Health & Safety
Dusting developments
Dust collection technology is under pressure to conform. Donaldson says
PowerCore is meeting environmental and economic demands
More stringent international restrictions on air pollution, the
Image 3
constraints for cost reduction in maintenance and service and
the demand for better energy efficiency led to a movement in
this rather conservative area of plant construction. The new
development of PowerCore is a good example.
In comparison to conventional dust collectors, the Donaldson
Torit units using the new PowerCore technology are up to 70 %
smaller (Image 1). The significance of this development
becomes evident with the following example: For a dust
collection unit, which previously had to be equipped with 81 bag
filters of each 2.40 m in length, now only 12 PowerCore filter
packs are required. Due to the easy filter pack exchange, great
savings result in the filter changeout (Image 2). nanofibres with diameters of only 0.2 to 0.3 microns, which form
a resistant web-like net with interfibre spaces that are
Image 1
significantly smaller than with conventional filter media. This has
the advantage that particles in the sub-micron and micro range
are already held back on the filter surface and not only in the
depth of the filter media. The nanofibre layer guarantees that
even the smallest particles are retained on the filter surface. This
results in the formation of a uniform dust cake, which can be
released reliably and with low energy input. Filters with Ultra-
Web media therefore still provide very low differential pressure,
even after a long lifetime. In contrast, conventional filter media
also bond the dust in the interior of the filter layers - with the
result that the differential pressure increases quickly and the
dust can only very insufficiently be released.
The flow optimised shape of the PowerCore filter packs in
conjunction with the Ultra-Web filter media allows a higher dust
load to be collected on the surface of the media flutes, as would
be possible with conventional fibre filters with a depth loading of
While previously 10 minutes had to be applied for replacing a 540 g/m
2
standard polyester. This high surface filtration
traditional bag filter, the time for replacing a filter pack is reduced performance combined with a patented pulse cleaning
to two minutes. Two essential factors have led to this technology, leads to the high performance increase on the
performance increase: As one of the leading providers of intake smallest footprint at the lowest pressure drop and a minimised
filters for heavy duty vehicles, Donaldson successfully energy input (Image 3). The performance comparison between
transferred experiences from this application area to the dust PowerCore with Ultra-Web filter media and 540 g/m
2
standard
collection technology. The PowerCore filter packs combine the polyester was performed by the Environmental Technology
latest findings of filter media manufacturing with the proven and Verification (ETV) Programme in an independent laboratory test
patented Ultra-Web nanofibre technology. based on ASTM D 6830-02 according to EPA PM 2.5. This test
Ultra-Web has a very high filtration efficiency of 99.999 % on confirms: PowerCore filter packs provide 78 % fewer emissions
particles with a size of 0.5 microns. The filter media consists of than standard polyester bags (Image 4).
The PowerCore dust collectors utilise a directed flow inlet and
Image 2
manage airflow and velocities below the filters. Hopper
sweeping as well as dust re-entrainment are avoided. The new
compact pulse cleaning system is designed to match the
obround shape of the filter packs. The resulting pulse flow
effectively covers the entire media pack and pulses the dust out
of the fluted channels. Computer-modelled flow analyses were
the basis for these solutions.
The reason why dust bridging between the PowerCore filters
48 Solids & Bulk Handling February 2010 www.solidsandbulk.co.uk
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