Automotive

Internal airbags keep liquid loads in place

A sketch of the Cairbag system, installed in a baffle-equipped tanker trailer
A sketch of the Cairbag system, installed in a baffle-equipped tanker trailer
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A sketch of the Cairbag system, installed in a baffle-equipped tanker trailer
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A sketch of the Cairbag system, installed in a baffle-equipped tanker trailer

Depending on what they're carrying, tanker truck trailers are often equipped with perforated baffles or solid bulkheads that divide the inside of the tank into multiple compartments. That way, when the truck stops, its liquid load won't all go sloshing forward in one big wave. Dutch engineer Dr. Erik Eenkhoorn believes that's not enough, however … which is why he created the Cairbag system.

According to Eenkhoorn, the problem lies in the fact that while baffles and bulkheads may keep liquids from moving fore and aft excessively, they do nothing to keep them from going side-to-side. As a result, when taking corners, the force of the liquid all moving to one side can be enough to tip the truck over.

"If you are carrying a load of tins of oil, you have to pack the tins in boxes and tie the load down with tarpaulin and ratchet straps," he says. "This prevents the load from shifting during transport. However, there is currently no way to secure a load of, for example, 20,000 litres of oil in a 40,000-litre tank. The result is that the liquid load sloshes around, which causes hazardous situations."

That's where Cairbag comes in.

The system consists of airbags that are inflated to fill up all the free space in the tank not taken up by the liquid. This holds the liquid down against the bottom of the tank, keeping it from moving. Not only does that add to safety, but Eenkhoorn states that the improvements in handling should also make the trucks five to six percent more fuel-efficient.

Eenkhoorn's company Accede currently manufactures the Cairbag system.

Source: University of Twente

6 comments
MD
And is the Airbag system able to be adequately flushed/washed/ cleaned. to allow uncontaminated transport of different products?? Also the longevity of the Membrane in contact with nasty volatiile substances.. It is interesting that tankers carrying most products are full (and the tanks should all be baffled in their void space - if Not then they aren't designed properly), it is usually only fuel tankers which make multiple stops in one run (or maybe small waste oil tankers collecting at Fish and Chip shops.).
mike13
Great concept and the linerbag could significantly reduce cleaning downtime and cost between different cargos.
JimFox
Naval architecture places emphasis on "free surface effect" which can seriously reduce transverse stability; ships are designed with longitudinal bulkheads in tanks to break up this 'free surface'. Many refer to this as 'sloshing' but it's not connected to the mass of fluid but rather the second moment of area of the water surface. Small experiment- fill a tall narrow container with water, carry it easily, no spillage; pour that same water into a wide shallow tray and see how hard it is to carry it without spillage- that is FSE. This applies to road tankers too, though the mass & centre of gravity do have major effect here. How FSE applies, I'm unsure.
a.l.
But why DON’T the tanks have longitudinal baffles along with the lateral baffles?
Craig Jennings
Is the air magically incompressible? Baffle balls.
Nik
It would seem that, longitudinal bulkheads would be just as effective, without the risk of punctures, caused by chafing on the internal surfaces, which would suddenly render the airbags useless. That would be more dangerous than not having them in the first place.
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