Rapid payback with blowers
July 01st 2008 A blower powered airknife system from ACI installed at Corus has achieved rapid
payback of just 21 weeks and is ensuring a more reliable quality of compressed air
With ever increasing competition from
around the world, manufacturing
companies are reviewing their
processes constantly to see if there
are ways of reducing costs. If the new systems
introduced also make a contribution to enhancing
the production process then that is a valuable
bonus. On this basis, the new blower-powered
Airknife moisture removal system installed on the
five-stand mill at the Corus Trostre Works, Llanelli
must be considered a genuine success because it
both saves money and helps to ensure quality.
Prior to the installation of the blower-powered Airknives,
compressed air delivered through 66 nozzles was used
to remove surface moisture (lubricant and coolant) from
steel strip as it exited the mill. This was both an
expensive process and one of variable performance due
to some inherent characteristics of compressed air that
impacted upon quality.
The 66 nozzles delivered a total of 1748 scfm at 5Bar.
This equates to more than 7HP/5kW per nozzle making
a total in excess of 345kW with an annual running cost
for a 48 week/year of approximately £75,000.
By comparison, the Airknife system, supplied by air
handling specialist Air Control Industries (ACI) of Chard,
uses just 60kW yet achieves more efficient moisture
removal. The result, payback was achieved in just 21
weeks.
In addition, while the compressed air supply was
vulnerable to demands for other operations within the
plant, resulting in inconsistent performance which
impacted upon quality, the blower-powered Airknives
deliver the required air output constantly. Air delivered
by the Airknives also has the benefit of being heated by
the blowers, as a result of air compression, making it a
more effective drying agent.
The original compressed air moisture removal system
was also vulnerable to contamination by oil and
moisture. This had the potential to cause imperfections
in the tinplate. With the new Airknive system air is
filtered at the inlets of both the enclosure and blower so
such problems are eliminated.
ACI's Airknife moisture removal system comprises a pair
of stainless steel chevron-shaped aiknives covering a
width of 1240mm fed at all times by four of the
company's 15kW EP10 blowers, which are housed in
pairs in acoustic enclosures. There are in fact six blowers
but two are on standby. Air from the blowers is
delivered to the Airknives, first via 200mm ducting and
then by two 150mm ducts.
The blowers are powered by inverter-controlled, highefficiency
EFF1 motors. This permits the blowers to be
ramped up and down as required whereas the
compressed air system was either on/off and could be
left on between production runs.
"Low-volume and applications which require low to
medium-pressure are an inefficient use of compressed
air", said Paul Millett, senior development engineer,
"whereas air delivered in high-volume at low pressure,
as supplied by the ACI blower-powered Airknives, is
ideal. In less than six months we have recouped our
investment and quality has also improved through the
reduction of imperfections caused by contamination
during the moisture removal process."
The metal strip passing through the tinplating mill varies
in width from 610mm to 1236mm and travels at speed
up to 1524m/min. More articles from Air Control Industries Ltd: | 
