| 摘要 |
A high-speed actuator to move a valve stopper to a closed position against a valve seat and an open position away from the valve seat is disclosed. The actuator includes a rod carrying first and second axially spaced solenoid armatures. The rod also has a valve stopper connector end. A first solenoid coil surrounds and is spaced from the rod to bias the first solenoid armature along with the rod and valve stopper toward the valve's open position. A second solenoid surrounds and is spaced from the rod. The second solenoid is axially spaced from the first solenoid to bias the first armature towards the valve's closed position. A linear variable differential transformer (LVDT) magnetically coupled to the second solenoid armature is included to determine the instantaneous position of the valve stopper relative to the valve's seat. The LVDT is responsive to the position of the second armature. The LVDT generates an instantaneous valve position signal in concert with the movements of the rod. A valve position control circuit is adapted to receive a valve position set point from a user's input, and a valve position feedback signal from the LVDT. The valve position control circuit includes first and second solenoid coil drive signals that urge the first armature, and hence the valve stopper to the valve position set point inputted by a user. A signal generator circuit is provided to vibrate the valve about a position set point in order to enhance material discharge down the discharge tube.
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