im boiling water at around 39C at 30C room temperature and 32C water aspirator temperature.
Im having the water cycle through a bucket with a fuel pump.
would using diesel fuel increase the vacuum by a lot?
if yes by how much?
I would put a gas washing bottle in between to not infuse the diesel with chemicals.
I know you can cool the water but thats very unprecise cause it thaws quickly.
[Edited on 20-2-2019 by LuckyWinner]VSEPR_VOID - 19-2-2019 at 22:27
I think that thicker liquids provide higher vacuums. Mineral oil is used sometimes but it is messy. Σldritch - 20-2-2019 at 01:34
As long as it is inert and liquid the only thing that matters is vapor pressure. Do not use fuel, use some high boiling oil or a glycol. You can also
decrease the vapor pressure by cooling your liquid of choice. Personally i would rather spend the money on a better pump than risk making a huge mess
with glycerol or mineral oil, i do not trust my aspirator at all.walruslover69 - 20-2-2019 at 17:20
You can't run a closed circuit vacuum aspirator using mineral oil or glycerol, they are too viscus. They are hard to pump through and the high
viscosity causes them to heat up very quickly so they can't really be used for this application.
I have actually been playing with the idea of making a very high vaccuum aspirator using a low vapor pressure fluid for awhile, but haven't gotten
around to it. The ideal working liquid has a high boiling point, low viscosity and is insoluble in water or whatever you are vacuum distilling. Twospoons - 21-2-2019 at 13:25
If you are starting to look at exotic fluids for your aspirator, maybe its time to just buy a mechanical vacuum pump.walruslover69 - 21-2-2019 at 14:19
I have a vacuum pump, its more about the novelty of building an aspirator that could produce a vacuum comparable to a single stage pump.Ubya - 21-2-2019 at 14:28