Best value pump for a 5L roto


It’s a welch but the motor is made by emerson. It is 1/2 hp 9amp and was on their chemical duty line around 2005-2012. It is the only one in that lineup to use the 3/8" intake and exhaust. I left it running over night and it was only slightly warm to the touch. It does sound like an air compressor, not as loud as like a shop air compressor but you can hear it outside. I could probably insulate the spot I have the exhaust plumbed to a little better but if I had close neighbors I wouldn’t be able to leave it running.

[edit] been running for 28 hours continuous with no issue at all. I’m at the point where its pretty much just water left to purge off (my alcohol was weaker than I thought) and I can see where my old pump might be better (it is rated for 10 micron where this one is rated for 33 micron). Of course with the old pump I would need to change the oil after 45 mins or stop for 20 minutes every 30 minutes or so. I feel so free now I can live my life while it runs :slight_smile:



Get a welch 2014B-01
It’s got a little dial to adjust vacuum levels. Can be used for the rotovap (up to 20L in size), and any similar vacuum application like filtration.

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Interesting. I am running the 2014 on a 2L. Didn’t realized I could use it on a 20L. I thought I would need to upgrade to a DryFast Ultra.



I’ve used the aquarium pump / bucket of ice water as well, works great for solvents with low boiling points (< 100 C)

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How’s this work out for your 5l roto? Used 2090b is much more affordable than most oilless pumps I see that would work…



do you use a cold trap with your 2522?



No cold trap used