LUBRICATION

PURPOSE/FUNCTION OF LUBRICANT To minimize friction and wear between two mating surfaces To extract heat To remove debris from the contact area, e.g combustion products in case of I.C. Engines Swarf in case of metal cutting operations Sometimes, to protect the lubricated or adjacent parts from corrosion.

IMPORTANCE OF MAINTENANCE Proper use of lubricants contributes towards increased life of equipment and plant, It leads to reduction in downtime and maintenance cost. The lubricants assist in ensuring the safety of operations. e.g. Shortage of oil/ lubricants in either brake system or gear system may cause serious problems in operation of the vehicle. Improper lubrication leads to disturbing sounds emanating from the moving parts.

PROPERTIES OF LUBRICANTS Viscosity : A measure of a lubricant’s resistant to flow. Oxidation Stability : Hydrocarbon oils react with O2 to form acid. Corrosion inhibitors : Moisture present in oil of condensing from atmosphere can lead to corrosion in engine. Rust inhibitor with oil afford protection. Pour point : Temperature at which oil stops flowing. Dewaxing oil or using pour point depressants are used to reduce the level. Flash Point : The temperature at which it gives off inflammable vapors. This weakens the oil film strength, sealing ability, it may be caused by fuel system leaks, ignition problem, etc. Acidity : It is measured in terms of potassium hydrooxide (KOH) needed to neutralize acidity. Total Acid No. (TAN) increases with service. The TAN is indicative of strong inorganic sulphuric acids which may lead to copper or lead bearing erosion. Total Base No. (TBN) is present to naturalize the harmful acids formed as a result of composition process. Detergenting : Detergent properties are required to keep combustion and oil degradation product in suspension and prevent their depOSiting and baking in high temperature zones.

TYPES OF LUBRICANTS Liquid Mineral Oils : Mineral oils are basically hydrocarbons often with some additives to introduce specific characteristic features in the oil. Mineral oils are classified as : Paraffinic : It contains significant amount of waxy hydrocarbons with little asphaltic matter. Napthenic : It contains asphaltic matter in least volatile fractions with little or no wax. Mixed Wax : It contains both waxy and asphaltic materials. Synthetic Oil : Synthetic oils are products produced under controlled conditions, Industrially from chemical base and additives. These are pure, idealized lubricants whose molecules are uniform in weight and shape. Synthetic oils are engineered to perform under rigorous conditions and extreme temperature.

TYPES OF LUBRICANTS Greases : A greases may be defined as solid to semi-fluid lubricant consisting of a dispersion of a thickening agent in a lubricating fluid. The consistency of grease depends on the percentage of thickener in the grease. Depending on the degree of consistency, greases are classified as Semifluid Soft Stiff Greases are also categorised as : Calcium based Sodium based Barium based

TYPES OF LUBRICANTS Advantages of greases : Disadvantages of greases : Convenience : Grease is easily retained where it is applied. Persistence: Lubricating film is retained on surface during shutdown. Protection : Minimum leakage thus encouraging the formation protective coating against corrosion. Cleanliness: Greases do not splash thus maintaining cleanliness of surfaces where they are applied. Disadvantages of greases : Poor Cooling Properties: Greases do not dissipate heat generated easily. Contamination: Greases can easily get contaminated by dirt, wear debris, oxidation products, etc. Low Speed of Application: Greases cannot be applied where working speed are over 2 m/s.A greases may be defined as solid to semi-fluid lubricant consisting of a dispersion of a thickening agent in a lubricating fluid.

TYPES OF LUBRICANTS Solid Lubricant A solid lubricant is defined as any solid used as powder or a film on a surface to provide protection from damage during relative motion so as to reduce friction and wear. Solid lubricants become necessary when : Fluid lubricants are undesirable if they are liable to contaminate product as in food machinery, electrical contacts, etc. Fluid lubricants are ineffective in hostile environments, high temperature, extreme pressures and fretting conditions. Some places bearings are in accessible and likely to be missed by routine maintenance. A common type of solid lubricant is graphite. Molybdenum disulphide in its powered form is often used on metal forming dies and on threaded parts.

TYPES OF LUBRICANTS Gas The following are some properties of solid lubricants. Solid lubricants are incapable of carrying away heat. Solid lubricants are immobile and they must somehow be bonded to the surface. Solid lubricants are capable of retaining their lubricating effectiveness at high temperatures. Gas Advantages A gas bearing is virtually frictionless, silent, and vibration free. Gas bearings can be used for extremely large surface velocities. A gas bearing can eliminate the risk of contaminating a process with lubricant. Lubricant (air/ N2) is cheap and available in abundance.

TYPES OF LUBRICATION Manual Automatic or self –designed Lubrication Gravity Feed Lubrication System Splash lubrication Forced feed Lubrication

LUBRICATING DEVICES

LEAK ARRESTING COMPONENT Gasket Packing Seals