Cool moves down the scale
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• Refrigeration specialist Hubbard and BOC Gases are jointly developing a new generation of cryogenic vehicle systems suitable for drawbars and smaller rigid trucks down to 10 tonnes gross.
New larger versions for semi-trailer use have already been developed but the smaller units which give eight to 10 hours of operation on radial delivery operations should be ready by October.
The new systems operate much the same way as BOC Gases' original Polarstream with a thermostatic controller, spray bars and sensors plus heavy liquid nitrogen (NO storage containers. But whereas the big semitrailer systems need larger vacuum-sealed twin-wall stainlesssteel tanks, Hubbard is currently developing much smaller storage tanks compatible with over-cab systems for rigid trucks.
The liquid nitrogen is carried at almost -200°C for a system that can bring temperatures swiftly down to -35°C but both the new trailer and the smaller rigid systems will also have a catalytic diesel heater that can raise the inner temperature to +25°C.
This means the new systems, particularly those for drawbars, will be of particular interest to operators trans porting tropical fruit or flowers.
The use of liquid nitrogen reduces "pull-down" time dramatically, is almost silent in operation and almost pollutant free, so it addresses many environmental issues.
It also becomes a favourable operation should there be any further increase in carbon fuel taxes or possible reductions in the tax concession on vehicle refrigeration systems.
One major stumbling block to a wider acceptance is the small number of N7 supply outlets.
BOC Gases is looking at ways of improving the number of such outlets and their strategic locations.