Load detection in washing machines

Load measurement in washing machines is required to ensure reduced operating costs and lesser environmental damage. The load must be measured before the washing starts, in order to determine the approprate dosage of detergent required to wash a certain amount of clothes. A cost-effective and efficient way to do this is by using magneto-inductive displacement sensors in the process. These sensors are directly integrated in the damper.

The sensors are capable of detecting the position of the piston in the damper continuously and with high dynamics. The sensor exhibits a highly compact structure and allows for a measuring range of 40mm and above. On loading the washing machine, the suds container sinks, thereby generating a change of displacement on the damper. The relationship between the displacement and loading lead to optimising the operation and washing results.

During the washing process, the sensor dynamically controls the imbalance of the drum and during the spinning process detects the rotational speed. It doesn’t depend on any additonal hardware to perform that operation. This enables an improvement in the device operation and spinning, which ultimately improves the service life of the machine. The magneto-inductive displacement sensors are designed for large volume applications and are easily integrated in restricted spaces. The measured values are output using a rectangular signal which is evaluated via digital inputs from micro-controllers.