Wireless In-Kiln Moisture Sensor for Lumber Drying

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Solution Overview

Problem

Current lumber drying monitoring systems face limitations such as high upfront and maintenance costs due to wired connections, lack of flexibility in sensor placement, and the inability to operate effectively in extreme kiln temperatures and humidity, leading to reduced battery life and inefficiencies in continuous processing environments.

Innovation Solution

A wireless sensor system that uses battery-powered sensors embedded within lumber stacks to measure moisture content, capable of operating in extreme temperatures and humidity levels, with power conservation methods that allow for extended battery life and flexible sensor placement, utilizing both capacitance and resistance measurements for accurate moisture estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wired metering devices are used to measure moisture content, then measurement accuracy is maintained, but installation cost and maintenance expense increase significantly due to conduit runs and cable installation

Engineering Contradiction:
Improvemoisture content measurement accuracyVSAvoidinstallation cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces wired mechanical connection systems with wireless communication technology. Sensors communicate moisture data via wireless signals (RF, Wi-Fi, Bluetooth) instead of physical cables, eliminating conduit installation while maintaining measurement accuracy through digital signal transmission.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the communication function from the physical wiring infrastructure. By removing cables and conduits from the system architecture, it eliminates the associated installation and maintenance costs while preserving the core measurement capability through wireless data transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If fixed wall-mounted metering devices are installed, then stable measurement points are established, but flexibility to change sensor locations is lost and reinstallation costs increase

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidsensor placement flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static, fixed sensor installation into a dynamic, reconfigurable system. Wireless sensors can be easily relocated along the lumber stack or between different kiln positions without permanent mounting infrastructure, enabling adaptive measurement points while maintaining stable data collection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent divides the monitoring system into independent, modular wireless sensor units that can be individually positioned and relocated. Each sensor operates autonomously without dependency on fixed wiring infrastructure, allowing flexible redistribution of measurement points across different locations.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If conventional batteries are used in wireless sensors, then portability and installation ease are improved, but battery life is severely reduced in high-temperature kiln environments

Engineering Contradiction:
Improvesensor installation easeVSAvoidbattery life
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent changes the operating parameters of the battery system by implementing adaptive power management that adjusts sensor polling intervals, transmission frequency, and processing intensity based on environmental conditions. This extends battery operational duration in high-temperature kiln environments while maintaining adequate monitoring functionality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements periodic measurement and transmission cycles instead of continuous operation. Sensors take measurements at optimized intervals and transmit data periodically, reducing overall power consumption and extending battery life while still providing effective moisture monitoring throughout the drying process.

Inventive Principle:
Principle #19Periodic action

4Productivity

If continuous monitoring is implemented in continuous processing environments, then productivity is improved, but energy consumption and battery drain increase

Engineering Contradiction:
Improvecontinuous processing efficiencyVSAvoidsensor power consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic monitoring cycles where sensors activate at intervals corresponding to processing stages rather than continuous operation. This reduces power consumption by keeping sensors dormant during stable phases and activating only when moisture measurements are needed for process adjustments.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent employs feedback-based adaptive monitoring where measurement frequency is adjusted based on process conditions. When moisture levels are stable or outside critical ranges, monitoring intensity is reduced. When approaching target moisture content or detecting anomalies, monitoring frequency increases, optimizing the balance between productivity and energy consumption.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enables efficient and flexible monitoring of lumber moisture content, reducing costs and improving operational efficiency by extending battery life and allowing for real-time monitoring in continuous processing environments, while maintaining accuracy and reliability.

Implementation Method 1

the sensor and the circuit are configured to establish a capacitance of a water content of at least a portion of the collection

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the sensor and the circuit are configured to establish a resistance of a water content of at least a portion of the collection

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP2870423B1Wireless in-kiln moisture sensor and system for use thereof
Publication Date: 2018.04.25 SCS FOREST PROD
  • EP2870423B1 patent drawingFigure 1~2
  • EP2870423B1 patent drawingFigure 3
  • EP2870423B1 patent drawingFigure 4

AI summary

A wood monitoring system and method is disclosed for monitoring lumber characteristics (e.g., lumber moisture) in environments of extremely high and prolonged temperature and moisture, e.g., a kiln. The monitoring system and method includes: (a) Sensors (provided within lumber stacks), wherein such sensors are battery powered and wirelessly communicate measurements indicative of moisture content of the wood adjacent to and/or between metal plates provided in an electrical circuit with the sensors and the wood between the plates; (b) Computer implemented methods and systems for wireless communication that conserve sensor battery power such that the sensors can operate for, e.g., six months within extremely adverse temperature and moisture environmental variations; and (c) Computer implemented methods and systems for estimating moisture content with a wood/lumber stack, and for predicting such moisture content (e.g., as a substantially steady state within the wood) after drying completion.