nibbo Posted October 28, 2011 Report Share Posted October 28, 2011 Hi all, I thought this may be of interest to every body !! With Petrol expected to reach £2 per litre by end of 2011 these tips that I received from a friend might come in handy. TIPS ON PUMPING PETROL I don't know what you guys are paying for petrol.... I am paying up to £1.35 to £1.50 per litre. My line of work is in petroleum for about 31 years now, so here are some tricks to get more of your money's worth for every Litre: Here at the Shell Pipeline where I work , we deliver about 4 million litres in a 24-hour period .. One day is diesel the next day is jet fuel, and petrol, regular and premium grades. We have 34-storage tanks here with a total capacity of 16,800,000 Litres. Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the petrol, when it gets warmer petrol expands, so buying in the afternoon or in the evening....your litre is not exactly a litre. In the petroleum business, the specific gravity and the temperature of the petrol, diesel and jet fuel, ethanol and other petroleum products plays an important role. A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps. When you're filling up do not squeeze the trigger of the nozzle to a fast modeIf you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimizing the vapours that are created while you are pumping. All hoses at the pump have a vapour return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapour. Those vapours are being sucked up and back into the underground storage tank so you're getting less worth for your money. One of the most important tips is to fill up when your Petrol tank is HALF FULL. The reason for this is the more Petrol you have in your tank the less air occupying its empty space. petrol evaporates faster than you can imagine. petrol storage tanks have an internal floating roof. This roof serves as zero clearance between the Petrol and the atmosphere, so it minimizes the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every litre is actually the exact amount. Another reminder, if there is a petrol truck pumping into the storage tanks when you stop to buy Petrol, DO NOT fill up; most likely the petrol is being stirred up as the Petrol is being delivered, and you might pick up some of the dirt that normally settles on the bottom. Happy Motoring. Nibbo Quote Link to post Share on other sites
sidescreen Posted October 28, 2011 Report Share Posted October 28, 2011 I always thought........ Temperature higher, s.g. lower. (specific gravity, proper english for that?) Temperature lower, s.g. higher. Regards - Raymond Quote Link to post Share on other sites
robnob Posted October 28, 2011 Report Share Posted October 28, 2011 (edited) . When you're filling up do not squeeze the trigger of the nozzle to a fast mode Thanks Nibbo! You're correct with the "don't use a fast filling mode" - an old pal of mine was a Trading Standards Officer who did the rounds of filling stations checking all the Gilbarco pumps, and always said to me, you must take time when filling your tank - everyone hammers the fuel in but take it slow and it costs you a lot less. Filling up when it's cool early morning is a good tip too. £2 before the end of 2011 though??- I hope not that soon !! Edited October 28, 2011 by robnob Quote Link to post Share on other sites
john.r.davies Posted October 28, 2011 Report Share Posted October 28, 2011 (edited) Nibbo, I'd never have thought that the density of fuel could change that much at ground temperatures. Ground, because the underground tank won't heat up much even on a hot, sunny day - dig a hole in the ground only six inches deep and feel how cool it is, even when the surface is hot (Not on a beach!) But if the lorry fleets take care about this why not me? Thanks for the tip! Can't do anything about a floating fuel cover in the tank, and anyway, it can only reduce the AREA available for evaporation, not the vapour pressure. The fuel may evaoporate more slowly, but surely the empty space above such volatile liquids is mostly vapour anyway? The Reid Vapour Pressure is the official measure of fuel volatility, but it is by definition measured at 100F, whihc may not be representativ eof normla storage conditions, but anyway. It varies according to the precise fuel mix which is set by seasonal temperature, and can be anywhere between about 5 and 14psi. The latter is atmospheric pressure, so would be a cold weather fuel. Vapour pressure varies with temperature, and when it reaches atmospheric the liquid boils! Below that, the proportions of vapour and nromal atmospheric gases above the liquid in the container will depend on the Law of Partial Pressure. At boiling point the space is filled with vapour alone. below that, subtract the vapour pressure from the atmospheric, and the remainder is air. In a storage tank, the space may be very large, an dits worthwhile to have a floater, but a cars' tank, even sitting in the garage, is too small to make it worthwhile. The air above the fuel will always, for all practical purposes, be saturated with vapour. If your tank is near empty then all that vapour will be flushed out through the filler cap when you fill up with liquid fuel. so thanks again, nibbo, good tip! John Raymond, Yes, low temp=high SG, but high SG means more mass of fuel in the same volume or higher density. SG is expressed in gms/unit volume. John Edited October 28, 2011 by john.r.davies Quote Link to post Share on other sites
Alpha206 Posted October 28, 2011 Report Share Posted October 28, 2011 This old chestnut's been doing the rounds for a few years... http://urbanlegends.about.com/od/automobiles/a/pumping_gas.htm http://www.snopes.com/inboxer/household/gastips.asp Quote Link to post Share on other sites
Clarkey Posted October 28, 2011 Report Share Posted October 28, 2011 (edited) Hi Nibbo Sorry to pick holes in this. I too have been involved in the Petrochemical Industry for over 15 years now and I have also delivered petrol for a living " All hoses at the pump have a vapour return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapour. Those vapours are being sucked up and back into the underground storage tank so you're getting less worth for your money. " We do not have second stage vapour recovery in this country. I.E. the vapours from your petrol tank are drawn back into the filling station tank. And as for the floating roof tanks, the main purpose of these are to stop vaporisation of the fuel (true) but it also stops the potential for an explosive atmosphere above the liquid. Petrol is only put into the underground storage via gravity. pumping petrol is a no no unless a special type of pump is used. there is very little disturbance of the fuel in the tank. as the delivery pipe goes down just about to the bottom of the tank, so that the fuel is entering the tank under the fuel , this stops agitation of the fuel and intern this stops over vaporisation of the fuel. Temperature does play a part you are right but petrol is sold @15deg as standard this also goes for the pumps at the service station, Edited October 28, 2011 by Clarkey Quote Link to post Share on other sites
Shezbo Posted October 28, 2011 Report Share Posted October 28, 2011 Whilst I thank our colleague for sending us this, genuine thought provoking tips, one blast on the loud pipe and all the above (very small, lets be honest) savings will be gone. A correctly tuned (TR6 in my case) would give much better returns..having said that I have honestly never ever measured the AHX's mpg, why worry, be happy Quote Link to post Share on other sites
john.r.davies Posted October 28, 2011 Report Share Posted October 28, 2011 Taking this to heart, I filled up the modern today. Tank plumb empty, and it takes 60 litres. Nozzle in hole, squeeeeeeeeeeeeze the trigger (memories of firearms training) And there it goes, ever so slowly into the tank. Hmmmmmm. HOW slowly? One thousand, two thousand, three....... Jesus! It takes ten seconds to deliver one liter! I'll be here for ten minutes at this rate! Stuff this for game for soldiers! Sorry, Nibbo, life's too short! John Quote Link to post Share on other sites
jobster Posted October 28, 2011 Report Share Posted October 28, 2011 and all this saves exactly how much? Quote Link to post Share on other sites
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