Which component is a spring-loaded, diaphragm-operated valve and actuator that requires steam pressure to close?

Which component is a spring-loaded, diaphragm-operated valve and actuator that requires steam pressure to close?

• A. Make-up valve
• B. Unloading valve
• C. Bypass valve
• D. Gland seal regulating station

Answer: (A)

This type of valve is designed to admit makeup water to the boiler and is controlled by a diaphragm actuator that is driven by steam pressure. The spring provides the opening force, so without steam pressure the valve tends to stay open to allow makeup water flow. When steam pressure is applied to the actuator, it presses on the diaphragm and closes the valve, stopping makeup water. This arrangement lets the system automatically regulate makeup based on steam control signals: as soon as enough water is present (steam pressure applied), the valve closes; when makeup is needed, steam pressure is reduced and the valve opens to let water in. Other components don’t fit this specific actuator arrangement—unloading valves, bypass valves, and gland seal regulating stations serve different purposes and aren’t spring-loaded diaphragm valves that rely on steam pressure to close.

This type of valve is designed to admit makeup water to the boiler and is controlled by a diaphragm actuator that is driven by steam pressure. The spring provides the opening force, so without steam pressure the valve tends to stay open to allow makeup water flow. When steam pressure is applied to the actuator, it presses on the diaphragm and closes the valve, stopping makeup water. This arrangement lets the system automatically regulate makeup based on steam control signals: as soon as enough water is present (steam pressure applied), the valve closes; when makeup is needed, steam pressure is reduced and the valve opens to let water in. Other components don’t fit this specific actuator arrangement—unloading valves, bypass valves, and gland seal regulating stations serve different purposes and aren’t spring-loaded diaphragm valves that rely on steam pressure to close.