Minnesota Special Engineer Boiler License Practice Exam

What is the main function of a globe valve?

1. Open or close a line

2. Throttle or restrict the flow

3. Prevent backflow

4. Isolate parts of the system

The correct answer is: Throttle or restrict the flow

The main function of a globe valve is to throttle or restrict the flow of fluid within a piping system. Globe valves are designed with a spherical body that allows for precise control of flow rates through the valve. This is achieved by adjusting the position of an internal disc or plug that can be moved up or down to create different openings. When a globe valve is partially open, it creates a restriction in the flow path, which allows for better control over flow rates compared to other types of valves, such as gate valves that are primarily used for full open or closed positions. The ability to finely adjust the flow makes globe valves particularly useful in applications where flow regulation is essential, such as in heating systems or in process industries where precise fluid flow control is necessary. While globe valves can indeed open or close a line and isolate parts of a system, their primary designed capability emphasizes throttling, making option B the most accurate choice. Additionally, preventing backflow is typically the function of check valves, rather than globe valves, which further clarifies the intent behind the correct answer.