ANTI-SCALING CONTROL ELEMENT FOR A ROTARY CONTROL VALVE.

摘要

A control element (54) for a rotary control valve is attached to a rotating shaft (56) by at least one ear (76). The control element includes at least two surfaces, the first surface (60) being generally sealable with a flow ring (64). The second surface (62) is generally recessed from the first surface to facilitate fluid flowing through the valve across the first surface to prevent scaling or buildup of foreign material on that surface.