POSITION DETECTION FOR ROTARY CONTROL VALVES

摘要

A rotary control valve (10) includes a flow control element (16) having a lower valve shaft (20) rotatably received in a non-magnetic body portion (28). A magnet (26) is coupled with the lower valve shaft (20) and rotatable therewith to produce an external magnetic field that varies in accordance with the angular position of the flow control element (16). A magnetic field detector (30) positioned in the external magnetic fiel d, is operable to detect the external magnetic field and to produce position signals representative thereof, such being indicative of the angular positio n of the flow control element (16).