Boilers

1. BASIC MECHENICAL
ENGINEERING
BME2003
Dr. D.K. Mudaiya

2. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
“BOILERS”
 A steam boiler or steam generator is a closed vessel in
which water is heated, vaporized and converted into
steam at a pressure higher than the atmospheric
pressure.
The heat energy required for steam generation
is produced by burning of the fuel in the furnace.
These fuels may be
 Solid fuels – Coal etc.
 Liquid fuels – Diesel, furnace oil etc.
 Gaseous fuels- Natural gas, LPG etc.

3. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
 The steam produced in the boiler may be supplied
 (a) To external combustion engine i.e. Steam engines,
Steam turbines etc.
 (b) At Low pressure for industrial process work in
cotton mills, Sugar industries, Breweries etc.
 (c) For producing Hot water, which can be used for
heating installations at much lower pressure.

4. COCHRAN
BOILER

5. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
Boiler Principle Parts & their Functions
Drum:- The boiler drum consists of shell and end
heads. The shell of the boiler consists of one or more
steel plates bent into cylindrical form and riveted.
 The ends of the shell are closed by means of the flat or
curved plates called Boiler heads.
 Grate:- it is the space located below the furnace and
consists of cast iron bars upon which the fuel is burnt.
 The air can pass through the space between the bars
and can support the combustion process.
 The ashes can fall down through these spaces.

6. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
 Furnace:- it is the space above the grate and below
the boiler shell.
 It is the space where volatile matter and combustible
gases are burnt and flue gases are generated.
 Flue Gases:- It is the hot mixture of products of
combustion, generated in the furnace.
 Heating Surface:- It is the surface of the boiler
which is exposed to hot flue gases on one side and
water on the other side.

7. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
 Water Space:- The space of the boiler occupied by
water is called water space.
 Steam Space:- The entire space of boiler shell which is
not occupied by water is called steam space.
 Feed Water :- The water supplied to the boiler is
called feed water.
 Working Pressure:- It is the pressure of steam
generated in the boiler and super
heater.

8. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
 Air Preheater:- The fresh air going to furnace is
preheated to improve the combustion process. The
device of air heating system is known as Air preheater.
 Economizer:- The feed water supplied to boiler is
preheated by the waste hot gases before they escape to
the chimney.
Therefore some of the waste heat is
recovered by feed water and plant efficiency improves.

9. SAGAR INSTITUTE OF RESEARCH AND TECHNOLOGY
 Super Heater:- It is a device which heat the
saturated steam generated in the boiler..
 The super heaters are located above the furnace .
 They increase heat content of steam without
increasing the pressure.
 Super heaters are always placed at first bend of the
flue gases.