Clextral Rotante drying technology gives petfood processors a new tool for fast, homogenous drying that meets the stringent quality requirements.

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:

1. The development of temperature resistant sensors; and
2. 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