Glossary


Element Data
GLOSSARY OF FILTER TERMS
ABSOLUTE RATING - The size of microns of the largest spherical particle that will pass through the element.

AREA - The surface exposed to the flow of a fluid.

BAR - A unit of pressure One (1)bar = 14.5 PSI.

BETA RATIO - The ratio of the number of particles greater than a specified micrometer in the influent fluid to the number of particles larger than the specified micrometer in the effluent fluid.

BUBBLE POINT - The differential gas pressure which when applied to a filter element submerged near the surface of a test fluid causes the first steady emission of gas bubbles from the filter element.

BUNA N - a Nitrile rubber seal compound. This is a generic term covering many formulations.

CENTIPOISE - A unit of absolute viscosity. One centipoise equals .01 poise.

CENTISTOKE - A unit of kinematic viscosity. One centistoke equals .01 stoke.

EFFICIENCY - The ability of a filter element to remove/retain a specific artifical contaminant in a specified concentration under controlled test conditions. Efficiency is expressed in percent.

FILTER ELEMENT - A porous device which performs the actual filtration process.

FILTER MEDIA - The porous structure upon which, or in which, fluid system contaminants are trapped.

FLOW FATIGUE RESISTANCE - The ability of a filter medium to resist structural failure or deterioration from cyclic loading.

GPH - Gallons per hour.

GPM - Gallons per minute.

INLINE TYPE FILTER - A filter assembly whose inlet, outlet, and filter element have a common centerline.

MEDIUM - The porous material that performs the actual process of filtration.

MICROMETER OR MICRON - A unit of length. A micrometer is one millionth of a meter or 0.000039" (39 millionths of an inch). Expressed in convenient terms 25 micrometers are approximately equal to one thousandth of an inch (.001").

MULTI-PASS TEST - A test used to determine the Beta Ratio of a filter element.

 COLLAPSE PRESSURE - The minimum differential pressure that a filter element is designed to withstand without permanent deformation.

CYCLE - Filtration interval; length of time filter operates before cleaning.

DELTA (D) P - Pressure drop.

DEGREE OF FILTRATION - A measure of the effiency of a filter element. Expressed in terms of percentage retention of standard contaminants, under defined test conditions (NOMINAL RATING); and the size in microns of the largest hard spherical particle that will pass through the filter element (ABSOLUTE RATING).

DIFFERENTIAL PRESSURE - The difference in pressure between two points in a fluid system usually in filtration systems expressed as P between a housing inlet and outlet.

DISPOSABLE FILTER ELEMENT - A filter element which is not recleanable and is therefore discarded and replaced at the end of its useful life. (Sometimes referred to as throwaway or non-cleanable element).

EFFECTIVE FILTRATION AREA - That area of the fluid medium in a filter element which is exposed to flow.

NOMINAL FILTRATION RATING - An arbitary micrometer value established by a filter manufacturer as a relative indication of aveage filtration capability.

PERMEABILITY - The relationship of flow per unit area to differential pressure across a filter medium.

PHOSPHATE ESTER BASE FLUIDS - Fire-resistant hydraulic fluids.

PSID (P) - Pounds per square inch differential.

PSIG - Pounds per square inch gauge = PSIA minus atmospheric pressure (14.696).

RATED FLOW - The optimum flow rate for which a filter is designed.

SPECIFIC GRAVITY - The ratio of the weight of a given volume of material to the weight of an equal volume of water.

SAYBOLT SECONDS UNIVERSAL - (SSU) A measure of viscosity. The time in seconds for 60 cubic centimeters (cc) of oil to flow through a standard orifice at a specific temperature.

VISCOSITY - A measure of the internal friction or the resistance of a fluid to flow. The standard unit of measure is poise or SSU.

Found In
Criteria
Seal Chart
Beta
Technical
Contamination
Glossary
Viscosity
Tests
Conversion
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