Sciencemadness Discussion Board

DIY recirculating aspirator issues

vakzo - 12-4-2016 at 17:40

Because I don't have access to a faucet in my lab, I attempted to build a device which recirculates water through an aspirator. It's bein run using an Everbilt 3/4 hp shallow well jet pump. The pump runs fine and generates a vacuum, but randomly shuts off after a small amount of time. The correct voltage is being supplied (and tests correctly where it is connected to the pump) and it doesn't seem to be a cut-in/cut-off issue as it happens randomly and the pressure reading was within the range the entire time. Anyone have any idea what could be causing this?

macckone - 12-4-2016 at 17:54

Obvious answers are overheating or bad pump.
Mine runs continuously with near max head pressure and no issues.
I have had the water get almost boiling and still runs.
I use a fountain pump with 15 ft head and 100 gpm.

vakzo - 12-4-2016 at 18:15

Do you know what specific brand/model yours is? I might end up just getting a new pump then.

protem - 13-4-2016 at 02:34

If you are looking at a new pump

http://topsflo.en.made-in-china.com/product/KMSxsZBopvpc/Chi...

I tried this and it works. It is a DC pump so a power source is required. The pump draws about an amp at 24 V. Very low heating effect - much better than a jet pump. Good vacuum. Bought one through aliexpress.

Sparklehorse - 13-4-2016 at 09:17

Does your pump have any adjustments on it? I have a shurflo pump in a similar set up and I had a similar issue until I adjusted the screw that sets the back pressure at which the pump shuts off. Before I did that the pump would cycle on/off repeatedly with the aspiration connected

chemrox - 13-4-2016 at 11:51

I bought Cole-Palmer aspirator pump for $40 and it's been honking along for ten years. It has dual aspirators and pulls <10 torr. It gets better when ice is added to the reservoir. If you're intent on building one look into running parallel aspirators. As others said your pump is probably the issue. A well pump is probably too high a volume and may not work with almost zero head of water. Also without running water how do you serve condensers? Another pump? Volatiles should be purged from your system. I run my rotovap condenser through my aspirator reservoir. That purges the volatiles.

vakzo - 13-4-2016 at 14:52

Quote: Originally posted by Sparklehorse  
Does your pump have any adjustments on it? I have a shurflo pump in a similar set up and I had a similar issue until I adjusted the screw that sets the back pressure at which the pump shuts off. Before I did that the pump would cycle on/off repeatedly with the aspiration connected


Yes but after a couple hours of adjusting the cut off to different levels there was still no improvement.
Quote: Originally posted by chemrox  
I bought Cole-Palmer aspirator pump for $40 and it's been honking along for ten years. It has dual aspirators and pulls <10 torr. It gets better when ice is added to the reservoir. If you're intent on building one look into running parallel aspirators. As others said your pump is probably the issue. A well pump is probably too high a volume and may not work with almost zero head of water. Also without running water how do you serve condensers? Another pump? Volatiles should be purged from your system. I run my rotovap condenser through my aspirator reservoir. That purges the volatiles.


I apologize for not elaborating. I have a water source, but it is a garden hose with low water pressure. I have a drainage out and a constant stream of water from the hose in to purge everything. Also what specific Cole-Palmer pump are you referring to as all the ones I seem to be finding are at least $150 used?

[Edited on 13-4-2016 by vakzo]