Centrifuge Filtering Design

Collecting, filtering and dewatering of WVO SVO vegetable oil. For Biodiesel producers too.

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Centrifuge Filtering Design

Postby burn_your_money » Sun Sep 04, 2011 8:01 am


I'm new here and to the whole WVO thing. I'm still in the R&D stage and don't even have a vehicle yet.

I've always liked the idea of a centrifuge for filtering and was planning on building my own from scratch. However, after seeing SunWizard's setup I decided it would be easier and possibly cheaper to just buy a centrifuge. I have not decided what brand to use yet but I want to get whatever one offers the highest g-force. I have emailed several vendors and will report back with my findings.

I've drawn up a diagram of how I would like to build my filtering setup. I'm sure most of you will recognize it. I didn't like the idea of walking away from 160F+ oil without any safety overrides built in so I added a couple. If you notice anything that I am overlooking please let me know. Also, I have no experience with wiring an AC relay. If anyone knows anything about it, that would be swell.

Image (clickable)

You can see I have 2 separate circuits. The pump controls has an adjustable float on it so that if the level in the barrel drops below a certain point the pump will shut off. This safety feature has a manual override switch for when I need to pump the WVO out into the storage tank.

The Heater Controls circuit has 2 safety switches, one is a temperature switch which will cut off around 180F and the second is a pressure switch that will cut off whenever the pressure is below ~6psi.

Looking at the Fluid Schematic you will notice there are 3 valves. Valve 1 is for preheating the oil. It will be open until the oil gets hot enough to run through the centrifuge. Valve 2 is to ensure that the water that is caught in the centrifuge does not get dropped back into the WVO on spindown. I may also use it for transferring the WVO from this tank to the storagetank. Or I may add a T in somewhere else to keep the clean oil from the dirty pipes. Valve 3 is to put some restriction (PSI) in the pipes during warm up when the centrifuge is being bypassed. This is needed otherwise the pressure switch won't close and allow the heaters to come on.

My main safety concerns were springing a leak, pump failure and overheating the oil. I think my design will cover those situations. Am I missing anything? Would it be possible to use the same float switch to control both circuits? With DC I don't think there would be an issue but I am not sure with AC.
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Joined: Sun Sep 04, 2011 7:32 am

Re: Centrifuge Filtering Design

Postby belchfire » Sat Apr 07, 2012 1:34 pm

You're on the vw diesel forum too, right? Just joined this one myself after acid ate up my pump. As for the relays; easy enough. Wire the control switches to the actuating coil. It should have the voltage printed on it. Make sure that it matches what you're using. Then you'll need a separate power source (with fuse) that will go to one side of the contactors. The load (heaters etc.) goes to the other side of the contacts. Switch energizes the coil, coil closes the contacts, off you go. Nice way to use a small trigger to control a high power device. Most relays of significant amperage rating are AC. You could run a DC coil to run AC heaters as the two are separate. More likely a 110v coil and 220v load.
I built a centrifugal separator modeling it after a honda bike oil filter. Haven't used it yet as I was thinking that simple filter bags would do the job. I'm shy about using a lot of machinery to process the oil as if it's not hot then it becomes a gummy mess. Running a propane torch on valves and pumps takes a lot of the fun out.
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Joined: Fri Apr 06, 2012 4:11 pm

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