This is a work in progress . Ive uploaded a bunch of pics  , I need a couple more and need to draw a couple of diagrams then put text to it all.
Im going to try to complete it before the end of the year.

This thread is to explain how stations work , a few tips to get cleaner fuel and what to look for.

OK First things first Gas Pumps are not the same as Dispensers . Most modern Stations Have what are called Submersible Turbine Pumps or STP for short . Normally Each tank has one STP which provide fuel to all the dispensers for that product . But of course there are exceptions to every rule , I just installed 2 stations in NC that have real gas pumps or pumps in the dispenser . Most of the time you can hear a pump in a dispenser , they are fairly loud compared to a dispenser on a STP.
Dispensers ... errr Pumps to most ppl
This is about simplest dispenser ,


A look in side , no pump in here , theres a incoming line , a meter which measures the fuel , a filter and a 2 stage valve.


A shear valve or Impact Valve . It cuts the flow of fuel off it shook hard .... car hitting the pump to prevent a gas fountain . Note the test port. Cant remember the pipe size for it right now .. maybe 1/4 or a size bigger standard pipe thread.


Standard dispensers flow 6-10 gals per minute


Ultra High flow truck stop dispensers 12 to 60 gals per minute ... How yall diesel owners love these babies , fill the tank in less then a minute and your done ..STOP DO NOT FILL YOUR TRUCK ON THESE . They are unfiltered and most of the time no strainers either ... I have spent literally days cleaning gunk out of these that goes directly in your tank .


Pumps like this is what you should get diesel on ... doesnt have to be that model of pump but note the how it has both diesel and gas , we call these 3+1 of 5+1s depending on the model . In other words it can blend 3 or 5 "grades" of gas plus have a totally separate product.  .... thats my truck

What does it take electrically
The back room of most modern gas stations built in the last 20 years , Breaker panels , Communication boxes for the Credit side and the pump side of a Dispenser , tank monitor , Relay boxes and various other sub systems .  One failure back here can easily take down the entire site.
The first pic is of a typical WAYNE brand equipment site about 15 years old the 2nd is of a Gilbarco brand equipment site 15-10 years old.





A close up of the standard relay we use for STPs . 220-240 volt .. 120 of course per leg and is activated by a 120 volt signal . The STP pulls about 5 amps depending on size .. no less then 3amps no more the 6.5 amps . If its not in that spec theres something wrong.



Tank fields
Cap colors
White =Regular 87
Blue = Midgrade 89-91
Red = Premium 93
Yellow= Diesel
Brown = Kero

Typical Tank field , note theres a Premium Midgrade and Regular tank here . Note the extra manhole covers , more on them in a later pic.


Heres another tank field , A regular tank and a premium Tank ....... where did the midgrade go ... they are selling midgrade.... This is a blended site the dispensers mix the premium and the regular to make midgrade . If you are a midgrade buyer be somewhat cautious of these sites . There is a little fudge factor in a most blends . 89 oct for instance is allowed from 65% reg 35% premium to 70%,30% .... Some Brands mandate a certain blend , BP and Exxons mandate that there sites run 65 35 , shell 66 34 most others its a crap shoot.  I have been to sites that have been way out of spec on purpose to give the customer more regular in which case I got the MAN involved , I hate thieves.  


Ok heres a tank layout . The first hole "Blue" is where the fuel is droped , the second is vapor recovery that has a plunger valve that prevents fuel from being dropped there but vapor to escape when the driver connects the vapor recovery line to it and to the truck. The next cap is where the probe for the tank monitor is located , the next one here is for the tank wall access to install sensors between the inner and outer tank walls on a double walled tank. The big one on the end is where the STP head is located , more on that in a later pic.


Heres the fuel drop , notice the cam locking cap off to the side , it has a place for a lock to prevent thieves with hoses and pumps . Next thing to notice is the pipe drop tube , its hard to make out in this pic but there is a aluminum pipe inside of the pipe. That drop tube goes to almost the bottom of the tank , alot also have a device built in with a float and a flapper valve to stop the flow in the drop tube when the tank gets close to full. The ones with the overflow check valve loose half the size do to the valve.


This is the STP head , the  STP is connected via 1.5 inch schedule 40 steel pipe about 12 feet below. The head contains check valves , leak detectors , and electrical connections . Here you can also notice the riser hieght above the tank , about 3 foot here on this one, normally they do not exceed 4 foot because with the tank being 92" to 126" in most retail installs it takes more and more to move it out the ground. I have not saw the bottom of the tank more then 15 feet below ground level . Note the tank monitor sump probe off to the side , it senses water or fuel in the sump.


