産品列表
免費電話:400-0000-343
Hot Product
當前位置:主頁 > News >

Working Principle of Electrical Valve Positioner

     Electrical valve positioner is designed according to the principle of force balance. Its working principle is a current signal controlled valve positioner developed on the basis of pneumatic valve positioner.
     When the current signal from the electric regulator is input into the coil of the moment motor component, a magnetic field is generated in the air gap of the moment motor. It acts together with the magnetic field produced by the magnet to produce a force to the left of the armature. The main lever (armature) rotates around the fulcrum point and the baffle is close to the nozzle. The back pressure of the nozzle is amplified by the amplifier and sent into the air chamber of the film actuator to make the valve. The rod moves downward and drives the feedback rod to rotate around the fulcrum. The feedback cam connected on the same axis rotates counter-clockwise and principally. The counter-lever rotates around the fulcrum through the roller. When the tension of the feedback spring and the tension of the spring to the main lever are equal to the moment of the torque motor acting on the main lever, the mechanical rod system reaches equilibrium state. At this point, the signal current corresponds to the valve position. Spring is used for adjusting zero position.
     The above mode of action is positive. If you want to change the mode of action, just turn the cam upside down and turn direction A into direction B, etc.
     The so-called positive positioner means that the signal current increases and the output pressure increases, while the so-called negative positioner means that the signal current increases and the output pressure decreases.
     As long as a positive actuator is equipped with a reaction locator, the action of the reaction actuator can be realized; on the contrary, as long as a negative actuator is equipped with a reaction locator, the action of the positive actuator can be realized.