| http://www.w3.org/ns/prov#value | - FIG. 2 is a vertical sectional view of the valve and actuator, similar to FIG. 1, but upon the bleeding of the pressure of well fluid from above the valve closure member so as to cause the valve retainer to move to its upper position, with the toggle link arrangement of the actuator held in an extended position to which it is lifted upon raising of the valve retainer to its upper position;
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