Classification of Steam Boilers

Classification of Steam Boilers Points : Classification of Steam Boilers Though there are many types of steam boilers, yet the following are important from the subject point of view: 1. According to the content in the tube (a) Fire tube or smoke tube, and (b) water tube
In fire tub team boilers, the flames and hot gases, produced by combustion of fuel, pass through the tubes (called multi-tubes) which are surrounded by water. The heat is conducted through the walls of the tubs from the hot gasses to the surrounding waters examples of fire tube steam boilers are: Simple vertical boiler, Cochran ti1er, Lancashire boiler, Cornish boiler, Scotch marine boiler, Locomotive boiler, and velox boiler.
In water tube team boilers, the water is contained inside the tubes (called water tube) which are surrounded by flames and hot gasses from outside. Example of water tube boilers are; Babcock & Wlcox boiler, stirling boiler, La-Mont boiler, Benson boiler, narrow boiler and Loeffler boiler. 2. According to the position of furnace (a) internally fired (b) Externally fired
In internally fired steam boilers, the furnace is located inside the boiler shell. Most of the fir tube steam boilers are internally fired. In externally fired steam boilers, the furnace is arranged underneath in a brick-work setting. Water tub steam boiler are always externally fired. 3. According to the axis of the shell (a) Vertical, and (b) Horizontal
In vertical steam boilers, the axis of the shall is vertical whereas it is horizontal in case of horizontal steam boiler. 4. According to number of tubes a) Single tube, and (b) Multi tubular
In single tube steam boilers, there is only one fire tube or water tube. Simple vertical & Cornish boiler are single tube boilers. In multi tubular steam boilers, there are two or more fire tubes or water tubs. 5. According to the method of circulation of water steam (a) Natural circulation, and (b) Forced circulation
in natural circulation steam boilers, the circulation of water is by natural convection current, which are set up during the heating of water. In most of the steam boilers, there is a natural circulation of water.
In forced circulation steam boilers, there is a forced circulation of water by a centrifugal pump driven by some external power. Use of forced circulation is made in high pressure boilers such as La-Mont boiler, Benson boiler, Loeffler boiler and velox boiler. 6. According to the use (a) stationary, and (b) Mobile
The stationary steam boilers are used in power plant arid in industrial process work. The are called stationary because they do not move from one place to another. The mobile team boilers are those which move from one place to another. These boiler are locomotive and marine boilers. 7. According to source of heat The steam boilers may also be classified according to the source of heat supplied for producing steam. The source may be the combustion of solid, liquid or gaseous fuel, hot waste gases as by product of oilier chemical process processes, electrical energy or nuclear energy, etc.