Boiler mountings and accessories with their construction with appropriate figures.

1. MADE BY : HET P PATEL
ENROLLMENT :216310319006

3.  MOUNTINGS - - Boiler mountings are the various
devices arranged on the boiler drum for boiler
safety, cleaning and control of steam generation
process.
 Boiler Accessories – For improving the
performance of the boiler and for its smooth
functioning, the equipment kept as integral parts
with the entire boiler system are called boiler
accessories.

4. 1. Water level indicator
2. Safety Valve
3. Pressure gauge
4. Steam Stop valve
5. Blow of valve
6. Feed check valve
7. Fusible Plug
8. Mud hole & Man hole

5. Function –
 The Function of a water level indicator is to indicate The
level of water In boiler shell constantly
Construction -
 two water level indicator are fitted into the boiler.
 These are fitted at the front end side of every boiler.
 Water level indicator consists of three cock as steam
cock, water cock, drain cock and glass tube.
 The steam cock connect or disconnects the glass tube
with steam space.
 The water cock connect or disconnect the glass tube
with water in the boiler.
 The drain cock is used to drain out the water in from
glass tube at interval to ensure that the steam and water
cock are clear in operation.
 The glass tube protected by means of a cover which is
specially made.

6. Function –
 In steam systems, safety valves are typically used
for boiler overpressure protection and other
applications such as downstream of pressure
reducing controls.
Construction -
 It consists of a cast iron body having two branch
pipes.
 Two separate valves are placed over the valve seat.
 A lever is placed over the valve by means of two
pivots.
 The lever is held tight at its proper position by
means of a spring.
 One end of spring is connected with the lever
while other end with the body of the valve.
 The valve is kept on it seats with help of spring
force.

7. Function – The function of a pressure gauge is to
measure the pressure exerted inside the vessel.
Construction –
 The gauge is usually mounted on the front top side
of the shell or on the drum.
 It is having dial which graduated to read pressure in
bar, above atmosphere.
 A Bourdon tube gauge with its interior mechanism
is shown in figure.
 The circular bent bourdon tube of oval-cross
section is close at one end and connected at the
other end to steam space of boiler through siphon
(U-tube).
 The siphon is filled with water which prevents hot
steam from entering the pressure gauge and keeps
the gauge cool.
 Closed end of bourdon tube is attached to a toothed
quadrant with help of link and pin. This quadrant
meshes with a small pinion on the

8. Function –
 It is very important safety device of a steam
boiler, which protects the fire tube
boiler against overheating.
Construction –
 It is fitted on the fire box brown plate or
over the combustion chamber.
 The fusible plug consists of two hollow
guns and one conical plug shown as figure.
 A hollow gun metal body is screwed to the
fire box crown plate of boiler.
 Another hollow gun metal is screwed to the
first body.
 Third plug is made from copper is locked
with the second plug by pouring metal in
to the grooves provided on the both plugs.

9. Function –
 it is used to control the supply of water to the
boiler and to prevent the escaping of water
from the boiler when the pump pressure is
less, or the pump is stopped.
Construction –
 The feed check valve is fitted in to the
water space of the boiler just below the
normal level of the water.
 It consist of a non-return valve, water inlet
pipe, outlet pipe, spindle, wheel
and gland as shown in figure.
 The outlet pipe of valve is connected with
the delivery pipe of feed pump.

10.  Function - It is used to regulate the
flow of steam from boiler to the steam pipe
or from one steam pipe to the other.
 Construction:
• The flange of valve body bolted to the boiler at
the highest part of steam space. It consists of
valve seat and nut. The main body of valve is
made of cast iron and valve seat made from gun
metal.
• When steam stop valve is placed directly over the
boiler and connected to the steam pipe line is
called the junction valve. If it is placed near to
prime mover than normally called steam stop
valve.
• The lower ends of spindle connected to valve
upper and pass through gland and yoke, and
connected with hand wheel. The gland is used to
prevent the leakage of steam.

