DinglabStainless Steel Aspirator Pump,Humboldt,Lab Vacuum Hydro Aspirators Filter Pumps

... If you do it right. It took a bit of effort to get the vacuum to work well, but eventually it did. It all comes down to sealing ANY possible leaks – tighten all your hosing with hose-clamps, and tighten the ever-living-hell out of this contraption. Finally, it seems to work a little bit better if you hold it sideways. I don't know why.But the vacuum it produces is pretty good. Works excellent with the Büchner funnel, but I haven't tried it yet with distillation. It's definitely on my todo list. Will update this when I work out what the vacuum produced is by measuring the boiling temp of water.

Pros: It's an effective aspirator pump.Cons: It took a long time to arrive directly from China, and there were some metal burs on the water inlet that had to be filed off.I'd gladly pay $2-3 more for this direct from a US supplier.

I am using this in a recirculating venturi setup to pump down a vacuum chamber. Theoretical minimum pressure should be the vapor pressure of water, but I'm only getting down to ~0.8atm (So, only ~0.2 atm pressure reduction). I am relatively certain that this is due to the pump and not a leak, as bubbles can be seen escaping into the re-circulation tank until the pressure stops dropping. Best guess here is that I'm using a water pump with either incorrect flow rate or incorrect pressure, but ZERO documentation provided, so I have no clue what might be causing the poor performance. Technically, the pump works, and can probably do some basic chemistry work, but does not do what I think it should be able to, I don't know why, and there is no way to find out.