Butterfly valves control flow through a circular disc or vane by turning the valve's pivot axis at right angles to the direction of flow in the pipe. They are normally used as throttling valves to control flow.
Globe valves are linear motion valves with rounded bodies, from which their name is derived. They are widely used in industry to regulate fluid flow in both on/off and throttling service.
Rotameters are typically tapered glass tubes positioned vertically in the fluid flow. A float within the tube rides upward in relation to the amount of flow.
