ABSOLUTE FILTRATION: The absolute filtration rating, or cut-off point, of a filter refers to the diameter of the largest spherical glass particle, normally expressed in micrometers (mm), which will pass through the filter under laboratory conditions.

BACKWASH: To clean a filter element by reversing the direction of flow through it.

COALESCING FILTRATION: A steady state process whereby aerosols are caused to come together into even larger droplets as they pass through the filter element’s fiber matrix, eventually becoming large enough to be gravitationally drained.

CARTRIDGE: A porous device, usually fitting in a filter housing, which performs the actual process of filtration.

EFFECTIVE AREA: The area of a medium that is exposed to flow and usable for its intended purpose—coalescing, filtering, or separating.

FILTER EFFICIENCY: A method of expressing a filter’s ability to trap and retain contaminants of a given size. Usually given as a percent.

FILTRATION RATING: A measurement of the average size of the pores of the filter medium.

HYDROPHOBIC: Non-water wetting. Having an antagonism for water. Not capable of uniting or mixing with water.

MICRON: A unit of length in the metric system. One-millionth of a meter or 0.000039 of one inch. Contaminant size is usually described in microns.

NOMINAL FILTRATION: The nominal filtration rating refers to a filter capable of cutting off a percentage by weight of solid particles of a specific contaminant (usually again glass beads) greater than a stated micron size, normally expressed in micrometers (mm), i.e. 90 percent of 10 micron.

PLEATED: A filter element whose medium consists of a series of uniform folds and has the geometric shape of a cylinder, cone, disc or plate.

PRE-FILTER: Filter for removing gross contaminate before the product stream enters a separator/filter.

PRESSURE DROP: The difference in pressure between two points, generally at the inlet and outlet of a filter.

SEPARATOR: A device whose primary function is to isolate contaminants by physical properties other than size.

WOVEN: A filter medium made from strands of fiber, thread, or wire interlaced into a cloth on a loom.

Rosedale Products (www.rosedaleproducts.com), a developer of technology for liquid filtration systems, provided the terms and definitions for this word search.