Edition 04/15

According to the Federal Statistical Office, annual sales of bakery goods total around EUR 18 billion. Behind this is an annual consumption of 85 kilogrammes per inhabitant, within which the general public prefers bread, which accounts for 63 percent of the total. With this type of food being so popular, the market is extremely competitive. The significance of larger medium-sized bakeries and industrial bakeries is increasing, accompanied by a constantly changing array of baked goods available in the market.

High requirements

Rye meal with bio certificate is a basic product, which Aerzen Brot und Kuchen GmbH of Lower Saxony stores in an external silo. If this type of grain is requested in a bread formula, a blower station takes over the pneumatic conveyance from the silo to a scale. Removal of grain from the silo is effected by rotary valves at discharge of the reservoirs, which convey the grain into the piping, from where, it is then blown into production. „Each part of a batter mix is transported individually, so that we can weigh it exactly“, explains Andreas Specht, Technical Manager of Aerzener Brot und Kuchen GmbH. For each batch, the around 200 employees of the Brotfabrik mix approximately one ton of flour and meal into a smooth dough. Five batches are processed per hour - a daily production quantity of 80 tons of bread. The figures clearly show the importance of the demands on the technology being used. Against this background, the industrial bakery has undertaken a modernisation programme and replaced the outdated blower for pneumatic conveyance with a modern unit from AERZEN – an energy-efficient Delta Blower E-Design GM 15 L (700 mbar, 1,038 m3/h, 30 kW). These units are designed for intake volume flows from 30 to 1,000 cubicmetres per hour and complement the rotary lobe compressors of series Delta Hybrid in the lower volume flow range.

Energy-efficient technology

In compressor technology, more than 90 percent of the life cycle costs can be attributed to energy consumption. This high percentage clearly shows that savings and operation correlate closely with each other. Energy consumption can be reduced by lower internal pressure losses of a blower, which has a positive effect on the energy bill. With the E-Blower, AERZEN has been able to increase the efficiency by at least four percent through constructive optimisations - among other things by flow-optimised direction of the intake air in the acoustic hood and the filter silencer. Moreover, the patented intake cone minimises pressure losses as well as sound emissions. Also quickly wearing absorption material was not used in the E-Blower - an additional protection against contaminations of the downstream process system and thereby of the final product. The E-Blower has further advantages with respect to energy efficiency through its revised cooling concept. In this case, an optimally placed and electrically driven fan replaces the widely spread mechanically coupled acoustic hood fans. The independent operation enables control of the fan power, so that in partial load operation with low dissipated heat, the fan can be run at lower speed. Also, in order to achieve more effective cooling, the AERZEN units suck on the cool front side, in order to have a possibly higher Delta T compared with With compressed air the required raw materials reach the “bakery”. the warmer rear side which has a pressure pipe connection. Andreas Specht points out, that in his company, energy efficiency gains play an increasingly important role in investment decisions - „especially in view of the long runtime of the machines“. In this case, AERZEN ensures the continuous application of IE3-motors for assuring the future of investments. A further criterion for the selection of the energy-efficient Delta Blower was the absolute oilfree conveyance of transport air. „We need a defined volume flow with the correct pressure and absolutely do not need devices with oil injection“, stresses the Technical Manager.

Ready availability

When designing the new blower, the already known pressure and volume data from the exchanged device could be used - this reduced the expenditure significantly. The modernisation work was limited to the exchange of the devices: - smaller adaptations concerning connection technology and the commissioning were finished in Support during commissioning of Delta Blower E-Design by an AERZEN technician just a few hours together with an AERZEN technician. The scope of supply covers the general installation control, as well as the analysis of important operating parameters during test operation with real loads. „We thus ensured, that, after modernisation, the unit works as well as before“, says Specht and notes that Aerzener Brot is pleased to be able to use standard components for the technical equipment. In comparison with special solutions, the use of standard technology means availability of spare parts and maintenance. This also applies to the blowers of AERZEN - spare parts can easily be purchased worldwide and installed without additional expenditure on adaptation work. Energy-efficiency and safe operation, combined with high availability, determine the technical equipment of all operational ranges at Aerzener Brot und Kuchen GmbH. Against this background, the company attaches great importance to energy-efficient equipment. Energy consumption is one of the most significant operational costs for the bakeries sector.