Use of Hygienic Load Cells Dramatically Reduces Cleaning Time of Filling Machines

A European research project on hygienic design in the food processing industry unveils the potential of using hygienic load cells in dosing and filling machines. The use of specially designed “hygienic load cells” of the type PW27 developed by HBM reduces the cleaning time of the sensor system of filling machines by as much as 29 percent. This turns the integration of these load cells into the food industry to a competitive advantage.

Traditional vs. hygienic

Several partners from research and industry have examined the possibilities to reduce the environmental impact of food processing through the use of hygienic machine components in the EU-supported “ECODHYBAT” project. As part of this program, HBM has supplied its aseptic load cells of the type PW27.

The examination was conducted by Ainia. Ainia is a technology center which has contributed to many projects under the framework of European initiatives and can look back on more than 25 years of R&D activities. Ainia investigated the degree of hygiene and the cleaning time of a PW27 hygienic load cell from HBM in direct comparison with a conventional load cell (PW15AH, also from HBM).

Hygienic load cells

Load cells are used for determining weight during filling, dosing and packaging in the food industry. They are often in direct contact with the substances to be weighed. Therefore, not only the precision of these sensors is crucial, but also their handling and easy cleaning in machines. Hygienic and aseptic load cells are optimized so that their shapes and surfaces prevent the accumulation of dirt and bacteria growth.

The PW15AH (left) and PW27 (right) load cells after use.

Research has shown that hygienic load cells have clear advantages: Cleaning of hygienic load cells could be completed faster, by 29 percent, than with conventional load cells. In the experiments, the two load cells were tested after being soiled with a solution of whole milk, fluorescein, ethanol and a dye. In the ECODHYBAT project, cleaning operations were tested in several steps and then analyzed. Finally, the time needed to remove 99 percent of the soiling from the load cells was measured in a number of test samples.

29 percent faster cleaning time for hygienic load cells

The average cleaning time of a conventional load cell was 4 minutes and 36 seconds. By contrast, cleaning the hygienic load cell took only 3 minutes and 11 seconds.  This means a total time saving of 29 percent. Thanks to the use of hygienic load cells, the machine can be cleaned more quickly and is thus ready for the new filling process in less time.

Time required to remove 99 percent of the soiling (in minutes):

 

Test 1 Test 2 Test 3 Test 4
PW15AH (conventional) 3.5 4 4.5 6.6
PW27 (certified) 2.5 4 2.6 3.6
Difference (min) 1 0 2 3
Time saving when cleaning the certified load cell 29% 0% 43% 45%

98 percent of the dirt swiped away in just one and a half minutes

The studies conducted by Ainia also show that a very high degree of cleanliness can be achieved faster with a hygienic load cell: 98 percent of the soiling on hygienic load cells could be removed after just 1.5 minutes, while only 80% were removed from the conventional load cell after the same amount of time.