Self-regulating valves with external intake represent a very versatile and easy-to-install solution whenever it is possible and preferable to control the actuator via a connection on the pipeline whose pressure you want to control.
Advantages
It is always possible to visually verify the exact degree of valve opening.
The trim is always mounted from the top side, making maintenance simple even with the valve installed on the line.
The size of the actuator does not depend on that of the valve, making solutions competitive in case of large valve sizes (≥ 8").
It is also possible to use standard pneumatic actuators converted for self-regulating action.
Disadvantages
They prove to be poorly efficient in cases of very low pressures to be controlled.
Overall dimensions are larger compared to the internal sensing solution.
