Wherever plastic granulates are conveyed and processed, capacitive sensors are used to monitor levels in pipes and in silos or through sight glasses in loaders on injection moulding machines. The sensor must reliably detect a wide range of different plastics. On the one hand this means different materials, residual moistures and temperatures, on the other hand the grain sizes and surfaces of the basic substances vary considerably.
The switch is easily adjusted to the medium by pressing a button. Owing to the separation of sensor head and electronics, level detection in crystallizers has become possible. The sensor head is suited for the high temperatures prevailing in that environment. The amplifier has to be mounted outside the high-temperature area. The special mechanical configuration ensures that the sensor is very insensitive to electrostatic discharges.
To reduce the type varieties the switching output is programmable as normally closed or normally open. Two highly visible LEDs clearly indicate the level even at a long distance.