I'm referring to the tankers up in Redding, where the step-son drives one for a living. He picks up Chevron at Chevron terminals, and delivers it to Chevron stations.

He picks up everyone else's gas in Chico (typically) and delivers it to everyone else.

His company doesn't do ARCO because they have some CA blend of ethanol called EC-1 or something, that screws up the delivery trucks as badly as the cars of people dumb enuf to run it (it is always the cheapest gas for sale up there).

Not really such as thing as an unmarked fuel tanker. They are strictly regulated and are marked on both sides with the company name, USDOT #, etc. They all say something, Shell, Chevron, Jimmy Boy's Fuel Hauling, etc.

The private motor carriers (companies) only carry their own stuff. Just like the only products you find in a Coca Cola truck are coca cola products, delivered to stores that carry coca cola - same idea for Shell, Chevron, etc. The fuel in those tankers is for them only. They don't haul for anyone else. They are a private motor carrier whose real money is not made by transportation but by selling the products. They cover most of their own stations, but not all of them. For those, they need to hire another carrier.

The for hire carriers are different. They don't profit from the selling of the product (e.g. gasoline). They make their living by transporting products. They do it for whoever needs it done. In small markets, they might be filling a couple of different gas stations out of their same tank. Fuel additives are best mixed in the cargo tank. Each low pressure cargo tank (fuel hauler) has seperate compartments of a known size. If Chevron needs 3,000 gallons, well, they dump the additive in the appropriate compartment and put in 3,000 gallons of fuel. That way the mixture is correct and the action of dumping the fuel into the compartment mixes it thoroughly. These types of cargo tanks are filled from the top through the man hole covers. The other compartments are filled with someone else's fuel, or different octanes or even diesel. Three, four, five compartments on most tank trucks. Sometimes more, plus the trailer... Lots of possibilities.

The compartments are not fully drained, there's always a little residue in the bottom. They are not cleaned between uses. Maybe it hauled diesel one trip and gasoline the other. Maybe Chevron with the additives one trip, then Sinclair the next trip.

When I was inspecting cargo tanks all of the time, I always checked the venting on the top which involves opening the manhole covers. I opened one that was filled with TRICK racing fuel. It smelled remarkably sweet. That was a suprise! Something that smells that good (for a fuel) is probably pretty expensive though, isn't it?

That's me at the bottom - 1st Hazardous Materials/Cargo Tank http://www.cvsa.org/programs/naic_2002.aspx

Bet you guys didn't know that about me, eh? Who knows what mad skills Pelicans have!

angela

Generally speaking, a tanker truck holds 10,000 gal, 5K in each tank. They can stop at 2 stops, but they won't drive far with a half a load in one tank. Ever driven a concrete delivery truck? concrete is a lot more viscous than gas, but that concrete truck will give you the heebie jveevies the way it wallows back and forth as you drive straight. A tanker has a big chance of flipping when half full. They will empty one tank of one gas here and the second tank over there.

At the transfer station the blend of gas and additives is loaded. There is no bag to add on the fly.

With very few exceptions, all the gasoline tankers in this country are alumimum. The problem with an uncompartmented tank is that if you put 9 or 10,000 gallons of fuel into it, when it sloshes - it will blow out the tank heads... So let's just use round numbers. Say the tank has one compartment and is 10,000 gallons and give gasoline 6 lbs per gallon (it varies in weight - several factors). So that would be 60,000 lbs of fuel sloshing around. The alumimum tank would fail. Plus, in most places, you'd be sorely overweight as 80,000 is the typical legal weight and that only leaves 20,000 for the tractor plus trailer, but that's not the point of the discussion.

The sloshing and the need for multiple products are the reasons that they are compartmented on low pressure tanks (MC 306 and MC406 are most common). There are also stiffeners inside of them to keep the tank from failing, but they don't really offer baffle protection.

