BY CLOSURE MOTION
Ball & Plug / Rotary Quarter-Turn
How the closing member moves relative to the seat — the geometry behind the family name.
Choosing Ball & Plug / Rotary Quarter-Turn
Quarter-turn motion rotates the closing member between operating positions. Ball and plug designs can both use this motion, but their passage, seats and control behavior differ. Actuator selection requires torque data through the cycle, not just the angle of rotation.
What to include in the RFQ
- Identify the valve family and on-off or modulating duty.
- Request breakaway, running and seating torque under the stated service conditions.
- Specify mounting interface, rotation direction, stops and feedback.
Selection scenario
When adding remote operation to a ball valve, review the torque under process pressure and the required failure state. Confirm both the mechanical coupling and accessory circuit.
Common selection mismatch
A quarter-turn actuator is not automatically interchangeable across equal-size ball, plug and butterfly valves.