Robertshaw Controls Company

Richard F Caldwell

Byron L Jackson

A fluid operated valve positioner having an actuator unit provided with a flexible diaphragm carrying a main valve member to position the same relative to its main valve seat in a valve unit in relation to the actuated position of the diaphragm, the actuating unit having a range spring acting on one side of the diaphragm and a fluid pressure chamber for receiving fluid pressure to act on the other side of the diaphragm. The actuating unit carries a position sensing member for sensing the position of the diaphragm. A tubular sleeve adjustably carries the sensing member and has a part thereof acting against the range spring to calibrate the same, the actuator unit having a tubular portion telescopically receiving the tubular sleeve therein and in an adjustable manner to calibrate the range spring and thereafter being fastened to the tubular sleeve to hold the tubular sleeve in its calibrated position.

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Knoxville, TN, United States of America

Richard F Caldwell