Which of the following is not an example of full-way valve design?

Which of the following is not an example of full-way valve design?

• A. Throttle valve
• B. Gate valve
• C. Ball valve
• D. Globe valve

Answer: (A)

A full-way (full-port) valve design aims to provide a straight-through passage that matches the pipe bore when fully open, minimizing resistance and pressure drop. Gate valves do this well: when the gate is raised completely, the flow path opens to the full pipe diameter. Ball valves can also be full-port, with the bore of the ball aligned with the pipe for an unobstructed path when open. Globe valves, even when fully open, route flow around the disk and through a curved path, so they present more obstruction and a higher pressure drop than a true full bore valve. The throttling valve, by its nature, is built to regulate flow by imposing a restriction; its passage is not a true full bore, even at maximum opening, so it does not provide a full-way design. Therefore, the not full-way example is the throttling valve.

A full-way (full-port) valve design aims to provide a straight-through passage that matches the pipe bore when fully open, minimizing resistance and pressure drop. Gate valves do this well: when the gate is raised completely, the flow path opens to the full pipe diameter. Ball valves can also be full-port, with the bore of the ball aligned with the pipe for an unobstructed path when open.

Globe valves, even when fully open, route flow around the disk and through a curved path, so they present more obstruction and a higher pressure drop than a true full bore valve. The throttling valve, by its nature, is built to regulate flow by imposing a restriction; its passage is not a true full bore, even at maximum opening, so it does not provide a full-way design.

Therefore, the not full-way example is the throttling valve.