Making a python syphon pump

[Mudfrog]

I'm tired of replacing the pump for my python kit. I bought some PVC last night to build one and I just have one question. If you look on the python's pump it a cone shaped portion inside of it which is pointed downward. Is this needed to create the vacuum? Or will the vacuum start if it is just a straight shot downward from the faucet?

 

[Sploke]

The cone-shaped nozzle is a necessary part of the eductor to create enough of a pressure gradient to draw water through the hose. Basically, since your tap has decent water pressure, it forces water through this narrow nozzle. As it enters the larger chamber, it creates a venturi effect that draws air and water through the hose from the tank. If you just have a straight hose coming off the faucet with a line from the tank T'd in, it won't work.

 

[Mudfrog]

Hmm.. ok. I would assume it would not need to be cone shaped then, assuming I understand you correctly. If I forced the water through a smaller piece of pipe inside of the larger tube this should have the same effect, correct?

 

[Sploke]

The idea is that you want a narrow, fast-moving stream of water being ejected into a larger chamber that has an inlet to provide flow through the venturi. I guess that if you used a narrow hose fit through a drilled cap might accomplish the same thing.