First filter design

Here's a photo of my original garage filtration and pump set up for processing waste vegetable oil for fuel. The top barrel contains the dirty wvo that I've collected from the restaurant and passed through a cone filter. There's a stand pipe in the bottom of the tank that allows for settling and a second stop-cock that will allow me to drain off the dirty oil on the bottom. I was expecting a lot out of this set up when I finished it. I thought that gravity would do most of my work for me and that the pump would practically be an afterthought, but I was wrong.


There were a couple of problems with this set up. First, gravity is no where near as effective as I'd thought it would be, at least near the bottom of the barrel. Second, the pump I used, an old aquarium pump I had lying around, was totally ineffective. I knew going into it that the pump wasn't the best fit for the application, but I wanted to see what would happen. At any rate, the magnetic drive impeller did little to move oil through the filter set up and my first batch of vegi was processed by the slow work of gravity. I think it took about a week to filter 10 gallons of oil.


So at this point, the system simply didn't work and I needed a new solution. My first attempt at a fix was a sump pump, also just lying around the garage, that rested at the bottom of the dirty barrel and pumped oil out. Initial results seemed good, but the flow quickly slowed to a trickle as the pump picked up all the settled particulates at the bottom of the barrel and pushed them into the filter. One nice side effect of using this pump was that it heated the waste oil quite nicely as it flailed along pushing out a few drops.