| Absolute Rating |
Particle size in micrometers removed at a given efficiency under a manufacturer’s defined test condition. Also an arbitrary term assigned by a manufacturer. Implied is 100%, but more than defined as 98.67%, 99%, 99.9% and 99.99%, according to the manufacturer. GPS defines absolute as 99.98%removal (Beta=5000) as determined by particle counting method. |
| Absorb/Absorption |
The process of a fluid being taken into the pores of a solid. |
| Adsorb/Adsorption |
To collect and hold a fluid on the surface of a solid. |
| Beta Ratio |
The ratio of the number of particles of a given size and larger upstream of a filter to the number of particles of the same size and larger downstream. |
| Bubble Point |
Pressure drop in inches of water required to expect the first steady stream of bubbles from a horizontal disc of wetted filter medium or a filter cartridge immersed in liquid. |
| Bubble Point Test |
A common, nondestructive method used to test the integrity of cartridge construction to compare relative porosities of filter media or to monitor product consistency as a quality control method. |
| Bypass |
Fluid flowing through a passage other than the filter medium and/or leakage around filter media seals. |
| Channeling |
Tendency for contaminant to pass through a low-density area of an inconsistent filter medium or around cartridge seal points. |
| Clarification |
Filtration of liquids containing small quantities of solids. |
| Collapse Pressure |
Pressure across a filter cartridge or bag great enough to cause it to collapse. |
| Colloids |
Suspension of submicron particles in a continuous fluid medium that will not settle out of the medium. |
| Contaminant |
Undesirable insoluble solid or gelatinous particles present in a fluid. |
| Filter Life |
The duration, measured in time or volume, that a filter can operate effectively between replacement and / or cleaning. |
| Density |
Mass per unit volume of a substance under specified condition of temperature and pressure. |
| Depth Media |
Generally, filter media that are thick and provide graded density construction. |
| Differential Pressure / Pressure Drop |
Difference in pressure between two points in a system. In filters, this is usually measured between inlet and outlet service of the filter housing. |
| Dirt Holding Capacity |
The weight of a contaminant fed to the filter during a test to reach a predefined Terminal pressure drop. |
| Double Open End (DOE) |
A filter cartridge configuration such that both ends are open and require housings with knife edge sealing devices. |
| Efficiency |
The ability of the filter medium to remove particles from the fluid stream. |
| Effluent / Filtrate |
The fluid that has passed through the filter. |
| FDA |
To be used for filtration of Foods, Beverages, Drugs or Cosmetics. All filter construction materials must comply with regulations established by the food and drug administration. |
| Filter Media |
Plural of filter medium. |
| Filter Medium |
The permeable material used for a filter that separates particles from a fluid passing through it. |
| Filtration |
Separation of particulate matter from a fluid by passing the fluid through a permeable medium that will trap a percentage of the particulate. |
| Filtration Efficiency |
That fraction of suspended particles retained by the filter. |
| Gauge Pressure |
Pressure greater than atmospheric pressure. |
| Graded Density |
Variation in a cartridge that results in the filter medium being more dense toward the core and less dense towards outside surface. This is useful where a wide range of particle sizes exists because it allows larger particles to be trapped towards the surface and smaller particles towards the core. |
| Hydrophilic |
The tendency of a surface to wet with water. (water loving) |
| Hydrophobic |
The tendency of a surface not to wet with water. (water hating) |
| Immiscible |
Incapable of blending or mixing into a single homogeneous phase. |
| Laminar flow |
Flow rate at which liquid is in a non-turbulent state (10 ft/sec) and should not exceed to maintain filtration integrity and consistency. |
| Mean Filtration Rating |
Average size of pores of filter medium. |
| Media |
Material in a filter element that separates solids from fluid. |
| Media Migration |
Contamination of the effluent by fibers or other material of which the filter is constructed. |
| Micron |
A unit of length. Correct term is micrometer, which is 0.000039 inch. Human eye can see a 40 micrometer particles. |
| Nominal Rating |
Micron size removed at a given efficiency under a manufacturer’s defined test condition. |
| Particle Removal Efficiency |
Removal of particles as a function of size as determined by counting individual particles. |
| Permeability |
The property of a filter medium that permits a fluid to pass through under a pressure differential. |
| Porosity |
A measure of the open area of a filter medium. Some times expressed as a void volume. |
| Single Open End (SOE) |
A filter cartridge configuration such that one end is sealed off by a closed end cap and the opposite end has a 222 o ring, 226 o ring or other seal device. Used in housings that are designed to accept 222 o ring, 226 o ring or other SOE cartridges. |
| Specific Gravity |
Ratio of mass of a solid or a liquid to the mass of an equal volume of distilled water, or of a gas to an volume of air under prescribed temperature and pressure. |
| Surface Media |
Filter media that are thin, cellulosic, micro fiber or membrane material and, due to their construction, generally provide high flow rate, low pressure drop, and high dirt loading capacity. |
| Suspended Solids |
Mixture of solids suspended in a fluid. Expressed in weight or volume. |
| Throughput |
Total volume of a fluid that passes through a filter before it must be replaced. |
| Turbidity |
Measure of the amount of haze or cloudiness caused by fine particles in a fluid. |
| Turbulent Flow |
Flow rate at which laminar flow(10 ft/sec) is exceeded and filtration performance is adversely affected. |
| Uniform Density |
Having the same weight per unit volume of filter media from the upstream to the downstream side of the filter. |
| Unloading |
Tendency for previously collected contaminants to be forced through the filter medium as pressure is increased. |
| Viscosity |
A measure of the resistance to flow of a liquid. Viscosity of a liquid varies appreciably with changes in temperature. |
