Wastewater New York State Practice Exam

What type of valve should always be either fully open or fully closed?

1. Globe valve

2. Gate valve

3. Check valve

4. Relief valve

The correct answer is: Gate valve

The gate valve is specifically designed to be either fully open or fully closed, which allows for minimal resistance to flow when in the open position and effectively stops flow when closed. This design is ideal for applications where full flow is necessary, and it's commonly used in larger pipelines or systems where the need to isolate areas of the system is important. In contrast, other types of valves serve different functions: globe valves are used for throttling and regulating flow, making them unsuitable for applications requiring a full open/close position; check valves are designed to allow flow in one direction and prevent backflow, and thus do not function as fully open or closed; and relief valves are used to automatically release excess pressure, operating under specific conditions rather than being fully open or closed. Therefore, the gate valve's capability to either allow unrestricted flow or block it completely makes it the correct choice for scenarios where such operation is required.