You need your dust collector to perform to its full potential and your expectations, therefore it is important to use the advanced surface-loading capabilities of nanofiber filters instead of traditional commodity filters. The combination of nanofiber filtration in conjunction with an optimized downward flow dust collector will result in less pulse cleaning cycles, less compressed air use and significantly longer filter life. Most importantly, this combination, in addition to maximizing overall system performance and efficiency, will bring significant savings in energy and operational costs.

Downward flow dust collectors are among the most common pieces of equipment used to remove harmful pollutants from such processes as grinding, sanding, thermal spraying and the manufacture of graphite, ink dyes, silica, talc and toner that produce submicron dust particles. These air pollution removal systems are critical to helping you control the air quality in your plant, increasing employee productivity and maintaining the performance of your manufacturing equipment.

Choosing an optimally designed downward flow dust collector is essential to providing clean workplace air. Although there are many factors to consider when evaluating the performance and quality of a cartridge collector, two elements are key to your purchase/use decision: quality of the filter media, and performance of the cleaning mechanism.

Both factors have the most overall profound impact on the air quality you will achieve and your filter life. If your collector is lacking in either of these two factors, your dust collection system will never perform to its full potential.

Filter technology

There are two types of cartridge dust collection filters and they differ in the type of substrate material and surface coating used.

Traditional commodity filters. Traditional commodity filters are straight cellulose (Figure 1) with one homogenous layer of cellulose fiber. Blended cellulose filters typically consist of 80% cellulose and 20% synthetic fiber. Sometimes these commodity filters come with a melt-blown surface layer added to improve efficiency at capturing submicron particles. As shown in Figure 1, if you look at any cartridge filter media through large magnification, you will see open spaces or “holes.” The smaller the holes, the better the media will be at capturing fine particulate.

Latest technology advanced nanofiber filters. The most technologically advanced and highest performing filters are nanofiber filters. These filters, such as genuine advanced nanofiber cartridges, use fibers 1/1,000 of a micron (Figure 2).

Just how small are these fibers? Consider that there are 25,400 microns in an inch. The lower limit of visibility with the naked eye is 40 microns. And, the average pore openings in your skin are 10 microns. As such, an extremely thin nanofiber layer on a cartridge filter is capable of capturing submicron particles and trapping them on the surface of the media.

Nanofiber filters are scientifically proven to outperform commodity filters in three main measures of quality: efficiency, pressure drop and emissions.

Higher efficiency

The fibers that make up nanofiber filters are produced using an innovative electrostatic process that yields the finest synthetic fiber used in any current filtration product. The thin fibers form a permanent mesh-like surface with exceptionally small openings, or pores. These tiny openings are extremely efficient in filtering even submicron particles (less than 1 micron) from the contaminated air stream.

In rating filter efficiency, the MERV1 (Minimum Efficiency Reporting Value) system is the industry-respected benchmark. The higher the MERV, (Figure 3), the better the filter’s efficiency and ability to remove submicron dust particles from the air and minimize emissions. MERV ratings are based on a scale of 1 to 20, and broken into three particle size ranges:

- Range 1 – 0.30 to 1.0 micron

- Range 2 – 1.0 to 3.0 microns

- Range 3 – 3.0 to 10.0 microns

Traditional filters are not efficient enough to be rated in Range 1 because they cannot capture dust that is in the 0.30 to 1.0 micron range. In Range 2, traditional filters are only rated to be 50 to 65 percent efficient. Importantly, this means that submicron dust passes right through commodity filters and back into the workspace and your employees’ breathing zones.

For reference, the manufacture of the following products that produce submicron dust would be a major problem with a commodity filter system:

- Graphite 0.3 micron

- Ink dyes 0.1 micron

- Silica 0.5 micron

- Talc 0.5 micron

- Toner 0.5 micron

While MERV is the most accurate efficiency measurement available, filters should not be selected on MERV alone. Other criteria, such as pressure drop, cleanability, compressed air usage and filter life are important in determining a filter’s total performance and life cycle cost. Commodity filters with a melt blown layer may achieve a higher MERV rating but operate at a higher pressure drop, have shorter life and require additional compressed air and electrical power to operate.

Lower pressure drop

The surface layer of a nanofiber filter provides the highest possible filtering efficiency. In effect, this nanofiber layer does the work, preventing particulate from building up within the filter’s substrate and restricting airflow. As a result, pressure does not build up as rapidly as it will with a commodity filter. Because the pressure drop is low, your dust collection system requires less energy to run, and you may be able to use a smaller, less expensive blower.

Reduced emissions

In addition to removing smaller particles from the air, nanofiber filters also reduce the amount of dust that escapes back into the workplace air. An unavoidable byproduct of the filter cleaning process is that a small percentage of the collected dust is released back into the atmosphere. Because nanofiber filters require less frequent pulse cleaning, total outlet emissions are reduced.

Commodity filters typically emit up to 35 times more dust back into the atmosphere than our nanofiber filters.

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Adapted from Parker Hannifin's white paper, "Nanofiber Filtration In Combination With Dusthog® SFC Dust Collectors."