310104b Rotary Control Valves 2017 TF (1)

Rotary Control Valves

Valves that rely on the rotation of the valve shaft to control flow.

Common Types of Rotary Control Valves

Ball valves, rotary plug valves, butterfly valves, positioned disc valves.

Ball Valve Characteristics

Uses equal percentage flow characteristics, resulting in low flow at initial openings and high flow at wide openings.

Seal rings or valve seats in Ball Valves

Typically made of Teflon (PTFE), providing tight shut off and aiding in self-cleaning of the ball face.

Segmented or Half-Ball Valve

A type of control ball valve that is trunnion mounted with a 90° sweep to full open.

V-Shaped Port in Ball Valve

Designed to achieve desired flow control characteristics with 90° rotation.

Plug Valve

A valve similar to a ball valve with a cylinder-shaped plug, offering straight-through flow and good recovery.

Eccentric Valve

A rotary stem valve with low operating torque and good recovery, allowing plug rotation into or out of stream flow.

Butterfly Valve

A compact valve that offers high capacity, high recovery, and low pressure loss, often used in process control.

Positioned Disc Valves

Valves that rotate a movable disc with holes to progressively cover or uncover fixed holes, providing variable choke for high pressure applications.

Tight Shut-Off in Rotary Valves

A feature indicating that the valve can completely stop the flow when closed.

Friction Forces in Ball Valves

These are high and require a relatively powerful actuator to operate the valve.

Elastomer Liners in Butterfly Valves

Provide the potential for 100% positive shut-off.

Fish Tail Disc Design

A design feature for butterfly valves that aids in flow control and valve functionality.