5 replies to this topic

[Light]

Dear members,

 

I have a question regarding the determination  of the exact location of control valve after the discharge of a centrifugal pump. Should it be located at the ground, or at some elevation higher or lower than that of the pump?  How is the exact distance determined? Does a process engineer determines this or he incorporates it in the hydraulic calculation as per the position set by a piping engineer? What are the important factors to be considered while determining the same?

 

Regards.

[fallah]

Light,

 

Mostly the process engineer incorporates the control valve in the relevant hydraulic calculation per the position set by piping engineer...

[Art Montemayor]

Light:

 

In accordance with my personal field operating experience, always place a pump's discharge control valve where it is safely and conveniently located for the operators and the maintenance crews to access, test, and maintain.  You might also need - from time to time - to actually see the length of the stroke to obtain an idea of the control action.

 

My personal preference when in operations was to have my control valves at a height of no more than 2 meters above grade - where possible.  This would allow for a relatively short platform.  Of course, these would constitute "ideal" operating conditions.  Sometimes, as engineers, we have to make hard decisions involving trade offs and this may involve having a control valve located out of sight and well above grade.  There are certain trade offs that I was always willing to accept - but never a situation where the safety of my workers was compromised.  And I would fully expect a piping design engineer to take those same considerations into his final design.

[fallah]

Agreed with Art viewpoints... and when I did believe the process engineer would follow piping engineer in control valve position...I have already supposed that the piping engineer has followed the relevant piping modeling practices and constraints in his/her 3D modeling of pumping system without generation of any obstruction in control valve accessibility and required maintenance... 

[Ganesh Buddha]

control valve can be placed anywhere after the pump discharge. the only prerequisite is that it should be after the flow measuring element...

[S.AHMAD]

Hi Light

Mr. Art, as normally done in the past, has given you good comments. Let me add my own experience is that you need to check the maximum possible pressure when the control valve is inadvertently closed either, for example, due to operator error or valve failure in closing position. If the max pressure is higher than the piping/fittings rating then try to locate the valve as close as possible to the pump so that the upstream piping is shorter to minimize cost for upgrading the piping/fittings. However, with this option, all vavles doenstream of the CV must be CSO. Better option is to install PSV at pump discharge.

Edited by S.AHMAD, 11 February 2016 - 10:58 AM.