Calorie
1. The amount of heat required to raise the temperature of 1 gram of water 1°C, at or near the temperature of maximum density. This unit is called a “small calorie”, or “gram calorie.” 2. The amount of heat required to raise the temperature of 1 kilogram of water 1°C. This unit is called a "large calorie" or “kilogram-calorie.”

Cams
Eccentric shafts used in most internal combustion engines to open and close valves.

Capacity
The amount of contaminants a filter will hold before an excessive pressure drop is caused. Most filters have bypass valves which open when a filter reaches its rated capacity.

Capillary Viscometer
A viscometer in which the oil flows through a capillary tube.

Capillarity
A property of a solid-liquid system manifested by the tendency of the liquid in contact with the solid to rise above or fall below the level of the surrounding liquid; this phenomenon is seen in a smallbore (capillary) tube.

Carbon
A non-metallic element - No. 6 in the periodic table. Diamonds and graphite are pure forms of carbon. Carbon is a constituent of all organic compounds. It also occurs in combined form in many inorganic substances; i.e., carbon dioxide, limestone, etc.

Carbon residue
Coked material remaining after an oil has been exposed to high temperatures under controlled conditions.

Carbonyl iron powder
A contaminant which consists of up to 99.5% pure iron spheres.

Case drain filter
A filter located in a line conducting fluid from a pump or motor housing to reservoir.

Catalyst
A substance which speeds a chemical action without undergoing a chemical change itself during the process. Now used in catalytic converters to control amount of unburned hydrocarbons and CO in automobile exhaust.

Catalytic converter
An integral part of vehicle emission control systems since 1975. Oxidizing converters remove hydrocarbons and carbon monoxide (CO) from exhaust gases, while reducing converters control nitrogen oxide (NOx) emissions. Both use noble metal (platinum, palladium or rhodium) catalysts that can be "poisoned" by lead compounds in the fuel or lubricant.

Catastrophic failure
Sudden, unexpected failure of a machine resulting in considerable cost and downtime.

Cavitation
Formation of a n air or vapor bubble due to lowering of pressure in a liquid, often as a result of a solid body, such as a propeller or piston, moving through the liquid; also, the pitting or wearing away of a solid surface as a result of the collapse of a vapor bubble. Cavitation can occur in a hydraulic system as a result of low fluid levels that draw air into the system, producing tiny bubbles that expand explosively at the pump outlet, causing metal erosion and eventual pump destruction.

Cavitation erosion
A material-damaging process which occurs as a result of vaporous cavitation. “Cavitation” refers to the occurrence or formation of gas - or vapor - filled pockets in flowing liquids due to the hydrodynamic generation of low pressure (below atmospheric pressure). This damage results from the hammering action when cavitation bubbles implode in the flow stream. Ultra-high pressures caused by the collapse of the vapor bubbles produce deformation, material failure and, finally, erosion of the surfaces.

Cellulose Media
A filter material made from plant fibers. Because cellulose is a natural material, its fibers are rough in texture and vary in size and shape. Compared to synthetic media, these characteristics create a higher restriction to the flow of fluids.

Centi
Hundredth

Centipoise (cp)
A unit of absolute viscosity. 1 centipoise = 0.01 poise.

Centistoke (cst)
A unit of kinematic viscosity. 1 centistoke = 0.01 stoke.

Centralized lubrication
A system of lubrication in which a metered amount of lubricant or lubricants for the bearing surfaces of a machine or group of machines are supplied from a central location.

Centrifugal separator
A separator that removes immiscible fluid and solid contaminants that have a different specific gravity than the fluid being purified by accelerating the fluid mechanically in a circular path and using the radial acceleration component to isolate these contaminants.

Cetane number (calculated)
The cetane number of distillate fuels as estimated from the API gravity and mid-boiling point by using a formula given in Appendix II of ASTM Method D 975. This estimate is used if a standard test engine is not available, or if the sample is too small for an engine test.

Cetane Number (Test method)
The percentage by volume of normal cetane, in a blend with heptamethylnonae (HMN), which matches the ignition quality of the fuel when compared by the procedure specified in ASTM Method D 613.

Cetane Number Improver
A substance which, when added to a diesel fuel, has the effect of increasing its cetane number. In this class are nitro alkanes, nitrates, nitro carbonates, and peroxides.

Cetane Index
An approximation of cetane number based on API gravity and mid-boiling point of a fuel.

Channeling
1. The phenomenon observed among gear lubricants and greases when they thicken, due to cold weather or other causes, to such an extent that a groove is formed through which the part to be lubricated moves without actually coming in full contact with the lubricant. 2. A term used in percolation filtration; may be defined as a preponderance of flow through certain portions of the clay bed.

Chemical stability
The tendency of a substance or mixture to resist chemical change.

Chip control (grit control, last-chance) filter
A filter intended to prevent only large particles from entering a component immediately downstream.

Chromatography
A method of separation based on selective adsorption. A solution of the substance is allowed to flow slowly through a column of adsorbent. Different substances will pass with different speeds down the column and will eventually be separated into zones. The column core can then be pushed out and the zones of material cut apart, or the zones can be eluted by passing more solvent down the column and collecting it in small fractions.
* Partition chromatography involves the selective solution of the desired material between two solvents. The final solvent, usually water, is used to wet the solid material packed in the column, and the first solvent containing the desired material is poured into the column as described.
* Paper chromatography is a micromethod. A drop of the liquid to be investigated is placed near one end of a strip of paper. This end is immersed in solvent which travels down the paper and distributes the materials present in the original drop selectively. Comparison with known substances makes identification possible.
* Gas chromatography is an analytical technique for separating mixtures of volatile substances. The procedure consists of introducing the mixture to be examined into the chromatographic column and washing it down (eluting it) with an inert gas. The column is packed with adsorbent material which selectively retard the components of the sample.

