Shaft seal 800mm basket centrifuge

The latest batch of centrifuges I get to play with have a different flavor of shaft seal. This one is broken.

No clue on the OEM yet, but digging to see if I can find that.

Broken element appears to be mostly carbon (graphite?).

@Soxhlet, @SidViscous , @TwistedStill : have you machined graphite? Would that be my shortest route to joy?!?


I’ve machined all sorts of carbon electrodes for an EDM machine. It’s no bid deal…just messy.

Are those wavy washers behind it? Oh the fun of mechanical seals.


Ive seen graphite machined for glassblowing molds at the neighbors shop, there are a few different densities of graphite and some are “harder” than others. But aside from the gnarly dust its not much different to work.


Hey, looks like you busted the mechanical seal, call the manufacturer for a replacement they should have them on the shelf. What brand is the fuge’?


I’m with @Soxhlet, probably not worth making the part. There’s a bunch of companies that manufacturer these suckers and you could likely adapt one of similar size with a shaft bushing or two pretty easily as well. I have machined graphite and it’s not a huge deal, but you’d likely want to make a fixture to keep the thing from exploding on the lathe. It does make a wicked mess lol. I do feel like most seals use some sort of polymer blend rather than straight graphite and I have no idea where you’d get it from other than the people selling you a replacement seal lol.

Edit: can you break out your calipers and get some measurements on that bad larry?


Yeah, working on figuring out where these came from. They were insulated after the fact (nice job too), and I’m not sure where to excavate to find a name plate. Trying to track down their paper work as a first response. Making the part is a last resort. I would totally expect a graphite/polymer blend these days

If you put up the length, face ID, face OD, shaft diameter and largest OD I can probably scare something up. Why do you suppose it failed? Looks pretty chewed up


Was missing a set screw (probably why they have filters upstream of their gear pumps now). It’s possible the guys who removed the rotor killed it, but tell has it that this fuge has been bitching since day one (at least 24 months I believe)…so it may have been a QC issue.


I’d head back with calipers now, except it’s in a locked room I don’t have access to until tomorrow. Calipers in my car!!


At your leisure Mr. Path


What the fuck is that? :rofl::joy::rofl:

Mind you, I work hard to not know what “work” or “production” mean either :shushing_face:


You know, leisure: that thing where you’re using both hands and your teeth to work tools to fix something in a miserably contorted position, boss man walks up to ask you to fix something else that just broke AND patiently waits to say it

I know, it’s called a pipe dream


:rofl: :joy: :rofl:
That made my day!

Thank you…


Still don’t know who built the 'fuge, but…

pretty sure I’m looking at a two part seal, and this is the part number.

that’s looking up from under the fuge, with the drive unit out. drive shaft is presumably 60mm (based on glyphs). this part looks fine, and is probably why unit has been successfully been “run like that forever”.

glyphs: Ceimin 60x80x8 CDL-1865 got me to

Ceimin Official Store - Amazing prodcuts with exclusive discounts on AliExpress but didn’t immediately turn up the “rest” of the seal (I didn’t realize I was looking at a two part seal yet).

as seen from INSIDE the bowl (top side). carbon and o-ring on broken seal shown earlier interact with feature shown here.

EASIEST solution does look to be to contact CEIMIN and not have to replace the lower half of the seal.

thanks for the assist guys!!

(It also brings me peace of mind to know that machining my way out of this hole is an option)


yeah, mechanical seal is two pieces loaded against each other with a spring, usually there is a stationary half and a rotary half. If you can’t get a replacement from them press the old seal out and measure the bore size, shaft size, and length I can probably find something suitable.


When you love what you do, it shows…


Defiantly go to the mfg for replacement first. Also buy one or two more whole seals if ya can. Even the fanciest double mech shaft seals from china are way cheaper than FlowServe (like 8X cheaper in my experience). And if ya do find yaself in a pickle and the mfg is no help and you aint got the time to make your own, these guys have saved the day for me before.