Lubricants requirements

The exact amount of lubricant required for extmsion depends on the design of the extmder, the reduction ratio (ie, ratio of the cross-sectional preform area to the cross-sectional area in the die), and the quality of the lubricant. A low lubricant content results in a high extmsion pressure, whereas a high lubricant content causes a poor coalescence and generates defects in the extmdate. 

Some U.S. governmental lubricant requirements for nontactical equipment is now acquired as Commercial Item Descriptions (CID), rather than against specific military numbers. A new classification system for shear-stable, high VI hydraulic fluids was balloted by ASTM in 1994. 

Some of the problems can be solved with specially selected oil grades. Another solution is synthetic oils, but cost is a problem particularly with silicone oils. Alternatives must be reviewed to match service life of the lubricant with lubrication requirements in the compressor. 

In addition, detailed analysis of the chemical and physical properties of different oils used in the plant can, in some cases, allow consolidation or reduction of the number and types of lubricates required to maintain plant equipment. Elimination of unnecessary duplication can reduce required inventory levels and therefore maintenance costs. 

There is a constant effort by both the supplier and consumer of lubricants to reduce the number of grades in use. The various lubricant requirements of plant not only limit the extent of this rationalization but also create the continuing need for a large number of grades with different characteristics. 

The lubrication requirements of gears vary considerably and create the need for specifically formulated products. This, combined with the diversity of automotive and industrial gear types, has led to the introduction of several specifications for gear lubricants (see Figure 52.7). 

A survey of the lubrication requirements, usually carried out by the lubricant supplier, can often be the means of significantly reducing the number of oils and greases in a workshop or factory. The efficiency of lubrication may well be increased, and the economies affected are likely to be substantial. 

The lubrication requirements for single-screw type compressors are not severe, but in oil-flooded rotary units, the oxidizing conditions are extremely severe because fine droplets of oil are mixed intimately with hot compressed air. In some screw-type air compressors, the rotors are gear driven and do not make contact. In others, one rotor drives the other. The heaviest contact loads occur where power is transmitted from the female to the male rotor here the lubricant encounters physical conditions similar to those between mating gear teeth. This arduous combination of circumstances places a great demand on the chemical stability, and lubricating power, of the oil. 

Lubrication requirements vary depending on application and coupling type. Because rigid couplings do not require lubrication, this section discusses lubrication requirements for mechanical-flexing, material-flexing, and combination flexible couplings only. 

LE Small, LL Augsburger. Aspects of the lubrication requirements for an automatic capsule-filling machine. Drug Devel Ind Pharm 4 345-372, 1978. 

Coatings Benefits Teflon More inert closure Flurotech Less lubrication required Purcoat Fewer particulates Silicone Improved machinability... 

Selection of the proper lubricant requires not only knowledge of the specific function which the lubricant is required to perform in the device being lubricated but also consideration of the interactions include chemical processes — such as corrosion of the metal parts... 

Lubricant requirements and specifications. The development of North American classification systems for the SAE began in 1911 on the basis of viscosity alone. In 1947, the API (American Petroleum Institute) developed a performance classification system for engine oils in terms of regular, premium and heavy duty lubricants. By 1952, the API and ASTM (American Society for Testing and Materials) further advanced the system to generally classify engine oils. In 1970, the TRIPARTITE of API, ASTM, and SAE was established to manage a completely new API classification system, see Fig. 2.12 (Haycock, 1993). 

Over the period of approximately 40 years as illustrated in Table 2.10, higher performance output was attained in engines by virtue of design criteria and the availability of enhanced lubricant additives and base fluid technologies (Copan and Richardson, 1992). These achievements have been accomplished with reduced quantities of lubricant required for maintenance and operation. Although the lubricant is a minor overall factor in vehicle operating costs, the investment in technology development has resulted in reduced oil waste and oil consumption, with substantially enhanced vehicle durability. 

New lubricant requirements and specifications of passenger car motor oils. 

The application of branched-chain alcohol diesters in part-synthetic lubricants is covered as one of the ways the petroleum industry is responding to the challenges brought on by the trend toward new smaller cars with more demanding lubricant requirements. 

This list differs from mechanical pump oil requirements primarily in the exclusion of lubricity demands. Because there are no moving parts in a diffusion pump, there are no lubricating requirements whatsoever (within some metal diffusion pumps there may be some rust prevention requirements under certain environments). 

Figure 4.18. Schematic sketching the experimental procedure used in 3D mesoscale self-assembly. Molding of a polyurethane prepolymer in a PDMS master generated polyhedra. Lubricant was added to the polyhedra in a water-filled Morton flask the use of liquid solder as a lubricant required the covering of selected faces with solder-coated copper tape. Axial rotation of the flask provided the agitation needed to cause collisions between liquid-coated pieces. The schematic depicts the formation and self-...

Wang, J. C., and Reynolds, D. J. 1994. The Lubricity Requirement of Low Sulfur Diesel Fuels. SAE Techn. Paper Ser. Warrendale PA Society of Automotive Engineers... 

The acetate yam emerging from the cabinet makes contact with an applicator that provides the lubricant required to reduce both friction and static formation in subsequent operations. With its surface lubricated, the yam passes around a feed roll that determines the rate of withdrawal from the spinning cabinet, and then to any of several desired packaging devices. 

There are three types of lubricants employed in solid dosage form manufacture. The first class of lubricant is the glidant. The flow properties of a powder can be enhanced by the inclusion of a glidant. These are added to overcome powder cohesiveness. The two other classes of lubricant are antiadherent excipients, which reduce the friction between the tablet punch faces and tablet punches, and die wall lubricant excipients, which reduce the friction between the tablet surface and the die wall during and after compaction to enable easy ejection of the tablet. The level of a lubricant required in a tablet is formulation dependent and can be optimized using an instrumented tableting machine. 

The two purposes, of lubricant supply or friction reduction, are of course not entirely distinct, since continuing friction reduction requires a continuing supply of lubricant. The difference lies in the fact that the amount of lubricant required to maintain low friction of the composite itself is relatively small, probably restricted to a film which may be only a few molecules thick. The more general lubrication of a bearing system will require an additional supply of lubricant which is at least sufficient to provide an equivalent film on all the bearing surfaces involved. With the inevitable wastage inherent in movement of lubricant to other surfaces, the lubricant demand will be much greater than for self-lubrication alone. 

Compressibility compression characteristics and the degree of lubrication required vary, depending upon the particle size and grade of sorbitol used. 

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