Which safety device is essential for preventing overpressure in a boiler?

The essential safety device for preventing overpressure in a boiler is the safety valve. The safety valve is designed to automatically release excess pressure when it exceeds a predetermined limit. This function is crucial because if pressure builds up uncontrollably within the boiler, it can lead to catastrophic failures, including explosions or ruptures. The safety valve helps maintain safe operating conditions by allowing steam or water to escape when necessary, thereby protecting the integrity of the boiler and ensuring the safety of the operation.

While the pressure gauge helps monitor the pressure levels within the boiler, it does not actively prevent overpressure; it simply informs the operator of the current pressure status. Similarly, although the water level indicator plays a vital role in maintaining proper water levels (which is crucial for safe operation), it does not directly address pressure control. Lastly, the fuel supply shutoff is important for controlling the input of fuel to the burner, but it does not provide pressure relief. Thus, the safety valve is the key component specifically designed to prevent dangerous overpressure situations in boiler systems.