While reading about oil it occured to me that transporting oil to far places is amongst the things that causes it to have a wider value spread. during the 20th century many liquid transport containers were round as a leak reduction measure. If you simply place an on road oil tank inside a big container though [O], then fill the gap between with oil you carry about a quarter more oil at a high efficiency infrastructure ready container. Thus you transport 4 loads of oil with three vehicles.

Now from a risk reduction perspective most of the oil remains at a round container, yet if there were a complexity, the spill would be of minimal size, at 1/4 or less of the volume. It is even possible that double hulling reduces the amount of actual spilled liquid generally.

I have not figured out the actual mass permitted on a RR car, yet I have read that RR is vastly more efficient than trucking. Even trucks benefit though, as they frequently carry a standardized container, which now carries 1/4 more oil.

Now on the West coast of the US, ships bring oil to refineries, some of which becomes gasoline with truck transport. compare that to less developed areas where people or cities are thousands of miles from refineries. Those places would benefit from [O] containerization of oil products. Also, only some oil products are dangerous. certainly any oil without a flashpoint at atmospheric pressure could be casually transported with a [O] containerization, after the system proved minimally risky they could then try transporting gasoline with a [O] structure.

If you watch a youtube video of developing world roads, then think about how all the fuel trucks could easily carry 1/4 more fuel per trip the [O] system creates more plentiful, more rapidly adapting, as well as cheaper oil supply at developing world areas.
-- beanangel, Jun 08 2012

Two problems: 1) A cylindrical container is structurally the strongest practical shape for shipping liquids. 2) Trucks already face weight restrictions when driving on public roads. If there were a need to haul more oil in a single load they'd simply make longer tanks, or pull two tanks at a time. In reality, a tractor pulling a full tank of oil is probably already pushing the weight limit for most roads it's going to be driving on.
-- ytk, Jun 08 2012


Regarding [1], I think that "corners" of the [O] would be strong enough; in effect, the [O] a square section but with the four sides braced by the O, so that would be fine.
-- MaxwellBuchanan, Jun 08 2012


I agree you cuold make it strong enough to handle the load, I would worry about the increased risk of damage to the corners and a resulting increase the risk of spills. The other advantage of round tanks is that they drain fully.

As an aside, round tanks in a rectangular frame to fit in a shipping contianer stack do exist.
-- MechE, Jun 08 2012


I have no doubt that you could make the corners strong enough to hold oil. My point was more that existing oil tanks are the shape they are because it's the most practical shape from an engineering standpoint, and there's no real advantage to changing them to a structurally inferior design.

Anyway, it's not clear that the increased construction, maintenance, and dead weight transportation costs with this design don't outstrip any cost benefit to hauling more oil in a single load.
-- ytk, Jun 08 2012


Actually, I should say that it's clear that the added costs don't confer a substantial benefit, or people would be doing it already. After all, they must be building new tanks all the time, which means engineers have to revise the design occasionally to account for the availability of new materials, new manufacturing techniques, and so on. If there were a more advantageous design available, I am certain they would be using it by now.
-- ytk, Jun 08 2012


The advantage here is sociocultural as well as engineering. I think that people at the developing world have logistics complexities such that transporting things with fewer containers benefits them, also each "dividing" of a material may introduce a brief delay as well as a value "markup" so if you deliver 2000 gallons of oil to a village, that is multifunctionally cheaper to the actual users than 1500 gallons per delivery.

The sociocultural benefit may only be partially apparent to the transporting company. Even at the US logistics causes most trucks to be single container with some 2 or 3 container vehicles occasionally visible.
-- beanangel, Jun 08 2012


Seriously?!

What "sociocultural" benefit lies in transporting liquids in square tanks versus round? I'm reasonably certain that nobody on Earth takes any social or cultural offense to round tanks, if they even think about it at all. So unless you can back that up or better explain it, the "sociocultural" aspect of your argument makes no sense.

As others have already pointed out, from a structural standpoint, this will not work. Don't believe us? Look at a paper milk carton. The sides bulge out a bit, don't they? That's fine, it only contains a half-gallon. But look at the amount of extra material there is on the bottom, and the engineering that has gone into relieving the stress points (namely, the corners) of the pressure of a mere half-gallon of liquid.

Now think about the pressure of 9,000 gallons of liquid. Containing that amount of fluid in a square or rectangular tank would require so much reinforcement as to make the materials and construction cost of the trailer more expensive than the truck needed to tow it, and it would make the trailer itself so heavy that it would be nearly impossible to tow anyway. It would need at least five or six axles to support the additional weight, making steering infeasible. The only way to make it a practical means of transport would be to dramatically reduce the liquid capacity in order to compensate for the considerable added weight of the reinforcing material.

[beany], you're re-inventing the wheel here; not only that, but you're not doing a very good job of it.
-- Alterother, Jun 09 2012


[alter], whilst I don't think [beany]'s idea is great, I don't think it would be as problematic as you suggest, since the square corners are basically just triangular fillets on the sides of a cylindrical tank.

However, structurally it might make more sense instead to have a large central cylindrical tank, surrounded by four narrower cylinders. This would give most of the extra capacity of the square format, but each compartment would be a structurally efficient cylinder.
-- MaxwellBuchanan, Jun 09 2012


That does make sense and would work fine, but B) there would be no need to house all five vessels inside a rectangular box, and 4) the existing tanks are already engineered to hold the maximum amount of liquid that can be efficiently hauled by a standard semi tractor. Adding the four 'corner tanks' would make better use of the available space and allow the trailer to be shortened (in fact, that would be a necessity), but it would use more material per unit of capacity (increasing construction expense and thus purchase cost), it would add more valves and fittings, (increasing upkeep expense), and it would imbalance the trailer unless a proportionally equivalent volume of product were removed from each of the five tanks at every delivery stop (drastically increasing delivery time and expense, thus increasing end-user cost).

And as to the square corners, any pressure placed against the structure from the inside would put enormous strain on the interior fillets, leading to systematic failure at the weld edges (because the face of the fillet weld is very strong, it transfers tension to the toe, 'pulling' the weldment in as the material around it is pushed outward). Heavy exterior reinforcement and buttressing as well as large, restrictive interior frames and gussets would be required to counteract this. Round is better.
-- Alterother, Jun 09 2012



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