how strong, and what type of pump should I use for winterization

hey there,
I will try to keep this short and simple. I receive a couple litres of ethanol extract to winterize each day. I am using a stainless steel Buchner funnel. I was wondering how strong of a pump I should use to be performing these winterizations.
Thanks for your time.

At a couple of litres you could use gravity.

A water aspirator will also do the job.

How are you planning to recover your solvent?


If you can find any used working refrigerator compressor. Connect one side of the hose with drier filter to the compressor suction line. The other side of the hose you can connect to your funnel or chamber.
or as above mentioned water aspirator

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Welch wob-l diaphram pump

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I have used gravity and it takes all day. I am recovering my solvent through a rotovap

We only use about 27hg

yep. You did say you only needed to do a couple of litres a day

Gravity, in the freezer, over night, will get that job done.

Or as @kali4nian suggests, you can diy a vacuum pump from a refrigerator compressor

A diaphragm pump of some flavor is the preferred choice


Is a cold trap still needed with a diaphragm pump? I was looking into a pump for vacuum filtering as well and saw the water aspirator pumps were about the same cost as a Welch wob-l. I like the idea of the aspirator not needing a cold trap, but don’t have good water pressure in the workshop so the pump seems like a good option.

I used a 390gph aquarium pump, 5g bucket, water lines, threaded hose to barb adapter for my 5l rotovap condenser. I also used the faucet way.

Have it drain back I to the bucket. Just add use as the hrs pass

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Here is the one I use for DCVC and filtrations. It is a full chemical duty pump and not cheap but there is zero need to worry about pump oil contamination or blown pump seals. This one has a pressure side I use in other parts of the lab too. It comes with a regulator and those are not cheap either so the cost is not so bad. The advantage of course is that it is the right tool for the right job. This is HUGE if the goal is to streamline operations.

No pump vapor trap needed.
From my order history


We’ve used various diaphragm pumps for doing filtration with relative success, at least on smaller scales. I’ve thrown a trap on the line as a precaution, but I’ve never seen anything condense in them, considering there shouldn’t be vapor present in the system

You could use the pump from your rotovap. If you promise not to tell anyone, I’ve also used a regular hvac pump for filtering :slight_smile:

Another good one is Welch pilot pumps. They are cheap diaphragm pumps.

You do not need deep vacuum or high can.

Good luck

We manufacture cryogenic temperature-controlled winterization systems that filter up to 15L in only a few minutes. Minimum capacity is 9L. You would only need to winterize one batch per week. DM me if you want more information.