Fusible Plugs in Air Compressors and Air Receivers
Fusible plugs are safety devices designed to melt and release compressed air when the temperature inside the equipment exceeds a predetermined safe limit. Here’s why they might be fitted in:
(a) Air Compressor:
- Internal Component Failure: If a component within the compressor, such as bearings or pistons, seizes or malfunctions, it can generate excessive heat. This heat can melt the fusible plug, releasing pressure and preventing catastrophic failure of the compressor itself. Examples include:
- Seized piston rings causing excessive friction
- Broken connecting rod leading to internal impact
- Loss of Cooling: If the compressor’s cooling system fails due to a water pump malfunction, clogged radiator, or other issues, the internal temperature can rise significantly. A melted fusible plug would then vent the pressure before overheating damages the compressor.
- Accidental Overheating: In rare cases, operator error or external factors might lead to overheating of the compressor. A fusible plug can act as a last line of defense by releasing pressure and potentially preventing an explosion.
(b) Air Receiver:
- Overheating: While less common than in the compressor itself, the air receiver could experience overheating if the compressed air entering it is excessively hot (lack of proper intercooling or aftercooling) or if there’s a malfunction in the pressure relief valve. The fusible plug would then melt and release pressure to prevent the air receiver from rupturing.
- Fire Exposure: In the unfortunate event of a fire near the air receiver, the fusible plug could melt due to the external heat. This would release the compressed air and potentially prevent the receiver from exploding due to excessive internal pressure caused by the fire.
Important Note:
While fusible plugs provide a safety measure, they are considered a last line of defense. It’s crucial to maintain the compressor and air receiver properly, ensuring proper cooling and functioning pressure relief valves, to prevent situations that would trigger the fusible plug. Early detection and addressing the root cause of overheating is essential for safe operation.