STEAM BOILERS

 STEAM BOILERS

                  Boiler is a product at many years of Engineering effort and expertise.This effort has produced a rugged ,compact and one of the safest units equipped with modern control for safe and efficient operation..

CONSTRUCTIONAL FEATURES

This is a smoke tube,single pass boiler which can be fired on a no of fuels.

eg:coal,baggase,husk and wood.Depending on the type fuel ,it has either balanced draught or an induced draught system.The boiler consists of 3 parts.

1:Refractory lined external furnace.

2:Shell and tube exchanger preesure part.

3: Atmospheric water preheater.

OPERATIONAL FEATURES

Fuel is burnt on the grate in the furnace and flue gases released during burning of the fuel enter the stroke tube and then the flue gas chamber to pass off to the chimney directly or via the water preheater.

SAFETIES AND CONTROL

1:Water level control.

2:Steam injector.

3:Steam pressure switch.

4:Flue gas temperature control.

MAINTENANCE

The performance of a boiler depends very greatly on the maintenance carried out.The boiler,its surroundings,water pipelines,filters,strainer etc should be kept clean to maintain proper fluid flow to boiler so that it works efficiently.The maintenance checks be carried out and preferably should be recorded on a log book daily by the boiler operator.

BOILER FEED WATER

Boiler is used for converting water into steam by evaporation in the boiler.Only the water gets evaporated and solids dissolved in the water remain in the residual water.Apart from getting converted into steam,water has many important function in the boiler which is to keep the heat exchanger portions cooled and heatly.To ensure that the water behaves as a proper cooling medium.It is essential to see the

1:The water continuosly wets the heating surfaces.

2:The water does not corrode the heating surfaces.

3:The water has necessary chemicals with in it such that a protective oxide layer is found on the surfaces.

DIGITAL TEMPERATURE CONTROLLER

This instrument is designed to suit applications requiring a highly accurate indication and control of temperature.The instrument provide a digital indication of temperature on a 3 and half digit seven segment LED display with a revolution of 1 degree celcius or 0.1 degree celcius.Sensor brake protection and ambient temperature compensation are added features of this instrument.

PRINCIPLE OF OPERATION

The millivolt output of the thermocouple is added to the output of the cold junction compensation circuit.The resultant of which is amplified and fed to the digital voltmeter which gives a readout of the same in terms of temperature in degree centigrade.The same output is also compared to a highly stable reference fixed by the position of the set potentiometer.The comparator through a buffer drives the relay which remains enegised as long as the measured temperature is below the set point.

BOILER

The force fan is used to suck in the air into the furnace at a high pressure.Firewood is burned inside the furnace and this heat is used to boil the water and the steam for cleaning purpose is made from the boiler.The shell tube type boiler is usually used.The feedback water used for the purpose is at 80 degree celcius.The preheating of water is done at economiser.The heat from the feedwater passed to the economiser.The feed water is filtered using softwater instrument.The dust from the economiser is collected in the dust collector and the water gas is send out through the chimney.Inorder to reduce pollution,the  chimney is created at a very big height.

ECODRAFT CONTROL SYSEM IN BOILER

Most solid fuel boiler are designed to operate under a negative furnace draft to the extend of -2 to -5 mm wc.Thin draft is critical both from the maintenance of proper combustion and ensuring safe and efficient operation of the boiler.In a typical solid fuel boiler 1D fan consumes the maximum portion of the allocated energy.In case we are all to control the 1D fan power consumption at part loads,while maintaining the necessary draft in the furnace.We can easily cut on our total power costs. The furnace draft is dependent 1 degree on the following

1:The amount of combustion air admitted into the furnace.

2:The amount of flue gases scavengered by the level switches indicating when the tasks are empty.