Yes I am making EHO. There is about 5-10% ethanol left in the oil solution when put into the oven. So If I’m putting 1000g into the oven there could be approx 100g of Ethanol flowing into the pump.
What micron/mtorr and temp do you pull your EHO to?
a rotoray vane pump will not appreciate that. certainly not long term.
I’d say your consultant was wrong. unless you’re running a diaphragm pump or an aspirator, you should have a cold trap on your oven when processing EHO.
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Isnt the rotary vane just going to pull some of the solvent out of the cold trap anyway? Even if I do frequent oil changes (1x-2x a week) is it still a problem to not use a cold trap?
it’s your pump.
Meaning it’s just going to kill the pump overtime?
I would blame ethanol ingestion for the premature failure of at least two of the rotary vane pumps that have died on my watch.
They were cheap, and I did EXPLICTLY list destroying two of them on my one of my early equipment lists. So I don’t feel particularly guilty about it. Ymmv
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I’m using a “Pro Series 11.3CFM Corrosion Resistant Two Stage Vacuum Pump” from best value vac. Would you consider this a “cheap” pump?
Ive kilt a few nice pumps from getting em too drunk , expensive mistake.
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At $2200? No. I would spend another $200 for a dry ice based cold trap. Or $1000 for a mechanical one off eBay.
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Hello I have a dumb question, I run Edwards 30 pumps, so what you explained here makes since, so my question is , can that same thing happen with these types of pumps I’m running, thus contaminating products I’m trying to purge of ethanol in the oven(AI)
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Yes. If you turn off the pump while the oven is under vacuum, and all the valves are open, vacuum oil can be pulled into the chamber.
Be disciplined about your order of operation. Remember to keep your pump turned on or isolated from vacuum.
I’ve walked hundreds of guys through this over the phone. If you’re still not sure, dm. I’m sure once we talk it through, it will make sense. Once you get it, you won’t make that mistake.
Here’s a video, start at minute 3
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Awesome thank you so much
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Edwards 30 has backflow protection built into it so theoretically you should not see a problem with oil being sucked out of the intake of the pump and into your system when you turn off the power to the pump. But having said that, I wouldn’t take a risk and I would recommend that you just stick to “normal” pump shut down procedure.
I don’t remember what pump it was at the time but many years back while distilling I took a bathroom break at that same time there was a power outage and all electricity went out, by the time I made it back to my work area my system was very contaminated with pump oil and it really sucked (no pun intended).
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So in addition to contamination by vac pumps, has anyone come across silicone/glycerin contamination coming from fluid type pressure gauges?
Interesting, I still think even on those E30s oil can still make it’s way through, a lot of what’s mentioned here on the posts make since, honestly at this point I’m better off buying new pumps, I got like one guy that does rebuilds and they still come back with issues, plus those E30s are discontinued, but thanks for your input, I didn’t know those had backflow protection built into those, idk maybe that feature or aspect doesn’t work long term, we beat those things up, constantly running at full vac.
The E30 was replaced with the 28
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You can absolutely get vac oil past the check valve via diffusion when under vac.
The check valve simply prevents oil being sucked from the pump when pressure is lower in the system than in the pump.
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No need to run filled gauges in most instances.
You might want them on the outlet side of your pump if you use that sort of thing.
Never seen glycerin in the hash, have definitely had solvent/hash escape the Borden tube. Took a second or twelve to comprehend why the rubber bung had taken off at high speed (first had to ID the projectile).
if I had not found the bung in the floor and replaced it earlier in the day I might have taken longer to understand the issue
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