Hydraulic machine classification

HYDRAULIC MACHINE
CLASSIFICATION
Prepared by : ahmed saad aboyossef

Fluid machine can be classified
by :
 Energy direction
 Fluid type
 Motion type
 Degree of reaction
ahmed saad aboyoussef 2

Energy direction in hydraulic
machine
Power absorption machine Power producing machine
 Pump
 Compressor
 Fans
 Turbine

Fluid type
Compressible In compressible
 Compressor
 Steam turbine
 Gas turbine
 Pump
 Hydraulic turbine

Motion type
Net positive displacement Dynamic head
 Rotary
 Reciprocating
 Centrifugal
 Special jet type

Net positive displacement
machine
Rotary
Gear machine
Screw
machine
Rotary piston
Reciprocating
Reciprocating
piston
Diaphragm

Pumps
o Pump is a hydraulic machinery that convert
mechanical energy to hydraulic energy
(pressure) .
o Pump have different types and use in
different fields .
o Used to pump a liquid from lower pressure
area to a High pressure area ,To increase Flow
rate andTo move liquid from lower elevation
to higher elevation.
o Convert electrical energy to hydraulic energy
.

Pumps
Dynamic head pump Positive displacement pump
 Low pressure.
 High flow rate .
 High efficiency with low
viscosity fluid .
 Flow rate and head depend
on system .
 HighViscosity application.
 High pressure .
 low flow rate .
 High efficiency with oil.
 pressure and flow rate
don’t depend on system
(fixed with any system) .
 lowViscosity application.

Positive displacement pump
Rotary Reciprocating
 Gear .
 Vane.
 Rotary piston.
 Lobe.
 Screw.
 Piston.
 Diaphragm

Gear pump
Gear
pump
Internal
gear
External
gear Gerotor

External
gear pump
• Consist of two gear
meshed externally .
• Max pressure in
operation is 300 bar .
• Easy in construction and
maintenance .
• Output flow is consistent
at the same speed of
shaft .
• Use in heavy equipment
.
• Oil is favorable fluid used
in this pump .

internal gear pump
• consist of two gear
meshed internally and
crescent to force fluid to
move from input to
output port.
• Max pressure to operate
is 300 bar .
• Uses as a charge pump
for piston pump in high
pressure hydraulic
circuit .
• Favorable fluid used in
this pump is oil .

Gerotor pump
• It is like internal gear
pump but replace small
teeth with big teeth and
remove the crescent .
• big teeth to force fluid to
move from input to
output port.
• Uses with fluid such oil.

Lobe pump
• Uses lobes to block fluid and
force it to move from input to
output port .
• There are great Leaking
because lobes is few and big .
• Uses with Liquid mud and
liquid which contain solid
bodies

Screw pump
• Consist of two
screws externally
meshed .
• When the driver
screw rotate ,
screws forced
fluid to move hi a
certain direction .
• Uses with heavy
fluid like matzo .

Vane pump
 Depend on centrifugal force to push the
vanes out from slot in rotor to block the fluid
and forced it to move from inlet port and
output port .
 Max pressure to operate 250 bar .
 Uses with fluid such as oil .
 Uses in heavy equipment.

Vane pump
Vane pump
Unbalanced balanced Variable
displacement

Unbalanced vane pump
• Have one inlet port and one
exit port .
• Have round geometry
• Due to pressure difference ,
there are a force which
bend the rotor .
• Have a fixed discharge for
every revolution at the
same speed .

Balanced vane pump
• There are two inlet and
tow exit port .
• Have a elliptical
geometry .
• There is no unbalanced
force .
• Have a fixed discharge
for every revolution at
the same speed

Variable displacement vane pump
• Have one inlet port and one exit
port .
• Have round geometry .
• Have a spring which change the
eccentricity between rotor and
cam ring .
• So , we can obtain a variable
output flow rate at constant
speed of rotor by controlling in
spring stretch .
• Rarely to use .

Rotary piston pump
Radial piston Axial piston
 Piston move radially to
pump liquid .
 Use to pump oil in
hydraulic circuit .
 Rarely to use .
 Piston move axially to
pump liquid .
 Use to pump oil in
hydraulic circuit .
 Use in heavy equipment .

Axial piston pump(fixed)
• High efficiency .
• Out put pressure
reaches to 500
bar .
• Displacement
depends on angle
between swash
plate and pistons
.
• Constant volume
flow rate at
constant speed
of shaft .

