Suction filters are used as safety filters to protect pumps from gross contamination which can cause them to grip. They are available in 3 styles :
- STR series immersed filters
- FAS external filters, for mounting externally above the oil level
- SF2 external filters, for mounting semi-immersed under the oil level
SF2 semi-immersed filters, which shut off oil flow while the filter element is being replaced, replace the butterfly valves usually used for servicing hydraulic pumps.