How many turns per inch do gate valves typically have?

Gate valves are designed to provide a tight seal when closed, enabling full flow when fully open. Typically, the standard for gate valves is that they have about three turns per inch for the operator. This means if you're setting a gate valve into a pipeline, for every inch of valve diameter, it usually requires roughly three full turns of the valve's handwheel or actuator to move from fully open to fully closed. This design allows for precise control over the flow of water, making gate valves suitable for applications where minimal pressure loss is desired, and they are generally used for on/off services rather than throttling.

Having a standardized number of turns is crucial for operators in order to be familiar with the typical requirements when adjusting valve positions. If a valve were to have fewer or more turns, it could lead to confusion or improper operation. The other options suggest fewer or more turns per inch, which do not align with the common manufacturing and operational specifications of gate valves. This standardization also helps in training operators and ensuring consistency across various installations.