Application of Smart Electrodes to logs, for timber assessment and Joule Heating
Speaker
Dr Bill Heffernan
Institute
Electric Power Engineering Centre University of Canterbury
Time & Place
Fri, 09 Aug 2019 14:00:00 NZST in Link 309 Lecture Theatre
Abstract
Based on work carried out over the past few years, the EPECentre team is developing a Smart Electrode capable of determining the shape and structure of unseasoned logs, based on the electrical conductivity
distribution.
Since unseasoned timber’s electrical conductivity has a strong temperature dependence, the temperature distribution within a log can also be determined by the method – this is significant for two processes carried out within the timber industry:
1. Heat treatment for biosecurity of exported/imported logs
2. Log softening (known as “conditioning”) prior to veneer peeling for plywood and LVL manufacture
Finally, if sufficient electric field strength is applied across a log, Joule’s effect can be used to provide the heat treatment using the same electrodes.
Figure 1. Modelled current distribution in the segments of a Smart Electrode applied to a typical radiata pine log, before and after Joule heating. The electrode has an overall diameter of 500mm, colour represents current per equal-area segment and trace represents actual segment current across a diameter. Left: 1000 segment electrode with isothermal “cold” log; Right: 500 segment electrode with “hot” log, just after Joule heating.
Biography
Senior Research Engineer
Principal Investigator – Joule Log Heat
Electric Power Engineering Centre
University of Canterbury