Axial piston pump(variable
displacement)
• Supply a variable flow
rate per revolution at
constant speed by
change the angle
between swash plate
and pistons with
control lever .

Rotary piston pump
Piston move
radially depending
on centrifugal force
.
Rarely in usage .

reciprocating pump .
• It is often used
where a relatively
small quantity of
liquid and high
pressure .
• Operate with 3
piston to avoid
flow pulsation .

Diaphragm pump
• a diaphragm is a sheet of a semi-
flexible material anchored at its
periphery and most often round in
shape.
• A typical design is to have air on one
side constantly vary in pressure, with
fluid on the other side.The increase
and decrease in volume caused by the
action of the diaphragm alternately
forces fluid out the chamber and draws
more fluid in from its source.
• Uses as Pressure regulators for fuel
systems in automotive applications .

Dynamic head pump
Centrifugal
Axial

Dynamic head pump
Centrifugal Axial
 Outlet flow is perpendicular
to pump axis .
 Supply head and flow
average .
 Common usage .
 Inlet and outlet flow is at the
same direction of pump axis .
 Supply low head and high
flow rate .

Dynamic head machine
Centrifugal
No of
suction
Single Double
Impeller
type
close
Semi
close
open
No of
blade
Single
Two
multi
Flow
direction
Radial
Axial
mixed
No of
stage
Double
Single
Multi

Compressors classification
Compresso
r
Positive
displacement
Reciprocating
Trunk crosshead
Rotary
screw lobe
Vane
Rotodynamic
Centrifugal axial

Applications of Air
Compressors
 Operating pneumatic tools : drills, screw drivers,
hammers etc.
 For pneumatic cranes and automobiles, railways
and presses
 For dusters and sprayers that are used in
agriculture
 CNC machine tools

Functioning of Air
Compressor
 Air is compressed and stored inside the air
receiver.
 The function of the air compressor is to
reduce volume and induce pressure in the
compressed air.
 The main function of the compress is to
convert electric energy into kinetic energy

Reciprocating or
Piston
Compressors
• Compresses gas using a
piston which is driven
inside in a reciprocal way.
• The gas or the air enters
and is stored in a
pressurized cylinder.
• Later, the gas or is
released through valves .

Rotary Sliding Vane Compressors
• Comprises a
cylinder that is
placed inside a
water jacketed
cylinder.
• The rotor forces
the air against
the wall thereby
compressing the
air and releasing
it afterwards .

Rotary Screw Compressors
• type of gas compressor .
• They are commonly used
to replace piston
compressors where large
volumes of high pressure
air are needed, either for
large industrial
applications or to operate
high-power air tools such
as jackhammers.

Centrifugal
Compressors
• Widespread use, many
applications .
• Gas is accelerated
outwards by rotating
impeller.
• Can be built for operation
as low as 5 psi, or operation
as high as 8,000 psi (35 kPa
or 55,000 kPa).
• Sizes range from 300 hp to
50,000 hp.

Axial compressors
• Gas flows in
direction of
rotating shaft.
• Can be built for
lower pressures
only 10 to 100 psi
(0.7 to 6.8 Bar).
• High flow rate
• Efficient.
• Not as common
as centrifugal .

Turbine
 A turbine is a rotatory engine that exerts
energy from fluid power and convert it into
useful work .
 Turbines split into hydraulic turbine , gas
turbine and steam turbine .

hydraulic turbine
 Hydraulic turbines convert the potential
energy of water into mechanical work.
 Three most popular hydraulic turbines are :
1. Pelton wheel (Pelton turbine)
2. Kaplan turbine (Propeller turbine)
3. Francis turbine

Classification of hydraulic
turbine
 According to type of energy at inlet :
1. Impulse .
2. Reaction .
 according to specific speed of turbine :
1. Low , less than 60
2. Medium , from 60 to 400
3. High , more than 400

Classification of hydraulic
turbine
 According to water head and quantity of
water available :
1. High head ,small quantity .
2. Medium head , medium quantity .
3. Low head , large quantity .

According to type of energy
at inlet
Impulse Reaction
 The impulse generated by
changing the direction of
flow of high velocity .
 .The fluid is accelerated
using a nozzle, which
changes its pressure head
to velocity head .
 all the available energy of
water is converted into
kinetic energy .
 The water is guided by the
guide blades to flow over
the runner vanes .
 at the entrance to the
runner, only a part of the
available energy of water is
converted into kinetic
energy and a greater part
remains in the form of
pressure energy.

