3 replies to this topic

[Abdelilah]

Hi dear all,

 

Currently, we are purchasing a condensate pumps and bidder send us the below comment :

 

Design criteria for head rise to shut-off for centrifugal pumps

 

Clause 6.1.11b of this specification indicates that for pumps in parallel operation, the head at 50% of rated operating point flow shall be at least 110% of head at the rated operating point.

 

Bidder would like to highlight that this requirement will result in a higher head rise to shut-off and this will not allow the optimum pump model selection.

 

Hence bidder proposes that the pumps which are in parallel operation shall have the head rise from rated flow to zero flow (i.e. shut-off) at least 10%. "

 

Would some one explain to us the meaning please and any comments or suggestions are welcome

 

Best Regards

A.Baghdadi

[Technical Bard]

They are trying to save you money.  What they are saying is that following your specification will result in a higher head rise to shutoff and thus higher MAWP for the casing and downstream piping.  Also, they are saying the pump will have lower efficiency and thus may need a larger motor.

 

If you don't understand what your own specification means, why did you write it that way?

[Abdelilah]

They are trying to save you money.  What they are saying is that following your specification will result in a higher head rise to shutoff and thus higher MAWP for the casing and downstream piping.  Also, they are saying the pump will have lower efficiency and thus may need a larger motor.

 

If you don't understand what your own specification means, why did you write it that way?

Dear Bard

 

First thank you for your valuable answer.

 

Then, I would to inform you that this specification has been done by supposedly reputed international companies that produced the FEED.

And now, we are receiving some clarification from bidder about this specifications and other specifications that we are trying to respond.

 

Best regards

Baghdadi

Edited by Abdelilah, 01 March 2018 - 05:15 AM.

[Technical Bard]

The specification was well written.  And I would advise that before sending out an inquiry, even if the specifications were written by a third party, that you completely understand what is in them.