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Finding the limits of my centrifuge and the sweet spot

Discussion in 'BioDiesel & Alternative Fuels' started by Mt_Man, Mar 20, 2021.

  1. Mt_Man

    Mt_Man Full Access Member

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    So I got a question the for those that continuous flow centrifuger out there. I just set my single pass centrifuge up so I could use it as continuous with a pump. First pass is from my dirty tote to a clean tote. Second pass is the recirculated from the bottoms of the clean tote through my fuge and into the top. I am hoping it gives it a mixing attribute. Also thought I could flow a little more. Just using my collection neumatic double diaphragm pump. Found out that the centrifuge plumping on the clean side can only handle about 112gph. Which is nothing for the diaphragm pump so it's turned way down, but could have been bad if I wasn't watching. I noticed at low air pressure it doesn't stay very consistent with it's flow rate and will speed up sometimes. It almost overflowed threw the bowl drain tube. I figured it was coming and was ready. The fuge has .5 inch drain coming out clean and bowl drain.

    So my question is what would be a good gph for it when it's set up this way? Is it better to do the 3gph I do from the dirty tote and gravity? Or should it be faster like 40-80gph? Trying to size the pump I need. I have several to choose from. I know I will have to pump about 3-5times the tote capacity to probably get it clean clean. The plan being, go until nothing really comes out in the centrifuge. Just like a lot of you do.
    I am also trying to see how well my single pass is doing.
     
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  2. Mt_Man

    Mt_Man Full Access Member

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    So been testing out the recirculating method. Seems to still be pulling out sludge. I rigged up a smaller pump that is doing about 75gph. I can't get it to run slower haha. Did about 3 hrs yesterday and doing another few today. Seems to be running happily. It is flowing fast enough to cause a dribble out of the bowl drain which is not a big deal.
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  3. Mt_Man

    Mt_Man Full Access Member

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    Ran the recirculating setup for 8hrs yesterday. And this is all it pulled out. So I think it is decreasing. I will fuge it into my other clean tote and see how much it gets out.

    I wonder how well the tote is mixing? I kinda want to try it with a 55 gal and see if mixing it up would be better. Kinda see why the pressure fuges they use a barrel instead of totes easier to be confident that it's getting clean.
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  4. Mt_Man

    Mt_Man Full Access Member

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    Oh that was the third time running the set up. Previous runs pulled out more. Each time seemed to decrease the amount being pulled out.
    Think that is a good sign
     
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  5. Mt_Man

    Mt_Man Full Access Member

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    Pump/fuge one last time as I transferred to my second clean tote. Got even less in the fuge, about 2.7hrs to transfer about 250ish gallons. Puts me in the realm of 90gph. Little higher then I was figuring. Still looks pretty good. I am finding that I need a more controllable pump. Probably try an electric pump next batch.
    Doing the first pass of the next batch right now.
     
  6. Kevin 007

    Kevin 007 Full-floater

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    Well I also think that since you are pulling less sludge out on every pass, it is working effectively.
    Have you given any thought to a pneumatic oil transfer pump? They will meter down to a pretty slow flow and they last. Of course it would have to have a steady supply of air and running a compressor may not necessarily be efficient
     
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  7. Mt_Man

    Mt_Man Full Access Member

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    I didn't think of that. I was running a compressor to do the testing with my pneumatic diaphragm pump so it would be similar. That is a good idea. I don't have one, but I will keep an eye out for one. I was thinking of adding a bypass valve and having some volume dump back into the clean tote. Very similar to the continuous flow centrifuges. I think a dc motor and speed control or a vfd would be nice.
     
  8. Fattima

    Fattima Registered User

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    Like your work. I'm thinking of doing something similar but was looking at using a pump feeding a header tank with a float switch to cycle the pump to keep the header tank topped up with oil. I've got a 12V gear pump here and a float switch is pretty cheap. Will have an overflow back to the main tank should the switch fail.
     
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  9. Mt_Man

    Mt_Man Full Access Member

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    Yah that would be a good idea. I built this a few years ago to do small batches. A buddy asked for me to fuge some oil so they could put it back in a dump truck that leaked really bad. It was worn out and only used it around the farm. It would be easy to add a overflow return. I think the best way to do it would be to have another tote and pump all at once and then let gravity do it all.
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    Last edited: Apr 7, 2021
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