Which type of valve is used to control the pressure in a boiler system?

• A. Flow control valve
• B. Safety valve
• C. Pressure-reducing valve
• D. Check valve

Answer: (C)

A pressure-reducing valve is specifically designed to regulate the pressure within a boiler system by reducing the inlet pressure to a lower, predetermined level that is safe for the operation of the boiler. This type of valve is crucial for maintaining optimal operating conditions and protecting the boiler from pressure that could exceed its design limits, potentially leading to unsafe operating conditions or damage.

The pressure-reducing valve works by automatically adjusting the flow of steam or water based on the current pressure in the system compared to a setpoint. When the system pressure exceeds this setpoint, the valve throttles the flow to decrease the pressure, ensuring stability and safety in the boiler operation.

In contrast, other types of valves serve different functions: flow control valves regulate the flow rate but do not specifically manage pressure, safety valves are designed to open and relieve excess pressure to prevent boiler explosion or accidents while maintaining normal operating conditions, and check valves ensure that flow only goes in one direction, preventing backflow but not controlling pressure levels.