Fibre-based sensor makes CIP more economical

In the food processing industry, high hygiene requirements need to be applied. The cleaning of production facilities must be completely reliable in order to guarantee the safety of food products. 

For closed containers or pipes carrying products such as milk, beer, or juices fixed cleaning routines apply. ‘The more, the better’ is the general rule in this case. Cleaning agents, water, energy, as well as the cleaning time are very generously calculated in order to ensure compliance with strict quality regulations. This safety margin is not only ecologically questionable but also economically unfavourable, because it causes unnecessary delays in the production process.

The F-Fiber sensor was developed at Fraunhofer IPM as part of the SensoRein project (sensor-based monitoring of cleaning requirements and cleaning results in closed systems). The project was funded by the German Federal Ministry of Food and Agriculture (BMEL) and coordinated by the German Engineering Federation (VDMA). The project was led by Vivien Behrendt.

The sensor makes it possible to adapt the clean-in-place (CIP) routines within closed vessels to better match the actual degree of contamination. 

F-Fiber consists of an optical fibre measuring 1mm in diameter, which is embedded in a stainless-steel ferrule. The fibre tip is integrated directly into the container wall of a food tank or food-conveying pipe. Alternatively, it can be attached to an existing connector using a flange. All further hardware components of the measuring system are located outside the production unit and are connected via the fibre.

At the inner wall of the tank or tube, the fibre tip is flushed by the tank or tube content. Over time, molecules accumulate on the sensor tip as well as on the surrounding tank wall, forming an unwanted deposit. The organic deposit emits fluorescence when excited with UV light via the sensor fibre. The emitted fluorescence is guided back onto a highly sensitive detector via the same fibre and evaluated. From the strength of the fluorescence signal, conclusions can be drawn about the degree of fouling. Based on these measured values, the cleaning process can be triggered and adjusted in real time. This is possible for many different types of food soil that can even occur during the same production process.