Answer / www.islamqa.com

#"Cv" for valve is known as: valve sizing coefficient or
valve flow coefficient

#It refers to " how many gallons per minute can pass
through a fully open valve under diffrential pressure of 1
PSI "

#Cv is a unitless value and by getting it's value we can
get the valve size in inch from tables.

#Cv is got from calculations using s/w provided by
manufacturer as we have many parameters affect its value,
and Cv value is critical as it affects valve size which
leads us - if wrong - to oversized valve or undersized
valve, which harm the process.

#Cv - as mentioned - is got from calculations using s/w,
but it has a basic formula for gas service and liquid
service.

#For liquid service:

Q = Cv (DP/ROH)^.5, ROH IS SPECIFIC GRAVITY

#For gas service:

Q = 963 Cv (DP(P1+P2)/ROH*T)^.5, T is gas temperature in
Rankin

Regards,

Ahmed Sabry
Control and Instrumentation Engineer
GPC - General Petroleum Company
ahmedsabry.online@gmail.com
CELL.: 00 2 0121367310

Answer / bhavesh

wecan seeing value of (cv)means cooficient of valve and as
per desined use pipeline in short we can define control
valve size as per desining requriment.

Answer / faiyaz

class 150 class 300 class 600 class 900 class 1500 its size of valve according to the size oil and gas and water will be flow

Answer / ashok

BY SEEING BODY SIZE AND NAME PLATE

Answer / venkatesh j

we can seeing valve size and valve tubing and valve colour

Please send the all question with answer related for interview.

1 Answers  

How flow control valve is working with pnuematic positioner and I/P convreter from command is given from remote

1 Answers   Ecil, GAIL,

what is the difference between hub and switch?

6 Answers  

Consider a level troll. i am getting a correct value in 4mA and 20mA. the value in the middle(30 to 60%)is disturbed and i am not getting the appropriate value. what is the solution to normalize the level and to get the correct value..

2 Answers   KNPC,

what is buoyancy law?

1 Answers  

How LVDT position transmitter works on DC supply(24vdc) from DCS, whereas transformer operates on AC supply? pls help..

1 Answers  

how ranges is decided for drum level or dearator level,in my pplant i have seen for boiler drum range is -1000 to 1000mmwc, while for dearator -2000 to 0 mmwc ,why they decided to take this range ?

2 Answers  

why is honed type flow orifice plate? what purpose it used? how to select this?

4 Answers  

Sir, I am working as a Instrument Engineer in Grasim Industries. Can any body provide question answer for interview purpose

0 Answers   Grasim,

what is plc? breif explain

3 Answers   APL,

Which standard of hazardous area classification used in India?

1 Answers   Orchid,

what is the principal of coriolis mass flowmeter

1 Answers