Advantages water tube boilers
1. Steam can be generated at very high pressures.
2. Heating surface is more in comparison with the space
occupied, in the case of water tube boilers.
3. Steam can be raised more quickly than is possible with
a fire tube boiler of large water capacity. Hence, it can be more easily used
for variation of load.
4. The hot gases flow almost at right angles to the
direction of water flow. Hence maximum amount of heat is transferred to water.
5. A good and rapid circulation of water can be made.
6. Bursting of one or two tubes does not affect the
boiler very much with regard to its working. Hence water tube boilers are
sometimes called as safety boilers.
7. The different parts of a water tube boiler can be
separated. Hence it is easier to transport.
8. It is suitable for use in steam power plants (because
of the various advantages listed above).
Disadvantages of water tube boilers
1. It is less suitable for impure and sedimentary water,
as a small deposit of scale may cause the overheating and bursting of tubes.
Hence, water treatment is very essential for water tube boilers.
2. Maintenance cost is high.
3. Failure in feed water supply even for a short period
is liable to make the boiler overheated. Hence the water level must be watched
very carefully during operation of a water tube boiler.