Look behind the scenes
Yoghurt is one of the exceptionally demanding conveyor media in the food sector.
On the one hand, it is vital to avoid strong shear forces so as to protect the valuable bacteria cultures and prevent separation of the different phases. On the other hand, the product, like almost all dairy products, is critical in terms of hygiene, which means that all pump materials have to meet food safety requirements and comprehensive cleaning has to be carried out regularly.
When setting up a new yoghurt line, a large dairy therefore decided on the NEMO® aseptic pump.
In order to meet the high hygiene requirements, it is a flexible rod, rather than open joints or joints filled with oil, that connects the drive to the shaft. This is heat-shrunk with the rotor and connection point, so that the transition is hermetically sealed. Because there is no friction between components at the connection, there is hardly any wear on the flexible rod and it needs no lubrication or seal, which means maintenance costs are very low. The materials used for the application in the dairy were stainless steel – in a polished version for the wetted parts – and a stator made of FDA-compliant elastomers, while a double mechanical seal in special hygienic design was used on the product side.
The layout of the pump was also specially designed for the CIP process: a bypass line and tangential cleaning ports ensure that the required cleaning fluid flow speed of 1.5 m/s is achieved throughout the system. In addition, the streamlined geometry of the conveying area prevents dead spaces or product deposits and enables the pump to be comprehensively cleaned and completely emptied.
To compensate for any possible fluctuations in the product flow, the pump was also combined with a variable gear and a frequency inverter. This means that the system conveys up to 20 m³ of yoghurt per hour at 10 bar in continuous operation without any problems – and without impairing the high quality of the demanding product.