Question

Sketch and describe the working of a Locomotive boiler. Show the

positions of fusible plug, blow off cock, feed check valve and superheater.

Mention the function of each. Describe the method of obtaining draught in

this boiler.

Answer 1

Working of locomotive boiler :

*The hot flue gases is generated through solid coal which is put on the fire grate and is ignited.

* To regulate the flow of flue gases to definite path fire brick arch is used for the directional flow of the flue gases before enter into the fire tube .

*These flue gases through fire tube will heat the water surrounding the tube like a blanket around it .

* By heating water continuously it's phase changes into steam ( saturated steam ) which is collected at the top dome .

* When steam is saturated it is guided to the superheater which superheats the steam .

* From superheater the steam goes to the piston cylinder arrangement which enables the piston to move which is connected to the wheels , ultimately wheels start rotating .

* Exhaust gases from the cylinder will help to enable to remove smoke produced during burning of coal .

Function of various parts:

1.) Fusible plug - It is a safety device or simply a fitting used in boiler , monitors over the water level in the boiler if water level is too low more heat produce will not be much absorbed by water ( superheated ) thus can damage the boiler .Thus fusible plug prevent it by melting of lead of fusible plug leads to pouring of water in the drum in the furnace , disrupting combustion and prevent bolier damage.

2.) Blow off cock- blow off cock- is used to blow of mud and sediment that's deposited on the boiler to have smooth functioning of boiler . It's is also used to blow off excess steam to prevent explosion of boiler when pressure exceeds the working pressure.

3.) Feed check valve : It is used to have control over the water supplies in the boiler and also to prevent back flow of the water .The main idea of using the feed check valve is to have sufficient supply of water inside the bolier for effective steam production .

4.) Superheater: The main function of super heater is to convert the saturated steam to superheated steam to enable to prevent the condensation of steam inside the bolier .Superheater increases the efficiency of the boiler .

Method of obtaining draught in the boiler :

The use of draught is to have flow of gases inside the boiler by creating a small pressure difference .

Generally draught is produced by using chimney , centrifugal fan, steam jet since in locomotive boiler we don't use chimney instead stack acts like a chimney in which exhaust gases from cylinder goes to blast pipe , from blast pipe exhaust gases pushes the smoke out of the locomotive boiler .so thus an artificial draught is created which pushes the smoke outside and create suction for hot flue gases to come inside the boiler .

The diagram is in the image captured.

please give positive feedback ?.