Can I use a velocity of 6 m/s in pump min flow line (recirculation to suction vessel). The fluid is clean water at 40 degree Centigrade. If I do not use this velocity the pressure drop in the line becomes so less that I have to use a very large DP across the control valve & this is becoming very close to the critical pressure drop.
|
Flow Velocity In Pump Minimum Flow Line
Started by ayan_dg, May 06 2008 09:39 AM
2 replies to this topic
Share this topic:
#1
Posted 06 May 2008 - 09:39 AM
#2
Posted 06 May 2008 - 02:04 PM
For clean water, I recommend the normal 5-7 ft/sec of average velocity. You should never qualify the size of line by the pressure drop you have across a control valve. If anything, it is always the opposite.
What do you mean by "critical flow"? There are many things today being defined as so-called "Critical" - and people fail to stop and define what they mean. If you are dealing with clean water, what is so critical about your flow?
If you are reluctant to take the full pressure drop across the control valve, that's OK. Simply install a 2-stage pressure reduction valve. This is what is commonly done with gas regulators when they are confronted with supersonic flow. You can also use a pressure regulator before your control valve.
What do you mean by "critical flow"? There are many things today being defined as so-called "Critical" - and people fail to stop and define what they mean. If you are dealing with clean water, what is so critical about your flow?
If you are reluctant to take the full pressure drop across the control valve, that's OK. Simply install a 2-stage pressure reduction valve. This is what is commonly done with gas regulators when they are confronted with supersonic flow. You can also use a pressure regulator before your control valve.
#3
Posted 08 May 2008 - 05:50 AM
Before I proceed to give you an answer, let me know what is the temp and pressure at which you handle water. Do you mean that you encounter pressure in the control valve below the vap pressure of water at that temp?
Also, 6 m/s is very high velocity if you are using carbon steel as the MOC.
You should be using 6 Fps as a design velocity for the min. circulation line and size the line based on pump min. ciruculation flow.
Also, 6 m/s is very high velocity if you are using carbon steel as the MOC.
You should be using 6 Fps as a design velocity for the min. circulation line and size the line based on pump min. ciruculation flow.
Similar Topics
Vacuum Pump Power EquationStarted by Guest_hysyshunter_* , 22 Apr 2024 |
|
|
||
Heavy Crude PumpStarted by Guest_Rahimzadeh_* , 13 Apr 2024 |
|
|
||
Flow Switch High RangeStarted by Guest_Lyne_* , 11 Apr 2024 |
|
|
||
Pump Sizing ConsiderationsStarted by Guest_panagiotis_* , 07 Apr 2024 |
|
|
||
Barometric Legs Line SizingStarted by Guest_panagiotis_* , 17 Mar 2023 |
|
|