Nitrogen gas is now used extensively for tyre inflation and inert gas suppression. Unlike compressed air, nitrogen, due to its inert nature, will not support combustion if it comes into contact with extremely hot aircraft brake units i.e. tyre bursts.
Other related applications include aircraft oleo strut maintenance (nitrogen prevents ‘oil foaming’ under heavy compression) and aircraft escape slide inflation systems.
Nitrogen is also widely used as an inerting gas for fuel tank “ top space “ and other flammable liquid and chemical inerting.
Aircraft Tyre Inflation
Many regulatory agencies require the use of nitrogen when inflating tyres.
Nitrogen provides a stable, inert inflation gas, whilst also eliminating the introduction of moisture into the tyre cavity. Nitrogen will not sustain combustion and limits degradation of the tyre material and wheel due to oxidation.
The majority of in-flight tyre bursts have been attributed to the tyres being weakened by foreign object damage or scuffing, creating a rapid release of pressure. Such failures are usually experienced after the undercarriage has been retracted for some time combining the effects of brake heat transfer, internal tyre temperature and differential pressure.
It is also possible for a tyre to fail explosively during flight without any significant prior degradation.
A tyre inflated with air when subjected to excessive heating, can trigger a chemical reaction resulting in the release of volatile gases. This chemical reaction in the presence of the oxygen may result in an in-flight fire or a tyre explosion in the landing gear bay. This is due to the fact that conventional pressure relief devices are unable to respond adequately to rapid increases in gas pressure and temperature which can occur with auto ignition.
Testing shows that the risk of auto ignition can be reduced by using an inert gas during servicing for tyre inflation.
Using nitrogen can deliver other potential benefits as it will tend to reduce wheel corrosion, tyre fatigue and the risk of fire from fusible plugs melting due to brakes overheating. Nitrogen is both used airside during aircraft turnaround as well as in the wheel and brake shop during maintenance overhaul.
Scientific Laboratory Gases
Parker domnick hunter has a complete range of gas generators for laboratory use. The ultra high purity hydrogen, nitrogen, CO2 free and zero air generators are cost effective, robust and offer a convenient gas solution for applications requiring higher gas flows.
The generators utilise fully regenerative and proven pressure swing adsorption technology to provide a continuous gas supply without the need for secondary purification. They are fully compatible with all know APCI and ESI interfaces.
Some models feature integral oil-free compressors to give increased security of supply that completely removes reliance on external air supplies.
Single or multiple instruments can be supplied to drastically reduce ongoing laboratory gas costs.
