Fabrication integrity point

The differential gas pressure at which the first stream of gas bubbles is emitted from a wetted filter element under standard test conditions.

Fatigue platelets

Normal particles between 20 and 40 microns found in gear box and rolling element bearing oil samples observed by analytical ferrography. A sudden increase in the size and quantity of these particles indicates excessive wear.

Fatigued

A structural failure of the filter medium due to flexing caused by cyclic differential pressure.

Ferrography

An analytical method of assessing machine health by quantifying and examining ferrous wear particles suspended in the lubricant or hydraulic fluid.

Film strength

Property of a lubricant that acts to prevent scuffing or scoring of metal parts.

Filter

Any device or porous substance used as a strainer for cleaning fluids by removing suspended matter.

Filter Efficiency

Method of expressing a filter's ability to trap and retain contaminants of a given size.

Filter element

The porous device, which performs the actual process of filtration.

Filter head

An end closure for the filter case or bowl that contains one or more ports.

Filter housing

A ported enclosure that directs the flow of fluid through the filter element.

Filter life test

A type of filter capacity test in which a clogging contaminant is added to the influent of a filter, under specified test conditions, to produce a given rise in pressure drop across the filter or until a specified reduction of flow is reached. Filter life may be expressed, as test time required reaching terminal conditions at a specified contaminant addition rate.

Filter media, depth

Porous materials, which primarily retain contaminants within a tortuous path, performing the actual process of filtration.

Filter media, surface

Porous materials, which primarily retain contaminants on the influent face, performing the actual process of filtration.

Filtration

The physical or mechanical process of separating insoluble particulate matter from a fluid, such as air or liquid, by passing the fluid through a filter medium that will not allow the particulates to pass through it.

Filtration (Beta) ratio

The ratio of the number of particles greater than a given size in the influent fluid to the number of particles greater than the same size in the effluent fluid.

Fire-resistant fluid

Lubricant used especially in high-temperature or hazardous hydraulic applications. Three common types of fire-resistant fluids are: (1) water-petroleum oil emulsions, in which the water prevents burning of the petroleum constituent; (2) water-glycol fluids; and (3) non-aqueous fluids of low volatility, such as phosphate esters, silicones, and halogenated hydrocarbon-type fluids.

Flow fatigue rating

The ability of a filter element to resist a structural failure of the filter medium due to flexing caused by
cyclic differential pressure.

Flow, laminar

A flow situation in which fluid moves in parallel lamina or layers.

Flow rate

The volume, mass, or weight of a fluid passing through any conductor per unit of time.

Flow, turbulent

A flow situation in which the fluid particles move in a random manner.

Fluid

A general classification including liquids and gases.

Fluid compatibility

The suitability of filtration medium and seal materials for service with the fluid involved.

Fluid, fire resistant

A fluid difficult to ignite which shows little tendency to propagate flame.

Fluid friction

Friction due to the viscosity of fluids.

Fluid opacity

Related to the ability of a fluid to pass light.

Fluid power

Energy transmitted and controlled through use of a pressurized fluid.

Flushing

A fluid circulation process designed to remove contamination from the wetted surfaces of a fluid system.

Force feed lubrication

A system of lubrication in which the lubricant is supplied to the bearing surface under pressure.

Friction

The resisting force encountered at the common boundary between two bodies when, under the action of an external force, one body, moves or tends to move relative to the surface of the other.

FTIR = Fourier Transform Infrared Spectroscopy

A test where infrared light absorption is used for assessing levels of soot, sulfates, oxidation, nitro-oxidation, glycol, fuel, and water contaminants.

Full flow filter

A filter that, under specified conditions, filters all influent flow.

Full-flow filtration

A system of filtration in which the total flow of a circulating fluid system passes through a filter.

Full-fluid-film lubrication

Presence of a continuous lubricating film sufficient to completely separate two surfaces, as distinct from boundary lubrication. Full-fluid-film lubrication is normally hydrodynamic lubrication, whereby the oil adheres to the moving part and is drawn into the area between the sliding surfaces, where it forms a pressure