Where is the safety fusible plug positioned in small vertical boilers________________?
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Answer: D. over the combustion chamber
Explanation
Safety fusible plugs are installed directly over the combustion chamber crown in small vertical boilers. This critical location ensures the plug remains submerged under normal operating water level conditions. If water levels drop dangerously, the uncovered plug melts from high combustion heat, releasing steam to extinguish the fire. Fusible plugs are safety devices made from low-melting-point non-ferrous metal alloys like gunmetal and lead solder. Vertical boilers require immediate fire suppression features to prevent catastrophic pressure vessel explosions from overheating. Melting plugs provide audible warnings and reduce furnace temperatures by venting steam directly into the firebox.
Option A is too broad because drums house multiple internal components rather than specific combustion crown areas. Option B mentions fire tubes, which are used in horizontal shell boilers rather than the specific crown sheet. Option C refers to steam domes, which collect dry steam far above the combustion chamber and water level.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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