Vacuum in loop
Vacuum in loop
(OP)
I've always noticed that at the top of cooling water loops at a high point (80-100' above grade), a vacuum develops at the top when a high point bleed is opened. The downleg of the pipe goes back to the cooling tower 70' below. I've associated this with the freefall of liquid accelerating in the down leg and detaching flow. Am I correct in my understanding?
I can't find any literature online about this. Is there a way to calculate the vacuum developed?
I can't find any literature online about this. Is there a way to calculate the vacuum developed?
-Mike





RE: Vacuum in loop
70' static head is about 30 psi of water. Check to see what the return pressure to your cooling tower is, I suspect it's likely 10 to 20 psi, that's enough to be well below atmospheric pressure at the highest point. Then on top of that, you need to include the frictional line losses which will further decrease the pressure at the highest point though I suspect that's a smaller effect.
RE: Vacuum in loop
-Mike
RE: Vacuum in loop
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