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INDEX Introduction.
History.
Classification.
Boiler Mountings.
Boilers Accessories.
Important Formulas of Boiler.
Reference.
INTRODUCTIONA boiler is defined as “a closed vessel in which water or other liquid
is heated and steam or vapour is generated”.
As per “The India Boiler Act 1923, a boiler is
a steam generating closed vessel whose minimum
capacity is 22.75 litres”.
In order to generate sream, boiler water is
subjected to heat produced by combustion of fuel
in the boiler furnace.
HISTORY
• In 298-306 AD the Romans built large baths with heated water.
• In 1679 the first boiler with a safety valve was designed by Danis Papin.
• In 1766 John Blakey patented the first water tube boiler.
• In 1804 an American, John Stevens made a boiler with a combination
of small tubes, connected at one end to a reservoir.
• In 1867 two American George Babcock & Stephen Wilcox Created a
water tube boiler name Babcock and Wilcox boiler.
------After that many modern boiler is created.
1) NATURE OF USE-
There are Three types of boiler------
Stationary Boilers-
Babcock & Wilcox Boiler.
Locomotive Boiler-
Traction engines, Steam rollers, Portable engine.
Marine Boiler-
Steam Ships.
2) POSITION OF WATER & FLUE GASES-
There are Two types of boiler------
Water tube Boiler-
Babcock & Wilcox Boiler.
Fire tube Boiler-
Cochran Boiler, Lancashire Boiler.
3) AXIS OF BOILER SHELL-
There are Two types of boiler------
Vertical Boiler-
Cochran Boiler.
Horizontal Boiler-
Lancashire Boiler.
4) POSITION OF FURNACE-
There are Two types of boiler------
Internally Fired Boiler-
Lancashire Boiler.
Externally Fired Boiler-
Babcock & Wilcox Boiler.
5) NATURE OF CIRCULATION-
There are Two types of boiler------
Free Circulation-
Lancashire Boiler, Cochran Boiler.
Forced Circulation-
Benson Boiler, La Mont Boiler, Loeffler Boiler.
6) NATURE OF FUELS USED-
There are Four types of boiler------
Solid Fuels-
Babcock & Wilcox Boiler.
Liquid Fuels-
Volex Boiler.
Gas Fuels-
Babcock & Wilcox Boiler.
Nuclear Boiler
7) NO. OF TUBES USED-
There are Two types of boiler-----
Single Tubular Boiler-
Cornish Boiler.
Multitubular Boiler-
Cochran Boiler.
BOILER MOUNTINGS Definition-
Boiler mountings are those mechanical appliances which are
considered essential for operating a boiler smoothly and safely and
which are usually mounted on the surface of a boiler.
1) WATER LEVEL INDICATOR
Function:-
It indicate the water level inside
the boiler vessel. It shows the level in the boiler
drum.
2) FUSIBLE PLUG
Function:-
It is use to protect the
boil against damage due to overheating
caused by low water level in the boiler.
3) MAIN STEAM STOP VALVE
Function:-
It regulate the flow of
steam from boiler to the steam pipe or
from one steam pipe to the other.
4) SAFETY VALVE
Function:-
They guard the
boiler against the excessive high
pressure of steam inside the drum.
If the pressure of steam in the
boiler drum exceeds the working
pressure then the safety valve
allows blow-off the excess quantity
of steam to atmosphere.
5) PRESSURE GAUGE
Function:-
It indicates the pressure of
steam in boiler
6) BLOW OFF COCK
Function:-
The function of blow-off cock is to
discharge mud and other sediments deposited
In the bottom of the water space in the boiler.
When it is open, water under the pressure rushes
out, thus carrying sediments and mud.
7) FEED CHECK VALVE
Function:-
It controls the supply of
water from the boiler when the feed pump
pressure is less than boiler pressure or
pump is stopped.
BOILERS ACCESSORIES Definition-
Boilers Accessories are those appliances which are
installed along with a boiler to improve the operating condition and
overall efficiency of the boiler plant.
1) FEED PUMP
Function:-
The feed pump is a pump
which is used to deliver feed water to
the boiler.
2) INJECTOR
Function:-
Injector is used to feed water
In the boiler. It is commonly employees for
vertical boiler and does not find its
application in large capacity high pressure
boilers . it also uses more space is not space
is not available for the installation for feed
pump.
3) ECONOMISER
Function:-
Economiser increases
the temperature of feed water using
waste of heat to flue gases leaving
the boiler through chimney.
4) SUPER HEATER
Function:-
The function of super
heater is to increase the temperature
of the steam above its saturation
point.
5) STEAM SEPARATOR
Function:-
A Steam separator,
sometimes referred to as a moisture
separator, is a device for separating
water droplets from steam.
6) AIR PREHEATER
Function:-
An air preheater is a
general term to describe any device
designed to heat air before another
process (for example, combustion in
a boiler) with the primary objective of
increasing the thermal efficiency of
the process.
7) STEAM TRAP
Function:-
Steam Trap is
automatically to drain away or
return to the boiler, the water
collected in the steam pipe or
steam jacket due to partial
condensation of steam without
allowing steam escape.
IMPORTANT FORMULAS OF BOILER Finding The Height Of Chimney:-
h=353H
h= Height of water column.
T1= Abs. Temp. of outside air.
H= Height of Chimney.
T= Abs. Temp. of chimney gas.
W= Mass of air required in kg. per kg of fuel
burnt in the boiler furnace
Finding Thermal Efficiency:-
T.E=`
W= Amount of steam produce per hour.
w0= Amount of coal burnt per hour.
h= Total heat of steam.
Cv= Calorific value of coal.
REFERENCE Books:-
Thermal engineering by A.R Basu.
Encyclopedia Britannica.
Internet:-
www.google.co.in
http://en.wikipedia.org/wiki/Boiler