Bottle counting in glass manufacturing facilities
Customer / Field / Equipment manufacturer
Enduser: Gerresheimer Germany / Glass bottle production
Production of glass containers for pharmaceutical use. After molding, glass bottles are lined up and transported on a transfer conveyor; here they must be counted. Their temperature ranges from 600 up to 1000 °C. Color and size can vary. Travelling speed can reach up to 500 bottles / min.
Previous tests with light barriers were unsuccessful due to the changing degree of transparency as a consequence of the bottle color; reliable detection was not possible. Capacitive proximity sensors are too slow to react. Moreover, previously used sensors could not resist the high bottle body temperature.
Previous solution / Competitor product
Light barriers or capacitive proximity switches.
A compact hot metal detector capturing the body temperature of the bottle.
Due to its round shape, the quantity of heat radiation emitted by the bottle to the sensor is larger in the middle than in the empty space between two bodies. Therefore, each bottle generates a switching pulse. Bottles with very little spacing can be detected by pointing the sensor onto the bottle neck.
Advantages compared to previous solution or competition
Infrared sensors have a very high switching frequency rate (1500 Hz) so that they can control conveyors travelling at high speed. Their water-cooled housing and glass lens are robust enough to resist the body temperature of the bottles; this allows for near installation.