How do you make a centrifuge go WOOF?

once upon a time, @anon16547145 warned us about the problem…

but when pressed for more detail, didn’t have anything he could share.

…other than it was from our silenced @spdking.

I had one of the fuges in my whirled go WOOF! today, and I figured it was worth mentioning.

I haven’t finished dissected it yet, as I’m on my way out of town today, but it’s pretty clear from the video and the aftermath what when down.

I expect to find that the shaft seal failed, followed by the lubricant being washed from the bearings, then achieving greater than 365C (auto-ignition temp for ethanol) in the bearings.

at the moment I don’t have much more I can share, other than operator freely admits “yeah, it was getting hard to spin by hand…”

…I rotated it by hand, and there are clearly chunks where there should be bearings. probably chunkier that when the operator started it, but he also admitted it was making more noise that usual too.

this happened near the end of final spin out, and was probably THE most gentle way this thing could have said “Fuck you buddy! I’ve been trying to tell you there was a problem with the bearings for weeks…”

I would guess this could only have happened at spin out, because the ethanol would have provided some lubrication or at least cooling until it was spun off. because these particular centrifuges were insulated, our solvent temps are in the -20C range, and there wasn’t a whole lot of O2 left after it went WOOF, there wasn’t much in the way of fire. The bags burned for about 15 sec after the initial flashover, and then it self extinguished. At room temp it would have been an entirely different experience.

PLEASE maintain your centrifuges!!

Listen for new noises. rattles need to be chased down, they mean something new is loose. check the belt guards for signs of crude. because that means they’re leaking. probably through the bearings. if you’re getting crude in your belt guard (through your bearings) you don’t have any lube in your bearings, and are just awaiting catastrophic failure.


Remember that CUP15 we saw rip itself apart when i was doing the original X-Spiral testing?


oh snap, sounds like a good story!?!? what happened??

@cyclopath i agree, friction probably caused a component to get to hot and it auto ignited the solution, scary, glad everyones ok!


Yikes, I’m glad everyone is okay, but scary moment indeed.

Regular maintenance is vital to survival especially when spinning flammable solvent at a high rate of speed.


yeah, but that was because the operator left the OEM spray head in there, sitting on the bag of biomass to submerge it during agitation; then set it to spin…and walked out of the room!

bent the drive shaft on that one.

edit: @RockSteady


Some people just shouldn’t life :sweat_smile:


You should definitely share this one @MagisterChemist :nerd_face:


just up thread…

maybe this is why Delta stopped providing the spray bar?


Why I don’t play loud music in my car… Why I made my girlfriend take her car in to the dealer, I heard something funny… Faulty motor mount… Under warranty…100 bucks… That problem was only going to get worse.

Love the diagnostic breakdown @cyclopath, what’s the typical operating RPM for that machine? How big is the drum, or rather what’s it’s mass?


Rotor is about 750mm across and weighs in the vicinity of 400lb before biomass.

I haven’t pulled this style rotor yet, so I’m guessing on the weight based on similar rotors I’ve pulled and weighed. Last one was 375ish

It was probably being driven at 40Hz, but without knowing what “upgrades” were made to the drive ratio (it’s closer to 1:1 than OEM, but I haven’t measured the pulleys) I don’t actually know what that equates to in G or rpm.

Motors are rated 1400ish rpm at 50Hz, so we’re probably only in the 800G range


When I was younger i would purposely listen to loud music to hide the noises! I knew the issues they just weren’t my priority.

But bumping gangster rap with a $3000 dollar sound system in my $300 92 Sentra was a major priority.



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I’m a big fan of the centrifuge configurations that have the motor up top, wish I could find another near Colorado for reasonable money. At least with those if a seal fails you just end up with grease on your extraction bags and basket, I think expecting a seal to deal with the combination of a harsh solvent, particulate matter and high speeds is asking for trouble sooner or later, and at least with the spindle up top if a seal fails the solvent doesn’t immediately wash out whats keeping the bearings lubricated


Yikes, glad everyone is ok!


Yikes, that’s a chunk of metal!! Geeze I’m glad it wasn’t a worse catastrophic failure. I’ve learned the hard way to check the rpms on machinery before energizing, or the settings in general. Used to run a 400 ton press break, over stomped some fine tooling this one time and broke the receiving tool. It shot a 3oz piece of razor sharp steel 40 feet across the shop space and it buried itself in a block wall. So lucky, so so lucky I didn’t hurt myself or anyone else… I bet that operator feels like a real dummy, I know I would.


I can mimic the noise of your car by gently pounding on my work bench, lololol. That’s rattle though!!!


damn dude, glad everyone is okay. Im sure this is not the first instance of this occurring in our industry. Im visualizing what this “woof” looked like, my toes are curled. Possible to share the vid of the “woof”? Might help others take preventative maintenance more seriously.


Hopefully, but people who aren’t thoughtful rarely change their ways.

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I’ll post when the centrifuge at my shitty job goes. Just hope it doesn’t take me with it.

Those rubber dampeners aren’t supposed to be a consumable… right?


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No, they’re not. But if they’re done, replace them. Then try and figure out your balance issues

Expected dissection did not take place this weekend. But poking at the operators today, I learned of a “large, dark colored leak”, from “we’re not sure where” last week. Pretty sure that was a solvent washing all the lube out of the bearings…