ElectrolyticBody - 5-3-2018 at 09:08
I was just wondering if anyone knew anything about these vacuum pumps. I've seen a few on eBay for what seems to be a fairly reasonable price but I
can't find much information about them. I've searched the forum and web to no avail. Any information is appreciated! I will probably get one if it
seems like a decent pump. Thanks!
Reboot - 5-3-2018 at 10:51
I'm not very familiar with them, but looking at it it's rather certainly a single stage diaphragm pump. This class of pump usually offers somewhat
low to moderate flow rates with moderate ultimate vacuum (often around 200 torr.) They're a good option for vacuum filtration, rotovaps, and less
demanding vacuum distillation applications. On the other hand, they may not pull enough of a vacuum for your tastes if you want to vac distill
things with higher boiling points. (The most dramatic drops in boiling point happen at high vacuum.)
Looking at the units on eBay it looks like many have pressure regulators, which is a handy feature (if still working.)
Most diaphragm pumps have only moderate chemical resistance and the diaphragm may not survive long if faced with a lot of solvents, for instance. On
the bright side, replacement diaphragms are usually easy to get, if not necessarily cheap (usually over $100.) The diaphragm is the equivalent to
the tires on a car; they wear out over time.
These look like they could be an excellent candidate for general lab use.
ElectrolyticBody - 5-3-2018 at 11:11
@Reboot thank you very much! Your reply was very helpful. Being that I don't foresee myself needing high vacuum for a long time, I may get one and try
it out for the sake of experimentation at the very least.
If I do decide to get one, I will update here and let everyone know how it performs!
happyfooddance - 5-3-2018 at 12:26
200 torr seems pretty useless for anything but filtration, a good water aspirator can do much, much better (ca. 50 torr) for cheaper ($17 USD).
A pump from a discarded refrigerator will do even better, though it has it's quirks, and is completely free.