Fusible Plug Functionality in Boilers
A fusible plug is a critical safety device used in boilers, especially small ones. Its primary purpose is to melt and release steam when the boiler temperature becomes excessively high due to a low water level. This prevents catastrophic failure.
Locating the Fusible Plug
The effectiveness of the fusible plug depends on its placement. It must be located where it can sense the dangerous overheating condition directly.
- The hottest part of the boiler, which would be exposed if the water level drops significantly, is the crown of the furnace or combustion chamber.
- Therefore, the fusible plug is strategically positioned over the combustion chamber.
- When the water level falls below the plug's level, the plug is exposed to the hot furnace gases, causing its low-melting-point core to melt.
- This melting releases the steam pressure, acting as an alarm and helping to cool the furnace crown.
Options like 'in the drum', 'in the fire tubes', or 'above the steam dome' do not provide the direct overheating detection needed for the plug's safety function.
The correct location ensures the plug activates precisely when the furnace crown is at risk.
Important Questions from Boilers
A device which is used to drain off water from steam pipes without escape of steam is called
______ is NOT a water tube boiler.
Which of the following pipe joints would be suitable for pipes carrying steam?
Filling or decking in a cooling tower increases the rate of heat transfer by providing
The valves mounted on the boilers which change the direction of flow of steam by 90° and valves fitted in the pipelines which allow the steam in the same direction are respectively called as _____.
