WHAT WE DO

Glossary of Terms

SAE: Society of Automotive Engineers, an organization serving the automotive industry.

SAE port: A straight thread port used to attach tube and hose fittings. It employs an “O” ring compressed in a wedge-shaped cavity. A standard of the Society of Automotive Engineers J514 and ANSI/B116.1
SAE viscosity: The viscosity classification of a motor oil according to the system developed by the Society of Automotive Engineers and now in general use. “Winter” grades are defined by viscosity measurements at low temperatures and have “W” as a suffix, while “Summer” grades are defined by viscosity at 100°C and have no suffix. Multigrade oils meet both a winter and a summer definition and have designations such as SAE 10W-30, etc.

Sample preparation: fluid factors that can enhance the accuracy of the particulate analysis. Such factors include particle dispersion, particle settling, and sample dilution.

Saturation level: the amount of water that can dissolve in a fluid.

Scoring: Distress marks on sliding metallic surfaces in the form of long, distinct scratches in the direction of motion. Scoring is an advanced stage of scuffing.

Scuffing: abnormal engine wear due to localized welding and fracture. It can be prevented through the use of antiwear, extreme-pressure and friction modifier additives.

Scuffing particles: large twisted and discolored metallic particles resulting from adhesive wear due to complete lubricant film breakdown.

Seal: A device designed to prevent the movement of fluid from one area to another, or to exclude contaminants.

Seal assembly: A group of parts, or a unitized assembly, that includes sealing surfaces, provisions for initial loading, and a secondary sealing mechanism that accommodates the radial and axial movement necessary for installation and operation.

Seal chamber: The area between the seal chamber bore and a shaft in which a mechanical seal is installed.

Seal face : It is either of the two lapped surfaces in a mechanical seal assembly forming the primary seal.

Seal face width: The radial distance from the inside edge to the outside edge of the sealing face.

Seal Swell (rubber swell): The swelling of rubber (or other elastomers) gaskets, or seals when exposed to petroleum, synthetic lubricants, or hydraulic fluids. Seal materials vary widely in their resistance to the effect of such fluids. Some seals are designed so that a moderate amount of swelling improves sealing action.

Semisolid: any substance having the attributes of both a solid and a liquid. Similar to semiliquid but being more closely related to a solid than a liquid. More generally, any substance in which the force required to produce a deformation depends both on the magnitude and on the rate of the deformation.

Severe sliding: Large ferrous particles which are produced by sliding contacts. Trend is important to determine whether abnormal wear is taking place.

Silt: contaminant particles 5 ¦m and less in size.

Silting: a failure generally associated with a valve which movements are restricted due to small particles that have wedged in between critical clearances (e.g., the spool and bore.)
Single-pass test: filter performance tests in which contaminant which passes through a test filter is not allowed to recirculate back to the test filter.

Sintered medium: a metallic or nonmetallic filter medium processed to cause diffusion bonds at all contacting points.

Sleeve bearing: a journal bearing, usually a full journal bearing.

Sloughing off: The release of contaminant from the upstream side of a filter element to the upstream side of the filter enclosure.

Sludge: insoluble material formed as a result either of deterioration reactions in an oil or of contamination of an oil, or both.

Solid: any substance having a definite shape which it does not readily relinquish. More generally, any substance in which the force required to produce a deformation depends upon the magnitude of the deformation rather than upon the rate of deformation.

Solvency: ability of a fluid to dissolve inorganic materials and polymers, which is a function of aromaticity.

Solvent: A material with a strong capability to dissolve a given substance. The most common petroleum solvents are mineral spirits, xylene, toluene, hexane, heptane, and naphthas. Aromatic-type solvents have the highest solvency for organic chemical materials, followed by naphthenes and paraffins. In most applications, the solvent disappears, usually by evaporation, after it has served its purpose. The evaporation rate of a solvent is very important in manufacture.

