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 Name                     :-  H.M.I.J.Herath

 Reg.Number          :-  EU/IS/2019/PHY/77

 Index Number        :-  PS2827

Classification of Lubricants

 

Lubricants can be classified into several chatergories by considering many factors.

We can classify them ,

• By state of matter

   1.Solid Lubricant

  
  
  The lubricants existing in solid form are the Solid  lubricants.They are preferred where the operating conditions re such that a lubricanting film cannot be secured by the use of lubricating oils or grease.

            eg:-) Graphite , wax , soap , Mica ,Chalk

  2.Semi Solid Lubricant

  
  A semi solid lubricant obtained by  combining lubricating oil with thickening agents.Lubricating oil  is the principal component and it can be either petrolium oil or a synthetic hydrocarbon of low to high viscosity.

             eg;-) silica , gel , grease , vaseline

  3.Liquid Lubricant

  
  The lubricants existing in liquid form  are the Liquid lubricants.

              eg:-) petrolium oil ,  mineral oil , blended oil , animal and vegitable oil Matter can exist  in one of three main states : Solid , Liqid  or it may be in gassious state. Lubricants  also exist in these  states.By considering those conditions lubricants have classidied into 3 chatergories.

• 
  

• By using purposes

Lubricants are largely used for automobiles, heavy industries, industries, and vessels. 

1.For Transportation Facilities

- Diesel Engine Oil

- Gasoline Engine Oil

- Diesel-electric locomotive Engine Oil

- Aeromotor Engine Oil

- LPG Engine Oil

- CNG Engine Oil

- Motorcycle Engine Oil

- 2-cycle Motor Engine Oil

- Automatic Transmission Oil

- Automotive Gear Oil

2.For Industrial Machine

- Hydraulic Oil

- Machine Oil

- Industrial Gear Oil

- Turbine Oil

- Circulating Oil

- Compressor Oil

Like that we canclassify the lubricant by considering their purposes.

 

• By viscosity

Viscosity is a measure of a  fluid's resistance to flow.By considering this factor again the lubricants have classified.Viscosity of these lubricants are not same , they are different fron each other. Their performance also chnge according to their viscosities.

So, to understand lubricants there is a method called called SAE (Society of Automotive Engineers) index. SAE is an international standard established for the viscosity of engine oil by the Society of Automotive Engineers.

They are in different grades.,

•  Single Grade

According to the viscosity grades in SAE table  the products  of grades expressed in a single number such as SAE 10W are single grade lubricants.

•  Multi Grade

According to the viscosity grades in SAE table  the products  of grades expressed intwo kind of number such as SAE 5W30 are multi grade lubricants.

The viscosity change of multi-grade lubricating oils at high temperature is smaller than that of single grade lubricanting oils.

• By performance

Properties of Lubricants.

 Here are the some important properties of lubricants.

• corrosion stability

• viscosity

• Aniline point

• flash & fire point

• Cloud & pour point

• Corrosion stability

Viscosity is a property which is offers resistance to flow and shear.If the viscosity is too low , a liquid oil film cannot be maintained two moving or sliding surfaces.in the other hand if the viscosity is very high , excessive force will result

Aniline Point

• It is the minimum equilibrium solution temperature for equal volumes of aniline and a lubricant oil sample.
• A lower aniline point of an oil means a higher percentage of aromatic hydrocarbons in it .
• A good lubricating oil should have high aniline point

Flash point and Fire point

• FLASH POINT – It is the lowest temperature at which the vapours that ignite for a moment,when a tiny flame is brought near it.
• FIRE POINT – It the lowest temperature at which the vapour of the lubricant oil burn continuously for at least five seconds,when a tiny flame is brought near it.

Cloud & Pour Point

 

            CLOUD POINT – When the lubricant oil is         cooled slow ,     the temperature at which it becomes   cloudy or hazy in appearance , is called its cloud point .

•  
•              POUR POINT – While the temperature at which   the lubricant oil cease to flow or pour , is called pour   point .

Characteristics Of Lubricants.

 In good lubricant there some characteristics.

• High boiling point.

• low freezing point.

• High resistance to oxidation and heat.

• Adequate viscosity for proper functioning in service.

• Non-corrosive properties.

When considering a good lubricant it should have high viscosity  index. Not only that their flash and fire points higher than the opperating temperature of the machine.The cloud and pour points of a good lubricant should always be lower than the operating temperature of the machine. And also their volatility should be low.A good lubricant  should have proper aniline point.Like that by considering these characters we can identify a good lubricant.

FLASH POINT & FIRE POINT

CLOUD POINT

Functions Of Lubricants

 

the main thing is lubricant forms an oil film on the surface of metals and converting solid friction into liquid friction to reduce friction.

they   reduced friction prevents heating and abrasion on the friction.

Oil will reduce the friction between two sliding surfaces by creating a protective film.  It also assists with heat dissipation by spreading out the heat in the system.

 

Functions of a Lubricant

• The primary function of a lubricant is to prevent friction by creating a boundary layer between two surfaces

• Dissipate heat from surfaces

• Transport contaminants to filters

• Protects from oxidization and corrosion

• Power transmission.

• There are about 6 basic functions of a lubricants

  ●     Lubrication - Provide a film between moving parts.

  ●     Cooling - Heat transfer.

  ●     Sealing - Filling in uneven surfaces.

  ●     Protection - From the corrosion and oxidation.

  ●     Cleaning - Keeping contaminants in suspension.

  ●     Damping and cushioning - Of components under higher stress.

  Here the main function is lubricants reduce thefriction,heat, and wear between the components which are contact with eachother in mechanical instruments.

Introduction to Lubricants

Lubricants are the substances which are used to reduce friction between surfaces in mutual contact.Any substance introduced between two moving sliding surfaces with a view to reduce the friction between them , is called Lubricants.

 

They are   very useful substances. Otherthan the industrial uses they are taking for cooking purposes , bio applications in human , ultra sound examinations , medical examinations etc.