An ALA Presentation On Air Compressors....

1. SARVAJANIK COLLEGE OF
ENGINEERING AND
TECHNOLOGY
ELEMENTS OF MECHANICAL ENGINEERING
(2110006)
COMPUTER ENGINEERING – II
B.E. – I YEAR

2. Topic
 Topic:-
Air Compressors
 Group Members:-
57. Mr. Vadodariya Keyur M.
58. Ms. Jain Rishika R.
 Guided By:-
Prof. Pankaj P. Gohil

3. Introduction
 The machine which takes in air or any other gas
at low pressure and compresses it to high
pressure are called compressors.
 A compressor used for increasing the pressure
of air is called as an air compressor.
 They are power consuming machines in which
mechanical work is converted into the pressure
head of air or gas.

4. Introduction
 They are also considered as Reversed Heat
Engine.
 Air Compressor – 1) Takes in atmospheric air,
2) Compresses it, and
3) Delivers it to a storage vessel
i.e. Reservoir.
 Generally, the compressors are driven by Prime
Movers(Electric motors, I.C. Engines or Gas Turbines).

5. Classification
 On method of compression :-

6. Positive Displacement Compressors
 Positive displacement compressors causes movement
by trapping a fixed amount of air then forcing
(displacing) that trapped volume into the discharge pipe.
 It can be further classified according to the mechanism
used to move air.
1.Rotary Compressor
2.Reciprocating compressor

7. Rotary Compressors
 The gas is compressed by the rotating action
Of a roller inside a cylinder.
 The roller rotates off-centre around a shaft so
that part of the roller is always in contact with
The cylinder.
 Volume of the gas occupies is reduced and
the
refrigerant is compressed.
 High efficient as sucking and compressing
refrigerant occur simultaneously.

8. Working Of Rotary Compressor

9. Working of rotary compressor:
https://youtu.be/fxDEK3Ymx30

10. Reciprocating Compressors
 It is a positive-displacement compressor that
1.Uses pistons driven by a crankshaft to
Deliver gases at high pressure.
2.The intake gas enters the suction manifold,
Then flows into the compression cylinder.
3.It gets compressed by a piston driven
in a reciprocating motion via a crankshaft.
4.Discharged at higher pressure.

11. Working Of Reciprocating Compressor


12. Working of reciprocatory compressor:
https://youtu.be/4ogkke0-mXM

13. P-v diagram for without clearance. P-v diagram for with clearance.

14. Positive Displacement Compressors
Advantages Disadvantages
Reciprocating  Wide pressure ratios
 High efficiency
 Heavy foundation
required
 Flow pulsation
 High maintenance
Rotary  Wide application
 High efficiency
 High pressure ratio
 Unsuitable for
corrosive or dirty
gases
 Expensive

15. Multistage reciprocating compressor
Multi-stage compressors comprises
series of cylinders Between each
stage, the air passes through a heat
exchanger, where it is cooled.
In a two-stage compressor, air is
then forced into an additional
chamber for pressurization to the
required extent. In a three-stage
compressor additional cycle is added.

16. Dynamic Compressors
 The dynamic compressor is continuous flow
compressor is characterized by rotating impeller to add
velocity and thus pressure to fluid.
 It is widely used in chemical and petroleum refinery
industry for specific services.
 There are two types of dynamic compressors
1.Centrifugal Compressor
2.Axial Flow Compressor

17. Centrifugal Compressors
 Achieves compression by applying inertial forces to the gas
by means of rotating impellers.
 It is multiple stage ; each stage consists of an impeller as
the rotating element and the stationary element, i.e. diffuser
 Fluid flow enters the impeller axially and discharged radially
 The gas next flows through a
Circular chamber (diffuser),
where it loses velocity
and increases pressure.

18. Working Of Centrifugal Compressor

19. Axial Flow Compressors
 Working fluid principally flows parallel to the axis of
rotation.
 The energy level of air or gas flowing through it is
increased by the action of the rotor blades which exert a
torque on the fluid
 Have the benefits of high efficiency and large mass flow
rate
 Require several rows of airfoils to achieve large
pressure rises making them complex and expensive

20. Working Of Axial Flow Compressors

21. Dynamic Compressors
Advantages Disadvantages
Centrifugal  Wide operating range
 High reliability
 Low Maintenance
 Instability at reduced
flow
 Sensitive to gas
composition change
Axial  High Capacity for given
size
 High efficiency
 Heavy duty
 Low maintenance
 Low Compression
ratios
 Limited turn down

22. Applications Of Compressors
 Compressors have many everyday uses, such as in :
 Air conditioners, (car, home)
 Home and industrial refrigeration
 Hydraulic compressors for industrial machines
 Air compressors for industrial manufacturing