What does the primary function of the OS&Y valve design relate to?

• A. The handle turns a stem that directly drives the gate
• B. It uses electronic actuation to move the gate
• C. The stem is turned by a ratchet mechanism
• D. It is a quarter-turn ball valve with an indicator

Answer: (A)

The main idea is that OS&Y is about direct mechanical control: turning the handle moves a stem that directly raises or lowers the valve gate. This outside stem and yoke arrangement lets you clearly see the valve’s status because the stem is visible and, in rising-stem versions, moves as the gate goes open or closed. That direct drive—no separate actuator or gear system—is what defines the OS&Y design. The other options describe actuation or valve types that aren’t characteristic of OS&Y: electronic actuation, a ratchet mechanism, or a quarter-turn ball valve with an indicator.