This is a very typical gasoline tanker. It hauls about 9000 gallons depending on ullage and has five compartments (though they often have just 3 or 4 in this size). I've never seen an individual tank on this type of vehicle that has a larger than 4,000 gallon compartment. When you are talking about chemical tanks like an MC 312, that's different, those are almost always a single compartment, occasionally two. But they aren't used to haul gasoline as their total capacity is lower than a 306/406 tank.

http://forums.pelicanparts.com/uploa...1233981666.jpg

This is a side picture of the above cutaway.
http://forums.pelicanparts.com/uploa...1233981687.jpg

Now here's the side shot. For each compartment, there is exit piping and valves, one set for each compartment. So this has 5. You don't have to dump the whole compartment either. There is a self-closing stop valve for each compartment. Throw the lever and it slams shut allowing the amount to discharge out that is needed, but no more.


http://forums.pelicanparts.com/uploa...1233981767.jpg

Now here's the side you never want to see (unless you did what I did for a living). This is the top side of a gasoline tank. You are looking at the manhole covers here. One for each compartment. This one, coincidently, is also five compartments.


http://forums.pelicanparts.com/uploa...1233981969.jpg

These are relatively fragile tanks. Comparison? These are roughly 3/16" thick in the heaviest area and made of aluminum compard to a propane tank that is about 1" thick of high grade steel. A strong fellow can stab a screwdriver through the side of a gasoline tanker. I've personally seen someone do it on a salvage tank.

How much they drop at each station is dependant on how much of which product the station takes. It's always best to empty fairly equally or from back to front. But if the large tank is in the rear and it's diesel, but the diesel customer is the last stop - that's the way it goes. It's all driver skill. These guys are required to have a "tank" endorsement (plus obviously an HM endorsement).

Personally? These guys are way underpaid for what they do...

angela

interesting - my dad worked for Herrin Motor Lines (liquid hauler in La., MS, E TX - later bought out by Miller) and I never knew more than 2% of that

I know in Hawaii the Costco gas comes from Tesoro, though there are only two refineries in Hawaii, the other being Chevron.

The part that just blows me away about this is that the truck drops at Costco and then anther station across the street. Same gas, same truck, same hauling distance. Stations are adjacent and there's 20 cents a gallon difference.

Costco insists it makes a profit on gasoline sales - it is not a loss leader. The "other" station's insist that the station itself is only making something like a nickel a gallon on gas.

So where did the other 15 cents go? Hmmm...

angela

Yeah, I picked a rather odd field of study, didn't I?

I was working for Oregon DOT when September 11, 2001 occurred. I was already qualified to inspect cargo tanks and small hazardous materials packages. My task for about the next two months was to inspect everything that hauled haz-mat, especially "hidden" packages inside of large trailers. It was an information gathering exercise. Who was hauling what, where were they going and who was driving. The info gathered in that time created a change in the regulations, most notably the requirement for security plans and security awareness training.

In that time period, I decided to specialize in hazardous materials. Hit the books all the time. It's a very complicated subject and is laid out within Title 49 in a most haphazard fashion. Greatly stretched my limited brain power...

Each year, there is a competitive event for truck inspectors. Each state or province in North America (and US territories) sends their best inspector for the competition. It's an "all around" type competition where you inspect different types of vehicles, driver paperwork interview/inspections, cargo tank and hazardous materials. I went in 1998 and 2002. I think I was 3rd or 4th overall both times, but in 2002 I won the Hazardous Materials and Cargo Tank division outright. That's US, Canada, Mexico, etc., head to head. Very cool.

Leveraged that knowledge up, left ODOT and went to work for a Government contractor as their training/Haz-mat expert. Did a technical director stint for a PHMSA (Pipeline and Hazardous Materials Safety Administration) to develop a Hazardous Materials Security Training, Development and Awareness project. Pretty cool as there are about 10,000 of those CD's out there right now. Nice to do something that is a useful tool for a long time.

