- Pages: 4
- Word count: 810
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Task 1: (P1) Describe the purpose and application of three different types of lubricant: What is Lubrication: Lubrication is a process or technique when a component is having been made smooth and slippery by the application of Lubricant. What is Lubricant: A lubricant is a substance which applies between two moving surfaces to reduce friction between them. E.g. Motor oil, Greases, Graphite, Glasses. Three different types of lubricant and the purpose they serve: Glasses: Glass is used as a Lubricant for having high viscosity. Usually glass is solid but in high temperature it becomes viscous.
Viscosity is a function of temperature but not of pressure which depends on the type of glasses. In addition having poor heat conductivity makes glass useful. Glass works as a thermal bar between hot components. Usually glasses use as lubricant in application of hot extrusion and shaping. Graphite: Graphite can be used as a lubricant either in its dry or liquid form. It works effectively specially in elevated temperature. Graphite can be applied to a component either by rubbing on it or evaporated to the components surface. Although graphite is a great lubricant but the downside of using graphite is, its needs to be used more often in the moving surface where the friction happen. Both Glass and graphite is a kind of Solid lubricant.
Solid lubricant is widely used rather than oil; even though oil reduces friction due to their fluidity and viscosity while solid lubricants have neither of these properties, but they are still capable of reducing friction and wear. Solid lubricants work in situations where liquid lubricators have no practical value. For instance, solid lubricants may be sprayed on the outer hull of a boat to avoid water contact. Greases: Greases are solid or semisolid lubricants and generally consist of soaps, mineral oil, and various additives.
Greases mostly used in roller bearing and low velocity applications due to high viscosity and sticky property to metal surfaces. Grease is widely used mainly because easy to handle and require only the simplest sealing devices. Although used widely in machinery, greases are of limited use in manufacturing processes. Greases are applicable when it is not practical to use oil. High quality greases can lubricate relatively inaccessible components without frequent uses. Greases can also extend the life time of old components which are previously oil lubricated because it provides a thicker film. Also this thicker film works as a noise insulator.
Task 2: P2: Describe the operation and maintenance of three different lubrication systems. Splash Lubrication: Splash lubrication is a method of applying lubricant, which helps to reduce friction to parts of a machine. In the splash lubrication of an engine, dippers on the connecting-rod bearing caps are submerged in oil with every rotation. When the dippers emerge from the oil trough, the oil is splashed onto the cylinders and pistons, lubricating them. Splash lubrication is suitable for small engines for example lawnmowers and small boat engine but not for automobile engine. This is because the amount of oil from first to last into has an impact on how well the engine parts can lubricated.
If there is not enough oil, the amount splashed onto the parts of engine will be insufficient. Also too much oil onto the machinery will cause excessive lubrication which can end up with problems. Force feed Lubrication system: Force feed lubrication systems are designed to deliver, monitor and protect oil delivery to pumps, compressors etc. In a typical force- feed lubrication system a shaft or motor pump oil from crankcase to the main bearings and the camshaft bearings. The main and the camshaft bearing are usually the items that are force fed while the connecting rods are fitted with dippers that supply oil to the rest of the component by splash.
Some configurations use small troughs under each connecting rod, which is kept full by small nozzles that deliver oil under pressure from the oil pump. These oil nozzles deliver an incredibly stream as speed increases. At very high speeds these oils are powerful enough to strike directly the dippers. This causes oil stream much heavier splash so that perfect lubrication provided to all components. Full Force Feed System: In a full force-feed lubrication system; the main bearings, rod bearings, camshaft bearings, and the complete valve mechanism are lubricated by oil under pressure.
In addition, the full force-feed lubrication system provides lubrication under pressure to the pistons and the piston pins. This is accomplished by holes drilled the length of the connecting rod, creating an oil passage from the connecting rod bearing to the piston pin bearing. However, this passage not only feeds the piston pin bearings but also provides lubrication for the pistons and cylinder walls. This system is used in virtually all engines that are equipped with full-floating piston pins.