Alternate Fuel: Waste Vegetable Oil WVO, Straight Vegetable Oil SVO, Used Cooking Oil UCO Prefilter System

I have been upgrading my filter system for years. I started out dumping the wvo through an old tee shirt into a 30 gal drum with a water heater element screwed through the side. I used a 10$ drill pump to push it through a whole house water filter. I made some changes a little at a time until I ended up with the filter I now have.

I moved up to a 55 gallon drum to increase the volume. I cut two six inch round holes in the top. A saws all, jig saw or grinder will work. I have a circle cutter for sheet metal, so I used that. I can hang filter bags or blue jeans inside the drum. I prefer jeans because they are $12 at the local Walmart, no waiting for UPS. I use wire ties to close off the pant legs. Since I have a welder, I attached a fitting to the drum to feed my harbor freight blue water pump. I used a step bit or uni bit to drill a hole just below the bottom ring on the drum to allow a 3/4" pipe nipple to be started. If you make the hole the right size the pipe will thread in and stay in place while you weld. I put a ball valve between the drum and the pump. I also put a pipe union after the pump so I can service the pump without draining the drum or disassembling the filters. My HF pump pushes the oil through 2 whole house water filters and one automotive filter. The house filters are cheap online. The automotive filter and filter head are from Petroparts. I use the same filter in the car. I have a pressure gauge before the first whole house filter and before the automotive filter. Checking the pressure on the gauge will tell you when it's time to change the filter. Pumping cold oil will show a higher pressure than warm oil. I have 15' of farm hose and a nozzle to fill my tanks.

I used a pressure switch for a well to control the pump. The pump only puts out 50-60 psi, but I like to keep it around 40 psi. Setting it higher can push debris past the water filter and clog the more expensive automotive filter. I installed a check valve after the pump to keep it from cycling off and on. I also have a temperature gauge before the filters. I like to pump when the oil is between 70-90 degrees. It is warm enough to flow, but cool enough to prevent fat from settling out in my tank.

I warm the drum with 60 watt heat tape, the stuff that keeps pipes and gutters from freezing when it's cold. It came with a built in thermostat that only turns on the heat when it's below 40 degrees. The stat is molded into a bump on the heat tape. I used a razor knife to get to it and remove it. You could replace it with a water heater thermostat, but I just connected the wires together (don't try to run a water heater element without a stat). I wrap the heat tape around the outside of the drum near the fitting for the pump. As water settles out it can fall below the heat tape and should not be stirred back up. It does not heat as fast as a water heater element, but I feel much safer using it. It also doesn't churn up the oil. I use standard fiberglass insulation around the drum to keep in the heat. I used a cheap indoor/outdoor thermostat to keep an eye on the temperature. The remote sensor is mounted near the middle of the drum.

Of course you should settle your oil as long as possible before dumping it into the filter bags. I have two 55 gallon plastic settling drums next to my filter drum. I transfer the oil with a modified small block Chevy oil pump (see my article on how to build one). The pick up for the pump is about six inches from the bottom of the drum. I can see through the plastic drum, so I always know how much oil is left.

Every spring I use a HF hand powered barrel pump to drain any water from the bottom of the 3 drums. Water pumps much easier than oil so I know when to stop. I drain about 5 gallons of water from each drum. If you are getting wet grease, you might need to drain it more often. I change the jeans by raising them up a few inches until they are out of the oil. Let it drain over night and throw away or burn them in your wood stove. I also change the first water filter because it catches most of the junk. I change the jeans and filter even if it doesn't need it. It's cheap insurance and I know I will go all year without a problem.

Build it cheaper.

I used a HF hand pump for two years before I went to electric. I pushed the oil through one whole house and right into the tank. It worked fine until I got tired of cranking it and upgraded to the electric HF pump. The pump was strong enough to push sediment past the filter and I started to clog my onboard filter. I solved the problem by taking a tip from Brian Miller on the Greasecar forum and doubled up the house filters. I went a step further and added the same filter I use in the car. I have had no problems after that. You could use a pump with a stand pipe to keep from welding the tank. Some pumps, like the HF water pump are difficult to prime, but the SBC pump will self prime. It can make a lot of pressure, so monitor it with a gauge while pumping or limit it with a well switch or pressure by-pass. You can save a little bit by skipping the farm hose and nozzle and going with a rubber hose and pvc ball valve or a thread on cap to stop dripping.

Using the filter. I fill the filter bags and use a water cooler jug to keep them topped off while I am away. When the drum is about 3/4 filled I turn on the heat. It is usually about 100-120 degrees by the time the drum is filled. I heat it for a day or two and turn off the heat. I don't use a thermostat and it heats up to 130-140 degrees in the summer. In the winter it stays about 120degrees. When the drum cools to 80 degrees I pump it out and start over. I try to do most of my filtering in the warmer weather and squirrel away what I need for the winter. This set up will work in the cold, it just goes slower. Adding another length of heat tape to the filters would help a lot.