Answer / magi

Exact positioning of the valve stem
To minimise hysterisis
To linerise a nonlinear system
To use in place where actuator cant produce sufficien force
to move the valve stem

Answer / satish m. patel, bilimora

The valve positioner is used for following reasons.
1. quick action control valve.
2. valve hysteresis.
3. valve used on viscous liquids.
4. split range.
5. line pressure changes on valve.
6. valve bench set not standard.
7. reversing valve operation.

Answer / sathis.b

we control the valve thru the positioner for the require
percentage we need.

for ex: if u want to open the valve 25%, the command give
from control room it will open or close thru' the
positioner also the forward or reverese of the valve
direction.

Answer / vinesh prajapati ,guj. +919974

1) Reduces HYSTERESIS due to function at gland portion
2) Improves Linearity
3) Works as a volume booster and Thus improve the speed of
Actuator opretion
4) Works as a span amplifier when spring range of actuator
is not 0.2 to 1.0 Kg/Cm2
5) Required whenever spli range control is required

Answer / vigneshkumar

Positioner:
A Positioner is like a proportinal Controller.The Set point is the control signal from the primary controller and the controlled variable is the Valve position.

Uses:

1.When the signal Pressure is not enough to operate the control Valve.
2.To make Split range between the valves.
3. It can be used to reverse the action of the actuator from air to open and to air to close & Vice Versa
4.To minimize the effect of Hystersis Effect.
5.To Minimize the Response time for the valve.
6.If the Actuator is spring less Positioner will be used.
7.If the Valve has high friction .

Answer / ddd

CONTINUOS FEED BACK /HYSTERSIS/BOOST UP AIR FOR OUTPUT

wich is coming the first HAZOP OR SIL

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