Hi Pilesar,
I would like to ask you something else regarding the control valves:
What should be the rule of thumb related to DP allocated to a control valve?
I have found different statements such as:
- Pvalve = 25% system pressure drop (including control valve) or Pvalve = 1/3rd system pressure drop (excluding control valve)
These statements made me a bit confused on how I will evaluate them?
Please see attached the example that I found here: Control Valve Sizing (pdf) – What Is Piping
In this example I calculate the percentage of DP for the control valve, which is equal to1.59/(1.59+0.7+0.7)=50% and not 25% as it is indicated in the rule of thumb.
Could you enlighten me a bit with this?
I have found also other statements such as:
For pumped circuit or compressor circuit it is recommended to take the control valve pressure drop from the corresponding pump/compressor calculation.
For pumped circuit, following guidelines can be followed
Control valve pressure drop shall be maximum among
- minimum 0.7 bar for rated flow case
- minimum 1 bar for normal flow case
- 25% of system frictional loss for rated flow case
- 33% of system frictional loss for normal flow case.
Thank you in advance!