Oil film bearings when properly designed and maintained became most reliable and satisfactory machine elements. Average unit pressure under certain condition may be as high as 205 kg/sq cm. The ships at sea use fluid film thrust bearing to transmit the thrust of propeller to hall structure.
The coefficient of friction in many cases is below 0.001. In contrast to rolling bearing sliding element bearings – viscosity plays an important role. In case of journal bearing, coefficient of friction is plotted against a parameter ZN/r, where Z = viscosity of lubricant in centipoise, N = shaft rpm, p = average pressure based on projected area due to “load” on it.
Tribological science plays a major role in cutting / core technology. Worldwide scientists developed superior lubricants with less friction and wear resistance. In diverse technological areas, this subject plays a crucial role. The ASME research committee on lubrication says that – the magnitude of energy conservation can potentially be obtained in four major areas: (1) road transport, (2) power generation, (3) turbine and turbo – machinery, and (4) industrial process technology.
What will happen if lubrication is not adequate?
With proper monitoring and regular lubricant change-over after fixed interval – the lubricant life as well as equipment life will be extended. The vibration indicator detects the bearing condition and infers about replacement.
Ecofriendly lubricants are the requirement of today, these lubricants are basically:
- Highly unsaturated, or high oleic vegetable oil (HOVO)
- Low viscosity polyalpholefins (Paos)
- Polyalkylene glycol (PAG)
- Dibasic acid esters
- Polyol esters
Transport sector
In India, 55 – 60% equipment damage is caused by poor lubrication. Improved tribological performance can provide the following benefits:
- Increased power output
- Less erosion
- Reduced fuel consumption
- Increased engine durability
In one I/C engine 48% energy consumption developed in engine is caused by friction loss. Even a small change of energy efficiency like – right air pressure, stoppage of engine at crossings, maintaining a speed of 45 kmph, can have a great impact with respect to oil savings, Table below provides an idea about loss analysis.
Power sector
In power sector, i.e., power station lubrication plays an important role since rotating machinery are everywhere – as well as they have to be in working conditions.
Based on working conditions, different grades of greases are applied to reduce friction in – excessive hot working condition /continuous duty cooling water is supplied.
Conclusion
Industrial tribology and its application in different sectors of economy is wide. But like volt, amp, power factor, kW savings in fuel is not measurable. Greases are formulated based on working condition. In IOC, HP lab, grease, lube oil are tested before marketing. It is still a subject with empirical formula.
Dr. Shivaji Biswas is a BEE accredited energy auditor. He is an Ex –Director of National Productivity Council, Kolkata. Also, he is the Proprietor of DS Cube Energy and Enviro Consultants.
