Heptylene - 23-5-2018 at 06:24
Hi,
I just bought a nice all-PTFE vacuum pump (KNF 820.3 FT.18) and delivery is expected for next week (yay!). I know that PTFE is not sensitive to
corrosive gases and solvents but I intend to use it to dry fine powders and I'm worried that the powder might damage the internals of the pump. So I
was thinking of putting some kind of filter before the vacuum port.
A gas wash bottle filled with a liquid is probably out of the question since that would lower the maximum attainable vacuum due to hydrostatic
pressure. (The loss would be about 10 mbar for 10 cm of liquid, so it's pretty bad since the pump is capable of 8 mbar.)
The second possibility was using a 250 ml RBF with a gas inlet tube, with the flask filled with glass wool or cotton. I think dipping the glass wool
in mineral oil could even help to catch the particles.
Do you think this method is good enough? Any other idea or advice? Should I add more filters?
P.S. I'm not actually a new member, I just lost login information to my previous account.
DavidJR - 23-5-2018 at 07:39
I have a very similar pump (KNF 810.3FT.18 - apparently yours is capable of double the flowrate of mine, but same absolute vacuum) - you won't be
disappointed with your purchase. FYI it was a lot heavier than I expected it to be, not that it matters really.
I don't know how sensitive it would be to dust/fine particles, but it looks like it would be easy enough to disassemble and clean out. I've attached
the manual which includes instructions for servicing.
Attachment: KNF Laboport Chemically-Resistant Lab Pumps.pdf (639kB)
This file has been downloaded 256 times
Heptylene - 25-5-2018 at 09:20
I'm glad you had success with your pump. I had a look at that user manual and it seems very easy indeed to open the pump heads, so maybe that dust
filter is not really necessary after all.
I'll go with my original idea and it should be enough to keep it clean.