Dryer Vent Duct Humidity Sensing for Accurate Cycle Termination
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Solution Overview
Problem
Existing dryer appliances often result in over-drying or under-drying of articles due to predetermined dry cycle times that do not account for the moisture content of the items being dried, leading to inefficiencies in drying processes.
Innovation Solution
A dryer appliance equipped with a humidity sensor and a valve system that alternately senses internal and external air humidity values, allowing for real-time adjustment of the dry cycle based on differential humidity measurements to ensure optimal dryness levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If predetermined dry cycle time periods are used, then the dryer operation is simple and consistent, but over-drying or under-drying occurs because moisture content is not taken into account
Solution Approach 1:
The patent implements a feedback control system where humidity sensors continuously monitor the humidity of air entering and leaving the dryer drum. The controller compares the differential humidity values and adjusts the dry cycle termination accordingly, replacing predetermined timing with real-time humidity-based feedback to prevent over-drying and under-drying while maintaining operational simplicity.
2Measurement precision
If humidity sensors are used to measure internal air humidity in real time, then appropriate dry cycle time periods can be determined, but the system becomes complex and unreliable
Solution Approach 1:
The patent uses the differential humidity measurement approach as an intermediary method. Instead of directly measuring the complex state of articles or using multiple sensors within the drum, the system measures humidity at two accessible points (air entering and leaving the drum) and uses the differential as a proxy indicator of article dryness, simplifying the sensing system while maintaining measurement precision.
3Measurement precision
If resistance measurements across articles are used to determine dryness, then real-time dry cycle adjustment is possible, but the system becomes complex and may still result in over-drying or under-drying
Solution Approach 1:
The patent replaces the electrical resistance measurement approach with a humidity-based sensing system. Instead of measuring electrical properties of articles, the system measures the humidity of air flows, which is a more reliable and simpler physical parameter to measure using standard humidity sensors, thereby reducing system complexity while improving measurement precision.
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
This solution reduces or eliminates instances of over-drying and under-drying by accurately determining the dryness level of articles through differential humidity sensing, ensuring efficient and effective drying processes.
Implementation Method 1
a humidity sensor positioned within the vent duct. Selective operation of the valve causes the humidity sensor to alternately sense internal air humidity values and external air humidity values.
Data Source
AI summary
Dryer appliances and methods for operating dryer appliances are provided. A method includes flowing internal air from a drum chamber through a vent duct of the dryer appliance, selectively actuating a valve to flow external air through the vent duct from external to a cabinet of the dryer appliance, and alternately sensing humidity values of the internal air and the external air.