Merits and Demerits of Water Tube Boiler over Fire Tube Boiler
Merits of Water Tube Boiler over Fire Tube Boiler:
- Generation of steam is much quicker due to the small ratio of water content to steam content. This also helps in reaching the steaming temperature in short time.
- Its evaporative capacity is considerably larger, and the steam pressure range is also high 200 bar.
- Heating surfaces are more effective as the hot gases travel at right angles to the direction of water flow.
- The combustion efficiency is higher because complete combustion of fuel is possible as the combustion space is much larger.
- The thermal stresses in the boiler parts are less as different parts of the boiler remain at uniform temperature due to the quick circulation of water.
- The boiler can be easily transported and erected at its different parts can be separated.
- Damage due to the bursting of water tube is less serious. Therefore, water tube boilers are sometimes called safety boilers.
- All parts of the water tube boiler are easily accessible for cleaning, inspecting and repairing compared to fire tube boiler.
- The water tube boiler’s furnace area can be easily altered to meet the fuel requirements.
Demerits of Water Tube Boiler over Fire Tube Boiler:
- It is less suitable for impure and sedimentary water, as a small deposit of scale may cause the overheating and bursting of the tube. Therefore, use of pure feed water is essential.
- They require careful attention. The maintenance costs are higher in water tube boiler compared to fire tube boiler.
- Failure in feed water supply even for a short period is liable to make the boiler overheated.