Hello Ankit,
I apologise, I was about to explain about that too in the above post but it slipped my mind.
Those two sections relate to the sizing of the Control valve on the Tank.
Once we calculate the inbreathing and outbreathing requirements, then we can size the inlet and outlet control valves on the expansion tank.
In the sizing procedure for control valves, we cannot directly calculate the size or valve opening required as all manufacturers have their own sizes and Valve Cv's.
So we select a valve with a given Cv from a supplier and then calculate our process Cv and compare if the valve Cv allows for this limit. If it doesn't, we select the valve with the next highest Cv.
The ratio of the Calculated Cv to the Selected Valve Cv gives us the valve opening required.
1. In the section "selected valve Cv and piping geometry", I have considered a sample valve I selected and it's Cv is taken from the manufacturer data to see if it is suitable for the flow conditions I have.
2. Piping geometry calculates the losses due to pressure drop at inlet and outlet reducers of the Valve in case the line size is different from the valve size, since those losses have to be accounted for at the inlet and outlet of Valve.
3. Once this is done, I size the valve in the "Valve Sizing" section and calculate the Cv I get from the flow formulae, and then compare it with the Selected valve Cv, and take their ratio to get % valve opening required for that specific valve to satisfy PCV regulation conditions.
And don't worry if you get a higher value for the inbreathing and outbreathing requirements as API 2000, 2014 edition is slightly more conservative. Just make sure your calculations are correct and confirm that is is valid in practical conditions from someone experienced. And find out from the person who made your datasheet if they are following the old API revision or the 2014 edition. Maybe that is the reason that your datasheet values are not matching with the calculated ones.
And also, just to inform you I have updated this spreadsheet in order to avoid such confusion in the future about sections.
Please find the updated spreadsheet here :
http://www.cheresour...ets/#entry99503
Regards,
Shantanu
Edited by shantanuk100, 18 November 2015 - 06:18 AM.