Answer Posted / aftab ahmed mazari
Following procedure should be done for control valve
calibration.
Suppose it is spring loaded and direct action.(Direct
action means at top of diapgargm signal and with the
increase of signal, stem will move downwards or the stem
will extend).Also valve is signal to close. Check its Bench
Set. Suppose it is 6 to 21 PSI.
1. Set pressure regulator of positioner at about 30 PSI.
2. Apply 3 PSI (4 mA if positioner is smart or electronics)
signal to Positioner.Gradullay increase signal. Note the
movement of stem.
3. Apply 6 (8 mA),9 PSI (12 mA), 12 PSI (16 mA) and 15 PSI
(20 mA) signal. Valve stem should move accordingly and
indicator must show 25%,50%,75% and 100%.
4. If error, remove it from zero and span of positioner.
5. If facing any error problem, give signal 50% and then
remove error. Rest will be ok automatically.
6. Suppose valve is normally closed and at any vent service
and signal to close as I mentioned earlier, then make shut
close of valve at 14.5, or 14.7 PSI. Valve may start
closing at 2.75PSI.
7. If valve is at control operation, like level, pressure
etc, then calibrate it accurately.No need to calibrate it
at 2.75 and 14.5 PSI.
aftabmazari@yahoo.com
Is This Answer Correct ? | 31 Yes | 3 No |
Post New Answer View All Answers
What is hp & mp seperator .& what is its working principle ?
Why do we have earthing cable in branch cable and shield in the same cable?
What is loop1 and loop2 in MTS LT?
why micro controller 8051/52's clock frequency is internally divide by 12 ?? and why it is further divide by 32 in UART serial communication ??
I want to measure and control level in tank of size 10*5 filled with gasoline, so plz give me the solution with clear details. how to select transmitter and sensors.
Please tell me details about Sox,Nox,SWAS analyser????
key phaser where is use and work
what is scale factor of proximitor & unit of the vibration.
How to Calibrate Ultrasonic flow Transmitter in Field
what is the calibration procedure for magnetic flow meter @ onsite
I have 0.75mm sq multicore cable (IS type) , can use instead of same type but 1.5 sq mm cable ? Note : The distance is around about 150 meter.
basic connection and principle of axial shift sensor n differential sensors in tubine describes n draw......
How does work A temperature valve or fv control valve in process plz brief me
anybody having Qatar Petroleum questions for instrument Technician offshore ....please send me
Why do we floating DC in DC system.