Page 58 - CITS - Fitter - Trade Theory

FITTER - CITS

MODULE 3

LESSON 8 : Lubrication and coolant

Objectives

At the end of this lesson you shall be able to
• define the lubricants its types and application
• define the coolants its types and its application
• state the recommended fluid for various metals.

Lubrication and coolant, types and appplication

Definition of lubricants: With the movement of two mating parts of the machine, heat is generated. If it is not
controlled, the temperature may rise resulting in total damage of the mating parts. Therefor a film of cooling
medium with high viscosity is applied between the mating parts which is known as a ‘lubricant’. A ‘lubricant’ is a
substance having an oily property available in the form of fluid, semi-fluid, or solid state. It is the lifeblood of the
machine, keeping the vital parts in perfect condition and prolonging the life of the machine. It saves the machine
and its parts from corrosion, wear and tear and it minimises friction.
Types of lubricants
a Liquid

Mineral oil: Mineral oil is one of the most commonly used liquid lubricants. It is derived from crude oil and is
suitable for general-purpose lubrication applications. Mineral oil provides good lubrication properties and is often
used in automotive engines, industrial machinery, and hydraulic systems. Ex. Petrol, diesel, kerosene.

Animal oil -lard oil, fish oil
Synthetic Oils: Synthetic oils are manufactured from chemically synthesized base oils and additives. They
offer superior performance compared to mineral oils in terms of stability, temperature resistance, and lubrication
properties. Synthetic oils are used in high- performance applications such as aerospace, precision machinery,
and high-speed engines.- Ex. silicon lubricant.
Vegetable Oils: Vegetable oils, such as soybean oil and rapeseed oil, can also serve as effective liquid lubricants.
They are biodegradable and environmentally friendly, making them suitable for applications where environmental
concerns are important, such as agriculture and food processing machinery. Ex. Mustered oil, coconut oil.
b Semi liquid lubricant
While not strictly liquid, greases are semi-fluid lubricants consisting of a base oil thickened with a soap or other
thickener. Greases offer better adhesion and staying power compared to liquid lubricants, making them suitable
for applications where frequent reapplication of lubricant is impractical.

c Solid lubricant-mica, wax
Application of lubricants:
• Reduces friction
• Prevents wear

• Prevents adhesion
• Aids in distributing the load
• Cools the moving elements
• Prevents corrosion
• Improves machine efficiency

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CITS : CG & M - Fitter - Lesson 7