Answer / samik

@17
Very nicely explained sir.

Answer / ashish namdev

YES

1. put air pressure at a certain value (according max air requirement for actuator full action )

2. then connect limit switch at several position (0-100 scale)

3. then make a logic for open & close control action with use limit switch feedback.

4. connect air inlet with solenoid or pilot valve.  

Ashish Namdev (Sr. Engg)
Jaypee Power Plant, 
Bina (MP)
  

Answer / ravi vaya

We can use control valve without positioner .
But control valve spring opareting range must be 3 to 15 psi

Answer / kamesh.g

No we can not control the control valve without positioner
eccept on-off type control valves ,Positioner main purpose
is boostup the air signal from I/P and put the position as
per your requirement ( Command)positioner link rod will
give the feedback to control valve air command air supply
so it can adjust the valve in correct position.

Answer / m.ra

Yes we can operate a control without a positioner in the
following condiotions.

1) Volume booster is not required.
2) Operation of control valve will be very sluggish.
3) Charecteristics of control valve cannot be changed.
4) If the valve is self regulation than also positioner is
not required.

Answer / ajith294

here more answers reagrading positioner

maximum of the answers are 'YES' especially Answer number
10,
then i have a doubt that how control a valve at 50% open,
with out a positioner.

if there is not a positioner, how we can control the valve
( control the pnumatic pressure is applied the
actuator)?????

if a valve it using fully open of fully close condtion
throgh Solenoid Valve ( bypass the air to actuator) is on
off valve.

Without a positioner we cannot control the valve through a
controller.

thanks

Answer / sandy

The name itself indicates the function of the positioner. A
control valve without positioner will act as a ON-OFF valve.

Answer / yogesh

On-off control valve can use without positioner. but globe
control valve can not use without positioner.

Answer / akg d gr8

yes, Positioner is used to show the position of the valve.

Control valve operates based on feed back from Transmitter
through PID Controller.

why we use 0.2 to 1.0 kg/cm2 output in control valve

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