Answer / renjith

For every control valve there will be option to manually
close the valve by adjusting a screw.

Answer / priya sharma

u can stop the air supply with the control valve accessory
that is the AIR LOCK

Answer / chaitanya

Generally if the control valve is not responding to
controller based upon its control philosophy it may get
operated by interlocks or it may go to fail safe condition
of the control vavle

Answer / nilmaheshin@yahoo.co.in....jit

Chitanya wrote correct answer. Priya and renjith are also
correct. But dear when any body is not present in field at
that time fail safe action is responding

Answer / karthikeyan

absolutely right answers(1&2)....we can operate in manually,and also to remove the air line because feed water control valve should be a air to open,in this if air fail it should be close....

Answer / ashwin jain

but wat happen if no 1 is there to control
manually..chetanya's answer is correct....

Answer / mrmk

Good Suggestion.But if a control valve fail to operate
there may be so many reason.In practical,If you want to
isolate/stop the flow immediately it can be done easily by
closing upstream isolation valve.

Answer / deepak

if something stuck in control valve then what will u do??

Answer / thiagaraj

thnx priya;ranjith.nilmaheshin nd karthi

How to calibrate the magnetic flow meter and how to correct the flow if it is showing more flow.

5 Answers   Bohra Industries Limited, TCL,

what is vibration sensor working principal and how many types its has??

5 Answers  

what is the different between deflection type measurement and null type measurement in RTD?

0 Answers   SHR Solutions,

What is the meaning of Dry contact and Wet Contact related to to sensors?

5 Answers   Emerson, Google,

Why DP level transmitter preferred for closed vessels and Radar level transmitter for open tanks??

2 Answers  

INtools Trainining

1 Answers   Monarch Techno Engineering Solutions,

why we are using MARSHALLING PANEL? what is the role?

5 Answers  

what is ABB DCS SYSTEM?

2 Answers   OMV,

why using negative supply for bentley nevada vibration system ?

0 Answers  

how can we caliberate interface level troll

2 Answers   Grasim, IOCL, KOC, Sankyu,

What is the right procedure for adjusting the gap voltage of bently nevada vibration sensor?

2 Answers  

can you suggest good traning institute in instrumentation ? (in automation, or designing)

5 Answers