Drying is a key step in petfood extrusion; it plays a major
role in the final quality of the product. Now twin screw
extruder manufacturer Clextral offers drying solutions for
petfood processors.
The company's Rotante dryer has distinctive features that
ensure complete homogeneity of petfood drying with less energy
consumption. The distinctiveness of the Rotante's technology is
due to its simple and ingenious design. It transfers product
through drying with uninterrupted Archimedes screws mounted in
a fixed position on a rotating drum. Each time the drum
achieves a full rotation, the product advances simultaneously
one step along the screws. This design ensures a continuous,
smooth product mix throughout the drying process, and the
linear product flow guarantees total control.
Processors can define drying zones inside the Rotante at
different temperatures and air speeds to achieve specific
product characteristics. Drying flow is annular along the drum
with high recirculation flow (80 to 100 000 m3/h).
The dryer provides a continuous product flow with no
dispersion of residence time. This means processors can easily
switch from one product to another without any risk of cross
contamination.
Another key feature of the dryer is the fines recovery
system. The regulated air speed from the circulation fans is
around 6 m/s to avoid dust stagnation in the upper part of the
assembly. Fines fall down the smooth, angled stainless steel
walls below and are channeled to two Archimedes screws, which
continuously extract them at the dryer base. All fines are
recovered for reuse, with no heat degradation, which can occur
on traditional dryers.
The Rotante has specific features to ensure energy
efficiency and long operating life:
- Maximum equipment insulation separates the controlled
internal temperature from the ambient temperature within the
factory. The stainless steel casing is fully sealed against
airflow. The entire unit has advanced heat-insulating, high
density rockwool bonded to the outside surface of the drum.
Exterior sliding polyester panels add further insulation.
Finally, the high integrity seals on the tilt doors
(providing access to the dryers) ensure that the equipment is
hermetically sealed.
- All of the mechanical components for the Rotante are
located outside the dryer drum so they are not affected by
the dryer heat. This layout of the mechanical components,
combined with the all-stainless steel design of the drum,
contributes to high reliability, easy maintenance, and long
life.
- All stainless steel material for every component that
comes into contact with the product.
- Simplified machine opening: easy access hatches are
located at the input collectors, as well as at the lower side
of the machine for quick inspection.
- Reliable and flexible process control by:
- The development of temperature resistant sensors;
and
- Computerization of complete lines, providing quick
response to system actions and reactions, and guaranteeing
the repeatability of production runs.
- Easy maintenance, through the choice of standard motors,
removable from the exterior, and the consistent use of
commercially available parts whenever possible (restricted
number of specific parts).
In order to meet each customer's requirements, Rotante
technology is modular. It can be built in accordance with
product/flow rate customer requirements.
Petfood processors interested in Rotante dryer technology
can contact Clextral to test the performance of this
technology. In CLEXTRAL's Firminy test center, two Rotante
machines are operational, one laboratory pilot project and one
industrial dryer.
Clextral Inc.
, 14450 Carlson Circle, Tampa, FL,
USA 33626, Tel: +1.813.854.4434, Fax:
+1.813.855.2269, E-mail :
clextralusa@clextralusa.com
, Website :
www.clextral.com
,
Clextral S.A.S
. B.P. 10, Firminy Cedex, France Tel:
+33.4.77.40.31.31, E-mail
clxsales@clextral.com
, Website :
www.clextral.com
