1) The document provides information on various types of boilers including Cochran boiler, Lancashire boiler, and Badcock and Wilcox water tube boiler. It describes the basic construction and working of these boilers. 2) The document also discusses common boiler mountings and accessories such as pressure gauges, water level indicators, safety valves, feed pumps, and air preheaters. It explains the main functions of these components for monitoring and controlling the boiler. 3) Additionally, the document covers other boiler auxiliaries like feed water heaters, superheaters, and draught systems. It describes how these systems enhance the efficiency and performance of boilers.

1. SHANKHERSINH VAGHELA
BAPU INSTITUTE OF
TECHNOLOGY
MECHANICAL DEPARTMENT
BOILERS
PREPARED BY=
Krishna Gondaliya-
(140750106032)
Ujas Patel-
(140750106096)
Keval Barbasiya-
(140750106004)
Ambili punnath-
(140750106106)
GUIDED BY=
Nishant Patel

2. INDEX
I. Introduction
II. Cochran boiler
III. Lancashire boiler
IV. Badcock and Wilcox water tube boiler
V. Boiler mountings and accessories

3. INTRODUCTION
 Steam boiler is a closed vessel in which
heat produced by the combustion of fuel is
utilized to produce steam from water, at
desired temperature and pressure.
 Boiler is a device used for generating
steam which is used for driving prime
movers like steam turbines or industrial
purposes like process heating.
 According to INDIAN BOLIER
REGULATION a boiler is a closed
pressure vessel with capacity exceeding
22.75 litres for generating steam under
pressure.

4. COCHRAN BOILER
 Cochran boiler is modification
of simple vertical boiler where
heating surface has been
increased by increasing
numbers of fire tubes.
 It is used for low rate of
steam generation.

5. CONSTRUCTION
 The boiler consists of a cylindrical shell,
hemispherical fire tube and chimney.
 The hemispherical crown of boiler gives good
strength to withstand steam inside the boiler.
 The grate is placed at the bottom of furnace
and ash pit is located below the grate.
 The wall of combustion chamber is lined with
the fire bricks.

6. WORKING
 The water is supplied to the boiler through feed
check value.
 The coal is introduced to the grate through the fire
door.
 The hot gases produced from furnace enters
combustion chamber through flue pipe.
 Heat transfer takes place from flue gases passing
inside the tube of water surrounded the tubes by
convection.
 The flue gases coming from of fire tubes enter into
smoke box.
 Finally they discharge to atmosphere through
chimney.

7. ADVANTAGES AND
DISADVANTAGES
 ADVANTAGES
 It is compact and
portable boiler.
 Initial cost of boiler
is less.
 It can be moved and
set up readily in
different locations.
 Easy and quick
installation.
 DISADVANTAGES
 Steam raising
capacity is less.
 Water along the
steam may enter the
steam pipe under
heavy loads due to
small steam space.
 Efficiency is poor in
smaller sizes.

8. LANCASHIRE BOILER
 Lancashire boiler is simple
in design, easy to operate
and less operating and
maintenance cost.
 It is commonly used in
suger mills, textile
industries where power
generation as well as
access heating is
required.
 It is one of the commonly
used as a stationary
boiler.

9. CONSTRUCTION
 It consists of a cylindrical shell and two fire tubes.
 The cylindrical shell is placed over the brick structure.
 One flue passes from inside the boiler, second from
below and third from the side of boiler shell.
 These three passes are formed by brick work, one
bottom flue and two side flue.
 A fire is provided at the end of the grate to prevent coal
and ash particles into the interior of the furnace tubes.
 Superheater is provided at the end of the main flue
tubes in passage of flue gases.
 While an economiser is at the end of the side flues,
before exhausting the gases to chimney.
 Damper is placed at the end of side flues.

10. WORKING
 The coal is introduced to the grate
through fire holes.
 The combustion of coal takes place in
presence of air which is regulated by
damper.
 The combustion will produce gases.

11. ADVANTAGES AND
DISADVANTAGES
ADVANTAGES
 Due to three passes of flue
gases, the heating surface
area per unit volume of boiler
is large.
 The fluctuations in load can
be easily met by this boiler
due to large reservoir.
 Easy operation, low
maintenance costs, easy to
clean and inspect.
 By use of economiser and
superheater, maximum heat
of flue gases is utilized, so
efficiency of boiler can be
increased.
DISADVANTAGES
 Maximum working
pressure is limited to 16
bars.
 Due to brick work, more
floor area is required.
 Response of pressure
build up is less.
 The furnace is inside
the tubes therefore the
grate area is restricted.

12. BADCOCK AND WILCOX BOILER
 It is used in stationary
and marine engine.
 The efficiency of this
boiler is much greater
than the fire tube boiler.
 This boiler is exclusively
used when pressure is
above 10 bar and steam
generating capacity is
required higher then
7000kg/hr.

13. CONSTRUCTION
 It consists of inclined water tubes, a steam and water
drum, a mud box and superheater.
 The drum is connected to up take and down take header
by short riser tubes.
 These headers are connected to a series of inclined
water tubes.
 The hand hole is provided in header in front of each tube
for cleaning and inspection of tubes.
 The baffles plates are provided in order to make the
circulation of hot gases in sine of wave form.
 A damper is fitted at back of boiler to ragulate the
draught and the furnace is equipped with chain grate
stroker to feed the coal to furnace.
 Soot doors is provided to clean the outside of the water
tubes & to remove soot.

