A boiler is equipped with various accessories to ensure normal operation, including pressure gauges, safety valves, water level gauges, high/low water level alarms, steam-water valves and blowdown valves. Of these, pressure gauges, safety valves and water level gauges are critical components that ensure safe boiler operation, serving as key indicators that enable operators to assess system conditions.

1. Pressure gauges: Pressure gauges are an indispensable safety accessory for boilers. Spring-loaded pressure gauges are commonly used in boilers due to their simple structure, reliable readings and ease of installation. Each boiler must be equipped with two pressure gauges that are connected directly to the steam space of the drum, facilitating data verification. To ensure the accuracy and safety of pressure readings, pressure gauges must be calibrated and inspected regularly.

Function: They are used to monitor and display steam pressure, guiding operators to maintain the system within safe, rated operating limits. They provide intuitive feedback on operating conditions and serve as the first line of defence against overpressure operations.

Importance: Operators use pressure gauge readings to control boiler operation within permissible pressure limits, ensuring operational safety. Valid pressure gauge calibration records are also essential for passing local government safety audits and compliance inspections.

2. Safety valve: A safety valve is a safety accessory that automatically controls the boiler’s operating pressure within a predetermined range.

Function: When the boiler pressure exceeds the maximum allowable operating pressure, the safety valve opens automatically to rapidly release steam and reduce the boiler pressure. At the same time, an audible alarm sounds to alert personnel, who can then take the necessary measures to lower the boiler pressure.

Common types of safety valve include lever-type and spring-loaded valves.

Importance: Prevents explosion accidents caused by boiler overpressure.

3. Water level gauge: A water level gauge is a measuring instrument that indicates the level of liquid present.

Function: It is used to monitor the water level inside the boiler drum in real time. Its primary function is to prevent accidents caused by low water levels, such as dry burning and explosions, or high water levels, such as steam carrying water, thereby ensuring the boiler operates safely.

Importance: It helps boiler operators to monitor water level fluctuations, maintain the water level within normal limits and prevent accidents caused by low water levels (leading to dry firing and explosions) or high water levels (affecting steam quality). 

These three major safety accessories typically work alongside other safety components, such as high and low water level alarms and blowdown valves, to form a comprehensive boiler safety system that plays a crucial role in ensuring boiler safety. Regular calibration and inspection of all boiler components extends the boiler’s service life and ensures the safety of its operation.