Just floats on a probe for the tank monitor. Note the gunk , they were in a diesel tank now you see why filters are a good thing. The small float floats on the surface giving fuel level readings the other float is designed to float on the water but not the diesel to give water level readings in a tank.


Tank monitor

Ah the tank monitor , this simple tan box made by veeder root is a very modular component . This brand is the most common and most of the time hidden in a back room but if you do see one up front take good note of it , it can tell you alot about the station . These things are as modular as a AR from kiss ones that just give fuel and water levels in the tank  that do basic scheduled tank leak test to full deck out ones that control the stps , monitor line pressure and check for leaks , inventory reticulation with the point of sale and monitor all sorts on sensors around the station shuting down things as needed.  They can call out to report problems via fax or internet and be dialed into the same methods , I can dial into them from my laptop and see tank levels and anything else that I could if I was there in front of it.


Oh noes High water , This was very common untill the ethanol switch over . I very rarely see high water alarms any more .....

Good info, answered some of my TEOWAWKI fantasy questions...

good info....but what your saying is unless we have a pump our selves or eletricity....were fuuuuuuuuuuu?

Nope.  You can siphon right from each of those tanks pictured.





We had an issue with a group of Mexicans parking their van over the tanks, lifting the lid and siphoning gas with a hand crank into 55 gallon drums.  In busy gas stations you never even notice it.  





I hated those tank monitors btw.  They always showed warnings and there used to be no way to bypass the alarms even when using a dial up to your distributor.  Things may have changed since 05 though.





EDIT:  long hose to siphon btw.  You do not want what is on the top.  Mix gas and water in a glass to see why.





 

must get in on 1

Like I said its a work in progress

Your Tank monitor wasnt setup right if they were pumping gas out and it wasnt going off . Should have gave a sudden loss alarm or if yall had BIR it would have saw it almost instantly .  

Theres more coming on all of that later though . Im watching defiance with the better half right now lol

Heh what did they do cut out a panel in the bottom of the van to get to the tank unnoticed?








 

Interesting stuff.

Thanks Hawk

They arrested a guy last year or the year before down TX LA area that had a chevy dually pulling a 30 foot inclosed trailer with a 10,000 gall tank they had a electric high vol pump . They would pull over the tank field and drop a hose in the tank from a door in the trailer floor . The Tank monitor and a alert cashier caught them at a site.

I remember that hitting the local news, and I was thinking of that case when I started reading this thread.

Yes. Hatch plus a hefty metal rod to move the lid in and out of position.  Then one Mexican held the other as he got down and pulled the cap.  You have more or less 2 lids to go through.  The one you drive over and one that acts as the real lid.  I'm not looking, but I am pretty sure it's pictured.  They dropped the hose down halfway into the tank then hand cranked it into a 55 gallon drum.  Who knows how often they had been doing this?  Back in 05 we were filling our big tank every day to every other day.  Now that's not the biggest C-Store in the world, but we weren't going to miss 55 gallons when it went out through the tank in that direction.  
 
 
 

sorry thats what i meant by pump...handcrank etc...but damn, nice to learn some things...and yankin that much gas damn...

We used to give away free popcorn at the station I had in the early/mid 90's.

Thread title reminded me of that

Thanks for taking the time to post this stuff.

Great info!  Thanks for posting this!

Awesome!  Hawk, thanks for doing this.

Good info, thanks.

lol, you put 'em in, I take 'em out.

I've probably done 200 UST pulls over the years.

Save and print.

Takes me back to the days when I managed a 24 hour Hess station during Odd/Even rationing.

I guess that most here know to not siphon from the bottom of the tank, since sediments and water lay there.

updated tank field some.

I built a pump system specifically for tapping into gas tanks like this. Basically it's a high volume automotive fuel pump hooked to some fuel hose and a 12 volt battery- through your car for example. If you have need of gas.....you have 12 volts is how I figure it....... Just a little something to have around.......

great information - thanks

Excellent info. Thanks for posting.

What is the satellite dish on top of the gas station roof for?  Every gas station in America has at least one dish.  

Credit card network . Lotto also uses sat.

not all brands uses V sat , all exxons , texacos ,shells and bps do though.

Tagscribe. interesting stuff

Are you sure it isn't a tool in the OPEC plot to keep prices high?

lol , im sure .

Just looked at my post.  My didn't make it into the thread.  Must be a BCAK error somewhere.

