Copy of `Lubrication and Oil Analysis Dictionary`

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Lubrication and Oil Analysis Dictionary Category: General technical and industrial > Oil terms Date & country: 25/09/2008, USA Words: 421

Elastohydrodynamic lubrication
in rolling element bearings, the elastic deformation of the bearing (flattening) as it rolls, under load, in the bearing race. This momentary flattening improves the hydrodynamic lubrication properties by converting point or line contact to surface-to-surface contact.

Elastomer
A rubber or rubber-like material, both natural and synthetic, used in making a wide variety of products, such as seals and hoses. In oil seals, an elastomer`s chemical composition is a factor in determining its compatibility with a lubricant.

Electrical insulating oil
A high-quality oxidation-resistant oil refined to give long service as a dielectric and coolant for electrical equipment, most commonly transformers. An insulating oil must resist the effects of elevated temperatures, electrical stress, and contact with air, which can lead to sludge formation and loss of insulation properties. It must be kept dry, as water is detrimental to dielectric strength – t...

Electrostatic separator
a separator that removes contaminant from dielectric fluids by applying an electrical charge to the contaminant that is then attracted to a collection device of different electrical charge.

Element (Cartridge)
the porous device that performs the actual process of filtration.

Emission spectrometer
works on the basis that atoms of metallic and other particular elements emit light at characteristic wavelengths when they are excited in a flame, arc, or spark. Excited light is directed through an entrance slit in the spectrometer. This light penetrates the slit, falls on a grate, and is dispersed and reflected. The spectrometer is calibrated by a series of standard samples containing known amou...

Emulsibility
the ability of a non-water-soluble fluid to form an emulsion with water.

Emulsifier
additive that promotes the formation of a stable mixture, or emulsion, of oil and water. Common emulsifiers are: metallic soaps, certain animal and vegetable oils, and various polar compounds.

Emulsion
intimate mixture of oil and water, generally of a milky or cloudy appearance. Emulsions may be of two types: oil-in water (where water is the continuous phase) and water-in-oil (where water is the discontinuous phase).

End cap
a ported or closed cover for the end of a filter element.

Engine deposits
hard or persistent accumulation of sludge, varnish and carbonaceous residues due to blow-by of unburned and partially burned fuel, or the partial breakdown of the crankcase lubricant. Water from the condensation of combustion products, carbon, residues from fuel or lubricating oil additives, dust and metal particles also contribute.

Entrained air
A mechanical mixture of air bubbles having a tendency to separate from the liquid phase.

Environmental contaminant
all material and energy present in and around an operating system, such as dust, air moisture, chemicals, and thermal energy.

EP lubricants
lubricants that impart to rubbing surfaces the ability to carry appreciably greater loads than would be possible with ordinary lubricants without excessive wear or damage.

EP oil
A lubricating oil formulated to withstand extreme pressure (EP) operating conditions.

Erosion
the progressive removal of a machine surface by cavitation or by particle impingement at high velocities.

Externally pressurized seal
A seal that has pressure acting on the seal parts from an external independent source of supply.

Extreme pressure
lubricant additive that prevents sliding metal surfaces from seizing under conditions of extreme pressure. At the high local temperatures associated with metal-to-metal contact, an EP additive combines chemically with the metal to form a surface film that prevents the welding of opposing asperities, and the consequent scoring that is destructive to sliding surfaces under high loads. Reactive compo...

Fabrication integrity point
the differential gas pressure at which the first stream of gas bubbles are emitted from a wetted filter element under standard test conditions.

Face seal
a device that prevents leakage of fluids along rotating shafts. Sealing is accomplished by a stationary primary seal ring bearing against the face of a mating ring mounted on a shaft. Axial pressure maintains the contact between the seal ring and the mating ring.

False brinelling
false brinelling of needle roller bearings is actually a fretting corrosion of the surface since the rollers are the I.D. of the bearing. Although its appearance is similar to that of brinelling, false brinelling is characterized by attrition of the steel, and the load on the bearing is less than that required to produce the resulting impression. It is the result of a combination of mechanical and...

Fat
An animal or vegetable oil which will combine with an alkali to saponify and form a soap.

Fatigue chunks
thick three-dimensional particles exceeding 50 microns indicating severe wear of gear teeth.

