There are various kinds of valve positioners out there. How might you say you need a pneumatic, electric, or electro-pneumatic positioner? Here, we’ll cover the stray pieces of valve automation with positioners, and a framework of valve positioner types.
A valve positioner is a device that changes the valve actuator’s situation considering a control signal. These positioners are best used in control applications because of their exactness.
Valve positioners are commonly mounted on the yolk or top bundling of a pneumatic actuator for straight control valves, or near the uttermost furthest reaches of the shaft for rotational control valves. For either arrangement, the positioner is related unequivocally to the valve stem or valve shaft. This considers what is going on to be differentiated and the position referenced by the controller. Exactly when a control signal differentiations from the valve actuator’s circumstance, the valve positioner sends the significant analysis to move the actuator until the right position is reached.
We considered 10 Reasons to Install a Valve Positioner so you can find ways that a positioner could additionally foster your control cycle. Here is a fast summation of inspirations to use a valve positioner on your pivoting or straight control valves:
- Ability to have fine control over a precise association.
- Accelerate response to change in process, considering speedier stacking and venting.
- Think about split running (one controller for two valves).
- Beat seating grinding in pivoting valves.
- Think about extended utilization of 4 – 20mA electronic signs.
- Limit valve stem squeezing crushing effects and the ensuing hysteresis. This is particularly huge for high-temperature squeezing materials like graphite.
- Discredit stream-activated reactions to higher strain drops and compensates for inside power disproportionate attributes.
- Grant the use of brand-name cams in rotating valves.
There are two or three kinds of valve positioners open. Dependent upon the sort of positioner, it either uses air or the ability to move the actuator. We ought to inspect a piece of the popular decisions.
Pneumatic
Pneumatic positioners get pneumatic signs (normally 3-15 PSIG). The positioner then supplies the valve actuator with the right vaporous pressure to move the valve to the normal position. Pneumatic positioners are normally safeguarded and can provide a ton of ability to close a valve.
Electric
Electric valve positioners get electric (by and large 4-20 mA) signals. They do a comparative job as pneumatic positioners do, but use power instead of vaporous pressure as a data signal. Three electric invitation types are single-stage and three-stage pivoting stream (AC), and direct stream (DC) voltage.
Electro-Pneumatic
Electro-pneumatic valve positioner converts current control signs to equivalent pneumatic signs. It uses a mix of both power and air, as deduced by the name.