Pressure driven ‘fuge VS. Gravity ‘fuge

[m67tang]

im going to be buying a new centrifuge ASAP, like next month. Was mostly gonna get pabiodiesel kit. Now I’ve found a nice second hand gravity centrifuge for a decent price.
I understand that on a pressure driven unit, you leave it running and recirculating.
On gravity type how do you get a second pass? Gotta pump it back up top again for re-gravity?

 

[spanky1205]

I believe one of the benefits of using a gravity centrifuge is you do not have to make a second pass. Take that with a grain of salt as I have never used any of them. PA Biodiesel had a number of videos explaining the different between their centrifuges and the benefits and draw backs of them. You could probably watch those and at least gain a better understanding.

 

[Armo]

Gravity feed is ment for a single pass. You are using lower flows its pretty much a calculation of time spent in the centrifuge for how clean it gets so high flows mean less clean time in the fuge. I use a super trickle flow where it takes at least 24 hours to make 50 gallons of clean stuff. I don't heat the oil and most times don't cut it unless its all heavy gear oil. I just set the flow and come back to clean oil. It runs a long time between needed cleanings though cleaning can be messy cause the bowl holds oil. One draw back is if you lose power some centrifuges out their have a design where if it doesn't spin it drains it into a bypass so the dirty wont dump into your clean batch but some fuges don't so if the power dies so does your clean oil.
I own a gravity feed setup and wouldn't go any other way even after a month settle period, a flow through 5 micron absolute filters, and a water separation filter I find crud and water droplets in my centrifuge.

 

[Coopons]

I'm running a little 55gph unit from pa bio diesel and it works well. It does recirculate and takes multiple passes to get my oil clean. I would like to buy one of there gravity fed units when funds allow.

 

[m67tang]

I’ve got my new 108 gph pa biodiesel fuge on the way to me. Soon to be oilin on the cheap again .

My last filtration setup was a filter style, it worked good for me at the time. After about 3 years it needed too much work to justify fixing vs buying a centrifuge like I really should have the first time. Live and learn.