Young chemist to the game - long time lurker - most question I have are answered just reading others but I havn’t seen it clearly explained as to why would wouldnt just wanna use diaphragm pumps over oil pumps?? Edwards(oil) were used on cryo extraction yet the latter was used for molecular distillation…the oil pump required much more maintence and eventually gives out…am I missing something?
Thanks in advance
Rotary vane pulls dweper vac than diafragm
it really depends on what you’re vacuuming on.
each does a different job in the lab due to pumping mechanism/chemical compatibilities/flow rate/vac depth requirements.
thanks for ur input
okay so its not as clear cut as I imagined. thanks!
Not even close. There are also other flavors of pumps that you haven’t touched on. Each has its place.
Diaphragm pumps are great for light vacuum. Especially when there is solvent involved. They will even handle liquid gracefully if you do something dumb like try and suck 20gal of solvent into a 15gal keg.
Rotary vane pumps are robust & the good ones will pull considerably deeper vac than their diaphragm based brethren. Given that any solvent or volatiles that make it past your cold trap end up in the pump oil, they do not handle inhaling liquid at all well.
Then there are the more exotic diffusion and turbo-molecular pumps when you really need to suck hard. Chances are those are out of your price range, in addition to being overkill for anything you’re currently considering
appreicate you!