Heating and Ventilating

Free running wheels continue their advance in climate boxes. With the high-performance C-series impellers, Ziehl-Abegg is providing a powerful, extremely economical and quiet backward-curved impeller. Les Fish, managing director of Ziehl-Abegg UK, discusses the advance
C-SERIES impellers from Ziehl-Abegg achieved measurable record highs in new comparison tests with conventional competitive products.

This technical lead results from the newly-designed impeller (patent-pending) with an optimised rotating diffuser. The C-series free-running wheel is available in diameters from 225mm to 1,120mm with a special blade design. This means flow rates of up to 110,000m3/h can be achieved.

The maximum static-pressure increases to 2,500 Pa. Because of the very high performance of the C-series impellers, a smaller impeller can often be used, or alternatively, a motor with less power can be fitted.

Furthermore, Ziehl-Abegg has optimised the entire plug-fan range with a standard motor. The new compact plug fan range has a galvanised steel plate design and its front plate has been provided with an integrated nozzle with an airflow-measuring device. As a result, simple start-up operation and precise volume flow control are possible. The fan selection can be carried out using the Ziehl-Abegg ZRV 32 selection program (accessible from the web-site). Ziehl-Abegg has thus further enhanced its position in the free-running wheel market segment.

Advantages of free-running wheels

Compared with traditional belt-driven fans, the main advantage of free-running wheels is the optimal control facility at the desired operating point. This is achieved using a frequency inverter. As it has direct drive, the maintenance normally associated with belt-drive is eliminated. Also, through the easy access, cleaning the impellers is simplified thus providing optimal hygiene conditions. Because of the compact fan assembly, air movement equipment can be made physically smaller, requiring the operator to sacrifice less space for installation.

A high degree of static impeller efficiency and free suction leads to high system efficiency, which in turn leads to significantly higher energy savings, depending upon the chosen operating point.

Ziehl-Abegg specialises in ventilation, drive and control technology. With more than 1,800 employees, it is one of the leading international companies in this sector. Along with the main factory in Germany, the manufacturer has more than 30 subsidiaries, production facilities, representations and business partners in more than 30 countries worldwide. And, the company continues to grow. For example, in the past year a 15,000m2 production centre for centrifugal fans was put into operation in southern Germany.

For further information, Tel: 01245 449010