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laventana
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Registered: 8-24-2006
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| Quote: | Originally posted by Nemo55
I would like to alleviate some of the misconceptions and misguided information here with some real world experience.
In the past i worked as a Pump Calibrator for a company (unnamed) contracted by the Big Oil companies and Suppliers.
My job was to measure flow through with my equipment (Truck Mounted)and calibrate the pumping rate put out by the Actual pump motor and Valve control
system.
This system of calibration is adjusted and tuned to the Digital machine head (customer read out) via a scaled vernier dial Valve which is located at
the Pump base.
The next time you are at the Fuel pump look at the sticker which says "Volume adjusted for temperature" this means that the rate of fuel pumped at a
given temperature will be different when temperature changes with a given season.
The Oil companies typically adjust the pumps (my job) to give a rate of 2% extra in the cold months and the same calibration will claw back 2% in the
hot months.
This adjustment when performed is very exact and true at the moment of setting, however..the calibration will not be true during the wild swings in
temperature of Day Time -Night Time,,or Summer Time -Winter times due to the very nature of the fuels Gasoline/Ethenol/Methenol as they do indeed
increase in volume and expansion in a given containment.
Typically the oil companies rip the public off to the tune of Hundreds of thousands of dollars every year PER FUEL STATION due to adjustments favoring
their side of the margins.
I know this because it was part of my job to make it this way. (I resented it always) i hope that i have put this argument to rest finally..
Your Welcome
[Edited on 8-15-2012 by Nemo55] |
hmmm interesting. real adjuster that does calibration... you will be
a wealth of information for us, the horses mouth so to speak...
Do all states require this seasonal calibration?
Yes this amount when added up over a year is very large at a single station, but in a car tank fill up my chem 101 off the cuff says somewhat
insignificant.
What is the co-efficient of thermal expansion for gasoline? in C or F
What is the temperature differential in general of the gas in a ground container that should be used say in the southwest.
And can you give us the precision tolerance amount that a gas pump is accurate to. EI +/- 0.01 of a gallon?
Do you ever touch the circuit boards or chips in the circuit boards and do verification of these chips? If not who does?
[Edited on 8-15-2012 by laventana]
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Cypress
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Location: on the bayou
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This is getting way too complicated! 
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Ateo
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Not one of my customers (gas station owners) has had their pumps calibrated twice a year for temperature correction - ever. Wonder when this was and
which state?
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Nemo55
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Posts: 61
Registered: 8-8-2012
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The chips are another techs problem, My job was to essentially measure flow through on my truck mounted equipment and adjust accordingly.
All States and Provinces SUGGEST seasonal calibration, but the oil companies are largely left to police themselves along with the Contracted
suppliers.
(the equipment on the truck was considered correct absolute)
As to the Formulas used to arrive at a given rate etc, this stuff i learned and answered during my training but quickly discarded when actually
working in the field because of the "Shop Calibration" on the truck mounted equipment, No need for the operator to do much else except use his/her
eyes, and the charts provided.
The Tolerance of any particular gas pump was largely immaterial unless there where wild fluctuations recorded.
For each ground container location there would be a (provided to me)check sheet giving any particular peculiarities but largely seen as insignificant
unless in cases of leaks or Contaminant penetration to the tanks.
In reality my job was reduced to that of a Mechanic Technician Service Person, as the equipment on the truck and its Calibration was monitored and
adjusted when needed, by a whole different department.
I don't have my manuals any longer(was required to return them when i quit) but wicki has the info you are looking for.(always made my head hurt)
http://en.wikipedia.org/wiki/Thermal_expansion
Most Station operators do not have the where withal to make any changes to the pumps without the help of the calibrating personnel (Me) and affecting
change with the digital equipment on the Pump Head readout was definitely largely(except for very crude adjustments)outside of my capabilities.
Mostly they will be found to have broken the Seal put upon the Calibration Valve(by someone like me)and adjusted the flow rate themselves.
The Customer would never know if the rate was + or - even 30% unless they where dispensing the fuel into a calibration vessel.
But you can rest assured that a full 75% of the pumps out there are adjusted to favor the Oil companies in the region of 2% which is very hard to
notice without the right equipment.
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Nemo55
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Posts: 61
Registered: 8-8-2012
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My work was in Canada although the company had it operations all the way through the United States.
Like i said, the Oil companies and Suppliers/Refiners(same animal)are left to police themselves.
Only a very few countries around the world have any Policing in this area of weights and Measurement.
The actual calibration and servicing of the pumps are for the benefit of the Pump owners and oil companies NOT the customers.
That the Customers may somehow reap any reward from their adjustments is largely by accident and not design.
