Material Handling Fans for Combustible Dust & Textile Fibres

Material handling fans are required where solid and bulky materials need to be handled or conveyed such as food processing and biomass applications. Dust explosions can occur in such industries where solid materials are treated and finely divided. Small sized particles are produced during manufacturing processes. Large particles fall while smaller particles remain suspended for unlimited periods. Powder is measured in microns. A micron is a unit of length equal to 10-4 (0,0001cm).

Food processing applications involve the efficient transportation of solid materials such as sugar, grain and flour to effectively manufacture the end product. ATEX material handling fans are generally required in this case due to the combustible nature of these solids.

The industrial fans play a crucial role in the transportation of fibres in the air within textile industries. During the production of non-woven fabrics, the used fibres are sometimes processed and carried along long distances to be distributed to machinery such as mixers and packing machines. The air is used as the method of transportation to carry a potentially large volume of fibres and therefore the chosen fan must be able to produce the pressure and airflow required in order to carry these textiles through the impellers while continuing to prevent a blockage in the system.

Optimisation of the entire system depends on selecting the right size fan with appropriate straight bladed impellers. In the industrial fan marketplace, we call these radial bladed fans, radial fans or material handling fans.

Many industrial fans can handle dusty or slightly dust air but only a limited range can work with textile fibres.

All textile processing, whether spinning, reeling or blending, produce fibre. The fibres created during this intensive process, can pose a hazard to buildings and employees when not managed responsibly as they can quickly accumulate. Dust can gather on surfaces such as suspended ceilings, rafters, roofs, ducts, crevices, dust collectors, and other equipment. When the dust is disturbed and under certain circumstances, there is the potential for a serious explosion to occur. The build-up of even a very small amount of dust can cause serious damage. Combustible fibre accumulation remains an issue in the textile industry but automated dust collection systems, high airflow systems and ATEX fans can create a proactive solution to prevent explosions from occurring.

The MBZM P/R and AAZA P/R fan ranges offer effective and efficient airflow and the safe explosion proof transportation of textile fibres.

Combustible dust is any material that has the ability to disperse in air and catch fire when exposed to an ignition source. Combustible dusts can include but are not limited to: most solid organic materials (sugar, flour, grain, wood etc). carbonaceous materials (charcoal, soot, textiles (lint, cotton), many metals and some non-metallic inorganic materials. Some of these materials are not “normally” combustible, but they can burn or explode if the particles are the right size and in the right concentration.


Dust explosions have also occurred in many other industries, including:

  • Agriculture (e.g. fertiliser plants, composting facilities, grain elevators, silos, etc.)
  • Food production (e.g. sugar factories, bakeries)
  • Chemical manufacturing (e.g. rubber, plastics, pharmaceuticals)
  • Fabric products manufacturing
  • Woodworking facilities
  • Metal processing and manufacturing (e.g., zinc, magnesium, aluminium, iron)
  • Recycling facilities (e.g. paper, plastics, metals)
  • Coal mining, processing, or coal-fired power plants

 

According to Dr. Luca Marmo, Ada Ferry & Enrico Danzi in their published paper: Journal of loss prevention in the process industries they state, “There’s a diffuse feeling that the risk of dust explosions in the textile industry is limited or even negligible.” The reality is that the risk is not negligible. Explosions are happening in this industry and causing loss of products, facilities, and lives.

According to Dust Safety Science, the paper reviews some case studies of dust explosions in the textile industry. The first one they mention is a 1987 linen dust explosion Harbin, China. On March 15, 50 people were killed and 177 injured in a series of explosions so violent that the seismographic records registered nine peaks. There was one primary explosion followed by eight secondary ones, all of them so devastating that 13,000 square meters of the factory were damaged.

The explosion originated in one of the nine dust collection units. Although the ignition source was not identified, the authors hypothesized that electrostatic discharge or a localised, glowing nest of material ignited the explosion, which propagated from the dust collector through the ductwork and involved all the other units in the carding section. The pressure lifted the dust layers on the floor, causing secondary explosions in the carding and spinning sections and underground textile stock areas.

The second case study referenced in the paper is a 2001 nylon flock explosion in Italy. This incident started in a dryer after it had been shut off so that threads could be retied. When the dryer was powered back on, the resulting explosion propagated back to the dust collector, and the other dryers and blew out the side of one of the ducts. There were also flash fires that injured three workers.

The third incident covered is a 1995 flock fire and explosion at Malden Mills in Massachusetts. 27 people were injured and over 40% of the plant was damaged. The cause was an electrical spark created by the electrostatic grid system at the beginning of the production line.

The last case study covered in the paper is a 2001 wool dust explosion in Italy. This facility, which carried out washing, carding, and wool combing activities, was full of dust containing vegetable residues. When smoldering combustion started in the basement, where several filtering cells were present, a huge deflagration occurred and caused a 20 to 30-meter flash fire, which was fuelled by the layers of dust. In this case, the impurities and oil vegetable residue on the wool fuelled the explosion.

 

For more information on our range of industrial material fans suitable for textile fibres contact our industrial team on sales@axair-fans.co.uk or call 01782 349 430.

 

Material Handling Fans | Radial Fans | Axair Fans UK (axair-fans.co.uk)

 

Axair Fans UK Ltd
Lowfield Drive
Wolstanton
Newcastle-Under-Lyme
ST5 0UU
England