The protection system of a steam boiler is mainly divided into three categories: safety protection, automatic regulation, and interlock protection. The core is to prevent dangerous working conditions such as overpressure, over-temperature, water shortage, overheating, and power supply.

Overpressure protection system
Function: To prevent the boiler pressure from exceeding the rated value and avoid explosion and pipe burst.
Composition
Pressure gauge: Monitors pressure
Pressure controller: Overpressure alarm, overpressure interlock furnace shutdown
Safety valve: Automatic pressure relief in case of overpressure, the last line of defense for safety
Action: Overpressure → Alarm → Fuel cut-off → Safety valve pressure relief.

Over-temperature protection system
Function: To prevent the pot water, steam and heating surface from overheating and burning out.
Protected objects: boiler water temperature, steam temperature, flue gas temperature.
Components: Thermocouple, thermal resistor, temperature controller.
Action: Over-temperature → Alarm → Load reduction/interlock stop
Furnace.

Water shortage protection system (including low water level)
Function: To prevent the water level from being too low and the pot from drying out, which could lead to pipe burst accidents.
Components: Water level gauge, electrode water level sensor, differential pressure transmitter, water level controller.
Action
Low water level: Alarm
Extremely low water level (lack of water) : Shut down the furnace immediately and cut off the fuel supply.

Overheat protection (overheat steam protection)
Function: To prevent the superheater from overheating, pipe burst and deterioration of steam quality.
Components: Superheated steam temperature measurement point, temperature regulation device, temperature controller.
Action
Over-temperature alarm
Automatically input the deheated water for adjustment
Severe over-temperature → Interlock and shut down the furnace

Power protection system
Function: Ensure power supply safety, prevent motor burnout and accidental start-up.
Content
Overvoltage protection: Alarm/power off when the voltage is too high
Under-voltage/under-voltage protection: Trips in case of power failure or low voltage to prevent automatic restart after power restoration
Phase loss protection: The machine will immediately shut down in the event of a phase loss in three-phase power
Short-circuit and overload protection
Emergency stop button (Emergency stop)

The protection system of a steam boiler can prevent accidents, ensure the safety of personnel and equipment, operate stably and reduce losses. It is an indispensable core device for the safe operation of the boiler.