Jump to content



Featured Articles

Check out the latest featured articles.

File Library

Check out the latest downloads available in the File Library.

New Article

Product Viscosity vs. Shear

Featured File

Vertical Tank Selection

New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

4

Pump Dischrge Control Valve Sizing

pumps discharge control valve pressure drop

3 replies to this topic
Share this topic:
| More

#1 Lyne

Lyne

    Veteran Member

  • Members
  • 33 posts

Posted 04 June 2024 - 08:25 AM

Hi,

 

How to set the pressure drop for the control valve at a pump discharge? I have different regimes and the control valve is at the booster pump outlet. is there a special requirements for such control vales ?

 

Thank you  



#2 snickster

snickster

    Gold Member

  • Members
  • 61 posts

Posted 04 June 2024 - 02:25 PM

Here is typical sizing criteria for good controlability:
 
Minimum Cv Capacity (Cv Required)
The selected control valve trim capacity (Cv selected) shall meet the
following:
1) An equal percentage trim shall operate below 93% travel at
maximum flow condition. If no maximum flow condition is
specified on the ISS, then the trim shall operate below 85% travel
at normal flow condition.
2) A linear trim and quick opening trim shall operate below 90%
travel at maximum flow condition. If no maximum flow condition
is specified on the ISS, then the trim shall operate below 75%
travel at normal flow condition. Anti-surge control valves shall
operate below 55% travel at maximum flow condition.
3) A modified parabolic trim shall operate below 90% travel at
maximum flow condition. If no maximum flow condition is
specified on the ISS, then the trim shall operate below 80% travel
at normal flow condition.
Commentary Note:
The specified percentage (%) travel positions are for sliding stem type
valves and need to be converted to degrees opening for rotary type
control valves.

Edited by snickster, 04 June 2024 - 02:29 PM.


#3 breizh

breizh

    Gold Member

  • Admin
  • 6,395 posts

Posted 05 June 2024 - 12:34 AM

Hi ,

To add to Snickster's reply, a paper and an excel sheet I prepared years ago.

Breizh

Attached Files



#4 walidd_23

walidd_23

    Junior Member

  • Members
  • 27 posts

Posted 10 June 2024 - 03:38 AM

Hello 

First of  all you need to determine the worst case which corresponding the maximum calculated Cv considering the following:

  1. Min pressure drop of control valve 0.5 -0.7 bar
  2. Max Operating pressure at receiving vessel or destination (HPA)
  3. Max liquid level at receiving vessel 
  4. Rated Flowrate 
  5. Min liquid level at supply vessel

With this condition you will determine the max flow valve condition and rated head of the pumps. 

 

After that you  can do the calculation for normal flow with normal operating pressure and level, and min flowrate to determine the full operating of the control valve.

 

For better estimation it is good to have pump curves  for normal and min case , I have attached and example for the valve hydraulic calculation of this 3 cases using Flowmax

 

Attached File  Valve Sizing Cases .pdf   397.38KB   21 downloads

 

Regards 

 

 


Edited by walidd_23, 10 June 2024 - 04:53 AM.





Similar Topics