working of compressor

1. NAME –RAMESH MAURYA
ROLL NO-1412240163
ME-76

2.  A Simple Compressor Cannot Provide High Compressed Air And High
Vacuum. For Obtaining These Two, We Need A Compressor And An
Exhauster Together. For That We Use A Single Unit System Known As
Expressor, In The Dual Brake Locomotives. Therefore Expressor Is Simply
Expressed As
Exhauster + Compressor = Expressor
Expressor Is A Reciprocating Type System.
It Has Six Cylinders, Which Are Arranged In A „W‟ Type Manner I.E., Two
Cylinders Are In A Vertical Position And Four In A V Shape. It Is An Air-
cooled System With Forced Feed Lubrication. For Cooling Purpose A Fan
Is Used Which Is Of A Forced Draught Type, Mounted On The Crankshaft.
The Oil Fill Capacity Is 30 Litres; The Oil Grade Being Servo Press 150-
IOC.

5.  The compressor model RR80101 is specially
designed to meet the high volume of air
requirement with moderate pressure, to be
used in the diesel locomotive of Indian
railways. The compressed air is used for the
application of brake, horns and wiper of
locomotive. This compressor is a two stage,
reciprocating “W” type, forced lubricated with
intercooler and aftercooler.

6.  1. Crank case or Housing
 2. Crank case end cover
 3. Inspection cover (with oil indicator and needle
valve)
 4. Oil seal
 5. Lube oil pump
 6. “S‟ pipe
 7. Oil strainer
 8. Relief valve
 9. Crank shaft with counterweight
 10. Main ball bearing
 11. Breather

7.  12. Connecting rod with needle bearing
 13. Bearing shell
 14. Cylinder (or liner sometimes, 2 low pressure and
a high pressure)
 15. Piston (2 low pressure and 1 high pressure)
 16. Wrist pin or gudgeon pin
 17. Ring on piston (2 compression ring, a scriber and
an oil ring)
 18. Head
 19. Air intake filter
 20. Valve (2 inlet and 2 discharge on each head)
 21. Cage cap
 22. Loader/Unloader

8.  23. Copper connecting pipe
 24. LP air manifold (for each LP cylinder)
 25. HP air manifold
 26. Safety valve
 27. Intercooler
 28. Aftercooler
 29. Fast coupling
 30. Fan coupling
 31. Intercooling and Aftercooling stut
 32. Magnet valve (earlier AC governor was used)
 33. Flexible pipe

9.  1. Crank case or Housing:
 It is used to hold the crank shaft assembly. It
is also used to fit cylinders, oil seal, lube oil
pump and most important work is to hold the
lube oil in it (approx. 21 lt).

10.  2. “S” Pipe:
This pipe is connected to lube oil pump. Its
other end crank case where needle valve is
fitted is connected. It work is to send
pressure created by LOP to needle valve.

11. 3. Crank Shaft With Counter Weight:
 In one crank shaft of compressor there are
two counter weights. Counter weights work is
to balance crank shaft and also to give
motion.
 Crank shaft pin is that part with the help of
whose connecting rod moves. With the help
of Connecting Rods, all piston moves in
cylinder (or liner) accordingly. Crank shaft
contain a gear with the help of whose lube oil
pump work efficiently

13.  4. Main ball bearing:
 On the both ends of crank shaft there are two
main ball bearings and function of bearing is
to move crank shaft easily.

14.  This is the part fitted on the crank shaft pin
which helps to reciprocate the piston easily
into the cylinder.
 On its bigger end to move it easily on the
crank shaft pin, a bearing shell is provided
(i.e. Bearing shell is made up of white metal)
whereas its smaller end has needle bearing
which provide easy movement on gudgeon
pin of the cylinder.


16.  6. Bearing shell:
A bearing shell is provided to move
connecting rod easily on the crank shaft pin.
 7. Cylinder (or liner, 2 low pressure and a
high pressure cylinder):
 In compressor, the cylinders are made up of
cast iron. Its main work is to hold the piston
in the center and to compress the sucked air.

18.  Compressor consists of two low pressures
(made up alloy aluminium) and a high
pressure piston (cast iron). There are four
rings on each piston. Topmost is
compression ring, second is scriber, third is
oil ring and the last one is again oil ring.
Piston has a hole in which gudgeon or wrist
pin which is held in it by snap rings from
both sides.

20. Fig1: Schematic view of compressor

21. When the piston of the low pressure cylinder moves
towards the bottom dead center, the combined action
of delivery valves return spring and the pressure
differential developed between discharge manifold
and the LP cylinder closes the delivery valves. At the
same time, inlet valves open due to the pressure
differential developed between the inside and outside
of LP cylinder. Air at atm pressure is drawn in
through the filters and intake valves into the LP
cylinders during the downward stroke of the pistons.
During the upward motion of the piston, the
combined action of inlet valves spring and the
pressure differential developed between the inside
and outside of LP cylinder closes the inlet valves.

22.  The air which is trapped in the cylinder, gets compressed. The
compressed air is forcibly open the delivery valves due to the formation
of pressure differential, which has been developed between the
discharge manifold and the cylinder. The compressed air is delivered
into the discharge manifold. The intercooler outlet manifold is provided
with the safety valves which relieves the pressure if it reaches beyond 50
psig (3.5kg/cm2) .

 Air leaves the intercooler, entering the HP cylinder through its intake
valve. As the HP piston moves upward, it compresses the air to a high
pressure, forcing it out through the discharge valve and connecting pipe
to the main air reservoir through an aftercooler. Air leaving the HP
cylinder is passed through the aftercooler to reduce the temp for the
application. A safety valve is mounted at the outlet of the HP cylinder,
which relieves the pressure beyond 200 psig (14kg/cm2). Both second
and first stacks receive power from the crank shaft individually. Crank
shaft receives power from the locomotive engine, which is coupled to
the crank shaft using a coupling .

23.  The crank case houses the crank shaft and the connecting
rod assembly, which receives and converts circular motion
into reciprocating motion. Suction unloader valves on the
LP cylinder head and HP cylinder head are operated
pneumatically when pressure in the air receiver is above
140psig (9.8 kg/cm2).
 When the pilot air is passed into the suction unloader valve
it keeps the suction valve open and air gets unloaded
through the air filter of the compressor. The air receiver is
sealed against leakage through the unloader assembly to
the atmospheric vent by the complete movement of the
unloader valve. When the air receiver pressure drops, the
governor assumes the cut in position.

24. THANK YOU