Making the most of nitrogen
Nitrogen use also leads to a reduction in the corrosion of wheel components and tyre liner compounds, as there is very little moisture present in the tyre due to the lower oxygen levels.
There is also improved pressure retention from the partial pressure of nitrogen being more stable than normal air.
With the added benefit of less corrosion from nitrogen filling, clients see cost benefits from longer maintenance intervals for wheel and rim components and less refurbishment costs for those parts.
Pulford’s NitroPlus systems are designed for varying fleet sizes and range in nitrogen delivery from 50m3/ hr up to 150m3/ hr, offering tyre inflation faster than most conventional air compressors.
By incorporating a large storage vessel, the system offers instant inflation for up to two 57- inch tyres and fast recharge times for multiple inflations.
Mining contractors are always very conscious of controlling costs and boosting productivity.
By producing nitrogen on- site, using compressed air and membrane separation, the resulting mobile site systems can be packed up and relocated according to changes in site demands and locations.
Pulford prides itself on being market- focused and continually supports the development of innovative new products.
PULFORD Air & Gas is one of Australia’s oldest air compressor companies, specialising in the design, manufacture and service of quality air compressors and nitrogen gas systems since 1925.
Since 2005, Pulford has concentrated on developing a nitrogen inflation system for the mining industry to increase the safety level of operators and site staff.
Its NitroPlus range of nitrogen tyre inflation systems are used across the transport and mining industries in Australia.
With systems currently in operation in the Hunter Valley and Surat Basin, as well as numerous South Australian and Western Australian mine sites, Pulford’s experience in the field has given the company the capability to design custom systems to meet each client’s specific needs in harsh Australian mining conditions.
Nitrogen is seen as the benchmark in safe inflation for mine trucks and with the tailored systems offered by Pulford, they can be matched to specific fleet sizes and truck types.
Each application is different, so Pulford takes the time to work through the application and clients’ specific site requirements.
As there are different ways of producing the nitrogen gas, it is important for the client to choose the most efficient and economical on- site generator in order to maximise the return on the capital purchase.
The systems can be designed for any range or applications from 1m3/ hr up to 3000m3/ hr, and from 90pc purity all the way up to 99.9995pc.
Why use nitrogen in tyres?
There are several compelling reasons to use nitrogen in tyres. Nitrogen has the benefit of being corrosion- resistant, it assists in tyre pressure retention ( since nitrogen is less likely to migrate through tyre rubber than oxygen) and, most importantly, it offers significant safety enhancements over air filling.
Most of the mining applications for nitrogen revolve around safety.
By filling tyres with nitrogen, there is less risk of a tyre exploding from a lightning strike, contact with power lines or a hot tyre event ( where the liner has delaminated from the inside of the tyre, causing heat and creating the potential for a tyre fire).
Nitrogen is used in fire suppression because it reduces the amount of oxygen in the air.
By removing the oxygen, one side of the fire triangle ( heat, fuel and oxygen) is also removed.
Without oxygen a fire cannot ignite and therefore a tyre cannot explode – this makes the equipment and the operator safer under a hot tyre event.
With a move to nitrogen there is the potential to eliminate hot tyre events and in doing this, the highest level of the hierarchy of control is enforced in a mobile fleet.
Machine operators can have more confidence in knowing that their machine will offer greater safety in the case of a hot tyre event.
How does it work?
With 20 years of nitrogen generation experience, Pulford Air & Gas has the equipment necessary to produce nitrogen on- site in any environment.
Compressed air is fed through different types of filtration applications including drying, particle removal and finally oil vapor removal before flowing into the membrane.
Membrane gas production is efficient from 90pc to 98pc, giving constant flow using separation technology.
As air passes through the membrane under different pressures and flow characteristics, the purity of the nitrogen gas changes to effect the gas requirement desired at the outlet.
The flow and pressure of the nitrogen gas are controlled to ensure that the desired purity for the system is achieved.
The industry standard for nitrogen in mine truck tyres is 98pc purity.
At this level, there is no risk of fire or explosion.
Nitrogen purity is measured at three positions: once at the system, next in the storage vessel and lastly in the tyre itself.
Aiming to further extend its expertise in the field of nitrogen tyre filling, Pulford is currently working on an in- tyre sensor capable of measuring the purity of the nitrogen inside the tyre in real time.
This will be trialled soon with a leading Australian mining company.
What are the benefits?
As anyone in the resource sector knows, minimal equipment downtime is imperative for improving productivity and reducing costs.
The biggest benefit of nitrogen-filled tyres is the elimination of the tyre fire risk with residual oxygen down to 5pc (95pc nitrogen in the tyre).