explains all about lubricants

1. LUBRICANTS
Presented by Dudala lakshmi tej

2. contents
Mechanism of lubricants
Types of lubricants
Properties of lubricants

3. There are mainly three
mechanisms;
Thick film lubrication
Thin film lubrication
Extreme pressure
lubrication

4. Thick film lubrication
It is mainly applicable for low load with
high speed
It almost avoids the contact between two
missionary parts
The thick is very high ie 1500Angstroms
The coefficient of friction is very low
It is also called as hydro dynamic
lubricant
In gernal bearings soft bearing rotates
with high speed

5. Thin film lubrication
It is mainly applicable for high load
with low speed
The coefficient of friction is very high
In this lubrication there is strong
interaction between metals
The oileness character is very high
 By the interaction of polar groups it
interacts the metal surfaces
It is also called as boundary film
lubrication

7. Extreme pressure
lubrication
The lubricants contains chlorides,
so2, bicarbonates which can easily
interact in it
They can interact to form as metal
chlorides and metal sulphates
It is suitable for high load with high
speed
It is suitable where thick and thin film
are not observed

8. Types of lubricants
Liquids
Semi solid lubricants
Solid lubricants

9. Greases or semi solid
lubricants
 A soap is dispersed into a hot lubricant
oil then it is called as greases
 It is emulsion in state
 It is also called as semi solid lubricant
 Depending upon these these are again
classified into various types
 Calicium grease: It withstands upto 80 c
 Sodium grease: It with stands upto 175c
 Lithium grease: It is very low less
than<15c
 Axel grease: It contains lime and resin

10. Solid lubricants
Solid lubricants are those which we
used in buses,commutator and
motors
Contamination of lubricants is
unacceptable in solid lubricants
There are two solid lubricants which
we mainly use
Graphite and molybendum
disulphide

12. Graphite
It is most widely used in solid
lubricants
It is very soapy to touch non flamable
and oxidized below 350 c
When graphite is dispersed in oil it is
called as oil dag
If it is dispersed in water it is called as
aqua dag
It is commonly used in
ac’s,lathes,general machine shop

13. Molybendum disulphide
It has very low coefficient of friction
less than 400<c
The fine powders of this may sprinkle
in surfaces of high velocities
It is also used along with solvents
and greases
Besides molybendum di sulphide
other substance like soap stone and
mica are used

14. Properties of lubricants
Viscocity
Vicocity index and red wood
viscometer

15. viscocity
It is the property in which the
residue to flow of a liquid is called
as viscocity
The viscocity of a particular
lubricant must be adequate
In viscocity two layers move top
layer moves faster than the front
layer

16. Viscocity index
The difference or change in viscocity
with respect to temperature called as
viscocity index
If the viscocity is high then it must be a
good lubricant
Viscocity index = L-U/L-H*100
Here u=viscocity at tested sample
100c
Here h =viscocity of oil at 100c

18. It is of two types red wood viscometer
1 and red wood viscometer 2
It is commonly used for the viscocities of
thin lubricant oils
It has jet of bore diameter as shown in
figure
It is inserted with kohilrausch flask in 50
ml flask
Two thermometers are inserted at the top
of the tube
At the middle of it oil is located and is
used to stir by the rod
Pointer is used to measure the level of
the liquid

19. At the bottom of the flask healing
tube is located which is used to heat
the flask
Levelling screw is used to tight the
entire apparatus
At the diameter of 1.82 mm and 10
mm length
Metallic oil cup is surrounded by
cylindrical copper path
This is the brief explanation of red
wood viscometer

20. THANK YOU FOR
WATCHING!!