Locator principle and working principle

Locator works

Valve positioner is the main control valve attachment.It will stem displacement signal as the input feedback measurement signal to the controller output signal as a set signal to compare the two when there is deviation, change its output to the actuator Signal, the actuator action, the establishment of the stem displacement and the controller output signal between the one-to-one correspondence. Therefore, the valve positioner to stem displacement measurement signal to the controller output for the set signal feedback control system. The manipulated variable of the control system is the output signal of the valve positioner to the actuator.

Locator principle of action

(1) Used to adjust the quality requirements of the important adjustment system to improve the control valve positioning accuracy and reliability. 

(2) For the pressure across the valve large (△ p> 1MPa) of the occasion. By increasing the pressure of the air source, the output force of the actuator is increased to overcome the unbalanced force generated by the liquid on the valve core and reduce the stroke error. 

(3) When the medium is high temperature, high pressure, low temperature, toxic, flammable, explosive, in order to prevent external leakage, the packing is often pressed very tight, so the friction between the stem and packing larger, this time With the positioner to overcome the delay. 

(4) When the transferred medium is a viscous fluid or contains suspended solids, the retainer can overcome the resistance of the medium to the movement of the valve stem. 

(5) For large diameter (Dg> 100mm) control valve to increase the output thrust of the actuator. 

(6) When the distance between the actuator and the actuator is more than 60m, the positioner can overcome the transmission delay of the control signal and improve the reaction speed of the valve. 

(7) Used to improve the flow characteristics of the control valve. 

(8) a regulator to control the implementation of two actuators split control, two locators available, respectively, to accept low input signal and high input signal, then an actuator low action, and the other elevation action, which constitutes a sub Process adjustment.