Sciencemadness Discussion Board

Quesrtions on vacuum and condenser pumps?

oxybate - 24-5-2007 at 18:38

As a relative newbie, its clear that I'll need two pumps for most reactions that I want to do:

1. A pump that will be sufficient to pump cold water through a reflux condensor.
2. A pump that when fashioned in an "aspirator setup" that will allow for a constant, strong vacuum for vacuum distillations.

A search of the threads available doesn't lend much help. So I ask you elders:

1. What are you using to pump cold water through your condensor? An ebay suggestions?

2. What pumps are you using in conjunction with an aspirator to achieve a respectable vacuum for distillation? Any ebay suggestions? I plan, as you must suspect, to use a "mini-sink" setup, where I'll have an amount of water pumped through an aspirator and re-uptaked through the pump.

Thanks for your help, in advance.

Sauron - 24-5-2007 at 18:56

If you live in a climate where tap water (from municipal mains) is sufficiently cold, use that, rather than recirculating. The heat carried away by the coolant goes down the drain. If you use an efficient condenser (West is better than Leibig) you do not need a lot of water velocity.

If you need to recirculate, like I do - tap water here is hot - you need not merely a pump but a recirculating chiller which is a combination of a small refrigeration unit and a pump. Generally these have adjustable thermostatic control and display temperature and setpoint. Not cheap but indispensible.

A vacuum system consisting of a reservoir for water, a submersible pump and one or two aspirators can be bought commerically or you can DIY if you are handy enough. I bought mine from Eyela, works great. So I am independent of local water supply for both cooling and aspirator vacuum. A tip about the latter: ice water pulls the best aspirator vacuum. So add lots of ice cubes to the reservoir water. Don't forget the overflow valve and hose.

Magpie - 24-5-2007 at 19:22

For the cooling water for my West condenser I use a small submersible pond pump sitting in a plastic dishwashing tub. When I get ready to do a distillation I make sure I have plenty of ice cubes on hand from my kitchen ice-maker.

[Edited on by Magpie]

evil_lurker - 24-5-2007 at 20:47

I'm looking at a rather large chiller myself for distilling and storing ether in a storage head.

But, I still have a pump and resevoir which I'm working on for an aspirator/condensor coolant supply.

Basically its an old cooler with the drain drilled out with a hole saw, a 3/4" "bulkhead fitting" screwed in, and a Harbor Freight tools 1" clear water pump. It'll be done when I put a couple more 90ยบ hose barbs on the suction line and plumb the top end.

It boast a whole half horsepower, continuous duty, 115 feet of head pressure, 10 feet of suction, and a max capacity of 330 GPH which should be plenty to run an aspirator.

Best thing though, its only around $35.