A question about pump strategy:
I have an aspirator set-up (5 gallon bucket, pump, aspirator) for stripping off solvent, and distillations down to 20 torr or so.
I also have a Harbor Freight two stage pump (good to 22.5 microns) which I am setting up as a dual purpose vacuum bagging pump for composite
construction, and also for doing low pressure distillation (below 20 torr) of what I expect would be relatively small batches.
The vacuum bagging system design:
http://www.joewoodworker.com/veneering/EVS/concept.htm
has PVC vacuum reservoirs totaling about 6 L in volume that will act also as particle settling chambers.
How much additional pump protection do I need to add? Options include a particle filter (perhaps just a SS mesh screen?), activated charcoal, an acid
remover (sodium carbonate?), a drying agent and a cold trap (would ice plus calcium chloride? suffice).
I am thinking that a drying agent is not really necessary, as the pump would typically encounter atmospheric moisture anyway in normal use. I would
guess that an acid remover and activated charcoal should be provided since some reactive chemicals would be coming across, even if not in large
amounts. Note though that the HF pump is not terribly expensive (currently $160) so heroic protection measures are not called for.
I also just learned of the Savant Gel pump which is acid resistant, and good to about 20-30 torr, and can be had for not too much on eBay (~$100). I
did not know about this pump, but it seems to fill the same role as the aspirator. Is there some justification for acquiring one? Does it have
significant advantages over an aspirator?
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