The working principle of electric pneumatic valve positioner

electric pneumatic valve positioner is designed according to the principle of force balance of work and its working principle is based on the pneumatic pneumatic valve positioner development of current signal control pneumatic valve positioner. When the current signal from electric regulator, the input to the torque motor coil components, in the air gap torque motor to produce a magnetic field, its function, together with the magnetic fields produced by permanent magnets make the armature produces a force to the left, the main lever ( Armature) Turn around the pivot ⒂, dampers near the nozzle, the nozzle back pressure after the amplifier amplification, into the film chamber actuator, pneumatic valve stem moves down, and turns feedback pole around the fulcrum, feedback CAM of connection on the same shaft turn counterclockwise to the Lord, make through roller pay lever fulcrum around the rotation, and the feedback spring ⑾ stretching, spring tension on the lever and the torque motor function in the main lever on torque is equal, machinery rod system balance. At this point, the certain signal current will correspond to a pneumatic valve position. Spring is adjusted by zero. Above action is positive effect, if you want to change the way we work, as long as will turn CAM, to become A to B, etc. , can. The so-called positive locator, is the signal current is added, the output pressure also increased; So-called reaction locator, signal current is increased, the output pressure is reduced. A positive role in executing agency as long as the mount reaction locator, can realize reaction actuator movement; Instead, a backlash actuators as long as the mount reaction locator, can achieve positive action of the actuator.