Filling
From Bytesmiths
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Fuel system: | Fuel system overview | Fuel system common components | Filling | Plumbing | Vegetable oil | Fuel system electrical |
Contents |
Fuel System Filling
Foot Filter
This keeps french fries and cigarette butts out of the tanks when dumpster diving. I like this filter because it is wide but only about 3 cm deep. This gives lots of surface area (so it doesn't clog very often) but because it is shallow, you can suck close to the bottom of a barrel without picking up gravity settled debris.
It is lightweight, with a plastic base, and cheap. I think it cost $3 or so. I got it from the same place I got the filler hose: Pacific Rubber and Supply, of Portland, Oregon. Any place that specializes in pumping and pump parts should have something similar.
GPI Flow Monitor
I found this little guy on eBay. It was supposed to be unused, and indeed looked bright and clean when I received it. However, it does not measure vegetable oil accurately, indicating only about 2/3rds of actual oil pumped. I'm not sure why, but it may be viscosity related, as this meter is normally used for diesel fuel. Anyway, it is still useful, as the 2/3rds math is pretty easy to do in your head, and watching it lets you keep track of progress.
It has a non-resettable total, and a resettable counter as well. In the photo, it's showing the ~300 gallons of vegoil that we used during our 2004 summer trip from Oregon to Maine and back.
Check Valve
Next in order from dumpster to tank is a check valve. This keeps oil in the hose from flowing back out through the flow meter and foot filter. This serves two purposes:
- It avoids an awful mess, and
- by keeping the hose full, it avoids re-priming the pump.
This particular one has 1" NPT threads and came from Home Depot. It is intended for water pumps, but seems to work just fine with vegoil.
Filler Hose
This 1" spiral-reinforced hose came from Pacific Rubber and Supply, in Portland, Oregon, for about $1.50 a foot. I have about ten feet of hose in my kit. The important features are its thickness and its reinforcing.
When I first started pumping dumpsters, I used 3/4" rubber hose. Unfortunately, the pump can generate a lot of suction, and vegoil is often pretty thick. The end result is the hose collapses under the suction force.
Having a thick hose helps in two ways. First, you always want the suction size of your pump to be thicker than the pressure side. Second, a bigger hose means stuff travels through it more slowly, thus you avoid sucking up gunk from the bottom of the dumpster.
DryLock Connector
This is really cool! I found these on eBay for a tiny fraction of what they must have cost. It's made out of solid stainless steel, with 1" NPT fittings. The center of each part is essentially a spring-loaded valve, so that when you separate the connectors, no fluid leaks out. When connected, pulling on the knurled collar separates the connector with little effort.
This connector makes it easy to do on-the-road harvesting without undue mess. I packed coveralls for our summer 2004 trip, expecting to be covered in waste oil. But the combination of DryLock connector, check valve, and storage (below) meant that I could take a shower, harvest some oil from some nasty dumpster, then go in the restaurant and eat, without more than washing my hands!
Fill/Recirculate Valve
This is the same component that is used to switch between biodiesel and vegoil, and it is also used to switch between left and right vegoil tanks.
In the fill position, oil is sucked through the foot filter, flow monitor, check valve, and hose by the pump (below), through the Racor filter (below), then into either the left or right tank, depending on the position of the Left/Right valves.
In the recirculate position, oil from whichever tank is not currently supplying the engine via the Left/Right valves is continuously recirculated through the pump and filter. With this, I can pump dirty oil into a tank if I'm in a hurry, then clean it while I'm driving. I have not really used this facility, except to test it, but in the future, I'm envisioning using my second tank as a biodiesel processor, and using recirculation for mixing during the reaction.
Oberdorfer Gear Pump
This sturdy pump will grind through the thickest oil without complaint. It has a 1/2 horsepower (30 amp) motor, and will deliver 4 gallons per minute at 90 pounds per square inch. This is enough pressure to rupture a fuel tank, which I nearly did the first time I filled!
This was yet-another-eBay find. They're about $500 new! I think I paid $60 on eBay. The seller had six of them, and I bought them all, but they were improperly packed, and half the pumps were siezed when I got them! Luckily, the vendor was honorable, and refunded my payment and paid return shipping. I re-sold the other two pumps at cost to members of our local biodiesel coop, where they are serving as waste oil collection pumps.
Gear pumps are typically not self-priming -- they are not particularly good at pumping air -- so I went to some trouble to make sure it was at the lowest point in the system, with a straight down path from the DryLock connector. Before running it the first time, I manually filled the hose before attaching the check valve, and I have not had any problems priming the pump.
Racor Cleanable Filter
In this diagram, the filter is actually upside-down. The holes on the left side of the bottom part (6) secure it to the chassis via two angles I welded in place, and the top(10) comes off by removing four nuts(12) from the top. Since it's operated at fairly low pressure, I often secure it with just two nuts, especially if I get into a nasty dumpster that has me cleaning the element every few gallons!
See also the clickable picture under DryLock, above.
Control
The pump and right/left tank valves are controlled by switches on a control box, so that the person pumping the oil can react quickly to any problems. The pump is controlled by the red, momentary contact "dead man" switch, so all the operator needs to do is drop the control to stop the pumping.
Storage
I cut the bottom 25 cm (10") from a plastic 200 liter (55 gallon) barrel, and use it to store the filler hose and filter cleaning supplies.
A plastic laundry detergent container is ideal for cleaning the Racor filter element. It has a snap-on, relatively liquid-tight lid, and isn't too tall to work inside. I keep a couple inches of mineral spirits in it with an old toothbrush. I can scrub the Racor element with the toothbrush and have it back on the Racor in a minute or so.
Issues/Problems
- I need to put a pressure relief valve around the pump. Gear pumps are "positive displacement" pumps, which is a fancy way of saying they can deliver tremendous pressure. Because the flow monitor is not calibrated, the first time I filled the tanks, I nearly exploded one, because I merrily kept pumping after it filled! --Accomplished, spring 2005. I actually used a water pump pressure switch to turn the motor off, rather than a relief valve. Adjustment is touchy, and I had to crank it down in cold weather to let oil flow without tripping the pump off!
- My storage is not complete, and my bin sits on the floor of the truck. In keeping with my "no loss of space" design goal, I'm going to mount a hinged shelf between the rear bumper, rear tire, chassis, and body skirt, where I can put the bin when not in use.
- The filter blockage lamp needs to be on the control box! Currently, filling is a two-person operation, with Carol watching the dash light for filter blockage while I run the pump with the control box. --Accomplished, spring 2005. I found a neat solenoid-controlled pushbutton switch, which I wired with a tiny relay so that when the filter clogs, the switch releases!
