarse filtration, with an absolute filtration accuracy of 50~180um; the oil return filter is a fine filtration, and the filtration accuracy is generally<20um.

4. Common structures are different: oil suction filters generally use metal mesh or line gap filter elements; return oil filtration generally uses high-precision filtration, such as fiber filter media folding.

5. The allowable working pressure and pressure drop are different: the suction filter is affected by the suction characteristics of the pump, the initial pressure difference is <=0.003MPa, the maximum pressure difference is <=0.02MPa; and the oil return filter limit pressure difference is generally 0.2~0.35MPa, working Pressure<1MPa.

6. The flow selection principle is different: the suction filter is selected according to the maximum flow of the pump, generally multiplied by a factor of 1.5~2 (note that the actual flow of the filter is selected, and the nominal flow needs to be calculated and converted);

The return oil filter needs to be based on the system's peak return oil flow, such as the differential cylinder return oil, etc., generally multiplied by a factor of 2 to 4 times.