Boiler mountings and accessories are devices used with boilers to allow them to function properly and efficiently. Important mountings include water level indicators, pressure gauges, safety valves, stop valves, blow off cocks, feed check valves, and fusible plugs. Key accessories are feed pumps, superheaters, economizers, air preheaters, and steam injectors. These components monitor conditions, regulate pressure and water levels, remove impurities, improve efficiency, and deliver water and steam as needed for safe boiler operation.

1. BOILER: MOUNTINGS AND
ACCESSORIES
Created By : Gunjan R. Mundra
Enrollment No. : 160010107026
Branch : Computer Engineering
Subject : Elements Of Mechanical
Engineering
College : A. D. Patel Institute Of Technology

2. BOILER MOUNTINGS
o Fittings which are mounted on the boiler for the
proper functioning.
o Boiler cannot function safely without the mountings.
o Followings are some of important boiler mountings
 Water level indicator
Pressure gauge
Safety valves
Stop valve
Blow off cock
Feed check valve
 Fusible plug

3. WATER LEVEL INDICATOR
 Indicates the water level inside
the boiler.
 Water level indicator is located
In front of the boiler in such a
position that the level of water
can easily be seen by operator.
 Two water level indicators are
used on all boilers.

4. PRESSURE GAUGE
 A pressure gauge is fitted in front
of the boiler in such a position
that the operator can conveniently
read it.
 It reads the pressure of the steam in
the boiler and is connected to steam
space by a siphon tube.
 The most commonly, the Bourdon
pressure gauge is used.

5. SAFETY VALVES
 These are used to prevent explosions due to excessive
internal pressure of steam.
 The escape of steam makes a audio noise to warn
the boiler attendant.
 There are four types of safety valves:
1. Lever loaded safety valve
2. Dead weight safety valve
3. High steam and low water
safety valve
4. Spring loaded safety valve

6. STEAM STOP VALVE
 The steam stop valve is located
on the highest part of the steam
space.
 It controls the flow of
steam from the boiler
to the main steam pipe.
 It shut off the steam
completely when required.
 The steam stop valve can be
operated manually or automatically.

7. BLOW OFF COCK
 The function of blow of cock is to discharge
mud and other sediments deposited
in the bottommost part of the
water space in the boiler, while
boiler is in operation.
 When it is open, water under the
pressure rushes out, thus carrying
sediments and mud.

8. FEED CHECK VALVE
 The feed check valve is fitted
to the boiler, slightly below
the working level in the boiler.
 Its function is to regulate
the supply of water, which
is pumped into the boiler
by the feed pump.
 It also prevents the returning of
feed water from the boiler if
feed pump fails to work.

9. FUSIBLE PLUG
 It is very important safety device, which protects the fire tube boiler
against overheating.
 It consists of metal plug fixed
in a gun metal with fusible
molten metal.
 This object is to put off fire in the furnace
when water level falls to an unsafe limIts.
 The furnace gases heat up the plug and
fusible metal plug melts, the inner plug falls down.
 The water and steam then rush through the hole and extinguish
the fire before any major damage occurs to the boiler due to overheating

10. BOILER ACCESSORIES
o These are devices which are used as integral parts of
a boiler, and help in running efficiently.
Some important accessories are
 Feed pump
 Superheater
 Economiser
 Air preheater
 Steam Injector

11. FEED PUMP
 Double acting reciprocating pump is commonly used.
 Pumps can be classified as simplex,
duplex and triplex pumps according
to the number of pump cylinders.
 It is used to feed the water
at a high pressure against the
high pressure of steam already
existing inside the boiler.

12. SUPERHEATER
 It is a heat exchanger in which heat of combustion products is
used to dry the wet steam, pressure remains
constant, its volume and
temperatue increase.
 Basically superheater consist
of a set of small diameter U tube
in which steam flows and takes
up the heat feom hot flue gases.
 Its purpose is to increase the
temperature of saturated
steam without rising its pressure.

13. ECONOMISER
 It’s a device used to heat feed water by
utilising the heat in the exhaust flue gas
before leaving through the chimney.
 It helps in improving the boiler efficiency.
 It is placed in the path of flue gases
at the rear end of the boiler just before
air pre-heater.

14. AIR PREHEATER
 It is used to recover heat from
exhaust flue gases.
 The air required for the purpose of
combustion is drawn through the
preheater where its temperature
is raised.
 It is installed between economizer
and the chimney.

15. STEAM INJECTOR
 A steam injector lifts and force the feed water
into the boiler.
 It is usually used for vertical and
locomotive boilers and can be
accommodated in small space.
 It is less costly.
 It does not have any moving parts thus operation
is salient.

16. …Thank You …