Fatigue life
the theoretical number of revolutions (or hours of operation) a bearing will last under a given constant load and speed before the first evidence of fatigue develops on one or more of the components.

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.

Fiber Grease
A grease with a distinctly fibrous structure, which is noticeable when portions of the grease are pulled apart.

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 to reach 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 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 point
the temperature to which a combustible liquid must be heated so that the released vapor will burn continuously when ignited under specified conditions.

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.

Flash point
the temperature to which a combustible liquid must be heated to give off sufficient vapor to form momentarily a flammable mixture with air when a small flame is applied under specified conditions. (ASTM Designation D 92.)

Floc Point
The temperature at which wax or solids separate in an oil

Gage
an instrument or device for measuring, indicating or comparing a physical characteristic.

Galling
a form of wear in which seizing or tearing of the gear or bearing surface occurs.

Gasohol
a blend of 10% anhydrous ethanol (ethyl alcohol) and 90% gasoline, by volume. Used as a motor fuel.

Gear
A machine part which transmits motion and force by means of successively engaging projections, called teeth. The smaller gear of a pair is called the pinion; the larger, the gear. When the pinion is on the driving shaft, the gear set acts as a speed reducer; when the gear drives, the set acts as a speed multiplier. The basic gear type is the spur gear, or straight-tooth gear, with teethe cut paral...

Gear oil
A high-quality oil with good oxidation stability, load-carrying capacity, rust protection, and resistance to foaming, for service in gear housings and enclosed chain drives. Specially formulated industrial EP gear oils are used where highly loaded gear sets or excessive sliding action (as in worm gears) is encountered.

Gearbox
A casing for gear sets that transmit power from one rotating shaft to another. A gear box has a number of functions: it is precisely bored to control gear and shaft alignment, it contains the gear oil, and it protects the gears and lubricant from water, dust, and other environmental contaminants. Gear boxes are used in a wide range of industrial, automotive, and home machinery. Not all gears are e...

Generated contaminant
caused by a deterioration of critical wetted surfaces and materials or by a breakdown of the fluid itself.

GPM
gallons per minute

Graphite
a crystalline form of carbon having a laminar structure, which is used as a lubricant. It may be of natural or synthetic origin.

Gravimetric analysis
a method of analysis whereby the dry weight of contaminant per unit volume of fluid can be measured showing the degree of contamination in terms of milligrams of contaminant per litre of fluid.

Gravity
See Specific Gravity; API Gravity.

Grease
a lubricant composed of an oil or oils thickened with a soap, soaps or other thickener to a semisolid or solid consistency.

Hardness
the resistance of a substance to surface abrasion.

Head
an end closure for the filter case or bowl which contains one or more ports.

Heat exchanger
a device which transfers heat through a conducting wall from one fluid to another.

Heavy Ends
The portions of a petroleum distillate fraction which are highest boiling, and therefore distill over last if the temperature is raised progressively.

Housing
a ported enclosure which directs the flow of fluid through the filter element.

hp or HP
horsepower

HVI
High Viscosity Index, typically from 80 to 110 VI units.

Hydraulic Fluid
fluid serving as the power transmission medium in a hydraulic system. The most commonly used fluids are petroleum oils, synthetic lubricants, oil-water emulsions, and water-glycol mixtures. The principal requirements of a premium hydraulic fluid are proper viscosity, high viscosity index, anti-wear protection (if needed), good oxidation stability, adequate pour point, good demulsibility, rust inhi...

Hydraulic motor
A device which converts hydraulic fluid power into mechanical force and motion by transfer of flow under pressure. It usually provided rotary mechanical motion.

Hydraulic Oil
an oil specially suited for use as either the specific gravity or the API gravity of a liquid.

Hydraulic pump
A device which converts mechanical force and motion into hydraulic fluid power by means of producing flow.

Hydraulic system
A system designed to transmit power through a liquid medium, permitting multiplication of force in accordance with Pascal`s law, which stated that `a pressure exerted on a confined liquid is transmitted undiminished in all directions and acts with equal force on all equal areas.” Hydraulic systems have six basic components: (1) a reservoir to hold the fluid supply; (2) a fluid to transmit the powe...

Hydraulics
engineering science pertaining to liquid pressure and flow.

