Hydraulic Filters

Hydraulic filters are used for handling petroleum-based oils, emulsions, synthetic hydraulic fluids and lubrication oils. A high percentage of all hydraulic system failures are caused by contaminants in the fluid. Applications include the following, mobile hydraulic including earth moving equipment, excavators, draglines, loaders, tractors, forest industry equipment, refuse vehicles, forklift trucks, mobile cranes, sweepers, airplane towing trucks, and lorries.  Marine applications include lube oil hydraulic filters for ship engines, standard and nonstandard magnetic filters for peripheral equipment, hydraulic winches, and ships' cranes. Off shore applications include oil rigs, stationary and peripheral equipment Industrial: die casting machines, power packs, test rigs, saw mills, mining machines, and lubrication filtration in the steel and paper industries. General industrial applications include die casting machines, power packs, test rigs, saw mills, mining machines, and lubrication filtration in the steel and paper industries.   Configuration, filter type, service limits, element construction, housing material, general features, and environmental parameters are all important specifications to consider when searching for hydraulic filters.

Configuration choices for hydraulic filters include filter element and housing assembly, filter elements only, and housings only.  The filter can be designed to handle petroleum based fluids, synthetic fluids, water, or water-based fluids.  Basic assembly choices for hydraulic filters include in-line, tank-mounted, spin-on, duplex, off-line or recirculating, pressure, return-line, breather, and suction.  Choices for technology types for hydraulic filters include full flow, full flow bypass, and proportional or partial flow.  In a full flow filter all of the fluid that enters the unit passes through the filtering element. The resistance to flow increases as the filter element becomes contaminated. The use of the nonbypassing type of filter eliminates the possibility of contaminated fluid bypassing the filter element and contaminating the entire system.  In a full flow bypass filter a bypass relief valve allows the fluid to bypass the filter element and pass directly through the outlet port in the event that the filter element becomes clogged.  In a proportional or partial flow hydraulic filter only a portion of the fluid flowing through a venturi throat is filtered during each cycle. Constant recirculation through the system will eventually cause all the fluid to pass through the filter element.  The bypass pressure setting is the differential pressure required for the bypass relief valve setting.

Service limits to consider when searching for hydraulic filters include maximum capacity rating, maximum pressure rating, and minimum particle size rating.  The filter element style can be a bag, a basket strainer, or a cartridge.  Choices for element material include wire mesh, cellulose or paper, fiberglass, synthetic fiber, activated clay, water absorption, or magnetic.  Housing materials include aluminum, PVC, steel, and stainless steel.  Additional features to consider when searching for hydraulic filters include integral bypass, high delta P indication, portable filter carts, reusable elements, and disposable elements.  An important environmental parameter to consider when searching for hydraulic filters includes the operating temperature.