The best way to siphon fuel

Picture by 10b travelling

…from a jerry can into your car. Some bad minded people might think I am talking about siphoning fuel out of the tank of a car….no, no, no….this is more to do with the chronic fuel shortages affecting Malawi with those who have jerry cans (chigubus) getting first dibs at the pump. But after hassling your way to the front of queue or paying the guy off to stand in the queue for you..what is the safest and most efficient way to get that fuel from the jerry can into your car.

An obvious choice. Poke around in the back seat of your car for a discarded bottle of water, cut in half. A funnel must have a wide, often conical mouth and a narrow stem. The wide mouth collects the fuel from the jerry can and runs through the narrow stem (the neck of the bottle) into the tank.  For those of you who bought black market fuel and are worried about damaging your engine…check out this funnel which filters out water, dirt, and debris. (Unfortunately not available in Malawi…but at least food for innovative thought).

A siphon (tube) works on the difference in potential between two containers one being at a higher level than the other. The flow of liquid is caused by a difference in hydrostatic pressure, which allows the liquid to be drained without being pumped through an uninterrupted path e.g. no air pockets in the tube.

Siphons works on the basis of gravity and need to be triggered before the liquid starts to flow. Most times its by sucking with your mouth…and often you can get a mouthful of fuel…bad idea! By vacuum suctioning on the lower end you lower the pressure in your lungs to beneath atmospheric pressure by expanding them. Once the liquid has passed the highest point in the tube, the continuous chain of  bonds between the liquid molecules in the tube, and the force of gravity, do the rest.

For more scientific explanations on how siphons work check out the Naked Scientist or American Physical Society or the Guardian Newspaper‘s elaboration on how Oxford English Dictionary got the explanation of how siphons work wrong for over 100 years.

Is there a way to siphon without getting a mouthful of fuel
It is very dangerous; the fumes alone can damage  lungs, and if ingested, fuel can damage the your throat and stomach. A siphon pump is a safe option, there are some battery operated pumps and some handheld pumps. Those in Malawi…must be saying well that’s great but how do I get one…..well I don’t have answers for that but what I can say is I have seen an extremely innovative way of suctioning whilst visiting my in-laws in Salima…where instead of sucking at the end of the pipe, you seal up as much as possible the hole of the jerry can (the source container – with for example a cloth). Leave a little of space for you to suck the air out of the jerry can, best done by sucking in one huge lungful. This creates a vacuum in the jerry can, the fuel then moves into pipe and through the siphon….and your mouth remains fuel free!

Tips on siphoning
–       The jerry can has to be at higher height that the fuel tank.
–       Avoid air bubbles in your siphon line.
–       Be sure to keep an eye on your fuel in the jerry can and make sure the hose stays fully submerged, otherwise you’ll end up with bubbles.

If anybody has other ideas please do share.