Answer / mohamed yousuf(instrumentation

according to the formula P=F/A

Actually we are applying the 2.5 bar pressure to the
diaphram actuator. By increasing the area of diaphram we
can increse the force acting on the diaphram and that muuch
of force is more enough to actuate the stem movement.even
though 40 bar pressure is applied only to the small area
(plug of the control valve).the force actiong on it will be
very small.

Answer / waseem ahmad

Mr. Bipinchandra is right but there are more possible
answers to this. 1) what is the differential pressure across
the valve? the pressure of steam might be 40kg but the
pressure of steam across the valve might not 40kg. 2) the
use of balanced plug in control valves allow us to control
high pressure fluids with minimum actuator force.

Answer / centhile r mohan

the 2.5 bar is used to control the valve by giving it to
the diaphragm to actuate it.so the process pressure 40bar
is controlled.

Answer / bipinchandra ravalia.

The 2.5 bar used to control the valve acts on the
Diaphragm. Now the area of the diaphragm is Large and thus
the Force Per Unit Area acting on the stem is very much
greater than the Process pressure of 40bar. Thus it is not
difficult to control this process pressure with the given
2.5 bar air supply to the control valve.

Answer / sagar,kptl

By using of pneumatic control valve,that control valve have a helical spring containing tension when give pressure 2.5 bar. That pressure force acting will control the 40 bar steam

.'.P=f/a

Answer / rajender

By using Pneumatic Control Valve(Plug valve)

Answer / r_vaya

That's why in high pressures line(like super heater's  steam in power plant)  having double seated globe valves.therefor double seated plugs has line pressure both side equal (upside same and down side same ) is equal to line pressure 0 
So thus, plug will operate according valve's pressure.....

Answer / ramesh4529

yet to find

Can anyone send most commonley asked Instrumentation questions and answers in cement industry please?

0 Answers  

How to calibrate smoke Dectector

0 Answers   KOC,

what is dc moter.

0 Answers   Jindal Steel and Power, Lupin,

i have calibrate rosemount make level transmitter , wht can i do ? my tank capacity is 30,000 liter

9 Answers   Equate,

can any one help me to get bel probational engineers sample question papers. I have applied for it.

0 Answers  

wht is dcs architecture ? can u give example?

3 Answers  

Why is it necessary to use compensation leg to measure the liquid level in a closed or pressurized tank?

0 Answers  

What safety precautions you will adopt to work on Steam service control valve?

1 Answers   QAFCO,

How do Foundation Fieldbus works? how the Communication Carries out from Foundation field bus,Field Devices and Controller? Were it's Application in the Field? For Which Signals this is Used? PLease Find this answer for this Question Detaile wise because i want to clear the Concept Regarding Foundation Field Bus,if Possible please attach the link of Document with Contails Diagramatic So that more esier for me.

3 Answers   Honeywell,

hello this is dhinakar i am completed my instrumentation engg . recently i got job in sugar industry side. i like to ask one question can any one say what are the things i have to follow know more about industrial instrumentation,,,,,,,

6 Answers  

Why we use the double acting control valve in flow line?

3 Answers  

what is the pressure in the tank when its level of liquid is 1.5 meters when its total capacity is 2 meters

2 Answers   Engro,