My current method of filtering oil is outlined below, it will no doubt be too small for some and too large for others. I run a small co-op and for me this system suits the needs of the members.

Filtering area:

1) Pre-filter barrel
2) Frybrid Still
3) Pump
4) Bulk storage
5) Filter
6) Delivery pump
7) Materials storage
8) Excess storage

The filtering takes place as follows:

As members bring oil in they pour it from the containers they collected it in into the pre-filter barrel through the pre-filter on top. The oil flows through the pre-filter until either the filter no longer flows or the barrel is 4/5 full. If the filter becomes plugged then it is replaced and the old filter disposed of.

Once the pre-filter barrel is 4/5 full the Frybrid still is used to suck the oil from the pre-filter barrel and into the still until it is 4/5 full and the heating element in the still is turned on. When the oil in the still reaches 140F the power to the heating element is turned off. I can tell if the oil in the still is 140F by simply touching the inner tank with my finger, it is exposed next to the upper heating element which has been disabled, if the tank is hot to the touch it is heated sufficiently (Note: 140F is as hot as the average person can continue to hold onto an object). The upper heating element can also be removed and replaced with a thermometer like part # 3946K116 from McMaster Carr (you will also need a 1” NPT to ½” NPT adapter like # 44705K293).

The oil in the heated still is allowed to settle for between 4 and 8 hours, even at 8 hours the oil in the still will remain hot. About 3 gallons is drained from the bottom of the still and a sample taken. I do this by draining the oil into a bucket, as soon as it looks clear I shut the drain valve and collect a sample (about a coffee cup) with a mason jar. The sample is tested using the crackle test. If it does not pass I drain more and retest, if I have drained 6 gallons and it does not pass I allow it to settle longer and retest, if it does not pass after further settling I will heat cycle it again and repeat.

When the oil passes the crackle test, the valves are moved to direct oil from the still through the bag filter and back into the still and the pump turned on, I will allow this to cycle for as much as an hour. The valves are moved again directing the oil from the still, through the filter and into the bulk storage tank (tote).

When the tote is full I fill the excess storage containers as required and keep then in a cool, dark place until they are needed by someone going on a trip or the volume in the bulk storage container drops. If the oil is taken on a trip the containers are returned empty and refilled, if the oil is used to refill the bulk storage tote it is pumped from the excess storage containers through the filter and into the bulk storage tote.

The Pre-filter barrel:

55 gallon open head drum with a level clamp closure. The top edge of the barrel is lined with a length of 5/8” coolant line split in half. Sections of bed sheet are laid over the coolant hose and clamped in place with the lever closure. I get the sheets from a local second hand store, they gets loads donated that they choose not to sell because they have small holes or stains and they are more than willing to give me a garbage bag full every time I stop in. Each sheet will make between 2 and 4 pre-filters and when they are clogged up I simply place them in a bucket to drain, and then drop them in the trash. Remember the slower the pre-filter is filtering the better it is filtering so don’t rush things. The first few buckets or cubies of oil will pass through the pre-filter quickly, this is because the fabric is not terribly fine and is likely passing particulates well above 10 microns, as the cake of particulate matter builds up, it becomes a more and more efficient filter passing only quite small particulates. This is the same theory behind sand filters and Diatomaceous earth filters.

Frybrid Still:

Mine is made from an 80 gallon electric water heater. Details of the manufacture are available here. Most cities collect water heaters at the dump (Solid waste disposal site) and they either dispose of them or they have a contract with a company to recycle them. If you call and ask they will usually be more than willing to tell you who the recycler is, call them and ask if you may have one. Typically they will be more than happy to hold one for you for free as they have already been paid to recycle it.

Details here.

Pump:

Details here.

Bulk storage:

I use a 275 gallon (1000 liter) “Tote” or IBC ( Intermediate Bulk Container), these are available from and barrel or container recycler and are often found free on craigslist. They are used for the bulk transport of everything from printers ink to cat littler. There are two common varieties, those with a wire cage and those with a tubular aluminum cage, either will work just fine but I prefer the tubular caged containers as they can be stacked 3 high rather than 2 high for the wire caged containers.

Filter:

I have not been happy with the FSI plastic bag filter housing 51655K6 from McMaster Carr at $260.00. It is difficult to find bags for in any size except 5 micron and the upper rubber gasket seems to be prone to leaks. I like the 6870K59 from McMaster Carr allows you to use a trade size 4 bag and is much better made at $350.00. I think it is a much better filter housing, it is aluminum with a stainless bag basket where the plastic unit has a plastic bag basket that can melt above 130F (I have melted 2), the aluminum housing has 3/4" NPT fittings where the plastic one has 2" NPT and you must make reducing couplings (every connection is a possible leak). Trade size 4 bags are available everywhere in every micron rating and are cheap, the larger bags are $5 and are hard to find.

I do not advise anyone use Whole House water filters, they are not made for hot oil and are designed in such a way that when the filter clogs it simply deforms and allows dirty oil to bypass the filter entirely.

Remember that the finer you filter your oil the longer it will last in storage and fine filtration saves your final filter in the vehicle.

Delivery pump:

Materials storage:

A simple shelf to hold filter bags, sheets for pre-filters, bung wrench, rags, cat litter, etc. I use steel wire restaurant shelves since they do not collect dust and are very easy to clean, the best deals I have found are at Costco or Fred Meyer where a 4 or 5 shelf unit can be found for $60 as opposed to $300 at a restaurant supply.

Excess storage:

I use 35 gallon plastic barrels, I prefer the 35 gallon drums because I can move them easily by myself even when full and two men can easily pick a full one up to load it. I look for the closed head drums with 2 two inch threaded bungs in blue or brown. I prefer the closed head drums as they are tougher than the open head drums and I prefer the blue or brown as they block more UV light than the white drums.

Centrifuge...

For those wishing to mount a Centrifuge on a Frybrid still this is the method I used. In the end I elected to use the still as I had been and I no longer use the centrifuge except in experiments. If further study shows that it has benefits which outweigh the effort and energy required to use it, I may again attempt its use. That said others have had great success and swear by the use of a centrifuge on the still.

I found that without the vent tube installed as shown that the centrifuge would fill with fluid and stop spinning. When installing this remove the close nipple mounted in the cold water inlet of the heater, look down in the opening and check for a vent tube made of plastic or a zinc annode and remove them if present through the hole before screwing in the pipe section on which you will be mounting the centrifuge.

The feed to the centrifuges pump can be taken from a "T" installed in the stills drain as detailed above.

Use of the centrifuge:

It is important that the oil be hot when it is being processed with the centrifuge, a temperature between 140F and 160F is advised. Once the oil has been pre-filtered and heated in the still the oil may be processed with the centrifuge, many users advise at least 6 passes through the centrifuge which processes oil at 1 gallon per minute, so 60 gallons would be processed in one hour and a batch of 60 gallons woul need to be processed with the centrifuge for at least 6 hours.

Method 1: Prefilter the oil and fill the still. Heat the oil in the still and turn on the centrifuge allowing it to run while maintaining 140F-160F for at least 6 hours, then pump the oil through the bag filter and into the storage tank or cycle it through the filter for another hour and leave the oil in the still to serve as your home fuel pump.