Blended paper media have been used in industrial dust collection and fume extraction systems for decades. Made up of cellulose (80-85%) and polyester (15-20%), they collect particles in a variety of dust, fume and/or smoke generating applications, such as metalworking, welding, plasma cutting and laser cutting. With the advancement and availability of nanofiber technology, these filters are now able to collect more – and smaller – particles than ever before, while at the same time lasting longer, using less fan and compressed air energy, and requiring less maintenance than their predecessors
What are nanofiber filter media?
Nanofiber itself is a synthetic polymer fiber, typically smaller than 200 micron and commonly found smaller than 100 microns, that is applied through a spraying process to the top of a filter media to enhance its filtration properties, provide higher efficiency, and improve cleanability. When viewed through a high power microscope, such as scanning electron microscope (SEM), you can clearly see a layer of very fine fibers that create what looks like a super fine screen sitting on top of the carrier media or substrate. Image 1 below is a top view of the nanofiber net atop a blended paper media. The very small fibers are approximately 100 nanometers with the larger fibers seen below are approximately 20 microns (20,000 nanofibers) and larger. Its this net like formation that provides all the benefits. Image 2 shows a cross section of the full media. At the top of the image, you can see how thin the nanofiber layer is compared to the rest of the paper media, about 1/3000th as thick. It can be hard to believe that something so small can be of so much value in air filtration.
| Image 1 Tope view of nanofiber net
||Image 2 Side view, nanofiber on 80/20 blender paper
Surface loading vs depth loading filtration
For decades in the air filtration industry, filters and filtration systems were designed such that high efficiency would only be achieved after hours of operation. At the start-up of a system with new filters, the filters would first need to get dirty before they provided the expected efficiency. Dirt on the surface of the filter, getting stuck in between the fibers of the media, and remaining over the life of the filter was done intentionally to increase filter efficiency, improve dust release during cleaning, and create the steady-state operating condition. This is what is called depth loading filtration.
Surface loading filtration is where the surface of the filter media does not allow dust to penetrate into the depth of the filter media. Dust collected by the filter remains on the surface. The dust is not needed to fill microscopic holes to improve efficiency, the surface is designed so dust easily pulses off and does not easily stick/remain during cleaning. With the advancement of nanofiber technology, more and more dust collector applications are switching to nanofibers on the surface of the filter media using the surface loading filtration mechanism.
The Nanofiber advantage
The advantages of surface loading the collected dust are many. Using nanofibers as the way to surface load dust may be the best option for your dust collection need.
- Easier dust cleaning – cleaning dust off the surface of the filter, as compared to pushing out of the depth of the media, is easier and faster. Less cleaning cycles and less compressed air usage reduces operating cost
- Smaller dust collectors – sizing of dust collectors is based on dust size, quantity of dust, and airflow. When filters are easier to clean and dust remains on the surface, more airflow per cartridge can be realized. This results in smaller collectors, less filters, and overall, lower cost to purchase and lower cost to operate.
- Energy reduction – with surface loading, better cleanability of the filters, and no dust trapped in the depth of the media, pressure drop across the filter remains lower. Using a VFD to maintain constant airflow, energy to run the fan is saved, reducing the system operating cost.
- Reduced maintenance – when filters clean easier and pressure drop stays lower, longer; the result is filters that last longer. With less time needed for filter changing, less filters to purchase, and less disposal costs, maintenance/operating costs are a real savings for the facility.
Depending on your facilities need, type of dust, and other application variables, as well as whether you need a new system or just upgrades to an older system, filters utilizing latest nanofiber technology likely will provide operational and maintenance benefits in the form of lower operating costs.
Nanofiber cartridge filters are set to become a new standard
Nederman’s new MCP dust collector, as well as most similar systems on the market, use cartridge filters. The blended paper cartridge media (type 175) has long been a standard component of our dust collection systems, but it is now being replaced by the new type 178 cartridge, blended paper with nanofiber. Equipped with nanofiber filter media, type 178 media can be used in many different systems and devices, such as Nederman stationary filter systems for dust- and fume extraction MCP, FMC, LCP, MJC, MJC Mini and SiloSafe as well as our mobile dust collectors and fume extractors FilterBox and FIlterCart, It can be retrofitted into several types of older machinery, and will become a standard component in all Nederman cartridge dust collectors.
In the future, we are likely to see nanofiber filter media continue to evolve, with even smaller fibers than today. This would, for example, make for even better surface loading, simpler cleaning, and increased particle collection efficiency. Stay connected with Nederman to learn firsthand when these future improvements will be available and other technology improvements that may benefit your facility.
If you have any questions about nanofiber filter media, and Nederman’s work in this field, you are welcome to contact me at [email protected]. You will also find plenty of other articles here at the Nederman Knowledge Center, covering areas such as combustible dust filtration, robotic welding fume extraction, 3D printing dust and fume extraction