8200 electric-pneumatic valve positioner is introduced from America Masoneilan, is the new product of 1990s. Mainly used for improve the Linearity of control valve, increase the speed of valve movement, overcome the unbalanced force of valve spool and achieve split control.

Features:

Impact structure、light weight、explosive components made up of the torque motor and connection box, as adopt components of standard structure, convenient maintenance and all screws are stainless steel

Easy to adjust zero and travel

Back and side of positioner can all be installed on the actuator

Easy to switch manual to automatic

Structure principle

Structure: positioner made up of torque motor, armature, spring, zero spring, nozzle of a baffle, amplifier, automatic / manual switching mechanism, the feedback spring, the feedback stem

Principle: When the signal current is input to the torque motor, the armature using spring as pivot to clockwise. Baffle near the nozzle, make nozzle back pressure  increase. diaphragm promote the pilot valve , air pressure resulting into the output pressure, and get into the actuator. push bar move down, and promote the feedback lever, the feedback spring. When the torque motor generated force and pulling force feedback built missile balance, a certain signal current corresponding to a certain degree of push bar