Sea swirl closed loop completed

[M.E.Milz]

Maybe I can explain it from a different perspective.

In open system where the water drains into a sump, and is then pumped back up to the tank, the pump must work to:

1) Raise the water up against gravitational forces, and
2) Overcome the frictional force caused by the plumbing.

In a closed system, the pump will still have to overcome the frictional force caused by the plumbing. However, it will not have to overcome the force of gravity because the water that is in the drain tube (the pipe coming down from the tank) will push downward (ie, in the same direction as gravity) with the same force as gravity pushes on the water that is rising in the return tube.

Thus, if you are using a closed loop, it does not matter at what elevation the pump is located at. It DOES matter haw far away the pump is because the further away, the greater the frictional losses of the plumbing. For example, if your pump is connected to your tank by 8' of flexible tubing, the frictional loss (and the "head") will be the same irrespective of whether the pump is located 8' below the tank, at the same elevation of the tank, or 8' above the tank.

 

[Kitta]

esmithiii,
If the output from the tank is higher than the input to the tank, then a vertical height would apply to that formula, right? If the input to the tank is lower, there is more water pressure apply to the output of the pump then to the input of the pump.

[ December 13, 2001: Message edited by: Kitta ]</p>

 

[esmithiii]

Kitta,

Not exactly. If both the intake to the pump and the output from the pump are under the surface of the water then no, there is still no difference.

Ernie

 

[esmithiii]

M.E.Milz: Well put.

Ernie