Strainers typically remove larger particles that are visible in a liquid or gas, while filters remove contaminants that are often so small, they cannot be seen with the naked eye.
A hydraulic filter is a component within a hydraulic system that removes damaging particulates by forcing hydraulic fluid through a porous filter element. The filter element catches contaminants and prevents them from re-entering the fluid flow and damaging other pieces of equipment further downstream
A hydraulic filter is a component used by hydraulic systems to continuously remove contaminants in the hydraulic oil. This process will purify the hydraulic fluid and protect the system from damages created by the particle contents.
Hydraulic filters protect your hydraulic system components from damage due to contamination of oils or other hydraulic fluid in use caused by particles. Filters are used to filters the return line oil before getting into the tank.