And then I clean 'em up.  At least in the old days, there's only two types.  Those that you know are leaking, and those that you haven't found the leak yet.  New systems are much better, but failures still happen, and spills tend to linger for a long time.

Hey, another environmental geologist!  We seldom get to the remediation stage - our clients are mostly very risk-averse banks.  If the site's bad, they run.  

I'm with you on the "it hasn't leaked ... yet" idea.  Just a matter of time.  Corrosion is a big problem out this way, acidic soils, good rain amount, bare steel tanks ...

I spend most of my time polishing a chair with my ass now.

I see you are using APC UPS units....about how long did they last before the battery went bad from getting run down to 0%?

I can tell those pics are not from Minnesota.  MPCA requires every dispenser to sit in its own plastic "sump" to prevent leakage from contaminating the ground.

I wonder what type of chair the lawyers that sued us into underground tanks polish.  Bet it's comfy

 

VA all new constuction does.
NC if ground is broke anywhere on site everything must be brought up to date.

great info with great pics. thanks for posting.

I have a question.  Why do BP stations pump so much slower than everyone else?

Thanks; nice job.

How deep are the tanks?
How big are the tanks?

Basically, how long of a hose does it take to hit bottom?

Yeah, there's all kinds of legal ramifications involved.  Personally, I hate lawyers of all types.  I'm a scientist.  They twist the truth for cash.  Totally opposing basic philosophies.  Still, bondsmen are lower.

Another update , some questions might be answered.


This is a tough one .
BPs as far as pumping goes should be the same as every one else in your area . But if you notice this with all the bps you visit , most likly they are all owned by one company and could be lacking on normal maintenance such as filter changes , or were built on bare minimum equipment such as 3/4 HP STPs instead of 1.5 HP STPs ... might even be older stations with 1/3 hp stps . They might have vapor recovery in the dispensers in which the  dispenser has a vacuum pump that removes one gal of vapor from your gas tank for every gallon of fuel it dispenses .Here some of the urban counties mandated that vapor recovery be installed , afterward some stations in surrounding counties built with that in mind but it never came .  Could be they are running water sensing filters that shut down flow if water contacts them ...... Im going to post on all of that later . .

With out me seeing it it is really hard to tell.

Actually you want whats on top- oil or diesel.  Thw water is heaver and sinks, forming a water bottom.

To the orginal poster: when you have a gas pump, with the pump in the dispenser, can they used standard (8'-12') USTs?  Reason I ask, is I couldn't get tuthill/fillrite or one other company to commit that their pumps would pump gasoline out of an 8' tank, with the top burried 24" deep, and pump all of the fuel out without the pump cavitating (due to the low vapor pressure of gasoline).  I ended up going with a vaulted AST, but I really wanted to order a bigger diesel tank (we were getting a new tank anyway and partition off one side as a 2000 gal gas tank.


To the poster that said all USTs leak- look at the STI permatank.  It's a fiberglass tank over a steel tank with a vacuum on the interstice.  if either wall is breached, the alarm goes off, and you have the product compatability and physical strength of steel, with the corosion protection of fiberglass.  Not cheap, and not made is a whol lot of shops, but it really minimizes the liballity.  Contractors tell me they are easier to install because they are strong like steel tanks, but without the delicate anticorosion coating.  We have about a dozen sites at work, either because the tank is too big (realistically) for a vaulted AST ( >=10,000 GAL), or in a few cases because the tank is intended as an emergency fuel source (for motor vehcles or off site generators) and the UST will handle the reduced turnover.  Compair this with hundreds of ASTs and probally twice as many LP tanks and 2 fuel cells.

Actually, I have also noticed that every BP station I have ever been to has been very slow. I travel from the Dayton, OH area to Pittsburgh, PA on a VERY regular, more then I would care to, basis. I have always avoided BP stations for the very reason that it seems to take forever and a day to fill up there. That reason and they never seem to have a good selection of drinks at BP . Anyway, im glad im not the only one who has noticed this phenomenon.

So how does the tanker come and fill the tanks when the parking lot is all full of ice and snow like it can happen here in MI?

and a goodly number of years back i'd helped my now deceased grandfather cut the tanks up and recycle the steel through his scarp yard...



[lionking voice] it's the cirrrrrrcle of gas, and it moves us all...[/lionking voice]



K.

Ethanol switch? Mandated ethanol content or something? How few people realise it's hygroscopic.

And I won't be using a high flow diesel pump anymore.