Which safety device is critical for preventing boiler over-pressurization?

The safety valve is essential for preventing boiler over-pressurization because it is specifically designed to release excess pressure from the boiler system. When the internal pressure exceeds a preset limit, the safety valve opens automatically, allowing steam or pressurized water to escape, thereby reducing pressure to a safe level and preventing potential damage or catastrophic failure of the boiler. This mechanism is crucial for maintaining the integrity and safe operation of the boiler, as over-pressurization can lead to severe accidents, including explosions.

Other safety-related devices may play roles in the overall monitoring and operation of the boiler. For instance, the pressure gauge provides important readings of the current pressure within the boiler system but does not actively control or reduce pressure. Similarly, the temperature gauge shows the temperature of the water or steam, which is vital for system management, but again does not intervene in pressure control. The flow meter measures the flow rate of water or steam but does not contribute to pressure relief in any way. Therefore, while all these devices are important for boiler operation, the safety valve is the critical component specifically designed to prevent over-pressurization.