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Unread 02/03/2008, 11:04 AM   #3
BeanAnimal
Registered Member
 
Join Date: Feb 2003
Location: Pittsburgh
Posts: 20,772
Thanks luke!

I have had the system running for almost (2) years now, exactly as shown above. The standpipe setup currently handles close to 1,500 GPH with no vortex. For proof of concept I have pushed almost twice that through with no vortex problems. I can run the water level with the tops of the elbows slightly exposed without a vortex being created.

Here is what I attribute it to:

A) The water is shallow, but it is not a pool. The overflow box is long and narrow and processes a fairly large volume of water. The water is moving rapidly and does not allow vortex forming eddy currents to get a foothold.

B) The rounded backs of the elbows and the large surface area of the intakes help prevent the vortex from forming.

I have used 1.25" x 1" street elbows as the intakes. They are very close to glass bottom (1/4" gap).

If I am not mistaken, the traps (in this case) would not help with the siphon velocity other than adding a slight amount of friction due to the added pipe length and eddy currents that form by the friction and change of direction in the elbows. The velocity of the siphon is controlled by the ball valve on the standpipe, though it is a very forgiving adjustment. Of course, the open channel standpipe is what makes the balance possible.


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