Solvent Extraction: A refining process used to separate components (unsaturated hydrocarbons) from lube distillates in order to improve the oil’s oxidation stability, viscosity index, and response to additives. The oil and the solvent extraction media are mixed in an extraction tower, resulting in the formation of two phases: a heavy phase consisting of the undesirable unsaturates dissolved in the solvent. And a lighter phase consisting of a high quality oil with some solvent dissolved in it. The phases are separated and the solvent recovered from each by distillation.

Specific gravity: the ratio of the weight of a given volume of material to the weight of an equal volume of water.

Specific gravity (liquid): the ratio of the weight of a given volume of liquid to the weight of an equal volume of water.

Spectrographic analysis: determines the concentration of elements represented in the entrained fluid contaminant.

Spectrographic Oil Analysis Program (SOAP): procedures for extracting fluid samples from operating systems and analyzing them spectrographically for the presence of key elements.

Spindle oil: a light-bodied oil used principally for lubricating textile spindles and for light, high-speed machinery.

Spin-on filter: a throw-away type bowl and element assembly that mates with a permanently installed head.

Splash lubrication: a system of lubrication in which parts of a mechanism dip into and splash the lubricant onto themselves and/or other parts of the mechanism.

Static friction: the force just sufficient to initiate relative motion between two bodies under load. The value of the static friction at the instant relative motion begins is termed break-away friction.

Static seal: A seal between two surfaces which have no relative motion.

Stationary seal: A mechanical seal in which the flexible members do not rotate with the shaft.

Statistical process control (SPC) : The use of control charts to track and eliminate variables in repetitive manufacturing processes, in order to ensure that the product is of consistent and predictable quality. If a chart reveals only chance variations that are inherent in the system, the process is said to be in a state of “statistical control’. If the chart reveals variations traceable to changes in equipment, procedures or workers, the process is said to be “ out of control”. Statistical process control differs from statistical quality control in that the former monitors manufacturing process parameters and the latter monitors product quality parameters.

Stick-slip motion : Erratic, noisy motion characteristic of some machine ways, due to the starting friction encountered by a machine part at each end of its back-and-form (reciprocating) movement. This undesirable effect can be overcome with a way lubricant, which reduces starting friction.

Stoke (St): kinematic measurement of a fluid's resistance to flow defined by the ratio of the fluid's dynamic viscosity to its density.

Straight mineral oil: Petroleum oil containing no additives. Straight mineral oils include such diverse products as low-cost once-through lubricants and thoroughly refined white oils. Most high-quality lubricants, however, contain additives.

Straight oil: A mineral oil containing no additives.

Strainer: a coarse filter element (pore size over approximately 40 ¦m)
Suction filter: a pump intake-line filter in which the fluid is below atmospheric pressure.

Sulfur: A common natural constituent of petroleum products. While certain sulfur compounds are commonly used to improve the EP, or load-carrying, properties of an oil, high sulfur content in a petroleum product may be undesirable as it can be corrosive and create an environmental hazard when burned. For these reasons, sulfur limitations are specified in the quality control of fuels, solvents, etc.

Sulfurized oil: oil to which sulfur or sulfur compounds have been added.

Surface fatigue wear: the formation of surface or subsurface cracks and fatigue crack propagation. It results from cyclic loading of a surface.

Surface filtration: filtration which primarily retains contaminant on the influent surface.

Surface tension: the contractile surface force of a liquid by which it tends to assume a spherical form and to present the least possible surface. It is expressed in dynes/cm or ergs/cm2.

Surfactant: surface-active agent that reduces interfacial tension of a liquid. A surfactant used in a petroleum oil may increase the oil's affinity for metals and other materials.

Surge: a momentary rise of pressure in a circuit.

Switch, pressure: an electric switch operated by fluid pressure.

Synthetic hydrocarbon: oil molecule with superior oxidation quality tailored primarily out of paraffinic materials.

Synthetic lubricant: a lubricant produced by chemical synthesis rather than by extraction or refinement of petroleum to produce a compound with planned and predictable properties.

Synthetic oils: Oils produced by synthesis (chemical reaction) rather than by extraction or refinement. Many (but not all) synthetic oils offer immense advantages in terms of high temperature stability and low temperature fluidity, but are more costly than mineral oils. Major advantage of all synthetic oils is their chemical uniformity.