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
A high-pressure boiler in which superheated steam evaporates feedwater in an evaporating drum, reducing salt-deposition risk in furnace tubes.
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?