Author Topic: WVO Centrifuge Design - thoughs ?  (Read 1462 times)

veggie

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WVO Centrifuge Design - thoughs ?
« on: June 18, 2018, 12:53:26 AM »
Hi All,

I have a design question as I fabricate a WVO cleaning centrifuge.
My initial design shown below incorporates a single tank with the "Fuge" mounted above.
The 26 liter tank will incorporate a sight level tube and a 1000 watt heating element.
The idea of the small tank is that I can process a Gerry Can at a time for small batches.
There will be a small gear pump mounted on the side of the tank which continually circulates the WVO
 up to the centrifuge where it gets cleaned and falls back to the tank.
Theoretically, the longer the unit runs, the more passes the WVO gets through the centrifuge.

Most users of this type of Fuge have a two tank system. One above which uses gravity to the feed the Fuge, and one below to collect the cleaned oil. Then they pump the cleaned back oil up to the original tank for another pass. This ensures 100% contact time for all the oil.

My Question:
After a lot of Youtube digging, I have not seen anyone use a single tank system like mine which makes me wonder...
Will ALL of the oil pass through the centrifuge 100% or will there be pockets of un-cleaned oil that never make the loops?
For me, the single tank system is a real space saver and I don't mind leaving the system running longer in order to get multiple passes though the fuge. But will ALL the oil get processed given a long enough run time?

Anyone with experience with this?

Cheers,
Veggie

Tank = 7 Gal (26 liter)
« Last Edit: June 18, 2018, 03:01:35 AM by veggie »
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mike90045

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Re: WVO Centrifuge Design - thoughs ?
« Reply #1 on: June 18, 2018, 01:42:38 AM »
If you can keep the oil thin and agitated, for long enough, it will be clean "enough"   Since it's operating in "bypass" all the time, all the clean oil you put back in, gets dirty.  Lather, Rinse, Repeat.

At some point, you have to put the clean oil somewhere.

glort

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Re: WVO Centrifuge Design - thoughs ?
« Reply #2 on: June 18, 2018, 02:18:49 AM »
Quote
But will ALL the oil get processed given a long enough run time?

Yes.

veggie

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Re: WVO Centrifuge Design - thoughs ?
« Reply #3 on: June 18, 2018, 03:18:16 AM »
At some point, you have to put the clean oil somewhere.

Ha..Ha...Yes, after several processing loops with the centrifuge spinning at 5000 rpm, the oil should be very clean.
At that point a valve gets opened and the pump pushes the processed oil into a clean oil storage tank.
Then the green centrifuge tank gets filled again with dirty oil.
The fats and particles collect on the inner wall of the centrifuge drum for cleaning later.
That's the plan anyway.  ;)

The Drum was purchased from a centrifuge manufacturer and mounts on the shaft you see in the center of the housing base..
The housing was fabricated from pipe.
« Last Edit: June 18, 2018, 03:20:33 AM by veggie »
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EdDee

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Re: WVO Centrifuge Design - thoughs ?
« Reply #4 on: June 18, 2018, 03:18:13 PM »
Hi V,

While it will certainly clean the vast bulk of the debris, I, personally, am going a slightly different route in the bits I am getting together... I will be using a "fill tank" to dribble the oil through the fuge first time round to collect most of the junk... thereafter it will be a single tank system which will recirculate until shut down...

Just my 0.00c worth.....

Cheers
Ed
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BruceM

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Re: WVO Centrifuge Design - thoughs ?
« Reply #5 on: June 18, 2018, 03:41:08 PM »
Ed's first pass filtering should dramatically reduce total processing time and energy to the same quality output, for those that care about that aspect.  Nice bit of practical engineering, Ed.

veggie

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Re: WVO Centrifuge Design - thoughs ?
« Reply #6 on: June 18, 2018, 07:20:23 PM »
Hi V,

While it will certainly clean the vast bulk of the debris, I, personally, am going a slightly different route in the bits I am getting together... I will be using a "fill tank" to dribble the oil through the fuge first time round to collect most of the junk... thereafter it will be a single tank system which will recirculate until shut down...

