This document discusses the classification and components of boilers. It begins by defining a boiler as a closed vessel that uses combustion to generate steam from water. Boilers can be classified based on their orientation, position of water and gases, location of the furnace, application, steam pressure, and water circulation method. Fire tube and water tube boilers are described based on how hot gases and water flow. Key external components of boilers like the shell, furnace, and firebox are identified. The Cochran boiler is then summarized as having a cylindrical vertical drum with a domed top and hemispherical firebox and horizontal fire tubes.

1. Subject : Elements of Mechanical
Engineering (2110006)
Topic :-
Submitted By:-
Dharmesh Raval Roll no :- 119079
Haresh Nakum Roll no :- 119080
Raviraj Singh Dabhi Roll no :- 119081
Rushit Makwana Roll no :- 119082
Jaykumar Jaiswal Roll no :- 119083
Bhalgamiya Vikas Roll no :- 119084

2. It is a closed vessel in which heat produced by the
combustion of fuel is utilized to generate steam from water
What is a Boiler?
The steam produced is utilized for :-
1. Driving prime movers like steam turbines , steam
engines, etc.
2. Industrial purposes like process heating.

3.  The Boiler can be classified as follows.
1. According to geometric orientation of boiler
1.Horizontal Boiler:- The axis is horizontal.
2. Vertical Boiler:- The axis is vertical.
Classification of Boilers
2. According to relative position of water and hot gases
1. Fire tube boilers:- In fire tube boilers, hot gases pass through tubes
which are surrounded with water.
2. Water tube boilers:-In water tube boilers, water circulates through a large
number of tubes and hot gases pass around them.

4. 3. According to location or position of the furnace.
1.Externallyfiredboilers :-Externally fired boilers have a separate furnace
built outside the boiler shell and usually below it.
2. Internally fired boilers:- In internally fired boilers, the furnace forms an
integral part of the boilers structure. The vertical
tubular, locomotive and the scotch marine boilers
are well known examples.

5. 4. According to the application
1.Stationery boilers :- A stationary boilers is one of which is
installed permanently on a land installation.
2. Mobile boilers:- It is a portble boiler having only one fire or water tube for
circulation of hot gases or water.
5. According to steam pressure
1.High pressureboilers :- Working pressure is higher than 25 bar.
2.Mediumpressureboilers :- Working pressure is between 10-25 bar.
3.Low pressure boiler:- Working pressure is between 3.5-10 bar.

6. 6. According to method of water circulation
1. Natural circulationboilers:- In this type of boler, water flow takes
place naturally by density difference of
water.
2. Forcedcirculationboilers:- In this type of boler, water flow takes
place by pump.
7. According to number of tubes in the boiler
1. Singletube boiler:- This type of boiler have only one fire or water tubes
for the circulation of hot gases or water.
2. Multi tube boilers:- This type of boiler have two or more fire or water
tubes for circulation of hot gases or water.

7. 1. Cylindrical Shell
2. Grate
3. Furnace
4. Fire hole
5. Ash pit (ash pan)
6. Smoke chamber (smoke box)
7. Man hole
8. Hand holes
9. Mud box
10. Steam collecting pipe (Anti
priming)

8. Cochran boiler
Cochran boiler is a cylindrical vertical
water drum with a hemispherical
domed top.
This domed shape is strong enough not
to require staying.
The fireboxis another hemispherical
dome, riveted to the base foundation
ring to give a narrow waterspace.
The fire-tubes are arranged in a single
horizontal group above this, mounted
between two flat vertical plates that are
inset into the boiler barrel.
The first of these plates forms a
shallow combustion chamber and is
connected to the firebox by a short
diagonal neck.

9. Cochran boiler
The water is supplied to the boiler through feed check valve. The coal is
introduced to the gratethrough the fire door
The hot gases produced from the furnace enters combystion chamber through
flue pipe.The hot gases produced from furnace enters combustion chamber
through flue pipe and enters into horizontal fire tubes.
Convection heat transfer take place from