THE PRECISE RECIPE FOR SPRAY COATING CEREALS
Close control plus flexible operation
A highly developed spray coating system for the application of oils,
syrups and liquors to cereals and other preformed products is embodied in
the latest production units manufactured by APV Baker. Emergence in its
present form follows long-term collaboration between APV Baker and spray
technology specialists Spraying Systems.
Industry requirements call for automated production processes whose
performance, translated into terms of cost and product quality, can
be controlled and monitored at every critical stage, with full traceability.
The coating operation itself must be precise, controllable, consistent and
reliable, so that the coat is of the correct weight and is evenly applied
throughout the product stream as it passes through revolving coating drums.
This involves close control of liquid volume, spray pattern and droplet size;
and also the prevention of nozzle blockages - a disruptive factor that could
interfere with consistent quality, with the threat of product wastage and
downtime.
According to APV Baker marketing manager Mark Shearsmith, "together we have
evolved a proven system for cereal coating that delivers all these benefits
without excessive cost, and yet is sufficiently flexible to be easily adapted
to the needs of individual customers."
In fine-tuning the basic design, APV Baker has been able to take advantage
of the multiple choices available from Spraying Systems. The company
manufactures an unusually wide range of automatic air atomising spray guns,
each gun itself offering a variety of performance bands through selection of
particular combinations of air/liquid orifice cap components - the 'spray
set-up'. Within these bands, liquid volume and degree of atomisation can be
varied by adjusting air and liquid pressures. On a number of guns, automatic
orifice cleanout is a standard option. Throughout the spray system, maximum
use can be made of catalogue-listed components.
"That's a plus point," says Mark Shearsmith, "in that it helps limit initial
costs as well as reducing inventories and shortening delivery times on spare
parts."
As presently optimised through development over a number of plants, a
typical APV Baker system for the application of coating oils to cereals
might comprise five air atomising guns in Spraying Systems' 1/4 JAU
series, mounted on a spray lance within a coating drum. A large cereal
plant will incorporate a number of these drums.
The spray set-up (liquid cap/air cap combination) has been chosen to allow
free flow consistent with the viscosity of the oils to be sprayed. An
extended combined shut-off and cleanout needle is incorporated to ensure
that that no orifice blockages occur. Solenoid controlled air pressure
actuates the needle against a spring, allowing liquid to flow until air
is cut off on signal - giving instant liquid shut-off and automatic orifice
cleanout. (The On/Off cleanout operation is controllable at up to 180
cycles per minute, though frequencies of this order would not normally
be required for cereal coating.)
The air control system, designed and manufactured by the AutoJet Technologies
division of Spraying Systems, includes solenoids and separate pressure
regulators for atomising air and On/Off control air, all housed within
a stainless steel cabinet.
Printer Friendly Acrobat Format. (pdf)
|
|
 |
| Spraying Systems' automatic air atomising gun 1/4 JAU Series,
with cleanout needle. |
|
