Article Details
(1) Used in important regulating systems that require high regulation quality to improve the positioning accuracy and reliability of the regulating valve.
(2) Used in situations where the pressure difference between the two ends of the valve is large (△p>1MPa). By increasing the air source pressure, the output force of the actuator is increased to overcome the unbalanced force produced by the liquid on the valve core and reduce the stroke error.
(3) When the medium to be adjusted is high temperature, high pressure, low temperature, toxic, flammable, or explosive, in order to prevent external leakage, the packing is often pressed very tightly, so the friction between the valve stem and the packing is large. At this time, a positioner can be used to overcome the time lag.
(4) When the medium to be adjusted is a viscous fluid or contains suspended solids, a positioner can be used to overcome the resistance of the medium to the movement of the valve stem.
(5) Used for large diameter (Dg>100mm) regulating valves to increase the output thrust of the actuator.
(6) When the distance between the regulator and the actuator is more than 60m, the positioner can overcome the transmission lag of the control signal and improve the valve’s action response speed.
(7) Used to improve the flow characteristics of the regulating valve.
(8) When one regulator controls two actuators to implement split-range control, two positioners can be used to accept low input signals and high input signals respectively. Then one actuator will act at low range and the other will act at high range, which constitutes split-range adjustment.
