Level measurement of liquid chocolate in an industrial bakery

Application Note | Food & Beverage

  • Improved stock management through automated level measurement
  • Reliable and accurate readings despite viscous, sticky liquid and moving product surface
  • Non-contact hygienic level measurement using 80 GHz radar with non-intrusive PEEK Lens antenna


An industrial bakery in France produces chocolate buns using liquid chocolate stored at +45 °C / +113 °F in a tank with conical top and bottom of 4.74 m / 15.55 ft height. Every four hours for ten minutes a rotating scraper removes the chocolate from the tank walls.

Measurement requirements

In order to ensure the uninterrupted supply of chocolate for the production of buns, the level of product inside the tank must be continuously monitored. The viscous and sticky liquid tends to build up, especially on intruding measuring probes. Apart from hygienic issues and increased maintenance costs, this can easily lead to inaccurate readings just like the moving product surface resulting from the scraper. In addition, the customer was looking for an automated measuring solution to manage his stock and reduce manual workload. As the tank was new, there had not been any measuring equipment installed so far.

KROHNE Solution

KROHNE installed the OPTIWAVE 3500 C. This 80 GHz FMCW radar level transmitter is dedicated to liquid applications with hygienic requirements. It has been installed with a DN 51 SMS 1145 hygienic connection and a flush-mounted DN 25 / 1.5" PEEK Lens antenna. Fitted on top of the tank, the device continuously measures the level of the liquid chocolate and automatically transmits the values to the control room.

Customer benefits

The customer has optimized the supply inventory and reduced their maintenance and production costs at the same time. The OPTIWAVE 3500 provides continuous and precise readings of the liquid chocolate level right up to the process connection. Its flush-mounted PEEK Lens antenna does not intrude into the tank which avoids deposit and keeps maintenance costs low. Thanks to its small beam angle, the radar is able to measure agitated product surfaces with an accuracy of ±2 mm / ±0.08". The measured values are automatically forwarded to the control room. Easy to install, commission and operate, this solution gives a fast return on investment altogether.

Products used


Radar (FMCW) level transmitter for liquids with hygienic requirements

  • Continuous, non-contact level measurement in small and narrow vessels, small storage tanks and agitated tanks
  • 80 GHz radar, flush-mounted Lens antenna
  • Measuring range: 0…50 m / 164 ft
  • -40…+150°C / +302°F; -1…25 barg / -14.5…362 psig