Indian Boiler Course presents this topic in a plant-oriented, examination-ready format. The lesson combines principles, construction, operation, safety, inspection points, troubleshooting and revision questions.
Definition and Purpose
Water and steam circulate inside tubes exposed externally to radiant and convective heat. Covers drums, headers, downcomers, risers, water walls, circulation, high-pressure suitability and tube-failure mechanisms.
Construction
Study the pressure boundary, heating surfaces, supporting structure, refractory, access doors, mountings and gas-side arrangement. Draw a labelled sectional sketch before memorising details.
Working Principle
Trace four paths separately: fuel, combustion air, flue gas, and water/steam. This prevents confusion and makes operational questions easier.
Advantages and Limitations
Evaluate pressure capability, steam-raising rate, load response, water content, efficiency, maintenance access, fuel flexibility, capital cost and consequences of failure.
Operation and Safety
- Confirm water level, valve line-up, instrument health and furnace condition before light-up.
- Warm pressure parts gradually to control thermal stress.
- Maintain combustion, draft, feedwater and steam pressure within approved limits.
- Respond immediately to low water, flame failure, furnace pressure excursion and tube leakage.
Inspection Points
Inspect water-side deposits and corrosion, gas-side erosion and overheating, tubes and tube ends, drums or shell, seams and welds, stays/supports, refractory, mountings and safety devices.
Revision Questions
- Explain construction and working with a labelled sketch.
- Compare this boiler with the nearest alternative design.
- List major hazards and safeguards.
- What would an inspector examine during an outage?