1. In general low-pressure devices with a pressure below 140kg/cm2, it is common to install only a suction filter, but a return filter and an air filter should also be installed.
2. In general medium and high-pressure liquid devices with pressures above 140kg/cm2, return filters are generally used to control the pollution concentration. However, when there are special requirements for reliability, a high-pressure pipeline filter should be used together.
3. To increase their reliability, electromagnetic proportional control valves or micro-flow adjustment valves should be equipped with terminal filters.
4. When using a servo valve, efforts should be made to reduce the pollution concentration of the system. Therefore, high-pressure and return filters should be used together; when the capacity is large, a circulation filter should be installed, and a terminal filter should be installed on the auxiliary pipeline.