When the planes hit the trade centers, each was carrying some 9 to 10,000 gallons of Jet A fuel. That's basically a high grade diesel. Real close to the same capacity a standard cargo tank olds. Trucks are alot easier to get ahold of than the planes.... Way, way easier. In the last 200 or 300 meters - you basically cannot stop a truck. Speed and sheer mass allow them to blow over barriers, bounce thru ditches and pile drive patrol cars out of their way. Trucks make really good bombs... Even worse if they are hauling poisonous gases, etc. There are specific rules for where these vehicles can travel, park, etc. That's why. If a haz-mat load (of particular dangerous types) is even seen near a stadium, etc., every red flag that exists starts waving. There is a whole nation wide hot-line procedure for those "incidents."

Even the rules for the driver's CDL have changed. Now the Haz Mat endorsement requires a specialized background check. Used to be you just passed a test, now it's a test and a background check. 'Course, that only slows down the honest guys... The bad guys aren't going to bother with such things.

Hazardous Materials, cargo tanks, etc., was definately a challenging field of study for me. But it allowed me to promote to higher paying jobs and contribute something (hopefully) to the safety of the general public.

Now you know why I seldom drink. I'm barely smart enough to do this and I definately cannot spare the brain cells... :D

angela

I don't get it. You have shown how the tank trailers are compartmentalized, yet still say the gas is the same throughout the load. I'm not bickering, I just have read differently on this and other forums. The conversion about fuel quality comes up a few times a year.

And, that must be a rather new design because I know I didn't see that many valves on trucks of years ago. I assumed they all had at least baffles.

Fuel is identical throughout the compartment of the tank. So the front compartment may hold a proprietary blend (general out of the spigot plus the additives), the second tank holds regular 87 octane, 3rd holds 89, 4th holds 91 and the 5th holds diesel. All the diesel in the compartment is the same, maybe it goes to two or three different customers, etc., as does the gas in compartments 2, 3 and 4. The proprietary guy doesn't want to share the contents of his first tank.

Another tank type that is very common is an MC307/407. These are easy to tell apart from standard gasoline tankers. From the rear, the standard 306/406 tank is egg shaped and it is flat across the bottom. The 307/407 tanks are round on the ends and usually flared toward the middle. Like two ice cream cones joined at the wide end (in the middle). This puts a big low spot in the center of the tank and allows full drainage. If you see one like that it is ALWAYS a 307/407. They can be rear discharge though and will not have that conical shape. They haul less than the 306/406 series tank, but they are a stronger tank. So they can be used for heavier products such as oxidizers and even some light corrosives (most corrosives are very heavy), asphalt and food products. They are not too bad to clean and purge completely. They are normally baffled. Good all purpose tank, but not one that you see in dedicated fuel delivery service as it can't haul as much product. These are usually single compartment tanks, but occasionally are two compartments. Total capacity is generally around 6,000 to 8,000 gallons (compared to the roughly 9,000 for a 306/406). They are a fairly strong tank with external ring stiffeners.

These are everywhere and you've seen them on a daily basis.

angela

This one has an insulated jacket (skin). They run steam thru and heat to help the product move during discharge (e.g. asphalt or Chocolate). this is a rear discharge tank and doesn't have the conical shape. But it is round on the ends (unlike the egg shape of the 306/407).

***edit...nuts where'd my pic go?*** sorry

This one is not insulated. You can see the external ring stiffeners exposed. With this shot, it's really easy to see the distinctive "belly" found in most (but not all) off the 307/407 cargo tank.

http://forums.pelicanparts.com/uploa...1234032504.jpg

This is a two-compatment MC307 that has failed in the middle.

http://forums.pelicanparts.com/uploa...1234032623.jpg

did those wayward youth cause that?

Angela;

When I said 'unmarked', I purposely didn't want to say the name of the company, but yes, this is the most reputable fuel hauler I have ever seen. All of the required markings are there, as well as the name of the company. The tanks are polished aluminum, but do not say "Chevron" or Shell, or "Costco" on them. But they drop at all of these places all the same.