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gmat · 01-31-2002, 04:49 PM

Flow resistance = water height. Strictly. I insist. (its not the place for a physics course so i wont argue over this)
I know, powerful pumps out there can bear like 11m or even 13m of water.
But not tiny weeny aquarium pumps we usually put in our comps. And there, having a 1m high tower case counts. No matter how you put it you've got 1m of water over your pump outlet (if it's at the bottom). Specially if you have 1/2" or wider all around. And the pressure of this water column will bring down your pump performance. Even in a sealed-closed loop. The pump has to start up and get things moving... And "centrifuge" pumps are not designed to withstand even moderate pressures.

That's why some ppl like Joe buy such powerful pumps.
They're less concerned by water height than by leak prevention... Those pumps dont produce more flow (on paper...) but have a great pressure differential.
My initial point was, putting 2 pumps in the circuit would help reduce that differential and therefore raise flow.

Oops i forgot. Air traps, resevoirs - most ppl have those. And ususally at the highest point. How do they count ? Open loop? Closed loop ?

01-31-2002, 04:49 PM	#21
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	Flow resistance = water height. Strictly. I insist. (its not the place for a physics course so i wont argue over this) I know, powerful pumps out there can bear like 11m or even 13m of water. But not tiny weeny aquarium pumps we usually put in our comps. And there, having a 1m high tower case counts. No matter how you put it you've got 1m of water over your pump outlet (if it's at the bottom). Specially if you have 1/2" or wider all around. And the pressure of this water column will bring down your pump performance. Even in a sealed-closed loop. The pump has to start up and get things moving... And "centrifuge" pumps are not designed to withstand even moderate pressures. That's why some ppl like Joe buy such powerful pumps. They're less concerned by water height than by leak prevention... Those pumps dont produce more flow (on paper...) but have a great pressure differential. My initial point was, putting 2 pumps in the circuit would help reduce that differential and therefore raise flow. Oops i forgot. Air traps, resevoirs - most ppl have those. And ususally at the highest point. How do they count ? Open loop? Closed loop ? Last edited by gmat; 01-31-2002 at 05:22 PM.