Hi Ed,

In a similar fashion, my raw oil will pass through a fine screen on the way into the single tank.
Everything else should get trapped by the centrifuge when subjected to 3000 G's (5000 rpm).

Based on the input from you fellas, I will proceed with a single tank system and see how it works out.

cheers,
Veggie
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veggie

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Re: WVO Centrifuge Design - thoughs ?
« Reply #7 on: June 18, 2018, 07:31:49 PM »
EdDee

Whilst I do not intend to run waste motor oil, there are many that do. Your centrifuge system should be a big help.
Here's what some are removing from their WMO...

https://www.youtube.com/watch?v=gCRXNTQgIv4

https://www.youtube.com/watch?v=o0Hys3VPgl0

keep us posted...
Veggie
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AdeV

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Re: WVO Centrifuge Design - thoughs ?
« Reply #8 on: June 19, 2018, 08:19:04 AM »
I started to make my own bowl using an old car brake drum... but I'm wondering if I shouldn't machine up an aluminium one from scratch... I'm concerned that the brake drum may not have enough strength to stay together at the sort of speeds I'm planning to rotate it.

Can I ask you a favour Veggie - how much does your bowl weigh, with lid? That's something else I'm contending with... the weight of the cast iron brake drum + a steel lid, might be a bit excessive...
Cheers!
Ade.
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glort

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Re: WVO Centrifuge Design - thoughs ?
« Reply #9 on: June 19, 2018, 11:50:11 AM »

Not so much the weight you have to worry about Ade, it's the balance.
Mate and I played with this years ago.  We gave up. It's exacting stuff. You don't need much imbalance for things to go pear shaped fast.

Mate and I went to great lengths and trouble to do a washing machine Tub size unit. Fiberglass'ed it all up, had it balanced on a machine for doing gas turbine assembly's ( he worked in an aircraft factory)  and set it all up.  Spun the thing and it was perfect. We were chuffed.  Added oil, no problem, smooth as. We got it.  Did a batch of oil, all good. Thing held about 25L so like everything else we did, had huge reserve.

Ran 100L of oil and then shut it down. and the thing would down the 25L of oil slumped, the thing started shaking and 2 Seconds later literally self destructed.  Ripped itself and all our careful work to pieces.
braver men may have rebuilt it but ours weren't that big and round to tempt fate twice.

A mate bought one of the Rotor Type Fuges and we set that up for him and tested it and it wasn't that much of an advantage over our conventional processing so we let the fuge dream go.

Bowl type is definitely the way to go but they are expensive to buy and we didn't have the resources to machine one.  Not what you got in the aircraft factory, it's what Division the machines you need are in and if you know someone that runs it.  :0)

For a brake drum you could work out the rotational RPM at say 100 MPH and then spin the thing equivalent of say 150 with safety.  As long as the drum is in good Nick to start with and balanced, you should have no problems.

Fuges are time machines. They accelerate settling time of oil.  I was concerned about water as I was using veg oil and Fuges will not get that out so I just took the easy way out and settled the oil.

veggie

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Re: WVO Centrifuge Design - thoughs ?
« Reply #10 on: June 19, 2018, 02:17:46 PM »
Can I ask you a favour Veggie - how much does your bowl weigh, with lid? That's something else I'm contending with... the weight of the cast iron brake drum + a steel lid, might be a bit excessive...

Hi AdeV, the spinning bowl does not have a lid.
Oil overflows the bowl and is caught in the outer chamber.
https://www.youtube.com/watch?v=PsLGX-RbKuQ
The bow weighs about 5 lbs.
I got it here...
https://www.wvodesigns.com/rpc-poboy-kit.html.html
It comes with a special taper lock hub which anchors it to a 5/8 shaft.

