Finally got a vacuum oven. It’s a Hardware Factor Store brand, 0.9 cubic ft. I have three options for pumps, a welch crv4 pro which I use for distillations (rather not use that one), a Robinair 15800 8cfm 2 stage rotary pump, and a Welch diaphragm pump for the rotary evaporator which can pull down to about 12 torr. I was planning to use the Robinair 8cfm pump, but I don’t have an oil mist filter for it yet. I’m also pretty limited for cold traps as I only have dry ice traps and no good way to store dry ice overnight.
Is there any reason why one might use a diaphragm pump instead of the Robinair? Should I just use the Robinair pump and plan to change the oil regularly? How big a deal is not having an oil mist filter?
Inside the vac oven I’ll have ethanol extracted oil (most of the ethanol will have been removed on the rotovap) which I’ll be attempting to get to a pull and snap and/or shatter consistency.
You’ll need a cold trap for purging eho. Get a mist filter from bvv and some robinair premium vac pump oil from ebay for the robinair 8cfm 2stage and you’re gtg. Not having an oil mist filter can contaminate an area and breathing in the fumes could be harmful to your health. You could also potential be spraying the area with oil. You can run a hose outside for the vapors but theres always gonna be a leak. Purging alcohol with a rotary vane requires some sort of dry ice/ liquid nitoegen cold trap because the vapors will eventually ruin the pump. I’m not sure if you can use a diaphragm pump for purging. I’m unsure on diaphragm pumps and purging. Only ever used them for the rotovap.
Dry scroll pump - agilent, across international, or Edwards. It might be Overkill but no oil and high contamination threshold. Put a cold trap on it anyway to increase time in-between rebuilds. I put two ovens on a single scroll with a single cold trap.
If you have an issue with c1d1 regs you can get something like a Welch chemstar 1400N
The reason I am considering using the diaphragm pump is so that I wouldn’t need a cold trap. I have that stainless one from BVV that I use on the rotovap and it works well enough. But it seems like it would be a hassle to keep it cold if running the vac oven overnight. You know what I mean? I’d have to come in and add more dry ice periodically which isn’t super realistic. The benefit of using the diaphragm pump that I see is that it eliminates the need for a cold trap (to some degree) and I don’t have to deal with oil mist. Thanks for the link to the BVV filters. I have a filter for my distillation pump but the Robinair that I have doesn’t have the same flange or what ever it is called to enable attachment. Pic related of the Robinair.
Diaphragm pump for now. What I do when I need to use both oven and rotovap is just seal the oven so that it’s under passive vac and swap the pump to the roto. Temporary solution tho.
Hi, I don’t want to open new thread just to ask one question, so I ask here…
Is this oilless pump good for vacume filtering ETHo and running a 5l roto vap?
I ask only because I can have a new one for 300 dollars.
