The privately owned British company, ACI was the first in the world to go
to market with an air knife. That was in 1991. Nowadays the company sells
air knife drying systems to OEMs and end-users around the world, turning
over some £1.5m in the sector. Next month at Drinktec in Munich, ACI will
present its latest take on blown-air drying systems for the bottling and
canning industries Jet Plate and Can Tunnel.
The drawbacks of conventional air knives are the initial set-up
difficulties and the necessity to mount them outside of the conveyor
guide rails, which tend to restrict the air flow. Jet Plate overcomes
these problems by incorporating the air slots within the guide itself -
in this case, a precise pattern of slots cut into panels of polyethylene
1000 (a commonly used wear strip material). These PE guides are mounted
in parallel to allow a single line of bottles to pass through. Air is
blown into plenum chambers, mounted behind each guide, and these maintain
around 3bar internally to ensure a consistent supply of drying air.
ACI says it can modify the slot pattern and angle to accommodate bottles
of various shapes and sizes. Early test pieces include a feathered array
of slots cut at an angle to ensure a down ward draught of drying air. All
slot configurations are designed and tested at the company's laboratory
using sample bottles travelling at bottling plant speeds on a test loop
conveyor system. Essentially, Jet Plate delivers at least twice the
volume of high-pressure air, from a position much closer to the bottles
than was previously possible. This big increase in drying performance has
been proven at a number of beta site locations, including the Stella
Artois bottling line at Magor in South Wales.
Can drying tends to be a far wetter process, compared with bottles, but
the Jet Plate system can still be applied. In the case of cans, a Jet
Plate with 'Y' shaped slots is located above the conveyor, between
vertical slide plates, which together form a drying tunnel - hence the
'Can Tunnel' concept, which is currently undergoing beta trials on
high-speed canning lines in a number of countries.