Scope of application and advantages of the drying system
The MASS continuous drying system PD is designed for heating products and drying pastes and lacquers. The paternoster design saves space and offers a high degree of utilization in a comparatively small area. The drying system can be converted to other products and guarantees a stable heating process with low energy consumption.
Mode of operation and structure of the drying system
A product carrier transports the products to be dried within the drying system through the process chamber, where the heating process takes place via convection heat. The heating system of the drying system consists of a modular process zone. This stainless steel process zone is equipped with several heating zones and cooling zones. It is made of double wall and inter-insulated with high quality insulating material, which enables stable drying heat with comparatively low energy consumption.
Each heating zone of the drying system is operated separately via a separate control circuit, so that it is possible to preselect the desired set temperature for each heating circuit. In each heating zone, the air is heated by finned tube heaters and circulated by a corresponding fan. Air is discharged into the process zone via perforated plates, which ensure a uniform air flow and thus guarantee constant heat distribution. The air is also returned from the process chamber via nozzle plates, which at the same time ensure that the air is guided evenly over the heating coils. Temperature control is performed on each finned tube heater via a PID control loop. The actual value temperature is recorded by a PT-100 sensor.
Technical data:
- Control accuracy +/- 2.0 K
- Temperature accuracy at the product: +/- 4.5 K in the holding phase
- Connection heating module: 400/480 V, 50/60 Hz
- Exhaust air and supply air heating module: each max. 800 m³/h adjustable
- Exhaust air cooling zone: max. 1,000 m³/h
- Maximum object temperature: 120°C
- ATEX / DIN EN1539 /ESD and nitrogen applications possible
Temperature Uniformity in the Paternoster Furnace
Temperature uniformity refers to the maximum temperature differences within a defined volume. To ensure all products undergo the same heat treatment, it is essential that the temperatures within the entire usable volume — especially during the holding phase after reaching thermal equilibrium — remain consistent. Thanks to years of experience and modern support through CFD simulations, MASS furnaces achieve optimal temperature uniformity throughout the entire working volume. This ensures uniform heat treatment of sensitive products and maximum process reliability. To optimize temperature uniformity, the three mechanisms of heat transfer must be designed for maximum efficiency:
- Convection: Convection describes the movement of gas molecules at different temperatures. Warm air rises while cooler air descends due to gravity. This mechanism is crucial for uniform heat distribution in furnaces and process systems and depends on both the temperature difference and the properties of the medium.
- Thermal Conductivity: All materials conduct heat from the hot side to the cold side until thermal equilibrium is reached. High thermal conductivity ensures efficient heat transfer, which is particularly important in industrial processes and for temperature-sensitive products.
- Radiation: Every body emits electromagnetic radiation depending on its temperature. Thermal radiation is a key factor in heat transfer within furnaces and drying systems and influences the uniformity of product temperature.
Temperature measurement on a MASS carrier in the heating zone at five positions. Optimized airflow enables fast and homogeneous heating across the entire carrier. |
Positioning of temperature sensors on a MASS carrier for capturing an integral temperature profile throughout the entire process cycle. |
Advantages of the Paternoster Dryer
- Free-standing towers allow chain-free movement through heating and cooling zones.
- Full MES integration for complete process monitoring and traceability.
- Automated loading and unloading via robots or portal axes.
- Modular design enables easy installation even in confined spaces.
- Proven reliability: our systems have been operating continuously worldwide for over 20 years.
Highlights of the MASS Paternoster Dryer
PD heating zone with horizontal gas flow driven by a recirculation fan. |
CAD section of the PD heating zone – showing zone separations and air-guide vanes. |
Schematic representation of horizontal airflow for uniform distribution. |
Be- und Entladung vor der Maschine. Optional automatische Roboterlösung. |
Loading and unloading in front of the machine. Optional automated robot solution. |
Modular design: up to 10 zones and more possible. |
Optimization of airflow using CFD simulations for uniform temperature distribution, improved energy efficiency, and increased throughput. |
Fully automated loading and unloading using robots. |
Fully automated loading and unloading of work carriers. |
View from bottom to top inside tower one of the Paternoster Dryer, loaded with product carriers. |
Product carrier with very small indexing pins for flat products. |
Product carrier inside the PD. Air baffles optimized for maximum heat transfer efficiency. |
FAQ – Paternoster Dryer
What are the advantages of a Paternoster dryer?
