A return line filter is positioned in the circuit just before the reservoir. Range of illustration usually found in return line filters is from 40-3 micrometers.

Advantages

1. A return line filter catches the dirt in the system before it enters the reservoir.
2. The filter housing does not operate under full system pressure and is therefore less expensive than a pressure line.
3. Fluid can be filtered fine since system pressure is available to push the fluid through the element.

Disadvantages

1. There is no direct protection for circuit components.
2. In return line full flow filters, flow surges from discharging cylinders,actuators and accumulators must be considered when sizing.
3. Some system components may be affected by the back pressure generated by a return line filter.