Circulating lubrication
A system of lubrication in which the lubricant, after having passed through a bearing or group of bearings, is recirculated by means of a pump.

Clean
100 particles >10 micron per milliliter.

Cleanable
A filter element which, when loaded, can be restored by a suitable process, to an acceptable percentage of its original dirt capacity.

Clean room
A facility or enclosure in which air content and other conditions (such as temperature, humidity, and pressure) are controlled and maintained at a specific level by special facilities and operating processes and by trained personnel.

Clearance bearing
A journal bearing in which the radius of the bearing surface is greater than the radius of the journal surface.

Cleveland open-cup COC Tester
Apparatus used in for the determination of flash and fire points of petroleum products flashing above 175°F, with the exception of fuel oils (ASTM Method D 92).

Cloud point
The temperature at which waxy crystals in an oil or fuel form a cloudy appearance.

Coalescor
A separator that divides a mixture or emulsion of two immiscible liquids using the interfacial tension between the two liquids and the difference in wetting of the two liquids on a particular porous medium.

Coefficient of friction
The number obtained by dividing the friction force resisting motion between two bodies by the normal force pressing the bodies together.

Cohesion
That property of a substance that causes it to resist being pulled apart by mechanical means.

Collapse
An inward structural failure of a filter element which can occur due to abnormally high pressure drop (differential pressure) or resistance to flow.

Collapse pressure
The minimum differential pressure that an element is designed to withstand without permanent deformation.

Color
A factor in the identification, rather than in the quality rating of a petroleum product - except where staining or appearance are considerations. See specific types of color under alphabetic listing.

Complex Grease
A lubricating grease thickened by a complex soap and a complexing agent.

Compound
1. chemically speaking, a distinct substance formed by the combination of two or more elements in definite proportions by weight and possessing physical and chemical properties different from those of the combining elements. 2. in petroleum processing, generally connotes fatty oils and similar materials foreign to petroleum added to lubricants to impart special properties.

Compounded oil
A petroleum oil to which has been added other chemical substances.

Compressibility
The change in volume of a unit volume of a fluid when subjected to a unit change of pressure.

Compression ratio
In an internal combustion engine, the ratio of the volume of combustion space at bottom dead center to that at top dead center.

Compressor
A device which converts mechanical force and motion into pneumatic fluid power.

Consistency
The degree to which a semisolid material such as grease resists deformation.(See ASTM designation D 217.) Sometimes used qualitatively to denote viscosity of liquids.

Contaminant
Any foreign or unwanted substance that can have a negative effect on system operation, life or reliability.

Contaminant (Dirt, ACFTD) capacity
The weight of a specified artificial contaminant that must be added to the influent to produce a given differential pressure across a filter at specified conditions. Used as an indication of relative service life.

Contaminant Failure
Any loss of performance due to the presence of contamination. Two basic types of contamination failure are Perceptible - gradual loss of efficiency or performance, and Catastrophic - dramatic, unexpected failure.

Contaminant lock
A particle or fiber-induced jam caused by solid contaminants.

Contamination control
A broad subject which applies to all types of material systems (including both biological and engineering). It is concerned with planning, organizing, managing, and imple-menting all activities required to determine, achieve and maintain a specified contamination level.

Coolant
A fluid used to remove heat. See Cutting fluid.

Copper strip corrosion
A qualitative measure of the tendency of a petroleum product to corrode pure copper.

Copper Dish Gum
The milligrams of gum found in 100 ml of gasoline when evaporated under controlled conditions in a polished copper dish; indicates the potential gum content of a material.

Copper Strip Corrosion
The gradual eating away of copper surfaces as the result of oxidation or other chemical action. It is caused by acids or other corrosive agents.

Core
The internal duct and filter media support.

% Correl
The percentage of peaks in the used oil infrared spectrum which match those in the reference oil. A sudden decrease in this value usually means that the oil was mixed with a different type.

Corrosion
The decay and loss of a metal due to a chemical reaction between the metal and its environment. It is a transformation process in which the metal passes from its elemental form to a combined (or compound) form.

Corrosion inhibitor
Additive for protecting lubricated metal surfaces against chemical attack by water or other contaminants. There are several types of corrosion inhibitors. Polar compounds wet the metal surface preferentially, protecting it with a film of oil. Other compounds may absorb water by incorporating it in a water-in-oil emulsion so that only the oil touches the metal surface. Another type of corrosion inhibitor combines chemically with the metal to present a non-reactive surface.

Coupling, quick disconnect
A coupling which can quickly join or separate lines.

Coupling
A straight connector for fluid lines.

Cracking
The process whereby large molecules are broken down by the application of heat and pressure to form smaller molecules.

Crown
The top of the piston in an internal combustion engine above the fire ring, exposed to direct flame impingement.

Cryogenics
The branch of physics relating to the production and effects of very low temperatures.

Cutting fluid
Any fluid applied to a cutting tool to assist in the cutting operation by cooling, lubricating or other means.

Cycle
A single complete operation consisting of progressive phases starting and ending at the neutral position.

Cylinder
A device which converts fluid power into linear mechanical force and motion. It usually consists of a moveable element such as a piston and piston rod, plunger rod, plunger or ram, operating with in a cylindrical bore.
 
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