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Obliteration -- a synergistic phenomenon of both particle silting and polar adhesion. When water and silt particles co-exist in a fluid containing long-chain molecules, the tendency for valves to undergo obliteration increases. OEM -- Original Equipment Manufacturer Oil -- a greasy, unctuous liquid of vegetable, animal, mineral or synthetic origin. Oiler -- a device for once-through lubrication. Three common types of oilers are: drop-feed, wick-feed, and bottle feed; all depend on gravity to induce a metered flow of oil to the bearing. Oiliness -- that property of a lubricant that produces low friction under conditions of boundary lubrication. The lower the friction, the greater the oiliness. Oiliness agent -- a polar compound used to increase the lubricity of a lubricating oil and aid in preventing wear and scoring under conditions of mild boundary lubrication. Oil ring -- a loose ring, the inner surface of which rides a shaft or journal and dips into a reservoir of lubricant from which it carries the lubricant to the top of a bearing by its rotation with the shaft. Open bubble point (boil point) -- the differential gas pressure at which gas bubbles are profusely emitted from the entire surface of a wetted filter element under specified test conditions. Organic compound -- a large class of chemical compounds whose molecules contain carbon and hydrogen. Oxidation -- occurs when oxygen attacks petroleum fluids. The process is accelerated by heat, light, metal catalysts and the presence of water, acids, or solid contaminants. It leads to increased viscosity and deposit formation. Oxidation inhibitor -- substance added in small quantities to a petroleum product to increase its oxidation resistance, thereby lengthening its service or storage life; also called anti-oxidant. An oxidation inhibitor may work in one of these ways: (1) by combining with and modifying peroxides (initial oxidation products) to render them harmless, (2) by decomposing the peroxides, or (3) by rendering an oxidation catalyst inert. Oxidation stability -- ability of a lubricant to resist natural degradation upon contact with oxygen. Oxidative degradation -- most common in small systems, oxidative degradation is the reaction of oxygen (in air) with fluid the reaction of which creates polymers or solids. These thicken the fluid and increase its viscosity. A more viscous fluid will be more difficult to pump, have poorer heat transfer characteristics as well as an increased chance of coke formation. Oxidation is also accompanied by an increase in the acidity (Total Acid Number TAN) of the fluid. Oxidation occurs more rapidly as the temperature is increased. At room temperature, the reaction rate is hardly measurable, however, at temperatures greater than 80°C the oxidation rate doubles with every 10°C increase in temperature. Paper chromatography -- a method which involves placing a drop of fluid on a permeable piece of paper and noting the development and nature of the halos, or rings, surrounding the drop through time. The roots of this test can be traced to the 1940s, when railroads used the "blotter spot" tests. Paraffinic -- a type of petroleum fluid derived from paraffinic crude oil and containing a high proportion of straight chain saturated hydrocarbons. Often susceptible to cold flow problems. Particle count -- the number of particles present greater than a particular micron size per unit volume of fluid. Particle density -- an important parameter in establishing an entrained particle's potential to impinge on control surfaces and cause erosion. Particle erosion -- occurs when fluid-entrained particles moving at high velocity pass through orifices or impinge on metering surfaces or sharp angle turns. Particle impingement erosion -- a particulate wear process where high velocity, fluid-entrained particles are directed at target surfaces. Patch test -- a method by which a specified volume of fluid is filtered through a membrane filter of known pore structure. All particulate matter in excess of an "average size," determined by the membrane characteristics, is retained on its surface. Thus, the membrane is discolored by an amount proportional to the particulate level of the fluid sample. Visually comparing the test filter with standard patches of known contamination levels determines acceptability for a given fluid. Penetration (Grease) -- measurement of the consistency of grease with a penetrometer. The penetration is reported as tenths of a millimeter that a standard cone, by gravity, will penetrate the grease sample. Periodic Table of the Elements -- The periodic table of the chemical elements, also called the Mendeleev periodic table, is a tabular display of the known chemical elements. First created by Dmitri Mendeleev, the elements are arranged by electron structure so that many chemical properties vary regularly across the table. Each element is listed by its atomic number and chemical symbol. The Periodic Table is an arrangement of elements in a geometric pattern designed to represent the periodic law by aligning elements into periods and groups. Elements with the same number of orbitals are in the same period and elements with the same number of electrons in the filling orbital and have other similar properties are in the same group. Permeability -- the relationship of flow per unit area to differential pressure across a filter medium. pH -- measurement of the acidity or alkalinity of an aqueous solution. The pH scale ranges from 0 (very acidic) to 14 (very alkaline) with a pH of 7 indicating a neutral solution equivalent to the pH of distilled water. Phosphate ester -- a synthetic lubricant that has superior fire resistance. A phosphate ester though generally has poor hydrolytic stability, poor compatibility with mineral oil and low viscosity index. Primarily used as a fire-resistant hydraulic fluid. Phosphorous (P) -- element number 15 on the periodic table of the elements. In the context of oil analysis phosphorus can be present as a contaminant in various sampled components and the origins can be from such sources as: oil additives and cleaning detergents just to name a few. Pinion -- the smaller of two mating or meshing gears; can be either the driving or the driven gear. Pitting -- a form of extremely localized attack characterized by holes in the metal. Pitting is one of the most destructive and insidious forms of corrosion. Depending on the environment and the material, a pit may take months, or even years, to become visible. Pleated filter -- a filter element whose medium consists of a series of uniform folds and has the geometric form of a cylinder, cone, disc, plate, etc. Synonymous with "convoluted" and "corrugated". Pneumatics -- engineering science pertaining to gaseous pressure and flow.
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