Lubrication - The Silent Component of Machinery

Written by Thomas Yoon

The function of a lubrication medium is:

1. To form a film between moving bearing components so that metal to metal contact is prevented. 2. To reduce friction and eliminate wear 3. To protect against corrosion 4. To seal against impurities like dust, dirt, water.

In order forrepparttar oil film to be formed betweenrepparttar 102779 moving bearing components,repparttar 102780 film must be sufficiently thick even under heavy load, high temperatures or vibrations.

Some sleeve bearings that has very heavy loads, like inrepparttar 102781 crosshead bearings of diesel engines, usually have provisions for injecting pressurized oil to floatrepparttar 102782 shafts. This method is called hydrostatic lubrication.

However,repparttar 102783 most common method of lubrication for sleeve bearings is byrepparttar 102784 hydrodynamic method. Whenrepparttar 102785 two surfaces of a bearing and shaft move rapidly relative to one another,repparttar 102786 oil is carried alongrepparttar 102787 shaft to fillrepparttar 102788 gap between shaft and bearing. When repparttar 102789 moving components become completely separated by a cohesive film of lubricant, hydrodynamic lubrication occurs. Hydrodynamic lubrication prevents wear in moving parts, as there is no metallic contact between them. The bearing metals can last for a long time.

During starting time,repparttar 102790 rotating shaft does not have sufficient speed to pick uprepparttar 102791 lubricant. The film separatingrepparttar 102792 moving surfaces is very thin - with onlyrepparttar 102793 thickness of a molecule. This is a condition called boundary-layer lubrication. With this condition, friction losses increases, producing heat, which raises repparttar 102794 temperature ofrepparttar 102795 lubricant, thereby reducing its viscosity so thatrepparttar 102796 load-carrying capacity ofrepparttar 102797 film is even lower. In worst case conditions,repparttar 102798 surfaces can even seize together.

Additives that Improve Lubrication Oils

Written by Thomas Yoon

Mechanical machines need lubrication. No machines can run for long without lubrication of its moving parts. At best,repparttar moving parts may wear out faster. At worst, entire machines can seize up and develop cracks. In severe conditions,repparttar 102778 heat built up can even cause explosions and loss of lives.

So lubrication is no small matter in machine operation.

Lubrication oil can last for a very long time in normal machine operation. By determiningrepparttar 102779 properties of lubrication oil, many machine operators will be able to know whetherrepparttar 102780 oil can still be used.

Some ofrepparttar 102781 important properties to watch for when buying or replacing lubrication oil is as follows:

Viscosity Viscosity Index Pour Point Oxidation Resistance Flash Point, Fire Point Alkalinity Additives

Some ofrepparttar 102782 additives that are put intorepparttar 102783 lubrication oil includerepparttar 102784 following:

Anti Oxidant - Amines, Phenols Corrosion Inhibitor Detergent and Dispersant - Ca, Ba, Compounds, Soaps Alkalinity - Ca, Ba Hydroxides Anti Bacterial - Biocides Oiliness or Wetting Agents - fatty oils, chlorinated wax Extreme Pressure Agents - organic compounds of Cl, S, P (for hydraulic, gear oil) Pour Point Depressant - Organic polymers (alkyl naphthalene) (for steering gear, refrigerator) Anti foam - Silicones Viscosity Index Improvers - organic polymers Emulsifying Agent - Polar Compounds (emulsifying but do not lose lubricating property)

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