Angel's share of petrol.

T

Tintagel

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I bought petrol from a garage in the Booterstown area of Dublin recently.

When I pressed the handle on the nozzle to release the petrol I would swear that nothing was coming out except air. After about 70c was clocked up on the price display system I felt the flow of petrol.

I have noticed this before but the "flow" usually starts after about 12c.

Is this the angel's share of petrol or what.
 
Understand what you're saying, but surely if it was a busy place the pumps wouldn't give the angel the time to build up his/her share?
 
When fuelling I sometimes take a note of the price per litre, say €1.50 a litre, I then pump 10 litres exactly in and check that it matches in money terms, in my easy math example that pump would show 10 litres purchased at a cost of €15, it's easy to do it with odd amounts, use a calculator but do check occasionally to ensure you are getting what you are being charged for.
 
One other possibility is that if the person before you was filling up a container, e.g. for a lawnmower then when they stopped the pump, the petrol in the hose drained into the container. Then when you started the pump, the hose had to refill.

Under normal, car filling conditions, this would not happen as the pump comes out from the body lower than the filler hole of the car.

This would only happen if they held the container at ground level, and I am assuming that the flow stops at the pump body, not at the nozzle. I do not know this for certain.
 
Palerider said:
When fuelling I sometimes take a note of the price per litre, say €1.50 a litre, I then pump 10 litres exactly in and check that it matches in money terms, in my easy math example that pump would show 10 litres purchased at a cost of €15, it's easy to do it with odd amounts, use a calculator but do check occasionally to ensure you are getting what you are being charged for.
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I think the question from the OP is, how can you be sure you are getting 10 litres of petrol and not 9.5 litres of petrol and 0.5 litres of air.
 
The pumps are tested regularly to check that they are working and recording correctly. The date of the test is usually displayed on or near the pump
 
Ceist Beag said:
I think the question from the OP is, how can you be sure you are getting 10 litres of petrol and not 9.5 litres of petrol and 0.5 litres of air.
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The pump is calibrated to operate as fuel is moving through, will it record just air passing through ?, I would not have though so as the fuel comes directly from the underground tank there should be no air or all air if that tank were empty, the nozzle is just a nozzle, you pay for what is pumped into that nozzle so ensure you get every drop you can.

Check as I suggested to verify.
 
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Palerider said:
The pump is calibrated to operate as fuel is moving through, will it record just air passing through ?, I would not have though so as the fuel comes directly from the underground tank there should be no air or all air if that tank were empty, the nozzle is just a nozzle, you pay for what is pumped into that nozzle so ensure you get every drop yu can.

Check as I suggested to verify.
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In all your time of doing this check, have you ever encountered a pump that wasn’t charging correctly / at the indicated price?

I would be amazed if you have, for reasons similar to the ones you’ve outlined above in relation to the mechanics of the physical fuel flow being measured, so too will the pump be set to multiply that fuel by the displayed unit price.
 
@Palerider , your 'check' has nothing to do with the OP's question. Your advice is simply to see if price per litre matches the total price of fuel measured as dispensed. Whereas the OP has stated:-
Tintagel said:
When I pressed the handle on the nozzle to release the petrol I would swear that nothing was coming out except air. After about 70c was clocked up on the price display system I felt the flow of petrol.
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If this was the case your 'check' would still be true, ie. simple calculation, multiply PPL X litres measured delivered.

BTW, there is no easy way to empty these hoses (without it being measured), regardless of whether they are held 1mm or 1000mm above the ground.
If this did indeed happen to the OP, I would suggest that maybe either the nozzle or hose was changed prior to him/her using it and was not purged before being put back into service.
 
Some people say that the best time to fill up with petrol is early in the morning or late at night when the petrol fills less volume i.e. you get more petrol in your tank than what the pump measures. (Irish pumps are calibrated at 12C (or 15C?)

Some will argue that there should be no difference as most tanks are underground, and therefore keep the petrol at a relatively constant temp.

Jim Stafford
 
Yep, there is some truth in this, but I would go for early morning as it would be at its coolest then. However the difference is minuscule, but you still get what the pump measures, its just that the fuel is, ever so slightly, denser.
 
SparkRite said:
@Palerider , your 'check' has nothing to do with the OP's question. Your advice is simply to see if price per litre matches the total price of fuel measured as dispensed. Whereas the OP has stated:-

If this was the case your 'check' would still be true, ie. simple calculation, multiply PPL X litres measured delivered.

----------------------------------------------------

It is not that I check regularly and any time I have I found no difference but fuel stations have been fined for differences, one comes to mind on the Quays in Dublin.

Let me elaborate as you admonish my attempt at responding to the op, if the pump is taking fuel from an underground tank then no air should be in the pipe work, the pump is calibrated based on liquid running though it, I asked whether air would make the pump record as fuel and cost it accordingly but don't have an answer for that, I would guess not, if it did then you are paying for air in the fuel which is not likely or an airlock.

As an aside if you'll humour me it is no harm for a paying customer to occasionally check the pump calibration.
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Jim Stafford said:
Some people say that the best time to fill up with petrol is early in the morning or late at night when the petrol fills less volume i.e. you get more petrol in your tank than what the pump measures. (Irish pumps are calibrated at 12C (or 15C?)

Some will argue that there should be no difference as most tanks are underground, and therefore keep the petrol at a relatively constant temp.

Jim Stafford
Click to expand...

Most new pumps now are temperature compensating, ie they will calculate the true volume of fuel as it if was at 15 degrees. Thats why you see so many forecourts getting shiny new pumps these days. these guys explain it better, (Ive no connection with them, just the first hit on google) http://petrosystems.ie/services/temperature-compensation/
 
From reading above I learned something new today. When you need petrol for your lawnmower, toddle down to the biggest petrol station. Use the remains in all the pumps @ Nil cost. You now have a free season of petrol for your lawnmower. Thank You AAM for the money saving advice.
 
Now Leper, I'm not sure this is the case, but I am going to test it out.
The next time I need to fill a 5ltr petrol can, I am going to drive my car to the petrol station, fill up the car, and place the can on the ground beside the filler cap. When the car is full, without touching the nozzle handle, I am going to move the can up to the nozzle and lower it to the ground. I will then see if the contents of the hose do in fact flow into the can. If they do, then my theory is correct, if they don't, then (as usual) I'm talking out a different orifice.

I shall report back my findings, and expect a cut from the fuel savings if true. Say 10% from all AAM members?
:D
 
SparkRite said:
I think you'll find that the above quote will be proven. All you'll get, if any, will be what's left between the trigger and the nozzle tip.
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So I was curious, and I can confirm that was my experience. Just a few ml in the nozzle.
 
Filled up the car yesterday while out in Bray and after reading this thread I noticed something similar to Tintagel's experience
Put the nozzle in the car and pulled the lever and I'd swear I was charged 50 to 70 cent before the fuel started to flow into the car

Edit
I should add that something in the back of my head is telling me that this is some sort of safety feature to prevent spillages on the forecourt
 
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