Consider a control valve action,the inlet air pressure is only 6 ksc but physi

Consider a control valve action,the inlet air pressure is only 6 ksc but
physically how it can be operate against 100 ksc line fluid pressure?

Question Posted / narasi23

2 Answers
7185 Views
SCS, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

Consider a control valve action,the inlet air pressure is only 6 ksc but physically how it can be ..

Answer / ys

actally pressure=force/area.. here ctrl valve operates
against a very small area(the plug seat area).so the force
required for this also less. hence the ctrl valve acts
against high pressure

Is This Answer Correct ?

7 Yes

2 No

Consider a control valve action,the inlet air pressure is only 6 ksc but physically how it can be ..

Answer / carl ellis

The reference to 6 ksc pressure means that the valve uses a
pneumatic actuator.

The ability of a pneumatic actuator to work against the line
pressure depends on the force that it can exert on the
valve's plug/cage/trim against the line pressure's force and
the bench setting of the spring.

A maximum of 6ksc of air inlet pressure can be exerted on
the total area of the actuator's diaphragm.

If the diaphragm area * air inlet pressure > plug area *
line pressure force + spring force, then the actuator will
move the valve plug. If not, the line pressure will move
the actuator.

A standard step in sizing a valve assembly with an actuator
is to check that the actuator can close against the maximum
line pressure and the spring setting at a given air supply
pressure. All vendors provide sizing charts for this purpose.

Is This Answer Correct ?

2 Yes

0 No

Post New Answer

More Instrumentation Interview Questions

Hi i am aneesh, done btech in applied electronics & instrumentatiin. And then i took mba in finance & marketing.After that i got placement in finance co and worked there for 3.5 yrs.Now i wanted to come back to engineering job.But without engg experience, i may not able to find an opening.i have done a course related to flow meters and ite calibrations. Kindly suggest where should i try to get a job?

0 Answers Qatar Petroleums,

Q- Control problem are mainly classified in _____ types. a-)4 b-)3 c-)6 d-)nono of these Few of them i know is 1- regulator type problem (eg- Air conditioner) 2- tracking problem (eg missile trcking problem) 3- sybernatics 4- optimal control problem

0 Answers Sail,

where using the 0-20ma in feiled instrumentation? why its using?

4 Answers

what is the input to be given in digital flow meter during the the calibration time?

0 Answers ONGC,

Why we are using 4-20 mA as Analog signal transmission other than 3 to 19 or 2 to 18 or 6 to 22 like wise ? What is the reason behind using 4 & 20 mA? Can anyone give proper technical reply ?

5 Answers Air Liquide,

How to calculate flow of air bubbler type level transmiter According hight and density

2 Answers Qatar Petroleums, RKS,

There are two chlorination tonners both are connected to two pressure swithes and the pressure switch is connected to SOV which operates the valve to changeover the tonner selection i.e if pressure one tonner goes low the other tonner should come in line if it is inautomatic selection design a circuit using relays ?

0 Answers

why we are giving negative supply for vibration sensors?

3 Answers Shell, Solex,

Why we use 250 ohm resistor in series with HART protocol communication?

13 Answers Chemtrols, Instec, Sabic,

How we calculate orifice plat size???

0 Answers

HOW TO CHECK THERMOCOUPLE AND RTD & WHAT IS THE DIFFERENCE BETWEEN THERMOCOUPLE AND RTD

14 Answers

What is the role of Integral in pid control?

6 Answers

For more Instrumentation Interview Questions Click Here