The multi-stage belt dryer manufactured by Theilen Maschinenbau GmbH is a continuous convection dryer. The product to be dried is conveyed in multiple stages on a ventilated belt through the dryer housing, where it is exposed to a stream of hot air throughout the process. A well-ventilated product layer is a prerequisite for this.
Even distribution of the material to be dried onto the conveyor belt is the foundation for a controlled and reproducible drying process. Our multi-stage belt dryers allow the drying process to be specifically tailored to the specific properties of the product.
Product feeding is typically performed via a distribution conveyor located upstream of the feed section of the multi-stage belt dryer. Depending on the properties of the material being dried, the product feed can also be supplemented by a leveling rake or a rotating, height-adjustable product leveler.
This ensures the product layer height is as uniform as possible, thereby fulfilling an important prerequisite for homogeneous drying.
The multi-stage dryer is used in particular when it is possible to reposition or transfer the material being dried during the process, and when this is beneficial for the specific product. Through the controlled transfer between the individual drying stages, the drying process can be optimally adapted to the product’s properties.
For suitable materials, the multi-stage process can contribute to an improvement in the quality and uniformity of the dried product.
The multi-stage belt dryer is divided into several drying stages—so-called stages—. The individual stages are connected to one another via defined transfer sections. This allows the product to be specifically transferred between the drying stages and fed into the next process step.
Each stage consists of several drying chambers. Each drying chamber has its own recirculation fan that directs the drying air specifically through the product.
Depending on the model, airflow can be directed from top to bottom or from bottom to top. This allows the airflow within the individual drying zones to be precisely adapted to the material being dried and the respective process requirements.
The combination of multiple drying stages enables differentiated process control throughout the entire drying cycle. This allows different conditions to be created within the individual stages and optimally tailored to the product.
A key advantage of the multi-stage belt dryer is that the product is repositioned multiple times during the drying process. At each transfer point, the product can be redistributed and the bulk height precisely adjusted. At the same time, the belt speed can be adapted to the respective process requirements, thereby controlling the product’s residence time in the dryer.
Thanks to the drying stages arranged one above the other or in series, a high drying capacity can be achieved on a comparatively small footprint. The multi-stage belt dryer thus offers a space-saving solution for applications with high demands on throughput and drying capacity.
Repeated transfer loosens the product pile and turns it over. This allows new product surfaces to come into contact with the drying air. For suitable products, this can contribute to more uniform and efficient drying as well as improved product quality.
The combination of multiple product turns, variable fill height, and individually adjustable belt speed makes the multi-stage belt dryer a particularly flexible drying system.
Our multi-stage belt dryers are manufactured primarily from high-quality stainless steel. The robust design is engineered for long-lasting and reliable operation and offers high resistance to the thermal and mechanical stresses encountered during the drying process.
Our multi-stage belt dryers can be equipped with high-performance electronic control and regulation systems. This allows the relevant process parameters to be precisely tailored to the specific material being dried and the desired drying conditions.
Among other things, the following parameters can be controlled:
Continuous real-time process monitoring enables the recording of relevant operating parameters and the early detection of deviations. This allows for targeted intervention in the process and helps ensure consistent drying quality.
In addition, demand-based control of the process parameters enables energy-efficient operation of the system. The drying capacity can be adapted to the specific product and the current process conditions.
Depending on the application, you can choose from different models of multi-stage belt dryers. Optional features are also available:
Our multi-stage belt dryers cover a vast range of applications, from entry-level equipment for continuous drying to large-scale industrial use, and from cut fruits and vegetables to plastic pellets for the chemical industry. The technical specifications are correspondingly diverse:
Gernot Ingenerf
Division Manager, Belt Dryers and Custom Systems
