Why are gate valves not used for throttling?

Gate valves are designed primarily for allowing or blocking flow in a pipeline rather than for regulating flow. When gate valves are used for throttling, significant issues arise due to their design and operational characteristics.

Wire drawing occurs when the disc of the gate valve does not properly seal against the seat when partially opened. This can result in the valve's edges wearing down over time, akin to drawing metal into a thin wire, which can compromise the valve's integrity and lead to leaks after prolonged use. Since gate valves are not meant for controlling flow, they cannot handle the turbulence caused by throttling.

Erosion is another critical issue that results from using gate valves for throttling. When the valve is partially open, the flow velocity increases significantly, leading to high-velocity jetting that can erode the valve material over time. This erosion can lead to a loss of material at the valve seat and disc, further impairing the valve’s ability to seal and function effectively.

The combined effects of wire drawing and erosion underline why gate valves are not suitable for throttling applications. They are better suited for full-open or full-closed operations where flow control is clearly defined, rather than in situations where variable flow and pressure management are needed. Thus, the reasoning supports