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Sci Tech
Less weight fire extinguishers
FIREFIGHTERS AND aircraft makers could benefit from a new chemical system that creates vast quantities of cool gas without using enormous pressurised gas cylinders.
Russian and Dutch scientists have developed a system that replaces hefty nitrogen usually used by fire extinguishers, says a report in New Scientist. . It weighs half as much and occupies half the volume say the researchers.
The reaction uses a block of a nitrogen-rich sodium azide compound that decomposes when heated by a detonator, generating hot nitrogen gas.
But cleverly — and the inventors will not say how — the heat of the gas is absorbed back into the permeable solid, raising its temperature so that the reaction can continue. And the gas can be released at temperatures as low as room temperature.
This new design does not need heat exchangers to cool the gas and also the reaction can last for several minutes add the scientists. Azides are generally shok sensitive and they can decompose spontaneously and explosively.
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