Hello Everyone:

Let me explain a design situation in simplified terms. The scenario is as shown below:

------- -------- -------- --------

P1 P2 P3 P4 P5

P1, P2, P3, P4 and P5 are the values of static pressures at different locations of the flow. Flow is taking place from 1 to 5. Lets say, P1>P2>P4>P5. But P3<P5, which is a location where there is some recirculation.

While designing a pump to drive the flow through the network, does it need to be designed to drive through a pressure drop of (P1-P5) or (P1-P3)?

Thanks, Thomas

Hello Everyone:

Seems like my browser is behaving strangely. One statement was not even complete even though I typed it. It needs to be as follows:

But, P3 < P5.

Please let know if it's not clear.

Thomas

i didn't quite understand your question but it seems like a simple hydraulics question. to solve these problems it helps to draw a pressure position graph (it probably has another name in your texts) where you put pressure on the vertical axis and position on the horizontal (it doesn't have to be to any scale) it should then become clear what the appropriate pressure rise is that your pump must supply. think of it as a roller coaster where the pressure is height.