describe different types of steam boilers, mountings and accessories

2. Steam turbine power plant

4. Definition :
 What is boiler :Boiler is a closed vessel in
which the water under pressure is
transferred into steam.
 Function :The function of boiler is to
transfer the heat to the water in the efficient
manner.
 Quality : A boiler must be designed to
absorb the maximum amount of heat
release in the process of combustion.

5. Application
POWER GENERATION : mechanical or electrical
power may be generated by expanding steam in the
steam engine or steam turbine.
HEATING : the steam can be used for heating
residential and industrial buildings in cold weather
and for producing hot waters for hot water supply
INDUSTRIAL PROCESSES : steam can also be used for
industrial processes such as for sizing and bleaching
etc. in textile industries and other applications like
sugar mills, cement, agricultural and chemical
industries.

6. Boiler Terms

7.  Boiler shell
 Combustion chamber
 Grate
 Furnace
 Mountings
 Accessories

8. Classification of boilers
1) ACCORDING TO THE CONTENTS IN THE TUBE:
a) Fire tube or smoke tube boiler
b) Water tube boiler.
2) ACCORGING TO POSITION OF FURNACE:
a) Internally fired boilers
b) Externally fired boilers
3) ACCORDING TO AXIS OF FURNACE:
a) Vertical boilers
b) Horizontal boilers
c) Inclined boilers

9. 4) ACCORDING TO NUMBER OF TUBES:
a) Single tube boilers
b) Multi tube boilers
5) ACCORDING TO METHOD OF CIRCULATION OF
WATER:
a) Natural circulation boilers
b) Forced circulation boiler
6) ACCORDING TO THE USE
a) Stationary boilers
b) Mobile boilers
7) ACCORDING TO THE PRESSURE
a) High pressure boilers
b) Low pressure boilers

10. Simple vertical boiler

11. Features :
 Vertical
 Single tube
 Internally fired
 Natural circulation
 Water tube boiler
 Low pressure boiler
 Upto maximum steam pressure of 10 bar
 Maximum evaporative capacity 2500 kg/hr of steam

12.  It produces steam at a low pressure in small quantities
 Used for power generation and at places where the
space is limited
 Consists of cylindrical shell
At the bottom of the fire box, is a grate
 Fire box is fitted with one or more inclined cross tubes
 Inclined cross tubes increases the heating surface area
 Man hole is provided at the top to clean the boiler
 It can be easily transported

14. Features :
 Vertical
 Multi tubular
 Internally fired
 Natural circulation
 Fire tube boiler
 Low pressure boiler
 Upto maximum steam pressure of 15 bar
 Maximum evaporative capacity 4000 kg/hr of steam

15.  It is an improved type of simple vertical boiler
Consists of an external cylindrical shell and a fire box
Shell and fire box are both hemispherical shape
Hemispherical shape gives maximum space and
strength to withstand the pressure of steam inside the
boiler
 Flue gases from the combustion chamber flow to the
smoke box through a number of smoke tubes
 The combustion chamber is lined with fire bricks on
the shell side

16. Bobcock and wilcox boiler

17. Features :
 horizontal, stationary and straight
Externally fired
Natural circulation
Water tube boiler
Minimum steam pressure 71 bar
Steam production rate 2000-40000 kg/hr
Efficiency 60 tp 80%

18.  it consists of three main parts
a) water drum
b) steam drum
c) water tubes
Two drums are connected with upatake and downtake
header.
Water tubes connected to the headers are inclined at
15° to the horizontal
Furnace is arranged below the headers
Dampers are fitted at the back of the boiler to regulate
the draught

19. Locomotive boiler

20. Features :
 horizontal, stationary and straight
internally fired
Natural circulation
Fire tube boiler
Minimum steam pressure 100 bar
Steam production rate 9000 kg/hr
Efficiency 70%

21. It consists of a cylindrical barrel with rectangular fire
box at one end and a smoke box at the other end
The fire box is entirly surrounded by water
The generated hot gases pass from the fire box to the
smoke box through a series of fire tubes and then
discharged ino the atmosphre through the chimney
The superheater tubes are palcecs inside the fire tubes
of larger diameter
Excahust steam is discharged through the blast pipe to
the chimney from the cylinders

22. High pressure boilers
FEATURES:
 Method of water circulation
Type of tubing
Improved heat adding

23. Lamont boiler

24. Features
Vertical boiler
Modern High pressure boiler
Water tube boiler
Forced circulation
Steam rate 50 tonnes/hr
Principle :
The circulation of water and steam mixture takes with
the help of an external pump which supplies water at a
higher pressure than in a natural circulation boiler

25. Loeffler boiler

26. Features
Vertical boiler
Modern High pressure boiler
Water tube boiler
Forced corculation
Steam rate 100 tonnes/hr
Principle :
Evaporate feed water by means of superheated steam from
the super heater. The hot gases from the furnace are used
for superheating

28.  As there are no drums, the total weight of benson
bolier is 20% less than other boilers. This also reduces
the cost of the boilers.
 As no drums are required, the transfer of the benson
parts is easy. Majority of the parts may be carried to
the site without pre-assembly.
 Since no drum is used, this is an once-through boiler
and the feed water entering at one end is discharged as
superheated steam at the other end.
 Circulating pump and downcomers are dispensed
with.

29. Features
 Vertical boiler
 Super critical High pressure boiler
 Water tube boiler
 Forced circulation
 Steam rate 135 tonnes/hr
 Efficiency is 90%
Principle :
Feed water enters at one end and discharges superheated
steam at the other end. The feed pump increases the
pressure of water to superctitical pressure and thus
directly transforms into steam.

31. Boiler Mountings
These are the devices which are mounted on the boiler for its
safe and proper functioning of the boiler
Various mountings are
 Water level gauge
 Pressure gauge
 Safety valves
 Blow of cock
 Fusible plug
 Feed check valve
 Steam stop valve

32. Water level gauge

33. Pressure gauge

35. Lever safety valve

36. Dead weight safety valve

37. High steam low water safety valve

38. Spring loaded safety valve

40. Blow off cock

42. Fusible plug

43. Feed check valve

44. Steam stop valve

45. Boiler accessories
These are the devices which are used as integral parts of
a boiler and help in running efficiently.
Various types of accessories are
Feed pump
Economizer
Super heater
Air pre heater

46. Economizer

48. Super heater