QH diagram of an evaporator pumps

[Kdolph]

Hi Everyone

I want to estimate the operating point of a series o pumps.}
I have a drawing attached in a excel format in the next link

http://files.engineering.com/getfil...d-a79d-4307c5c33347&file=ESQUEMAS_BOMBAS.xlsx

There are two pumps of my interest right now (Pump 1 & Pump 2)

How I should focus the analysis of the system curve for the circuit of the pump 1.
Should I analyze the circuit from the point A to the point 1 or from the point A to the point D.
If I choose the second case (from point A to the point D) how is affected the pump curve in the 1-D section. How can this be represented on a Q H diagram.

I know how the parallel pumps QH diagram are representated, but in this cases there are two pumps that suctions from different sources and then act like a parallel system.

I will appreciate your help.

 

[BigInch]

why are 1 and 2 connected?

you must get smarter than the software you're using.

 

[LittleInch]

I assume you've simplified this, but maybe too much as it is not possible to see where the pump 1 feed supply actually goes to. You also need to describe the process a bit more, e.g. does your control valve shown next to point 1 control on pressure or flow or both?what does the control valve at point C do? Where does the flow go to? Only then can we figure out what can be done.

Given you have a control valve at point 1, I think A to pt 1 is your key issue. At point 1 it is then at the same pressure as the discharge from pump 2 but has higher flow than A to 1, but maybe a bigger pipe also. Some flow clearly goes 2 to C which is equal to or less than A to 1?

You simply need to divide up the flow system into sections and join the dots where the junctions are where pressure has to be equal in the branches.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way