* Dr. Mukesh Singh
India is predominant in agricultural economy. After the onset of Green revolution, our food grain production shoots up very rapidly. Now there is a big question that how could we sustain our food production with steady growth to feed the rapid growth of population. Today our farmers are utilizing many types of farm machines for the production of agricultural crops. These machines operate under varying loads, temperature and weather conditions. The day to day operation under field condition requires a thorough maintenance of the machines. The lubrication for farm machinery is very important because they always work under off road operating conditions. Selection of proper lubricants such as Oil and grease form an integral part of maintenance. There are several types & makes of lubricants, to suit the lubrication requirements for varying conditions, generally obtained from animal fats, vegetable oil, mineral oils and synthetic polymers.
Animal fats are used as lubricants for a very limited use in mechanical devices. The common animal lubricants are lard oil, fish oil and tallow. The principal disadvantage of these lubricants is that they cannot stand heat & oxidize to become gummy. The castor oil, cotton seed oil and linseed oils have been utilized in a bullock driven equipments, however, only castor oil has proved its use for engine lubrication. The use of vegetable oil may be helpful for lubrication of slow moving machines.
The petroleum products serve as the source of lubricating materials. The lubricating oils is used in transmission and engines, where as the greases are used in bearings, nipples, joints etc. of the agricultural machines.
There are several characteristics for the testing of the lubricants such as kinematic viscosity, specific gravity, cloud and pour point, flash & fire point, carbon ratio and acid value. The temperature is the prime cause for change in kinematic viscosity; therefore a lubricant must possess sufficient viscosity and lubricating ability. Generally, the lube oil used for engine lubrication in summer is of higher viscosity than that of winter; however the transmission oil also has a higher grade of viscosity.
Greases are mixtures of metallic soap and petroleum oil. Several additives are being used to provide stabilization, oxidation resistance, rust-prevention and thickness of Grease. The soap serves as a thickening agent, particularly at certain temperature during operation. The greases are classified either on the basis of soap such as sodium base, aluminum-base, lime-base and mixed base or consistency as fluid. Zero number grease stands for semi solid / fluid. Very soft for No. 1, soft for No. 2, medium for No. 3 and hard for No. 4. Greases are also classified according to use as cup greases, ball and roller bearing grease, gear greases, chassis greases etc. These semi solid lubricants are commonly used for slow moving parts, when pressure is high. They are also being used for the concealed or inaccessible such as wheel bearing, springs, universal joints, water pumps, axle and bearings etc.
Nowadays several multinationals have been playing in the lubricating oil manufacturing sectors along with the Indian ones. Everybody is popularizing the products, so as farmers we have to look at the cost and operating cost of each product. Especially for farm machines, because it operates in dirty and muddy situation. Proper sealing as well as regular refilling is needed for better, trouble free and economic operations of agricultural machines.
*Senior Scientist (F.M. & P.) L.P.M. Section, I.V.R.I., Izatnagar.
(Extracted from AgriGold India's SwarnaSedyam)