14. WORKING
 The water is feed into the drum through the feed
check valve.
 Due to gravity water passes through the short
raiser tubes, header and fills up the inclined water
tubes. Then water collects in the drum.
 Initially one half of drum is filled up with water. The
coal is introduced to furnace grate by help of
stroker.
 The coal is fired, hot gases produced is first forced
to move upwards between tubes. The damper
controls the flow of air into the furnace.
 Due to heating of the water density of water
decreases. Low density water moves upward in
water tubes.

15. CONTINUE......
 The water tubes just above furnace is heated
comparatively at higher temperature than the
rest of it. Therefore low density water
converted into the steam.
 Then the steam enters through the
antipriming pipe and flows in the superheater
tubes where it is further heated and is finally
taken out through the main stop valve and
supplied to the engine when needed.

16. ADVANTAGES
 The steam generation capacity of this boiler
is very high, about 2000 to 40,000 kg/hr.
 Replacement of defective tubes is easy.
 The draught losses as compared to other
boilers is minimum.
 It is used in power stations for generating
large quantity of steam.
 Boiler is required less space area compared
to fire tube boilers, and offers greater
operational safety.

17. BOILER MOUNTINGS
PRESSURE GAUGE
 It is an instrument
measure the pressure
of steam in boiler.

18. WATER LEVEL INDICATOR
 Indicate the water
level inside the
boiler. It shows level
of water in the boiler
drum.

19. STEAM STOP VALVE
 To regulate the flow
of steam from boiler
to the steam pipe or
from one steam pipe
to the other.

20. FEED CHECK VALVE
 To control the supply of
water to the boiler and to
prevent the back flow of
water from the boiler
when the feed pump
pressure is less then
boiler pressure or pump
is stopped.

21. BLOW-OFF COCK
It performs two functions
 To discharge periodically a
portion of water which contains
mud, scale or sediments at
bottom of boiler vessel while
boiler is in operation. We know
that water feed to the boiler, it
contains some sediments and
dissolved salts, it is not
converted to steam, but
diposited on the bottom of boiler
vessel. So blow off cock useful
to discharge a water which
contains mud, sediments, etc.
 To empty the boiler when
necessary for cleaning,
inspection and repair.

22. FUSIBLE PLUG
 To protect the boiler
against damage due
to overheating
caused by low water
level in boiler.

23. SAFETY VALVES
 To release the excess steam when the pressure of steam
inside the boiler increases higher than the safe pressure.
Safety valve are used to maintain safe pressure inside the
boiler.
 As soon as pressure of steam inside the boiler increases
higher than the safety pressure, safety valve automatically
opens and excess steam rushes out into the atmosphere still
pressure drops down to normal value. Safety valve generally
mounted on the top of the shell. All boiler should have at least
two safety valves.
 The safety valve may be classified as
1) Dead weight safety valve
2) Lever safety valve
3) Spring loaded safety valve
4) High steam and low steam water safety valve

25. BOILER ACCESSORIES
FEED PUMP
 Function
 To feed the water into the boiler through the
feed check valve.
 It is used to deliver feed water to the boiler
under pressure.
 It is a device of boiler use to supply proper
amount of water at least equal to that
evaporated in the boiler.
 These pumps are classifies as
1) Reciprocating pumps – simplex, duplex, triplex
2) Rotory pump
3) Centrifugal pump

27. FEED WATER HEATERS
 FUNCTION
 To increase the temperature of the feed water
before it enters into the boiler.
 Feed water heaters can be classified based on
heat utilized for heating feed water
I. Economiser
II. Exhaust steam feed water heater

28. ECONOMISER
 It is a device in which the
waste heat of flue gases
is utilised for heating the
feed water.
 Function
 To increase the
temperature of feed
water using waste heat
from the exhaust steam
from boiler is utilised for
heating the feed water.

29. EXHAUST STEAM FEED WATER
HEATER
 It is a device in which
the heat from the
exhaust steam or steam
from boiler is utilised for
heating the feed water.
 Function
 To increase temperature
of feed water using heat
from exhaust steam of
steam turbine or steam
from boiler.

30. SUPERHEATER
 Function
 To increase the temperature
of the steam above its
saturation point.
 The steam generated above
the surface of water is always
wet.
 The main negative effect of
supplying wet steam to
steam turbine or steam
engine are errosion of turbine
blades, pipes etc., and
condensetion losses occurs.
 Therefore steam must be
superheated before
supplying to steam turbine or
steam engine.

31. STEAM SEPARATOR
 Function
 To remove the suspended
water particles from the
steam.
 Steam is collected from the
boiler may be wet, dry or
superheated, but many case
steam becomes wet due to
loss of heat during passing
in steam pipe.
 The use of wet steam in a
engine or turbine is not
economical.
 So there is need to seperate
the water particles from the
steam.

32. STEAM TRAP
 Function
 To drain away
automatically the
condensed steam
from steam pipes,
steam jackets and
steam seperators
without permitting
any steam to
escape.

33. AIR PREHEATER
 Function
 To increase the
temperature of air
before it supply to the
furnace using heat from
flue gases passing
through chimney.

34. DRAUGHT SYSTEM
 It is a pressure difference required to maintain constant flow of
air to discharge the exhaust gases through the chimney to
atmosphere.
 Function
 Draught system creates pressure difference to introduce
required quality of air to the grate for combustion of fuel and to
carry away the burned product of combustion and discharge to
atmosphere.
 Classification
I. Natural draught – chimney
II. Artificial draught – 1)Steam jet = a)Induced fan
b)Forced fan
2)Mechanical = a)Induced fan
b)Forced fan
c)Balanced(induced &
forced fan)

35. YOU