Month: December 2022

 Draught Draught is a small pressure difference causing flow of flue gas and air through the boilers. It is necessary for efficient combustion and to release the gases at sufficient height to avoid local pollution. There are mainly three types of draughts—induced draught, force draught, and natural draught. Natural draught is pressure difference of hot… Continue reading CHIMNEY HEIGHT CALCULATION

The function of pressure reducing valve is to maintain constant pressure on its delivery side of the valve irrespective of fluctuating demand of steam. This is achieved by throttling of steam passing through the pressure reducing valve. It is generally used in low capacity boilers where it is difficult to maintain constant delivery pressure with… Continue reading Pressure Reducing Valve

The function of a steam separator is to separate the suspended water particles carried by steam on its way from the boiler to the engine of turbine. It is installed in the main stream pipe very near to engine. The constructional details are shown in Figure 4.28. Figure 4.28 Steam Separator The steam from boiler enters the… Continue reading Steam Separator

The function of steam trap is to drain the water condensed due to partial condensation and jacket without allowing the steam to escape through it.

The injector is a feed pump which is used to deliver feed water into the boiler under pressure. It is mostly used in vertical and locomotive boilers. It is not suitable for large power plants. It consists of group of nozzles so arranged that the steam expanding in these nozzles imparts kinetic energy to a… Continue reading Injector

The function of feed pump is to feed the feed water to the boiler. Different types of feed pumps used in boilers are reciprocating, centrifugal, and injector. Centrifugal or rotary pumps are used where large amount of water is required. For small boilers, reciprocating pump and injectors are used.

Steam generated in the boiler is wet due to contact with water. To get superheated steam, a device known as superheater is used in the boilers. The function of superheater is to super heat the steam up to desired level. It is a surface heat exchanger, located in the path of the flue gas. The… Continue reading Superheater

Air preheater is a device for recovery of waste heat from flue gas and is placed in the path of the waste flue gas going to chimney. Waste heat if the flue gas is transferred to the air before entering into the furnace to support the combustion of fuel. It is placed in chimney and… Continue reading Air Preheater

Economiser is a type of heat exchanger which exchanges some parts of the waste heat of flue gas to the feed water. It is installed between exit of the furnace and entry into the chimney. Generally, economiser is placed after feed pump to avoid the problem of priming in feed pump. If economiser is installed… Continue reading Economiser

The devices used in boiler to increase its efficiency and quality of steam are known as accessories. The names of some important accessories are as follows: