no I haven't. But according to his mod, he used 3/4" on both inlet/outlet, used 3/8 airline (not sure if it was 3/8 id, or od) and didn't have a problem. I'm wondering how the new set up is done that he put pictures up of on the other thread. He had a T on it. so I'm wondering if pulling the airline back further allowing more water to get sucked in will allow more air? His initial set up showed that his airline "venturi" was in the 45 elbow that he slipped on what appeared to be a 1" section of possibly 3/4" pipe.
Here's some interesting info that liveforphysics sent me when I pm'ed him about venturis, he's some kind of hydro engineer or something:
Quote:
CSA = Cross Sectional Area. Sometimes called XSA. Sorry about the field specific jargon.
The diagram you included does show the method for manifolding multiple air inlet points that I was trying to describe.
By stretching PVC you can easily drop 1" PVC down to a 1/4" ID. It's important to remember that you will not see such a critical flow choke from this sort of drop in CSA provided the taper is smooth and gradual, which is how PVC naturally forms when you heat and pull it.
|
So basically, taking a piece of 1" pvc pipe, heating it, and pulling it to get 1/4" id inside, you could speed up the water so fast that it's pulling vast amounts of air. he also suggested using the manifold method I mentioned either here or the other thread by drilling multiple holes in the stretched pipe to get many smaller holes vs. one air source.. here's where he said to put it:
Quote:
Due to the turbulence caused by the steps when the reducer bushings are used, I recomend stretching the PVC to create the desired drop in CSA. After stretching, I would drill a series of small radial holes directly behind the thinnest CSA point.
Since connecting these holes to a common feed would be very difficult, I recomend slipping this proper venturi into the next size larger PVC or bushing or whatever part it slips into easily. Then drill a single large hole, thread it and thread a large barbed nipple into the side of that bushing/pipe that fits over the outside of your venturi.
This should enable you to have a proper venturi for a low cost with excellent performance.
|
So in essence, stretching a piece of 1" pvc to have 1"id hole ends, and whatever we deem as practical as the smallest id in the "middle" and then as soon as the thinnest part starts to increase in diameter again, drill a few small holes around the radius, then take this stretched pvc and hopefully some how get it into a T fitting or a 1 1/4" piece of pipe. then thread a fitting on or just glue the airline directly to the pipe, which I think would be easily done on a T vs. the straight pipe.
Sorry, this got really long, but is very interesting. it's obvious that some pumps will only be able to handle so much air before choking, but this seems logical on how to get more air in. The problem it seems that is brought up with choking is that the air bubbles coming in are way too large and causing the pump to stop and start, if the air was brought in by a bunch of tiny bubbles, I think there wouldn't be a chance for the pump to stall, but would chop them up... what do you think Jeff? did you catch all that
