Product Description: Model 8200 electric-gas valve positioner is one of the products introduced by Masoneilan in the United States. It is a new product launched in the 1990s. Mainly used to improve the linearity of the regulating valve, speed up the valve action speed, to overcome the unbalance of the regulating valve spool force and to achieve division control. Its characteristics are as follows:

Compact structure, light weight, explosion-proof parts by torque motor and junction box

Due to the use of standardized structural parts, it is easy to maintain. All screws are made of stainless steel

Zero position and stroke are easy to adjust;

The back and side of the positioner can be installed on the actuator;

Easy to switch from automatic to manual operation.

Structural principle

Structure: The positioner is composed of torque motor, armature, spring, zero adjusting spring, nozzle a baffle, amplifier, automatic/manual switching mechanism, feedback spring, feedback rod and so on.

Principle: When the signal current is input to the torque motor, the armature rotates clockwise with the spring as the fulcrum. The baffle is close to the nozzle to increase the pressure of the nozzle back pressure chamber. The diaphragm pushes the pilot valve, from which the air source pressure becomes the output pressure and enters the actuator. The push rod of the actuator moves down, and drives the feedback rod, feedback spring, etc. When the force generated by the torque motor is balanced with the tension of the feedback projectile, a certain signal current corresponds to a certain position of the push rod.

Technical parameter

Input impedance: 250Ω ± 25Ω

Air source pressure: 0.14 ~ 0.7MPa

Explosion-proof type: flameproof type (dⅡBT4), intrinsically safe type (iaⅡCT4)

Basic error: ± 1.0%FS (CAM type ± 2.5%FS), FS is the full range value (&plusmn in CAM form; 2.5%FS)

Return difference: 1.0%FS(lever type) 1.5%(CAM type)

Dead zone: 0.2%FS

Gas consumption: 500L/h (when the air source pressure is 0.14MPa under standard condition)

Weight: 2.5kg