Hydraulic filter element are a must in any fluid power system. These devices filter out contamination from the fluid medium, keeping the system running smoothly.
While most such environments are closed, there is always the possibility that plastic and rubber particles from abraded machinery become detached, or that dust and dirt enter the circuit. Rust or other oxidation may occur and damaging chemical compounds may form in the medium. Since over 85% of all system failures are due to contamination, it is extremely important to have high quality hydraulic filters in place.
The type of hydraulic filter like Hydac, PALL, Leemin and others which is appropriate for a given system depends on the nature of contaminants likely to be present. While most filters are put in place to remove particulate matter, air and water can also be concerns. Certain hydraulic filters are able to separate extremely small particles from the medium, in some cases with sizes as tiny as micrometers.
HDYAC hydraulic filter element
What are the different hydraulic filter element media types?
Hydraulic filters come in a variety of materials: wire mesh, stainless steel, microglass, paper, cellulose and 80/20. They may have multiple layers and different backings to meet predetermined performance criteria. Depending on their materials and construction, they may be able to capture surface and/or depth contamination. Here is a look at the different types of hydraulic filter.
Wire mesh filter elements
Made of steel, this type of filter is usually used for surface cleaning. Because of limitations in wire size and construction, it is not able to filter out very fine particles. The main advantage of wire mesh filters is that they have greater longevity than other types, since they may be cleaned and reused. They are typically used with hydraulic fluids, coolants and lubricants.
Stainless steel filter element
The construction of this type of filter is similar to that of wire mesh filters, only stainless steel is used. While this material allows mostly for the capture of coarser particles, it is superior to wire mesh media in that it will not corrode and can withstand higher pressures.
Microglass is often used by Pall for Example.
Microglass hydraulic filters are considered to provide the best filtration quality. They are made by bonding micro-fiberglass material with resin which is randomly set into a multi-layer composite. Because of the finer weave as well as the presence of multiple layers, this type of filter is more efficient at capturing fine particulate matter and has a much greater dirt-holding capacity than wire mesh filters. They are used in systems which are particularly sensitive to contamination, such as servo valves and piston pumps.
Cellulose paper filters
Cellulose paper hydraulic filters are manufactured from resin-impregnated cellulose filter media which is then pleated and assembled into the finished product. While it does not filter as effectively as microglass, nor does it hold much dirt, it is relatively cheap and can be recycled when it is no longer useful.