Hi Glort,
Fortunately the oil I get has very little water. (I trained them well  ;) )
However...there is always some water and my experience is that these types of centrifuges do a pretty good job of dewatering if the oil is hot enough.
In this example (not mine) you can see the steam leaving the processed oil ( at the 1:00 minute mark ).
https://www.youtube.com/watch?v=OksXHSWidMs
My unit has vapour ports in the lid and in the discharge line to channel moisture out.
1st generation fuges spin at 3600 rpm motor speed but with the use of 3 phase motors and variable frequency drives newer fuges can now run up to 6000 rpm making over 4000 g's. That really takes advantage of the sight specific gravity differences between water and oil. My thoughts are that multiple passes should eventually leave the oil quite dry, but until I run it ...I won't know for sure.

onward,
Veggie
« Last Edit: June 19, 2018, 02:25:54 PM by veggie »
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AdeV

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Re: WVO Centrifuge Design - thoughs ?
« Reply #11 on: June 19, 2018, 08:17:09 PM »

Not so much the weight you have to worry about Ade, it's the balance.

...

For a brake drum you could work out the rotational RPM at say 100 MPH and then spin the thing equivalent of say 150 with safety.  As long as the drum is in good Nick to start with and balanced, you should have no problems.


Balance - agreed... and I have no way to balance it other than statically, which is almost certainly not good enough... However.. my unit will be nowhere near 25l in capacity; that must have been a bloody monster of a machine!

I reckon the capacity of my brake drum, by the time you've added the centre spigot & lid, will be around 1.5-2 litres tops. It's about a foot/30cm across, if I recall correctly, and about 5"/12cm deep. I'd like to spin it as fast as humanly possible...

Assuming it used to live inside a 13" wheel (which seems about right, given its age), that would have had a 4 or 5" sidewall tyre fitted, so about 23" total rotational size, which is about 72" circumference (handy), or 6ft.

100mph is 8,800ft/min, so the brake drum is doing 1470rpm just about. So your safety margin gives me 2200rpm. I was hoping for at least 3600, and maybe even higher...

Next up - work out how many g's that is. That's beyond me tonight... I'll have a go tomorrow.


Anyway, as I wouldn't trust it not to explode at very high speeds, I intend to wrap it in a 5mm thick steel enclosure. I guess I should be able to calculate the centrifugal forces on the side of the bowl at a given RPM, then assume a 1lb lump flies off I can calculate the energy in that when it strikes the outer casing, which will tell me if I need to put a second 5mm steel ring around the inner one for protection purposes... although I might just do that anyway. Steel is a LOT cheaper than internal organs, and a damn site easier to replace...
Cheers!
Ade.
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glort

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Re: WVO Centrifuge Design - thoughs ?
« Reply #12 on: June 20, 2018, 01:41:31 AM »

Get a brake Drum off an older Ferrari or something fast.
Should take a Higher RPM.   :0)

mike90045

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Re: WVO Centrifuge Design - thoughs ?
« Reply #13 on: June 20, 2018, 05:11:39 AM »
.... then assume a 1lb lump flies off I can calculate the energy in that when it strikes the outer casing, which will tell me if I need to put a second 5mm steel ring around the inner one for protection purposes.........

Once one lump flies off, I would assume the rest would follow in the next half second. So all the unbalanced drum will be shedding into your containment ring.   And if there is a spark and the oil is hot enough......

glort

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Re: WVO Centrifuge Design - thoughs ?
« Reply #14 on: June 20, 2018, 07:56:35 AM »

 And if there is a spark and the oil is hot enough......

You'd still be shoving shit up hill trying to light it if you tried unless the oil is about 200oC which is not going to happen!
 Spent enough time trying to burn oil of all types to know!   :laugh:

That's the beauty of this stuff, it's pretty inert unless you really go to effort to get the stuff to burn.