Hydrocarbons
compounds containing only carbon and hydrogen. Petroleum consists chiefly of hydrocarbons.

Hydrodynamic lubrication
a system of lubrication in which the shape and relative motion of the sliding surfaces causes the formation of a fluid film having sufficient pressure to separate the surfaces.

Hydrofinishing
a process for treating raw extracted base stocks with hydrogen to saturate them for improved stability.

Hydrogenation
In refining, the chemical addition of hydrogen to a hydrocarbon in the presence of a catalyst; a severe form of hydrogen treating. Hydrogenation may be either destructive or non-destructive. In the former case, hydrocarbon chains are ruptured (cracked) and hydrogen is added where the breaks have occurred. In the latter, hydrogen is added to a molecule that is unsaturated with respect ot hydrogen. ...

Hydrolysis
breakdown process that occurs in anhydrous hydraulic fluids as a result of heat, water, and metal catalysts (iron, steel, copper, etc.)

Hydrolytic stability
ability of additives and certain synthetic lubricants to resist chemical decomposition (hydrolysis) in the presence of water.

Hydrometer
an instrument for determining either the specific gravity of a liquid or the API gravity.

Hydrophilic
Compounds with an affinity for water.

Hydrophobic
Compounds that repel water.

Hydrostatic lubrication
a system of lubrication in which the lubricant is supplied under sufficient external pressure to separate the opposing surfaces by a fluid film.

Hypoid gear lubricant
a gear lubricant having extreme pressure characteristics for use with a hypoid type of gear as in the differential of an automobile.

Hypoid Gears
Gears in which the pinion axis intersects the plane of the ring gear at a point below the ring-gear axle and above the outer edge of the ring gear, or above the ring-gear axle and below the outer edge of the ring gear.

ILMA
The Independent Lubricant Manufacturers Association (ILMA) is a trade association of businesses engaged in compounding, blending, formulating, packaging, marketing, and distributing lubricants.

ILSAC
The International Lubricant Standardization and Approval Committee (ILSAC) is a joint committee of AAMA and JAMA members that assists in the development of new minimum oil performance standards.

Image analyzer
a sophisticated microscopic system involving a microscope, a television camera, a dedicated computer, and a viewing monitor similar to a television screen.

Immiscible
incapable of being mixed without separation of phases. Water and petroleum oil are immiscible under most conditions, although they can be made miscible with the addition of an emulsifier.

In-line filter
a filter assembly in which the inlet, outlet and filter element axes are in a straight line.

Incompatible fluids
Fluids which when mixed in a system, will have a deleterious effect on that system, its components or its operation.

Indicator
a device which provides external evidence of sensed phenomena.

Indicator, differential pressure
an indicator which signals the difference in pressure between two points, typically between the upstream and downstream sides of a filter element.

Indicator, pressure
an indicator that signals pressure conditions.

Industrial Lubricant
Any petroleum or synthetic-base fluid or grease commonly used in lubricating industrial equipment, such as gears, turbines, and compressors.

Influent
the fluid entering a component.

Infrared analysis
A form o absorption spectroscopy that identifies organic functional groups present in a used oil sample by measuring their light absorption at specific infrared wavelengths; absorbance is proportional to concentration. The test can indicate additive depletion, the presence of water, hydrocarbon contamination of a synthetic lubricant, oxidation, nitration, and glycol contamination from coolant. Fou...

Infrared spectra
a graph of infrared energy absorbed at various frequencies in the additive region of the infrared spectrum. The current sample, the reference oil and the previous samples are usually compared.

Infrared spectroscopy
an analytical method using infrared absorption for assessing the properties of used oil and certain contaminants suspended therein. See FTIR.

Ingested contaminants
environmental contaminant that ingresses due to the action of the system or machine.

Ingression level
particles added per unit of circulating fluid volume.

Inhibitor
any substance that slows or prevents such chemical reactions as corrosion or oxidation.

Inside-mounted seal
A mechanical seal located inside the seal chamber with the pumped product`s pressure at its O.D.

Insolubles
particles of carbon or agglomerates of carbon and other material. Indicates deposition or dispersant drop-out in an engine. Not serious in a compressor or gearbox unless there has been a rapid increase in these particles.

Intensifier
a device which converts low pressure fluid power into higher pressure fluid power.