06-29-02 10:26
No 326763
Hello,
I am pretty serious about getting a vacuum pump with the following specs:
36 LPM (240V, 50 HZ)
2 STAGE
50 MICRONS VACUUM
2800 RPM
0.15 Litres oil capacity
6.5 kg
This particular one is a tool, used by tradesmen in car air industry. This is the cheapest pump i can find in Australia, which goes into micron vacuum scale.
Quickly checking the available pressure calculators:
50 microns = 0.05 Torr = ~ 0.07mbar
Would i be correct in thinking that this is considered fairly "deep vacuum" and is suitable for laboratory work such as vacuum distillations of ketones.
I also checked the nomograph, and according to my calculations, this pump will boil water at just below 0 degrees Celcius - does this sound right?
Thank you,
Sponsan.
(Newbee)
06-29-02 10:49
No 326764
generally a diaphragm pump seems to be the best for universal lab use. Make sure that the pump is resistant to solvent vapors! Usually an end vacuum of 10 mbar is well enough for most purposes. It is very difficult to get below 1 mbar if you work under normal conditions (rubber connections, small tube diameter, not perfectly dry conditions etc.). UTFSE for more info.
(Hive Bee)
06-29-02 17:24
No 326808
I think the 50 u is not realistic, it is something called the ultimate vacuum atainable with the pump. If you have a vacuum gauge and connect it to your pump, most probably you will get something like 0.40 mm Hg or so, typically. It looks like a good pump, though. Avoid water and solvent vapours, lots of posts on this. Also, your will have to change your oil frequently ( rotary vane kind ) and / or to use a trap.
(Greenhorn)
06-29-02 17:31
No 326811
I think I know exactly which pump your looking at. Swim had a vac pump that pulled safrole at 70-72c and it was rated at 15 microns. Make sure to change your oil frequently. Swim didn't and the pump broke from all the solvents and other shit. The only thing about having a very strong pump is a good seperation with close boiling compounds.
We'll soon find out if I'm a chemist or not!
(Stranger)
06-30-02 04:42
No 327020
Thanks guys. I will build a cold trap into the system to reduce the damage to the pump. Looks good though, good price as well, almost as cheap as a second hand one and they are very rare to come by around these parts.
I actually wasted about 2 hours ringing the entire list of aircon parts people from the phone book and got nowhere. Then came across this pump by accident.
Thank you,
Sponsan.