Moisture Variability Quantification in Wood Drying

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Solution Overview

Problem

The lumber industry faces challenges in ensuring consistent moisture content in wood products, leading to variability that affects product quality, value, and efficiency in drying processes, as existing methods struggle to accurately quantify and manage sources of moisture content variability.

Innovation Solution

A method is developed to quantify the contribution of various sources of moisture content variability in wood products, using data analysis and statistical models to identify and prioritize opportunities for reducing variability, which includes obtaining moisture content data, identifying sources of variability, and implementing executable steps to impact these sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If controlled drying processes are used in kilns, then moisture content is reduced, but variability in moisture content remains due to differences in drying conditions between and within kiln charges

Engineering Contradiction:
Improvemoisture content consistencyVSAvoidmoisture content uniformity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent segments the drying process into distinct hierarchical levels (kiln charges, packages, courses, and pieces) to systematically identify and quantify variability sources at each level. This segmentation allows targeted intervention at specific stages rather than treating the entire drying process as a uniform system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback through statistical analysis of moisture content data collected at multiple hierarchical levels. By quantifying variability contributions from each level, the system provides feedback on which stages require process adjustments, enabling continuous improvement of drying consistency.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If moisture content is reduced to improve product value, then dimensional stability and durability improve, but variability in moisture content leads to over- or under-drying losses

Engineering Contradiction:
Improvemoisture content controlVSAvoidproduct value loss
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent performs preliminary statistical analysis of variability sources before final drying decisions are made. By identifying which hierarchical levels contribute most to variability, the system enables proactive process adjustments that prevent over- or under-drying, thereby preserving product value.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter being controlled from simply average moisture content to the distribution of moisture content across multiple hierarchical levels. This parameter transformation allows detection and correction of variability issues that would be invisible if only mean moisture content were monitored.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8793010B2Method for reducing overall variability of moisture content in wood products
Publication Date: 2014.07.29 WEYERHAEUSER NR CO
  • US8793010B2 patent drawing
  • US8793010B2 patent drawing
  • US8793010B2 patent drawing

AI summary

The present disclosure includes a method for quantifying contribution to overall variability of moisture content in wood products and associated computer software. The method comprises the steps of obtaining moisture content data for the wood products and identifying one or more sources of variability in the moisture content data. A contribution to overall variability from each of the one or more sources of variability is then quantified. One or more opportunities to impact the overall variability are then quantified, each of the one or more opportunities being associated with one or more executable steps.