20L Rotovap + Welch Duoseal 1402 : Good Pairing?

HK_Esquire · April 21, 2019, 9:00pm

You guys think this belt driven Welch 1402 duoseal will work for my 20L rotovap? I got the welch super cheap locally and trying to find a use for it. Thanks for any input fellas. specs below

-HK

GroovyOctopusLabs · April 21, 2019, 9:14pm

If its good enough for spd I’m sure it’ll work, though you may want a cold trap. I think a regular diaphragm pump will work well enough for a rotovap.

square_root_pharms · April 21, 2019, 9:15pm

It will pull down far lower than you need. Might want to use a needle valve or something to bleed it so it doesn’t pull down too low

HK_Esquire · April 21, 2019, 10:12pm

@GroovyOctopusLabs
@square_root_pharms

Thanks guys. good call square root on the needle valve if use the welch on the rotovap.

I do also have a 12L SPD. Sogevac roughing pump for volatiles. Yall Think the welch could handle the large volume system for the main body? I also have a alcatel 2021i laying around I could probably run in series with the welch…

Psilisophical · April 22, 2019, 3:21am

Those welches are too strong for rotos, and to slow for large systems. they will work for both but do yourself a favor and grab a good diaphragm that will last a loong time

HK_Esquire · April 22, 2019, 3:27am

I have a sogevac as my roughing pump for the volatiles on my SPD. Think the slower Welch would be able to handle the main fraction since the vapor flow would be slower?

If not I’ll just use the pump for my TC filter or throttle it back for the rotovap. Thanks for the reply

Psilisophical · April 22, 2019, 3:42am

it definitely will work on main body but itll be slower than a good direct drive like the Welch crv16 which has 12.6 cfm or the Edwards E2M28 which has around 20.

YOu can use it on the roto but definintely get a vac controller for it, you wont have to run it below 200torr, and that will keep you from constantly having to drain the oil of the pump.

HK_Esquire · April 22, 2019, 4:21am

Thanks Man.

jimmytian8 · April 22, 2019, 11:16pm

Hey HK

I would recommend using water cycle vacuum pump for your rotary vap.
As said, you don’t need high vacuum for the rotary vap.
And if you use normal vac pump, you might need to add a cold trap to catch all ethanol vapor that didn’t condensed.
A water cycle vacuum pump did not reach high vacuum and will not be damage by ethanol vapor.
Let me know if you are interested in one. I know some shop selling for $1300 per unit

HK_Esquire · April 22, 2019, 11:34pm

Thanks man, I might just reach out about that.