A position regulator is provided which is effective to control, via a control unit, a pressure medium circuit to operate at different working pressures. The regulator comprises two or more pressure transmitting elements which divide an internal space into a number of pressure chambers, the pressure transmitting elements being arranged for axial movement within the position regulator. The invention provides pressure transmitting elements defining the pressure chambers which comprise diaphragms or the like which are attached in mutually spaced relationship in the position regulator and which, when subjected to a force, permit axial displacement movements.
An actuator for a rotary valve preferably embodying a diaphragm motor operated by pressure fluid. A driving sleeve is reciprocated linearly by the diaphragm motor and within said sleeve is a rotatable shaft, which is axially aligned with the diaphragm motor and driven by a ball screw. A driven sleeve is fixed to said shaft and receives the stem of the valve. All parts are in linear alignment. Means are provided for limiting the extent of the linear movement of the parts.
The dual actuator valve of the present invention deploys both the primary and secondary actuator elements in a single, common control chamber. Therefore, the present invention provides a dual actuator valve having dimensions that are the same as, or similar to, the dimensions of a single actuator control valve. It will be appreciated that the actuator elements may be of diaphragm type or piston type actuator elements. The primary actuator element is mechanically linked to the valve plug and regulates the flow though the valve, while the secondary actuator element remains in a fully open position. Should the primary actuator element fail to operate the valve due, for example, to diaphragm rupture, failure of the primary control system, or any other reason, the secondary control system activates the secondary actuator element, which then effects movement of the primary actuator element thereby resuming flow regulation or closure of the valve as necessary.
