Author Topic: Cheap centrifuge?  (Read 541 times)

dieselspanner

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Cheap centrifuge?
« on: August 30, 2018, 09:21:12 AM »
Hi All

So, as I got home in the Landy (a 1999 TD5) I sat a moment and listening to the centrifugal oil filter spool down, it takes around 25 seconds, I started to think.(I'm sure Ed has warned about this in the past)

If a steering pump motor, running around 125 PSI,  was rigged to a centrifugal oil filter housing, with a standard filter would it pull enough crap out to make it all worthwhile?

I know there's bigger ones on large marine diesels, I've ended up quite grubby servicing them!

If you've nothing to do when you're next round your dad's scrapyard, Glort.........

Anyone any ideas?

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

glort

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Re: Cheap centrifuge?
« Reply #1 on: August 30, 2018, 01:49:42 PM »

Random thoughts on the subject......

If you have the space to settle your oil in drums or IBC's, you are far better off doing that then centrifuging.
CFing is costly to setup ( even in comparison to settling) does not dry the oil, is fairly energy intensive and you can get results that are every bit as good for practical purposes with conventional methods.... and the oil is dried at the same time.

PS pumps do more like 1000PSI unless you modify them with a by pass.  They do not like dirty oil and will chop little pieces into smaller ones making it harder to filter them out.  The seals in PS pumps may be deteriorated by veg or engine oil depending on that type they are to start with.
PS pumps have very high pressure being a close tolerance positive displacement pump but a pretty small Flow volume.

I thought about these CF's many years ago and was looking at one from an old Albion bus engine.  The passages were very small internally and would be very easily blocked. There is not a lot of Crumbs and particles in engine oil  and what there is measures Microns in size rather than MM.
Even the commercial Oil jet propelled fuges have small orifices that require the oil to be at least filtered through some felt or the like to get it clean enough to prevent blockages.

People get overly pedantic about cleaning their oil and go over the top with it.
Commercial diesel is Filtered to 10Um ( microns)  the water filter cartridges I used to clean my oil were 5 and I'd I could find them, 1Um.  Twice to 10 times as clean as pump diesel.  To start getting excited about having your oil cleaned to fractions of a MM is pointless.  Engine will never know the difference and in economics and time, you are far better off just to change the fuel filter every year if you need to.  Most onboard Diesel filters are 7-10 Um anyway. Anything smaller that passes through is of no consequence.

Filtering finer than the onboard Filter captures is like thinking you got more in your bucket because you let the hose overflow it for 5 min.

How many Pumps you want me to pick up for you Stef?

Was thinking of driving one off an electric motor to push high pressure oil through a Nozzle  for a burner.

dieselspanner

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Re: Cheap centrifuge?
« Reply #2 on: August 31, 2018, 05:48:28 PM »
Hi glort
Don't send me too many, I wasn't going to rush out and try it, it was just an idle moment idea!

The oil I get comes in 10 liter transparent plastic bottles, once left to stand for a few weeks and then filtered through an old tee shirt or similar, is gin clear, with no sediment after further standing in the same (clean) bottles.

it looks so good you'd not be scared of using it again, the only down side is it either smells of fish or doughnuts, depending on what he's been frying!

I'm running 80 / 20% WVO / Dino in a Landrover Series III, with an early '90's 200 TDI, it's a bit down on power and I'll probably have to up the Dino as the weather gets colder to get an easier start but I'm more than happy with it.

The first couple of tankfuls lead to two blocked filters as the veg oil cleaned out the 40 year old tank and plumbing, but after striping and cleaning the injectors it's settled down and runs nicely.

Cheers
Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

LowGear

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Re: Cheap centrifuge?
« Reply #3 on: August 31, 2018, 07:31:07 PM »
I bought one that was fitted to a Miami transit bus.  It lays fallow on my seperaterinomatic critter.  I've kind of moved on to other projects.
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veggie

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Re: Cheap centrifuge?
« Reply #4 on: September 13, 2018, 02:50:21 PM »
I built such a setup using a mini oil centrifuge and a gear pump to supply enough pressure to spin the fuge up to 10K rpm.
Findings...
-Those units are much too small for cleaning useful quantities of waste veggie oil. Remember that in a vehicle engine the 6 liters of oil in the crankcase passes through the centrifuge hundreds of times, which aids it's effectiveness.
-The tiny internal jet ports plug after a short time.
-They don't remove enough crap even after multiple passes. Even though the inside housing of the of the fuge was caked with sludge, a lot of the micro junk and heavier fats remained in the oil. I will not use them again.

Part of the problem is that the oil must generally be heated in order to pass thru the micro jet ports which make the rotor spin at the necessary speeds. Heating the oil makes the centrifuge work better, but it also thins the heavier fats and makes them flow with the oil instead of being removed.

I agree with Glort that pre-filtering and settling settling is one of the best ways to de-water and clean WVO.
Some have a lot of success by adding 20% gasoline and then settling. The thinner mix seems to help particulates settle out and also aids in the separation of heavier fats.

In my opinion, of equal capability but much faster is a large bowl (9" to 12") high rpm (3600 or greater) centrifuge which creates 4000 G's (or more) of force. These are very effective in producing clean WVO.
Heavier fats, water, and particles are separated quite effectively when those 'G' forces are at play

veggie
« Last Edit: September 13, 2018, 11:53:11 PM by veggie »
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Matt12

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Re: Cheap centrifuge?
« Reply #5 on: October 26, 2018, 05:49:18 AM »
Hi All

So, as I got home in the Landy (a 1999 TD5) I sat a moment and listening to the centrifugal oil filter spool down, it takes around 25 seconds, I started to think.(I'm sure Ed has warned about this in the past)

If a steering pump motor, running around 125 PSI,  was rigged to a centrifugal oil filter housing, with a standard filter would it pull enough crap out to make it all worthwhile?

I know there's bigger ones on large marine diesels, I've ended up quite grubby servicing them!

If you've nothing to do when you're next round your dad's scrapyard, Glort.........

Anyone any ideas?

Cheers Stef

I think it's a good idea too, no reason why it wouldn't work, only thing is, is a PS pump a high head, low flow type of pump, would it maintain pressure at a flow rate suitable to feed the centrifuge.  I think 30 psi is sufficient to power the centrifuge, but more would be better.
Cheers, Matt.  Aus.