Pelton Wheel (Pelton turbine)
• Pelton wheel is a high head turbine. It
is used with heads of more than 500 .
• The flow of water is tangential to the
runner. So it is a tangential flow
impulse turbine.
• A Pelton runner consists of a single
wheel mounted on a horizontal shaft.
• Water falls towards the turbine
through a pipe called penstock and
flows through a nozzle.
• The high speed jet of water hits the
buckets (vanes) on the wheel and
causes the wheel to rotate .

Kaplan turbine
• Kaplan turbine is a low head
turbine and used for heads of
less than 80 meters .
• The turbine wheel, which is
completely under water, is
turned by the pressure of
water against its blades.
• Guide vanes regulate the
amount of water reaching the
wheel.
• Use in ship .
• Water enters the runner vanes
axially and leaves axially, hence
it is called axial flow turbine.

Francis turbine
• It is used when the head is
between 80 to 500 meters. i.e. it is
a medium head turbine.
• It is a mixed flow reaction turbine.
• A Francis turbine rotates in a
closed casing.
• Its wheel has many curved blades
called runner vanes as many as 24.
• Its shaft is vertical.The wheel of a
Francis turbine operates under
water.
• The guide vanes and stay vanes
control the amount of water
flowing into the runner vanes.

Steam turbine
 ATurbine is a device which converts the heat
energy of steam into the kinetic energy & then to
rotational energy.
 The Power in a steam turbine is obtained by the
rate of change in momentum of a high velocity
jet of steam impinging on a curved blade which
is free to rotate.
 The basic cycle for the steam turbine power
plant is the Rankine cycle.The modern Power
plant uses the Rankine cycle modified to include
superheating, regenerative feed water heating &
reheating.

CLASSIFICATION OF STEAM TURBINE
Simple impulse turbine Reaction turbine
 the drop in pressure takes place in
fixed nozzles as well as moving
blades.The pressure drops
suffered by steam while passing
through the moving blades causes
a further generation of kinetic
energy within these blades, giving
rise to reaction and add to the
propelling force, which is applied
through the rotor to the turbine
shaft.The blade passage cross-
sectional area is varied (converging
type).
 In the reaction turbine high
pressure steam from the boiler,
passes through the nozzle.
When the steam comes out
through these nozzles the
velocity of steam increases &
then strike on fixed blade. In
this type of turbine there is a
gradually pressure drop takes
place over fixed & moving
blade.

Advantages of Steam turbines
 Thermal Efficiency of a SteamTurbine is much
higher than that of a steam engine.
 The SteamTurbine develops power at a
uniform rate .
 In a steam turbine there is no loss due to initial
condensation of steam.
 In SteamTurbine no friction losses are there .

Disadvantages of steam turbines
 High efficiency is ordinarily obtained only at
high speed.
 Turbines can rotate in only one direction.
 These devices are heavy and cumbersome.

Gas turbine
 Use in power plant .
 Working principle :
1. Air is compressed(squeezed) to high
pressure by a compressor.
2. Then fuel and compressed air are mixed in a
combustion chamber and ignited.
3. Hot gases are given off, which spin the
turbine wheels.

Gas turbine
 Hot gases move through a multistage gas
turbine.
 Like in steam turbine, the gas turbine also has
stationary and moving blades.
 The stationary blades
 guide the moving gases to the rotor blades
 adjust its velocity.
 The shaft of the turbine is coupled to a
generator.

Applications of gas turbine
 drive pumps, compressors and high speed
cars.
 aircraft and ships.
 Power generation (used for peak load and as
stand-by unit).

Advantages of gas turbine power
plant
 Storage of fuel requires less area and handling is
easy.
 The cost of maintenance is less.
 It is simple in construction.There is no need for
boiler, condenser and other accessories as in the
case of steam power plants.
 Cheaper fuel such as kerosene , paraffin, benzene
and powdered coal can be used which are cheaper
than petrol and diesel.
 Gas turbine plants can be used in water scarcity
areas.
 Less pollution and less water is required.

Disadvantages of gas turbine
power plant
 66% of the power developed is used to drive the
compressor.Therefore the gas turbine unit has a
low thermal efficiency.
 The running speed of gas turbine is in the range
of (40,000 to 100,000 rpm) and the operating
temperature is as high as 1100 – 12600C. For this
reason special metals and alloys have to be used
for the various parts of the turbine.
 High frequency noise from the compressor is
objectionable.

Gas turbine

Thank you

Hydraulic machine classification

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