11. FUNCTION: To discharge mud and other
sediments deposited in the bottom most
part of the water space in the boiler, while
boiler is in operation.
 To drain-off boiler water
CONSTRUCTION
 It is fitted on the boiler shell directly or through
the short branch of pipe at lowest part of the water
space.
➠ It consists of gun metal conical plug having a
rectangular hole, spindle with yoke a shown in fig.
➠ The plug meshes accurately into the similar
casing.
➠ The plug spindle is generally rotated by mean of
spanner on the top of the yoke, two vertical slots
are provided for fixing spanner.

12. Function:
 Manholes and hand holes are
required for cleaning, inspection,
and repairing of the boiler.
 The manhole is provided for the
entrance of a man inside the boiler
shell whereas the hand hole is for a
hand.
CONSTRUCTION :
 Generally they are elliptical in
shape and cover is provided. The
size of the manhole is usually 400
mm x 300 mm.

13.  ECONOMIZER
 AIR PREHEATER
 SUPER HEATER
 FEED PUMP
 STEAM SEPREATOR
 STEAM TRAP

14. FUNCTION:
 The economizer allows the heat from the
flue gases to transfer to the boiler feed water,
which raises the water's temperature. The
heated water is then used to make steam or
hot water. Economizers can be very effective
at saving energy. In some cases, they can
reduce fuel consumption by up to 20%.
CONSTRUCTION :
 An economizer used in modern high
pressure boilers is shown by a line
sketch. It consists of a series of vertical
tubes. These tubes are hydraulically
pressed into the top and bottom
headers. The bottom header is connected
to feed pump.

15. FUNCTION:
 The purpose of the air pre heater is to
recover the heat from the boiler flue
gas which increases the thermal
efficiency of the boiler by reducing the
useful heat lost in the flue gas.
CONSTRUCTION :
 Air Preheaters have a shell and tube
type construction where exhaust
heat from the flue gases is
transferred to the air when they
come in indirect contact with each
other. Air Preheaters consist of a
shell where tubes are arranged in a
square or triangular pitch and are
welded to a tube plate.
 Depending upon the type of operation
and ease of cleaning, flue gases & air can
be allowed to travel either shell side or
tube side interchangeably.

16. FUNCTION :
 A superheater is a vital part of the a boiler
system that is used to increase the overall
efficiency of a thermal power plant. More
specifically, it is a device which converts wet
steam (saturated steam) into dry steam as dry
steam contains more thermal energy.
CONSTRUCTION:
 There are many types of super heaters. A
combination type of radiant and convective
super heater is shown in figure.
 Both these super heaters are arranged in
series in the path of flue gases.
 Radiant super heater receives heat from the
burning fuel by radiation process. Convective
super heater is placed adjacent to the furnace
wall in the path of flue gases. It receives heat
by convection.

17. FUNCTION
 They serve to feed a steam
generator such as a boiler or a
nuclear reactor with a quantity of
feed water corresponding to the
quantity of steam emitted. Today,
all boiler feed pumps are
centrifugal pumps.
CONSTRUCTION
 The feed pumps used may be of
reciprocating type or rotary type
(centrifugal pump).
 The reciprocating pump may use
plunger or piston. It is driven by a
steam engine or electric motor.
 The piston rod of the steam engine
is connected directly with the
piston rod of the pump

18. FUNCTION:
 A steam separator, sometimes
referred to as a moisture separator or
steam drier, is a device for separating
water droplets from steam.
 The simplest type of steam
separator is the steam dome on a
steam locomotive.
CONSTRUCTION :
 The separator with baffle plates is
shown in figure.
 It consists of a cylindrical vessel. The
vessel is fitted with baffle plates.
 A water gauge is fitted to indicate the
water collected in the separator to
drain away to separated water.

19. FUNCTION :
 The duty of a steam trap is to discharge
condensate, air and other incondensable
gases from a steam system while not
permitting the escape of live steam.
CONSTRUCTION
 The only moving part is the disc above the
flat face inside the control chamber or cap.
 On start-up, incoming pressure raises the
disc, and cool condensate plus air is
immediately discharged from the inner
ring, under the disc, and out through three
peripheral outlets.
 Hot condensate flowing through the inlet
passage into the chamber under the disc
drops in pressure and releases flash steam
moving at high velocity. This high velocity
creates a low pressure area under the disc,
drawing it towards its seat.