Detection of micro-bubbles in thin hoses and tubes

Balluff STM GmbH: Reliably detecting microscopically small gas bubbles in clear liquids is inherently difficult, just due to the size of the objects. Moreover, during optical procedures it is difficult to obtain uniform illumination of the liquid column and thus uniform sensitivity over the entire diameter, due to the refraction of the light in the curved hose walls.

STM has developed a reliable solution for this: Several micro-optical sensors simultaneously illuminate the liquid in different directions. With their movement through the measurement range, the light is diffracted or scattered at the micro-bubbles due to their approximately spherical shape.

The signals received from the individual sensors are analysed with regard to their dynamic components in the evaluation electronic unit. Each pass, even of tiny bubbles, gives signal peaks that can be reliably detected.

Due to its modular design, the sensor can be quickly and easily adapted to specific hose diameters and materials.