Hexavalent - 6-6-2012 at 03:11
I appreciate that there have been numerous threads on vacuum pumps previously, but I felt that it would be appropriate to open another here to discuss
your opinions on different commercial models for the amateur.
What is your opinion on this pump, e.g. for vacuum filtrations with a 250ml, 5cm buchner filtration setup? The air blower side could also be useful
for blowing air over solutions to encourage evaporation.
http://www.ebay.co.uk/itm/20-Hg-12V-DC-VACUUM-PUMP-Hobby-Lab...
[Edited on 6-6-2012 by Hexavalent]
99chemicals - 6-6-2012 at 03:54
That looks like it would just be a minuature vacuum cleaner. (a turbine type) I do not think it could pull a decent vaccum. Plus the motor would
probably over heat after long ussage.
Hexavalent - 6-6-2012 at 04:10
Really? I thought it was a piston-and-barrel type, as seen on car air compressors, but as you say it may well be a turbine type.
Would it be OK for short periods of use - perhaps bursts of 30 seconds to 1 minute for a filtration, cooling for 10-15 seconds, and then resuming? The
description specifies 'for lab use', but I guess most Chinese products like this do so these days.
woelen - 6-6-2012 at 04:29
I'm not an expert on vacuum pumps, but my feeling is that such a Chinese product is not what you want. Besides chemistry I am also in electronics and
I once made a big mistake, purchasing a lot of electronic components from Chinese sellers on eBay. More than EUR 100 I spent, but the components were
of really bad quality (diodes, which break down well below the specified breakdown voltage, capacitors with excessive leakage currents or simply
breaking down at 2/3 of maximum applied voltage) and with a complex thing like a pump I would be even more careful.
If I were you I first would go for a cheap glass water vacuum pump. This cannot draw a deep vacuum, but it is good enough for vacuum filtering and you
have no issues with corrosion and overheating.
Hexavalent - 6-6-2012 at 04:36
I have had one of those aspirators before, but in stainless steel....and I hated it. Had to go outside and blast the water full speed from the hose to
get a fair vacuum from it.....
woelen - 6-6-2012 at 06:28
Full speed from the hose? That was a bad aspirator. I have a glass one and it works quite well from a moderate flow of water. I certainly do not need
to fully open the tap. I use it inside and let the water run down a sink, or I collect the water in a tub for other purposes.
Keep in mind, that for filtering purposes you only need to use the aspirator for ten minutes or so, and for such periods the loss of some water is not
a real issue in most countries. Of course if you are running the vacuum for extended periods of time then a pump is a better option.
Hexavalent - 6-6-2012 at 06:36
Indeed . . .the aspirator was made of SS (I think) and was given to me from my school science technician. They let the older students use plastic
ones, which work from a standard lab tap apparantley.
Would a medium-flow stream of water from a water display suffice for indoor use? Also, where can one acquire a glass or plastic one? I cannot
realistically build one and my only source of equipment is eBay