Abstract: An automatically-calibrating electrically-controlled diaphragm valve actuator has a stepper motor controlled by a controller mechanism for moving the actuator within a diaphragm valve. A reference position indicator is provided to signal the controller mechanism when the valve actuator is at a reference position within the actuator's linear stroke. A method for automatically calibrating an electrically controlled diaphragm valve actuator includes the following steps. The actuator is initially driven to a reference position. Second, the actuator is driven a first number of steps. Third, the actuator is returned to the reference position. Fourth, it is determined whether fall back has occurred. Fifth, a second number of steps is determined based upon whether fall back has occurred. Sixth, the actuator is driven the second number of steps in order to compensate for the fall back.

Abstract: An automatically-calibrating electrically-controlled diaphragm valve actuator has a stepper motor controlled by a controller mechanism for moving the actuator within a diaphragm valve. A reference position indicator is provided to signal the controller mechanism when the valve actuator is at a reference position within the actuator's linear stroke. A method for automatically calibrating an electrically controlled diaphragm valve actuator includes the following steps. The actuator is initially driven to a reference position. Second, the actuator is driven a first number of steps. Third, the actuator is returned to the reference position. Fourth, it is determined whether fall back has occurred. Fifth, a second number of steps is determined based upon whether fall back has occurred. Sixth, the actuator is driven the second number of steps in order to compensate for the fall back.

Abstract: An air valve actuated by an electric motor has a cylindrical inlet section. The inlet section defines a seating surface upstream of which is a support grid. A backplate to which the actuating motor is mounted is supported by a plurality of rods that extend downstream of the inlet section. A damper assembly includes a generally planar damper mounted for movement axial of the inlet section. The damper assembly includes a splined rod which extends upstream of the damper and into a cooperating spline in the support grid. A threaded spindle extends downstream of the damper plate through a cooperatively threaded motor-driven drive gear which is mounted for rotation on the backplate. Because a portion of the damper assembly is splined, the damper assembly cannot rotate and is driven axially within the valve by the rotation of the drive motor and drive gear.

Abstract: A normally closed pneumatically actuated air valve for use in a variable air volume air distribution system has a unitary inlet section which supports a damper assembly and actuator through a support grid disposed in the inlet section. The damper assembly is mounted for axial movement, on a fixed spindle and guide piston, under the impetus of the expansion of a pressure chamber defined by a portion of the damper assembly and a diaphragm which conformably surrounds the guide piston. A biasing spring acts on a surface of the fixed guide piston and on the damper assembly to bias the damper assembly toward a seating surface of the inlet section.

Abstract: A normally open pneumatic air control valve includes an inlet section which defines a seating surface and a support grid. A support plate, located downstream of the inlet section, is itself supported by a plurality of rods extending from the inlet section. A damper assembly is disposed for movement axial of the inlet section and is supported for such movement between the inlet section support grid and the downstream support plate. The damper assembly is actuated by the admission of a pressurized gas to a chamber cooperatively defined by a housing fixed to the support plate and a diaphragm disposed therein. A spring acts on the fixed grid support of the inlet section and on the damper assembly to urge the damper assembly away from the inlet section so that the valve is biased to the open position.