1. Water level indicator : This device indicates the exact level of water in the boiler tube.
2. Safety valve : It is a mechanical device used to safeguard the boiler, in case the pressure inside the boiler rise above its normal working atmosphere.
3. Pressure gauge: The pressure gauge commonly used is the bourdon pressure gauge mounted on the from top of the boiler shell.
4. Steam stop valve: The function of the steam stop valve Is to stop or open the steam supply from the boiler to the point of application.
5. Feed check valve A valve placed at the boiler end to regulate the flow of water.
6. Main hole : It is the opening provided of cleaning or inspection.
These are those devices which are installed with a boiler and its neighboring area to increase the efficiency of the boiler. These are not the essential part of the boiler and thus without installing these devices, the boiler operation can be accomplished though at a lower efficiency.
The following are the important accessories of the boiler :
• Feed water pump
• Pressure reducing valve
• Air pre heater
• Super heater
• Steam drier or separator
• Steam trap
1. Feed water pump : The feed water pump is used to feed water to the boiler.
2. Injector : Function of the injector is the same as that of feed pump i.e. to deliver feed water to boiler under pressure.
3. Pressure reducing valve: The function of the pressure reducing valve is to maintain constant pressure to its delivery side of the valve irrespective of fluctuating demand of steam from the boiler.
4. Economiser: A considerable quantity of heat of the plant is
carried away by flue gases, so to utilise these waste heat. An economizer is placed in the path of the flue gases to preheat the feed water.
5. Air pre-heater : The function of the pre- heater is to heat the air before it enters the combustion chamber.
6. Super heater : Super pre-heater is used for stationary boiler. The function of the super heater is to convert dry saturated steam into super heated at the desired temperature.
7. Steam drier: The function of the steam drier or separator is to separate water particles from steam before it is supplied to the point of application.