What do you mean by “against” a vacuum? Vacuum at the pump inlet and higher pressure at the pump outlet?
And what do you mean by “better”? (Just trying to understand on my end)
Yes, and by better I mean faster flow.
I could be misinformed (though I’ve also seen this first-hand)… Can you explain why colder temps would result in faster flow if the pump inlet is under vacuum and the outlet is at positive pressure?
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As you get farther way from the boiling temp you increase npsha and the pump will perform better.
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Sounds like fake news, time to research
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Shit, you might be right, I’m gonna just leave this here
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Fake news.
Bird up.
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couldn’t resist, Eric Andre is one of my faves…
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Quick update on the N. B. Oler pump I linked above.
It’s slow and not self priming, but it pumps -80 ethanol. I’m getting about 7 gallons per minute at -80. Had issues with the priming at first but then I stuck a check valve on the inlet and primed once with a diaphram pump. I haven’t had to prime it since. I’ve pumped probably about 1000 gallons of -80 so far.
It’s a good option if you need something that’s not fast but gets the job done.
Also if you end up getting it, switch out the plastic mount for something less brittle when cold. That was a poor design choice.
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update on that CPI methanol pump. EZ-8 Methanol Pump [137700-01] - $399.99 : Westech Equipment - Since 1971
Turns out I probably can blame the cold…
that poor toggle switch has a copper (alloyed presumably) spring as the contactor…getting that to -50 and asking it to still be a spring eventually got to be too much for it. So the replacement will also fail.
the fix is to move the switch.
thanks @MagisterChemist for pointing that out to me.
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Just an FYI if ordering from westech. Follow up a couple days after u order to confirm they are sending it. For some reason they decided to hold my order and wait until i contacted them before sending it. They claimed that residential shipping is too risky for them lol also gave me some bs about how they wont be ready until the 14th of this month… so if u order from them, follow up or else they will just sit there with ur money
And they were a bit shaddy imo (said they sent emails and called me multiple times, but they also cant show me the emails they sent previously when i asked them to show them)
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Do you think this pump would work if it wasn’t ran for continuous flow (ran for 3 minutes then shut off, 15 minutes cool/warm up time, then ran again)?
it is not designed for continuous duty at rm temp. it does continuous duty at -40 or -50C just great (4hrs was the longest I pushed it in actual “continuous” duty)
the only problem I had with it was the switch failed at about the 3month mark when it was pushed towards 24/7 duty. it was running 8min on, 12min off, and was a block of ice for days at a time.
if the switch was moved out of the enclosure the contacts wouldn’t get brittle…
Edit: of course, moving the switch means it’s no longer in a sealed housing, so you’ve lost your safety rating…give some thought to where/how you perform that trick if the switch fails and you decide to move it.
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Looks like it’s time to re-engineer hose and try em out!
Thanks for the input!
don’t forget to disassemble and clean the pieces thoroughly to remove the OEM lubricant.
sold for moving for methanol. saw no indication that heptane denatured ethanol was problematic. no clue on other solvents.
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what sucks about air operated diaphragm pumps for cold ethanol is that they also act as a heat exchanger between process fluid and pressurized air. You’ll notice the air going into the pump comes out noticeably colder and the ethanol going in comes out warmer. Depending on where your compressor is located, this can be quite impactful in warm weather.
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Check out the mag-drive cold ethanol pumps from viking pump
They’re darn pricy though!
I didn’t think so, but everyone is working with a different budget. For what they are and the capabilities I think they’re very fairly priced.
Like 6k for a self priming -80°C explosion proof ethanol pump is worth it for me