An electron in the outer shell of an atom that takes part in forming chemical bonds or in the flow of electrical current.
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RESTRICTOR
A device for producing a deliberate pressure drop or resistance in a line by reducing the cross-sectional flow area.
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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.
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COMPRESSOR
A device which converts mechanical force and motion into pneumatic flow power.
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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.
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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 chemical action that is not completely understood, and occurs when a small relative motion or vibration is accompanied by some loading, in the presence of oxygen.
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BYPASS VALVE
A valve mechanism that assures system fluid flow when a preselected differential pressure across is exceeded; the valve allows all or part of the flow to bypass the filter element.
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LAMINAR FLOW
A flow situation in which fluid moves in parallel lamina or layers.
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BYPASS FILTRATION
A system of filtration in which only a portion of the total flow of a circulating fluid system passes through a filter at any instant or in which a filter having its own circulating pump operates in parallel to the main flow.
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HYDROLYTIC STABILITY
Ability of additives and certain synthetic lubricants to resist chemical decomposition (hydrolysis) in the presence of water.
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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.
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