Stress-based kiln drying of Gmelina arborea Roxb. Lumber

Issue Date

10-2016

Abstract

The study evaluated the kiln drying of 25-mm thick Gmelina arborea Roxb. lumber using conditions based on changing shrinkage rates following the procedure developed by Fuller under US Patent No. 5,873,182 dated 23 February 1999. For comparison, a separate kiln drying run was done following conventional, moisture content (MC)-based drying schedule. To monitor shrinkage, a linear variable differential transducer was mounted across a sample board that was coupled to a data acquisition system. Real-time shrinkage data was processed and the graph of dynamic shrinkage versus time provided information on peak stress, stress reversal and reduction of shrinkage rates. These transitions were taken as signals to advance kiln drying conditions to the next step prescribed in the MC-based drying schedule, which allowed prompt changes in kiln settings. The early transition in internal kiln drying conditions resulted to reduction in kiln drying time by 30 to 36%. The quality of the dried lumber was evident in the more uniform final moisture content distribution of the dried boards, less steep moisture gradient, and the absence of residual stresses in the boards dried in a kiln where changing shrinkage rates were used as basis for operation and control.

Source or Periodical Title

Philippine Journal of Science

ISSN

0031-7683

Volume

145

Issue

3

Page

297-307

Document Type

Article

Physical Description

illustrations, graphs

Language

English

Subject

Gmelina lumber, Kiln drying schedule, Moisture content, Real-time shrinkage, Short/long term slope comparison, Stress-based kiln drying

Digital Copy

yes

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