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[SawsanAli311]

Hi Everyone, 

 

The title was cropped: '' 

Pumps Operating Under A Common Suction Header But With A Segregated Discharge headers''

 

I have an existing produced water system which requires a capacity upgrade. It consists of tanks and disposal water pumps. we will be adding one new tank in parallel with the existing two tanks and two new pumps to operate under the same suction header of existing two pumps (which operate in parallel with a common discharge) . Accordingly, a total of 4 pumps (identical in capacity) will be operating with a common suction header from the three (2 old+1 new) tanks. Ofcourse, the existing suction header size was checked to be hydraulically adequate with respect to velocity and pressure drop and not affecting the existing pumps NPSHA nor differential head much. 

 

The new pumps can't be sharing the same common discharge with the existing 2 parallel pumps due to the velocity and high backpressure constraints. Accordingly, we are proposing to have a segregated discharge of the two new pumps with an individual FCV at each pump discharge set at the BEP. 

Accordingly, the new system cannot be considered to involve 4 parallel running pumps as they don't have a common discharge. 

Existing Tanks level control is adjusted via an FCV located on the existing common discharge.  It is proposed now to have a split range level control for the 2 existing + 1 new tank acting on the old FCV as well as the FCVs on the individual new pumps. 

 

The question is, is this considered design has an odd scheme? have anyone attempted connection pumps in parallel with the same suction header but not with the same common discharge (not so parallel) I believe if we provide the new pump vendor with its own system curve, then pump design would be independent from the existing pumps. Additionally, in case of the dynamic scenario of pumps tripping, the new pumps would be safeguraded with their individual discharge FCV (which can also be cascaded with PIC control for run out protection). 

 

Thanks in advance 

Edited by SawsanAli311, 02 September 2018 - 12:59 PM.

[Bobby Strain]

How about a sketch at least.

 

Bobby