Pneumatic & hydraulic hight tech SPKT

8/28/2013
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Chapter 1
Overview
Pneumatic & Hydraulic Technology
Ho Chi Minh City University of Technical Education
Overview
Instructor: Phan Thi Thu Thuy
Higher Engineering Education Alliance Program
Chapter 2:
Air Generation
Chapter 2:
Air Generation
Pneumatic & Hydraulic Technology
Ho Chi Minh City University of Technical EducationHo Chi Minh City University of Technical Education
Air Generation
and Distribution
Air Generation
and Distribution
Instructor: Phan Thi Thu Thuy
Higher Engineering Education Alliance Program
Contents
Air compressorAir compressor
1
Air dryersAir dryers
2
Air receiverAir receiver
3
2
Air receiverAir receiver
3

Air distributionAir distribution
4
Air service equipmentAir service equipment
5
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1. Piston compressor
2. Two stage piston compressor V -type
3. Two stage piston compressor double acting
4. Piston – diaphragm compressor
Air compressorAir compressor
1
3
4. Piston – diaphragm compressor
5. Sliding vane rotary compressor
6. Screw compressor
7. Roots compressor
8. Turbine compressor
9. Turbine compressor – four stages – radial compressor
10. Axial turbine compressor
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Objectives
1. Given name of several air compressors, be
able to classify compressors based on working
principle within 5 minutes
2. After attending the lecture, be able to
describe the working principle of certain positive
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describe the working principle of certain positive
displacement compressors within 5 minutes
3. After attending a lecture, be able to explain

the differences between intercooler and
aftercooler within 5 minutes
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Compressor types
Types of
compressor
Reciprocating
piston
compressor
Piston
Diaphragm
Rotaty piston
compressor
Flow
compressure
Radial - flow Axial – flow
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 Reciprocating compressor are very common and provide
a wide range of pressure and delivery rates.
 For higher pressures multistage compression is used
with intercooling between each stage of compression.
Piston
compressor
Diaphragm
compressure
Sliding vane
rotary
compressor
Roots
compressor

Radial - flow
compressure
Axial – flow
compressure
Two – axial
screw
compressor
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Compressor types based on
working principle
The major classifications of compressors are positive
displacement and dynamic type.
 Positive displacement can be further divided into
(a) Reciprocating (b) Rotary.
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In case of positive displacement compressors increase
the pressure of air/gas by reducing the volume.
 Dynamic compressors divided into
(a) Radial (b)Axial.
Dynamic compressors increase the air or gas velocity,
which is then converted to increase the pressure.
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Compressor types
The optimum range of pressure for reciprocating
compressors are approximately:
 Up to 400kPa (4 bar/58 psi) Single stage
 Up to 1500kPa (15bar/217.5 psi) Double stage
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 Over 1500kPa Treble or
multi-stage

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1. Piston Compressor
Piston compressors compress atmospheric air
against an existing higher pressure at the exit
port.
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1. Piston Compressor
Consisting of:
1. Crank shaft
2. Piston
3. Piston rod
4. Cylinder
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4. Cylinder
5. Inlet valve
6. Exhaust valve
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1. Piston Compressor
The crank shaft rotates
clockwise. Crank shaft
and piston are connected
be piston rod.
Piston moves downwards
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Piston moves downwards
and sucks air from the
atmosphere.
Valves open due to
differential pressure and

not mechanically.
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1. Piston Compressor
After passing through
lower dead point, inlet
port closes and exit port
opens. The air is being
pushed against the
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pushed against the
prevaling pressure.
Point of valve opening
depends on valve
design.
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2. Two stage piston compressor
V-type
 Two pistons are driven by
one crank shaft.
 The air, compressed to
certain degree passes
from the left cylinder
through the intermediate
Intermediate Cooler
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through the intermediate
cooler before given it’s
final rate of compression in
the right cylinder.
 The compression ration in

the first stage is
determined by the degree
of cooling obtained.
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2. Two stage piston compressor
V-type
The three main types of air coolers are:
 Precoolers: heat exchangers that cool the air before it
is compressed.
 Intercoolers: heat exchangers that cool the air between
the compressive stages of a multi-staged compressor.
 Aftercoolers. heat exchangers that cool the air after it
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 Aftercoolers. heat exchangers that cool the air after it
has been compressed.
 Precoolers and aftercoolers commonly employ water as a
medium for heat dissipation, whereas intercoolers
commonly use air as the cooling medium.
 A typical intercooler is composed of three different parts:
a fan, fins, and core tube.
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3. Two stage piston compressor
double acting
This type will compress air
during the upward and
downward stroke.
Crank shaft and piston rod
move the piston downwards.
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The exhaust port on the

piston rod side and the inlet
port on the piston side have
opened so that compression
and suction takes place
simultaneously.
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3. Two stage piston compressor
double acting
 The same principle is also
employed in the second
stage.
 The cylinder of the second
stage is smaller than the
cylinder of the first stage
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cylinder of the first stage
because the volume of
compressed air is less.
 This compressor is equipped
with a cross piston drive.
 The positive advantage of this
more precise bearing is a long
service life.
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4. Piston – diaphragm compressor
 The working principle of this
compressor is the same as that
of a piston compressor, but
sealing is provided by a
diaphragm.

 The diaphragm usually permits
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 The diaphragm usually permits
a shorter piston stroke only.
 The advantage of this type is
air, free of oil contamination.
 Compared with other
compressors designs the
sealing of compression volume
is simplified.
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5. Sliding vane rotary compressor
 Drive and compressor shaft are
identical and are placed
excentrically in a round cylinder
volume.
 A rotor is fitted on the shaft with
slots and sealing vanes. The
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slots and sealing vanes. The
vanes are pressed against the
cylinder wall due to rotational
forces and spring action.
 When rotating, the vanes move in
and out of their slots resulting in a
large number of chambers with
differing volumes.
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5. Sliding vane rotary compressor
The largest volume is

on the suction side,
the smallest on the
pressure side.
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For higher air
pressures multiple
stage compression is
usually employed.
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6. Screw compressor
Screw compressors consist
of two screw type profiles to
rotate against each other.
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Video
6. Screw compressor
Both screws are driven
to rotate in opposite
directions.
Air is being compressed
continously between the
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continously between the
screws and the side
walls of the housing.
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7. Roots compressor
This type of compressor
employs two profiled

shafts which rotate one
against the other.
A volume of air trapped
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A volume of air trapped
in the chambers
between the profiled
shafts and the housing
is pushed against the
pressure at the exit side.
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Video
8. Turbine compressor
The shaft is driven at
high revolutions.
Turbine sections on
the shaft accelerate
the air to a high
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the air to a high
speed.
Several stages are
required, each stage
will increase the
pressure at a ration of
approx 1.3
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9. Turbine compressor - four stages-
radial compressor
Turbine compressor of

this type with
distribution of the
driving force via gears
are designed for very
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are designed for very
large volumes of
compressed air. There
are intermediate
coolers between the
various stages of
compression.
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10. Axial turbine compressor
The air moves through
the vanes and is
accelerated in the
direction parallel to the
drive shaft.
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drive shaft.
For low pressures
only.
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