The main advantages of a Paternoster dryer are its compact design, optimal air distribution, and the resulting homogeneous temperature profile. This ensures highly efficient and uniform drying with minimal floor space and low energy consumption.
Can Paternoster dryers operate under inert atmosphere?
Yes. While Paternoster dryers typically operate under air, inlet and outlet locks can be integrated that only open briefly. This allows the system to run under inert gas atmosphere with extremely low oxygen partial pressures, making it ideal for sensitive or reactive materials and pastes.
Why is no continuous oven used?
A conventional tunnel oven would be significantly longer and require much more floor space. The Paternoster concept utilizes vertical space efficiently and ensures superior gas flow and uniform air circulation around the products. This results in a compact, energy-efficient, and stable drying process.
Who invented the Paternoster?
The original Paternoster lift was invented in 1884 by English engineer Peter Hart, who designed the first continuously moving passenger elevator for the General Post Office in London. The system consisted of an endless chain of open cabins moving slowly upward on one side and downward on the other.
In Germany, this principle became popular in the early 20th century, particularly in office and government buildings in cities such as Hamburg, Berlin, and Nuremberg. For safety reasons, the construction of new Paternoster elevators is now prohibited in most countries.
In industrial applications, however, the Paternoster principle has been successfully adapted and modernized. Unlike the lift, the Paternoster dryer deliberately avoids a continuously moving chain — lubricants in the hot zone would evaporate and cause product contamination. MASS instead employs a clean, low-maintenance, and process-stable design.
What is CFD?
CFD simulations (Computational Fluid Dynamics) are computer-based flow simulations used to calculate how gases or liquids move and behave within complex geometries. They make it possible to analyze and optimize parameters such as flow distribution, temperature fields, and pressure conditions — without the need for extensive physical experiments.
Are MASS Paternoster Dryers Suitable for Cleanroom Use?
Yes, the MASS Paternoster Dryer is perfectly suited for cleanroom applications. Its freestanding towers and the placement of lubricants and drives outside the heating and cooling zones ensure a contamination-free thermal process, ideal for sensitive products. Optional cleanroom variants guarantee that cleanroom conditions are fully maintained.
How Does a MASS Paternoster Dryer Work?
The MASS Paternoster Dryer operates on a vertical circulation principle: products are continuously moved through freestanding towers across heating and cooling zones. This ensures uniform, contamination-free thermal treatment.
What Advantages Does the MASS Paternoster Dryer Offer Over Conventional Systems?
Unlike chain-based systems, the MASS Paternoster Dryer is freestanding, reducing maintenance and wear. Lubricants and drives are positioned outside the product zones, ensuring a fully contamination-free thermal process, ideal for sensitive products.
How Energy-Efficient Is the MASS Paternoster Dryer?
Thanks to its optimized circulation technology and separate heating and cooling zones, the dryer is highly energy-efficient, helping to reduce operating costs and minimize environmental impact.
Which Products Are Suitable for the MASS Paternoster Dryer?
The dryer is ideal for sensitive or sterility-critical products that require contamination-free drying. Common applications include pharmaceuticals, food, electronics, and laboratory products.
Can the MASS Paternoster Dryer Be Used in Cleanrooms?
Yes. The standard version is already cleanroom-compatible. With the optional cleanroom variant, cleanroom conditions are fully maintained throughout the drying process.
How Easy Is It to Clean a MASS Paternoster Dryer?
Thanks to its freestanding towers and external drives, cleaning is simple and quick. There are no hard-to-reach chains or moving parts in the product zones.