full port ball valves and reduced port ball valves
A full port Ball Valve has an oversized ball so that the hole in the ball is the same size as the pipeline resulting in lower friction loss. Flow is unrestricted, but the valve is larger. A standard port ball valve is usually less expensive, but has a smaller ball and a correspondingly smaller port. Flow through this valve is one pipe size smaller than the valve's pipe size resulting in slightly restricted flow. In reduced port Ball Valves, flow through the valve is two pipe sizes smaller than the valve's pipe size resulting in restricted flow。
A trunnion ball valve has a mechanical means of anchoring the ball at the top and the bottom.
Manually operated Ball Valves can be closed quickly and thus there is a danger of water hammer. Some ball valves are equipped with an actuator that may be pneumatically or motor (electric) operated. These valves can be used either for on/off or flow control. A pneumatic flow control valve is also equipped with a positioner which transforms the control signal into actuator position and valve opening accordingly.
