A Smart Electrode for Heating and/or Determining Timber Properties of Logs

Recently, work has been carried out in New Zealand to develop Joule heating as a treatment for logs of Pinus radiata and other forestry species. Such heating has been shown to be of value in three applications, namely: phytosanitary treatment of export logs; pre-peel conditioning of veneer logs; and pre-sawing conditioning of collapse-prone Eucalyptus globoidea logs. To develop and control a reliable Joule heating method, an electro-thermal model of a log was built, for which the thermal and low-frequency electrical properties of unseasoned timber properties were measured, as functions of temperature between ambient and around 90° Celsius. Applying a current sensing electrode to one or both face/s of a log, and imposing a voltage between this and a return electrode, a current flows, with greater intensity in the sapwood than the other timber regions. By splitting the current sensing electrode into a sufficient number of segments, with some image enhancement techniques, the resulting current density map can be used to accurately determine the shape and dimensions of the various timber regions. The design of a proof-of-concept system employing 121 electrode segments is described, with practical results. The method and system described are novel, and are covered by patent US 11,181,318 B2, held by Heffernan et al.