Which safety device is crucial for preventing boiler explosions?

The pressure relief valve is a critical safety device in steam boilers because it is specifically designed to prevent excessive pressure build-up within the boiler system. When the internal pressure exceeds a predetermined limit, the pressure relief valve automatically opens, allowing excess steam to escape. This function protects the boiler from explosions that can occur due to excessive pressure, which can lead to catastrophic failures and endanger lives.

While other devices have important roles in boiler operation—such as the thermostat, which regulates temperature, and the water gauge glass, which provides a visual indication of water levels—the pressure relief valve is the primary safeguard against potentially dangerous overpressure situations. The coal feeder, on the other hand, is responsible for supplying fuel to the boiler and does not contribute directly to safety regarding pressure regulation. This makes the pressure relief valve the essential component for maintaining safe operating conditions in steam boiler systems.