Steam Generators The boiler or evaporator is that part of the steam generator where phase change or boiling occurs from liquid (water) to vapour (steam), essentially at constant pressure and temperature. The term boiler is traditionally used to mean the whole steam generator.
Boilers Boiler may be defined as a closed vessel in which steam is produced from water by combustion of fuel. According to ASME a steam generating unit is defined as: “ A combination of apparatus for producing, furnishing or recovering heat together with the apparatus for transferring the heat so made available to the fluid being heated and vapourised ”.
Boilers Steam generated is employed for: (i.) Generating power in steam engines or steam turbines. (ii.) Heating the buildings in cold weather and for providing hot water supply. (iii.) In textile and chemical industries, sugar mills
Boilers Primary requirements of steam generators or boilers are: (i.) Water must be contained safely. (ii.) Steam must be safely delivered in desired condition (as regards its pressure, temperature, quality, required rate).
Classification of Boilers Horizontal, Vertical and Inclined Horizontal boiler – If the axis of the boiler is horizontal. Parts of horizontal boiler can be inspected and repaired easily but it occupies more space. The vertical boiler occupies less floor area. Fire Tube and Water Tube Fire Tube – the hot gasses are inside the tubes and water surrounds the tubes. Eg: Cochran,