And you are correct, that some gas station owners(especially independents) don't have calibration done on any regular basis.
| Quote: | Originally posted by Ateo
Not one of my customers (gas station owners) has had their pumps calibrated twice a year for temperature correction - ever. Wonder when this was and
which state? |
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Cielomar
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Posts: 71
Registered: 12-5-2010
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There was a thread similar to this last August. The gas stations in Todos Santos (in town one only) and in Pescadero are owned by the same guy and
they rip off drivers by 12-15%. I was told by Mexican fiends to always use the lane closest to the road and to always order fuel by the liter. You
don't have to be exact. So a 20 gallon tank will hold about 80 liters so I just order the amount closest to the 1/4 tank fuel marks on my gauge
(20,40,60,80 liters). Bam- I got about 10% better fuel millage on the first tank.
Doing some research I was told that there is a software program all the unscrupulous dealers buy that plays with the peso amount only. They get
tipped-off when Profeca is coming and turn the fuel counters back for the hour or so while being tested and then go on robbing people once Profeca
issues the label you'll see displayed on the pumps. Others suspect that Profeca is on it but I'm not going to go there
Some station owners won't do this (the Pemex outside Todos Santos driving toward La Paz is owned by the ejido and is honest) but I suspect they are
few and far between. Pemex knows all about it but chooses to support their dealers rather than the people. Is there a theme here? Don't worry the
new PRI president will clean up this mess in the first month.
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Nemo55
Junior Nomad
Posts: 61
Registered: 8-8-2012
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The problem as always can be traced back to the Oil companies, they give margins so small that the Station owners have very little profit after all
costs are factored in.
Remember when service stations had full service?? have you ever wandered why they no longer do??
| Quote: | Originally posted by Cielomar
There was a thread similar to this last August. The gas stations in Todos Santos (in town one only) and in Pescadero are owned by the same guy and
they rip off drivers by 12-15%. I was told by Mexican fiends to always use the lane closest to the road and to always order fuel by the liter. You
don't have to be exact. So a 20 gallon tank will hold about 80 liters so I just order the amount closest to the 1/4 tank fuel marks on my gauge
(20,40,60,80 liters). Bam- I got about 10% better fuel millage on the first tank.
Doing some research I was told that there is a software program all the unscrupulous dealers buy that plays with the peso amount only. They get
tipped-off when Profeca is coming and turn the fuel counters back for the hour or so while being tested and then go on robbing people once Profeca
issues the label you'll see displayed on the pumps. Others suspect that Profeca is on it but I'm not going to go there
Some station owners won't do this (the Pemex outside Todos Santos driving toward La Paz is owned by the ejido and is honest) but I suspect they are
few and far between. Pemex knows all about it but chooses to support their dealers rather than the people. Is there a theme here? Don't worry the
new PRI president will clean up this mess in the first month. |
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laventana
Nomad
Posts: 216
Registered: 8-24-2006
Member Is Offline
Mood: sharing
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| Quote: | Originally posted by Nemo55
The chips are another techs problem, My job was to essentially measure flow through on my truck mounted equipment and adjust accordingly.
All States and Provinces SUGGEST seasonal calibration, but the oil companies are largely left to police themselves along with the Contracted
suppliers.
(the equipment on the truck was considered correct absolute)
As to the Formulas used to arrive at a given rate etc, this stuff i learned and answered during my training but quickly discarded when actually
working in the field because of the "Shop Calibration" on the truck mounted equipment, No need for the operator to do much else except use his/her
eyes, and the charts provided.
The Tolerance of any particular gas pump was largely immaterial unless there where wild fluctuations recorded.
For each ground container location there would be a (provided to me)check sheet giving any particular peculiarities but largely seen as insignificant
unless in cases of leaks or Contaminant penetration to the tanks.
In reality my job was reduced to that of a Mechanic Technician Service Person, as the equipment on the truck and its Calibration was monitored and
adjusted when needed, by a whole different department.
I don't have my manuals any longer(was required to return them when i quit) but wicki has the info you are looking for.(always made my head hurt)
http://en.wikipedia.org/wiki/Thermal_expansion
Most Station operators do not have the where withal to make any changes to the pumps without the help of the calibrating personnel (Me) and affecting
change with the digital equipment on the Pump Head readout was definitely largely(except for very crude adjustments)outside of my capabilities.
Mostly they will be found to have broken the Seal put upon the Calibration Valve(by someone like me)and adjusted the flow rate themselves.
The Customer would never know if the rate was + or - even 30% unless they where dispensing the fuel into a calibration vessel.
But you can rest assured that a full 75% of the pumps out there are adjusted to favor the Oil companies in the region of 2% which is very hard to
notice without the right equipment. |
thanks for the detailed post I do appreciate it....
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