| 摘要 |
A hermetically-sealed actuator for a rotary valve is provided in which a valve operator (38,30) is operative to move a stem (32) axially but not rotationally, axial movement of the stem, in turn, producing rotation of a rotary cam member (34) that is operatively connected to rotate a valve spindle (26), the axially movable stem (32) being hermetically sealed by a bellows mechanism (36), thus hermetically isolating the rotary cam member from the valve operator, the maximum angular extent of rotation of the cam member (34) being determined by the ramp cam angle and angular extent of helical slots (54) formed in the rotary cam member and which are engaged by trunnions (52) fast with the stem (32). <IMAGE> |
