How to compare filter elements
How to compare filter elements?
The filter industry is in a state of confusion about rating their filters. Customers want a simple way to compare filter elements so the micron ratings system was invented. A micron rating is an arbitrary value assigned to a filter by the manufacturer, not an actual measured value. It quotes a particle size without establishing the filter’s efficiency at removing that size particle.
The type, shape, and size of solids in the fluid to be filtered have an important effect on efficiency. No single filter element can have an optimum removal for all these material forms. Experience has shown that overall filtration efficiency can be improved by combining different types of filter elements. The different properties of the elements complement each other; the upstream element removes specific solids that would otherwise end up on the downstream element. For instance, a stainless steel, back washable strainer can be used to remove solids 10 microns and larger, thereby extending the life of the second filter element.
Since the micron rating cannot be verified, filter manufacturers feel safe in assigning any number that they want. It is not recommended to use micron ratings to compare filter elements.
