How much crud should I be getting in my centrifuge

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
Hi guys, just done first runs through new centrifuge and I’m getting pretty much nothing out of it. Yes my oil is good, yes I’ve been careful to select the best oils only for this but I still expected more crud, what’s the usual to expect?
 

Mt_Man

Full Access Member
Joined
Nov 12, 2017
Posts
224
Reaction score
89
Location
Portland, Oregon
Depends on the batch. If it's very clean to begin with then probably not going to get much out. Opposite is true is it is really dirty, will get a bunch out.
What's your setup like? Thinning or heating before fuging? Single pass or multiple pass setup? Ambient temperature/temperature prefuge?
I noticed a decrease in what I get out with a decrease in temperature so might be a factor. I have had batches that barely pulled anything out and was worried too. Also some oil hold sludge and h2o better then others. So might be that too.
 

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
Depends on the batch. If it's very clean to begin with then probably not going to get much out. Opposite is true is it is really dirty, will get a bunch out.
What's your setup like? Thinning or heating before fuging? Single pass or multiple pass setup? Ambient temperature/temperature prefuge?
I noticed a decrease in what I get out with a decrease in temperature so might be a factor. I have had batches that barely pulled anything out and was worried too. Also some oil hold sludge and h2o better then others. So might be that too.
Ambient temp 30deg c
Oil temp 60deg c (heated)
Thinned with jet fuel 70L wmo 40L jet fuel
5 passes n nothing to speak of, I have been very selective on my oils and they are well settled but I still expected to get something out with a centrifuge, I’m definitely going to filter this down to 2-3 micron before going in Ute as I don’t trust that the fuge has done the job, currently passing from 1 drum to another but I’m going to modify it now to recirculate in the one drum n leave it running long periods of time too see if this helps, Ive read just about every thread n here n I’ve got nothing! Zilch out of my oil, even a finger nail of crud would have made me happy,
 

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
When these fuges are on a vehicle or stationary engine filtering the engine oil they contain a paper filter element, I wonder if using these will help collect more crud.
 

u2slow

bilge rat
Joined
May 8, 2007
Posts
1,594
Reaction score
604
Location
PNW
We centrifuge lube oil at work; engines are fitted with them.... More like 70-90°c and no thinning/dilution.

Other sites, the centrifuges are standalone. Then the temps are more like 90-95°C and they incorporate a water seal to help separation. (Also no dilution.)

We use a paper liner on both types, it really just makes the crud peel out easy vs scraping and wiping.
 

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
Yeah ok so the paper will not trap more crud, the instructions with my fuge say not to heat oil more than 60-70degc cause the pump seals won’t take it, I find that hard to believe though as when I left the pump circulating the oil/jet fuel afterwards to ensure it was well mixed the pump was too hot to touch by hand just from pumping the oil around, (heater was removed by this stage)
 

Mt_Man

Full Access Member
Joined
Nov 12, 2017
Posts
224
Reaction score
89
Location
Portland, Oregon
Yep always good to have a QC filter. Sounds like you have very clean oil. Nice. I have been told that when recirculating polishing/cleaning fuel tanks need to filter 3x the volume of the fluid volume to insure that all of the fuel is all passed through the filter(what ever it is) at least once.
 

Mt_Man

Full Access Member
Joined
Nov 12, 2017
Posts
224
Reaction score
89
Location
Portland, Oregon
Oh and if the contaminate is the same or close to the specific gravity of the fuel the a fuge won't get it out but a filter might.
 

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
Yeah ok mate thanks, so 3x what L per min my fuge is will equal 1 pass per L of oil, so say 100L needs to pass through at a rate of 300L to count as 1 pass on a recirculating set up. My oil Ive sourced is black but not black if that makes sense, it doesn’t stain my fingers, hardly stains the rags cleaning up spills. It’s well settled and the mate I get it from only saves the clean stuff for me, all gear oils coolant and used Diesel engine oil and anything black and sooty goes to his main waste storage, I get all the decent stuff put into a clean 44 and then I age it in pods at home, I would have preferred a large fuge like you have but they start at 19k over here, that’s same price as a new 6.5L chevy
 

Mt_Man

Full Access Member
Joined
Nov 12, 2017
Posts
224
Reaction score
89
Location
Portland, Oregon
Damn that is spendy for a fuge. I think you are on the right track. So if you have a 100L container and 3x means 300L worth of filtering. So if your fuge is flows at 150L per hour (lph) then you would have to run it 2 hours to have filtered 300L(100L over and over). But that doesn't seem long enough. I have filter some batches for a weeks straight and remove a bunch of sludge each fuge cleaning. Just have to play around and see. Run it for 5hr and see if it's different then 2hr. Might have to be careful with temps like you talked about. Good way to know if it's clean is if your QC or truck filter plugs and needs replacing then you know it's not getting everything it should be.
I have two fuges in series now and the first one definitely doesn't get all the sludge and the second seems to be pretty close to the first in amount removed. Some day I will make a few more fuges and see how many it takes to get it all clean out reliably. I have noticed that the amount of sludge will be high for days then all changes quick and drops off fast to next to nothing. I am running about 25gph through them. Might be a little fast. Then my final pass is into a separated tote to prove it all has gone through the fuges and I can see just how much sludge is pulled out the final time if it is clean. Then qc of a 1micron sock filter in housing.
 

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
Ok thanks mate, I’ll turn the temp up a bit today n run it In circuit as I modded my drum yesterday, see if I can get something out of it, I got 2 fuges but one pump was guna set them up side by side so one feeds the other and then back again but I’m not sure this is any better than in circulation
 

Far Right

Registered User
Joined
Nov 24, 2022
Posts
113
Reaction score
74
Location
Australia
Ok so ran it at 90deg c through my fuge for 6 hrs. I did get more out but it was so little extra that I dont see the Benifits in going longer than I did as it’d take a lot of that to block up filters. I’m guessing my source oil is extremely clean and well settled,
 

Mt_Man

Full Access Member
Joined
Nov 12, 2017
Posts
224
Reaction score
89
Location
Portland, Oregon
Yep sounds like it's pretty clean and diminishing returns. Are you sucking front the bottom and putting back in the top for your fuge? That should give you the best way to make sure your getting good mixing for recirculating.
 
Top