Prof. Dr. Uwe Hampel
Phone: +49 351 260 2772
Fax: +49 351 260 12772, +49 351 260 2383

Process microscope

Foto: Fig. 1: The optical flow microscope. ©Copyright: Christoph Schunk

Fig. 1: The optical flow microscope.

Foto: Fig. 2: Detection of non-spherical bubbles ©Copyright: Christoph Schunk

Fig. 2: Detection of non-spherical bubbles

The process microscope was developed to measure gas bubbles and particles in process fluids. It can be used for a large number of applications. Commercial optical sensor technology, which is usually based on the scattering of light, is usually very expensive and technically complex. This system provides a much simpler approach to particle and gas bubble measurement.

The technique used by the camera system is based on bright-field illumination. The typical appearance of a bubble or particle in a bright-field microscopy image is a dark object on a bright background. The lighting and camera unit face each other and can be mounted in a tube or process vessel. This method also achieves a very high accuracy, determined by the quality of the optical system and the resolution of the image detector, in determining volumetric and form-specific particle parameters, especially at high gas contents/particle densities and complex particle shapes.

Short exposure times of 1 µs allow sharp images to be captured even at high flow rates. Also remarkable is its low system requirements, e.g. it only requires a Gigabit Ethernet interface on the PC side. The process microscope includes a software application for algorithmic evaluation of the recorded image sequences.

With the software bubbles and particles can be measured and their parameters - such as axes, orientation and size - can be determined. The software allows the calculation and visalization of size distributions.

The process microscope can be used in various fields of industry and science where the formation, solution or behaviour of micro gas bubbles are of diagnostic interest. Examples are the investigation of

  • Chemical reactions with local gas release or evaporation,
  • Electrolysis,
  • Fermentation,
  • Cavitation,
  • Boiling processes,
  • Gas solubility and dispersion.

Typical parameters

Resolution: 656 x 492 (256 grayscales)
Network interface: 1Gigabit Ethernet
Frame rate: up to 120 frames per second
Maximum pressure: 10 bar
Temperature: 0 ... 45 °C
Supply voltage: 9 ... 36 V DC
Distance: 5 mm ... 10 mm
Measurement range: 6 µm ... 3 mm


Prof. Dr. Uwe Hampel
Phone: +49 351 260 2772
Fax: +49 351 260 12772, +49 351 260 2383