Lubricants Operational conditions

Substantial amounts of EPM are also used as additives to lubrication oils because of its excellent heat and shear stabiHty under the operating conditions of automobile engines. 

Most often, the bearing or the lubricant is blamed for the failure. This is like blaming the fuse for an electrical failure. The failure is most likely a result of some abnormal operating condition, or lack of proper maintenance. In short, something causes the bearing to fail prematurely. 

If the operating conditions change (for example, materials, lubrication)... 

Non-lubricated screw compressors have very close clearances and thus they are designed for limited ranges of discharge temperature, temperature rise, compression ratio, etc., all of which can cause changes in thesc clearances. Lubricated compressors have a somewhat broader tolerance to changes in operating conditions, but they are still more limited than reciprocating compressors. 

Lubricating oil analysis, as the name implies, is an analysis technique that determines the condition of lubricating oils used in mechanical and electrical equipment. It is not a tool for determining the operating condition of machinery. Some forms of lubricating oil analysis will provide an accurate quantitative breakdown of individual chemical elements, both oil additive and contaminates, contained in the oil. A comparison of the amount of trace metals in successive oil samples can indicate wear patterns of oil wetted parts in plant equipment and will provide an indication of impending machine failure. 

The entrainment of air in lubricating oil can be brought about by operating conditions (for example, churning) and by bad design such as a return pipe that is not submerged. The air bubbles naturally rise to the surface, and if they do not burst quickly, a blanket of foam will form on the oil surface. Further air escape in thus prevented and the oil becomes aerated. Oil in this condition can have an adverse affect on the system that, in extreme cases, could lead to machine failure. The function of an anti-foam additive is to assist in the burst of air bubbles when they reach the surface of the oil. 

The hydraulic oil must provide adequate lubrication in the diverse operating conditions associated with the components of the various systems. It must function over an extended temperature range and sometimes under boundary conditions. It will be expected to provide a long, trouble-free service life its chemical stability must therefore be high. Its wear-resisting properties must be capable of handling the high loads in hydraulic pumps. Additionally, the oil must protect metal surfaces from corrosion and it must both resist emulsification and rapidly release entrained air that, on circulation, would produce foam. 

The process of transition from hydrodynamic to boundary lubrication can be described qualitatively by plotting the measured friction coefficients against film thickness, which depends on the operational conditions, such as load, sliding velocity and lubricant viscosity. A typical diagram known as the "Stribeck Curve is schematically shown in Fig. 27, in which the friction coefficients are given as a function of, ... 

EP oil—lubricating oil formulated to withstand extreme pressure (EP) operating conditions. See EP additive. 

The purpose is to outline undesirable reactions between chemicals, including impurities and ancillary products (for lubrication, cleaning) or between chemicals and materials of construction under all operating conditions. 

The right principle of lubrication is to put the right lubricant in the right place at the right time. The right oil is determined by many factors (e.g., viscosity, correct additives, operational conditions). The following are examples of a... 

The "classic combinations" of elements arise due to specific problem identification. Some of the elements such as silicon, iron, chromium and aluminum are from the wear of liners and rings pistons or from the air induction system and contamination. Lead, tin and aluminum are from the wear of bearings and pistons, from lack of lubrication and coolant contamination. A sudden upward change above the maximum concentration limit mentioned above of any metallic element suggests an increased wear rate, and possibly abnormal operating conditions (Erickson and Taylor, 1984). The interpretation of wear analyses is often greatly enhanced by additional tests which detect contamination of fuel, water and antifreeze. 

As discussed earlier, lubrication of direct compression formulations is one of the more complex and difficult problems faced by a pharmaceutical scientist. The ideal lubrication operation provides the mildest mixing conditions that guarantee sufficient homogeneity of the lubricant. Magnesium stearate, provided as a finely divided powder, is one of the most widely used lubricants in the pharmaceutical industry. Many formulations are sensitive to the lubrication process when the formulation uses magnesium stearate powder. 

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