report
3.4.8 Product examples

Ultra-Web®

Donaldson, Inc. a supplier of industrial dust collectors offers UltraWeb® filter media for a variety of applications.

UltraWeb® consists of nanofibres produced by an electro spinning process. Electro spinning uses an electrical charge to draw very fine fibres of about 0.2 to 0.3 micron from a liquid. Electro spinning combines properties of electro spraying and conventional solution dry spinning. After the electro spinning process a web-like net is build up by the nanofibres with very fine inter-fibre spaces smaller than conventional filters.^[31]

The very fine web-like net structure has the advantage that particles with lengths in the range of micron or submicron will be rejected at the filter surface. Particles can be easily released during the self-cleaning process. Thus, filter life increases.

The differential pressure of the nanofilter rises more slowly than that of conventional filters. The reason is that the filters can be de-dusted more effectively. That has a positive influence on operating costs.

Experiences in different industry sectors prove that web-like nanofibre filter media show a lifespan up to two times longer than conventional filters.

Fig. 6 shows electro spun nano fibres on a polymer substrate like in Ultra-Web® filter media.^[32]

Fig. 6: Electro spun nano fibre on a polymer substrate

Fig. 7 shows the nano-modified commercial filtration cartridge from Donaldson, Inc.^[33]

Fig. 7: Commercial air filtration cartridge using nanofibre-filter media

SelRO®

Koch Membrane Systems distributes a line of chemically stable nanofiltration membranes for caustic, acid, and solvent streams, which find many important and pioneering applications in food, pharmaceutical and chemical industries^[34].

Most commercially available nanofiltration membranes can not be used in harsh environments and aggressive media like high temperatures, organic solvents and acid or base environments. However, there is an increasing industrial demand in nanofiltration membranes which can withstand such harsh environments. The SeIRO® product line fulfils these market requirements over a wide operation range. These nanofiltration membranes are characterised by a superior chemical and thermal stability in comparison to conventional solutions.

SYMMETRIX®

Finetex Technology Global Ltd., a mass manufacturer of electro spun nanofibres, has provided nanofibre coated filter media for MAHLE, the Stuttgart-based engine components and systems specialist, to produce the new SYMMETRIX® air filter system^[35].

While conventional air filters feature star-shaped designs, SYMMETRIX® is a wound filter that has a large number of alternately closed channels. The resulting axial thru-flow offers aerodynamic characteristics that are extremely favourable. At the same time, the dirt collection capacity is increased by more than 150% at the same physical size. By using an extremely thin filter medium with a lining of nanofibres, it has been possible to achieve very high overall collection efficiencies with increased free flow areas and reduced pressure loss at the same time^[36].

The core innovation of is the main filter element which allows a favourable flow in a spiral shaped filter element. The company claims that the dust holding capacity of SYMMETRIX® is nearly three times higher when compared with the capacity of a round filter. Furthermore, the pressure loss is better when compared with conventional solutions. This is clearly of advantage in terms of longer maintenance intervals and engine performance.