Measuring the moisture of wood chips

The Berthold LB 568 analyzer provides an online and real-time moisture measurement of digester-fed wood chips. The LB 568 generates multiple microwaves in a wide frequency range, emitted by an antenna below the conveyor. The microwaves penetrate the wood chips and are received by a second antenna above the belt. When penetrating the wood chips, the microwave signal‘s characteristics change in terms of attenuation and phase shift. These changes directly correlate to the wood chip moisture. Variations in layer thickness and bulk density are compensated with the use of a radiometric bulk density compensation system component. The complete system thus provides a stable and reliable moisture reading. The microwave moisture analysers are installed at the feeding line to the digester and the transmitter is mounted close to the LB 568s. Depending on the sampling representativity and measurement conditions a typical accuracy of better than ±1.0 % (1 sigma) can be achieved.

Customer benefits

  • Accurate moisture leads to accurate „bone dry“ solids addition leads to accurate digester chemical charge
  • Measurement independent of wood species
  • Operates reliably at moisture levels up to and above 50%
  • Transmission measurement provides representative sample as opposed to traditional „surface only“ measurements


  • Installs around existing conveyor belts
  • Noncontact measurement
  • FCC compliant
  • High measurement repeatability
  • State-of-the-art microwave transmission technology covering the whole material cross-section


3 Results

Berthold's Measurement Solutions

MicroPolar LB 567/568

Microwave moisture analyzer for all kind of bulk materials, noncontact, reliable, and virtually maintenance free

LB 571 Microwave Resonator

Sensor for online moisture measurement of bulk materials