I was just curious if anyone if filtering and reusing their old vacuum pump oil, and if so what kind of filtration methods are used?
I use grade 20 synthetic oil and it is a bit spendy but every time I start to do my planned lab to see what it takes to redistill the oil and renew it thusly it really just takes a whiff to change my mind. My pump oil gets some hella nasty smell to it and because I can smell it then it means volitiles which must be purged for the oil to operate as new again.
There is no filter that could reasonably be expected to remove the volitiles that collect that I could think of. I even paper napkin designed a pump oil filtration to be used on the pump while operating to include direct oil cooling. Even then my design implemented a cooker portion to remove volitiles. I realized pretty quick that the expense of returning vacuum oil to service was not worth it given that new pump oil is readily abailable and then garaunteed to be pure. I use a lot of charcoal in my fireplace instead of firewood normally. I dispose of the oil by using it to start the coals so at least it is repurposed.
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I use grade 20 synthetic oil and it is a bit spendy but every time I start to do my planned lab to see what it takes to redistill the oil and renew it thusly it really just takes a whiff to change my mind. My pump oil gets some hella nasty smell to it and because I can smell it then it means volitiles which must be purged for the oil to operate as new again.
There is no filter that could reasonably be expected to remove the volitiles that collect that I could think of. I even paper napkin designed a pump oil filtration to be used on the pump while operating to include direct oil cooling. Even then my design implemented a cooker portion to remove volitiles. I realized pretty quick that the expense of returning vacuum oil to service was not worth it given that new pump oil is readily abailable and then garaunteed to be pure. I use a lot of charcoal in my fireplace instead of firewood normally. I dispose of the oil by using it to start the coals so at least it is repurposed.
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I use grade 19 as well. I buy all my pump oil from vacoil.com. I remember @anon42519203 telling me a place a bit cheaper but that was a long time ago and my brain dont work that well anymore. I think is like $40-50 a gallon. I feel like it would take me more than an hour to clean up my oil and my time is worth more than $40-50 a hour which makes purifying my vac oil uneconomical.
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Thanks guys, that’s kinda what I expected. I just want to be as efficient as I can.
19 ultra from cacejen vacuum has the best vapor pressure rating out of all of them (lowest vac with contaminates) and its pretty cheap. Usually buy it in 5gal quantities… i cant remember the price but i think its $140🤔 so way cheaper then $40/gal… also since we only use 1.5L at most per run… thats only like $6-15 per change
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There is also a difference between 19 and 19 ultra… my ultimate vac depths have all been done on ultra… the difference of vapor pressure at 25C between the two is 10^-5 vs 10^-6… doesnt seem like much… but the difference between 1 and 10 micron is about the same in
Comparison
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Filtering vacuum pump oil with a lot of moisture and particulate is not a great idea. The oil does breakdown with heat and moisture. Unless you are using a full synthetic oil I would just recommend frequent changes to assure proper vacuum levels and preservation.
If you can afford it there are some good dry pump options that don’t require vacuum pump oil and eliminate product contamination from hydrocarbons from a phenomenon called “back streaming” which occurs with wet pumps. We have sold dry pumps to extraction labs by Pfeiffer, Leybold, Agilent and Anest Iwata.
For now frequent oil changes is good for your pump and vacuum levels. We have a 19 Grade oil and flushing fluids that works for all two stage pumps.
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Change your vac oil every night. But make sure you heat up your vac before changing. I-19 pump oil is the best. Just make sure the oil is totally clear.
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