Clothes Dryer Dryness Control Using Load Size and Air Flow Sensing
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Solution Overview
Problem
Existing clothes dryers inaccurately determine the dryness of clothing due to variations in load size and air flow conditions, leading to either over-drying or under-drying, as the target moisture voltage is not adjusted for these factors.
Innovation Solution
A clothes dryer system that includes load size and air flow parameter generating modules, which provide input parameters to a processor to select a target moisture value from a lookup table, adjusting for different load sizes and air flow conditions by sensing inlet and outlet temperatures and generating appropriate parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed target voltage is used for moisture detection, then the control system is simple, but the dryness detection accuracy deteriorates due to variations in load size and air flow conditions
Solution Approach 1:
The patent implements dynamic adjustment of the target voltage based on detected load size and air flow conditions. Instead of using a fixed predetermined voltage, the system continuously adapts the target voltage value according to actual operating parameters, resolving the contradiction between system simplicity and measurement accuracy by making the control parameter dynamic rather than static
Solution Approach 2:
The patent changes the target voltage parameter based on detected load size and air flow conditions. By adjusting this critical parameter according to actual operating conditions, the system maintains high detection accuracy without requiring complete redesign of the control architecture, thus balancing simplicity and precision
2Ease of operation
If the target voltage is set for average load size, then the system is easy to operate, but the drying precision deteriorates for small or large loads
Solution Approach 1:
The system automatically detects load size and air flow conditions, then self-adjusts the target voltage without requiring user intervention. The controller autonomously selects appropriate target voltages based on detected parameters, maintaining ease of operation while achieving precise drying control for varying load sizes
Solution Approach 2:
The system uses feedback from load size detection and air flow sensing to continuously adjust the target voltage. This closed-loop approach ensures that the target voltage always corresponds to actual operating conditions, maintaining high drying precision while keeping the user interface simple
3Productivity
If the moisture sensor is mounted at the front of the dryer drum, then the air flow effect is maximized, but the measurement precision deteriorates due to increased frequency of clothes contact affecting the filtered voltage signal
Solution Approach 1:
The patent compensates for the position-induced signal variation by dynamically adjusting the target voltage based on detected air flow conditions and load size. This parameter adjustment compensates for the increased contact frequency effect, maintaining measurement precision while preserving the benefits of front-mounted sensor positioning for air flow efficiency
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 system ensures more accurate control of the drying cycle by adjusting the target moisture value based on load size and air flow conditions, reducing errors in dryness detection and improving drying efficiency.
Implementation Method 1
an inlet temperature sensor for sensing temperature of the heated air flowing into the drum
Implementation Method 2
an outlet temperature sensor for sensing temperature of air exiting from the drum
Implementation Method 3
a moisture sensor for providing a moisture signal indicative of the moisture content of the clothing articles
Data Source
AI summary
A clothes dryer has a degree of dryness control system that is responsive to moisture level of clothing articles tumbling in a drum and a target moisture value to control the drying cycle of the clothes dryer. The clothes dryer has a load size parameter producing module and an air flow detection parameter module. These modules generate one of two parameter conditions used by the processor to modify or select an appropriate moisture target value. The load size producing parameter module generates one of a small load input parameter and a large load input parameter. The air flow detection module produces one of a first and second air flow parameter to be utilized by the degree of dryness processor. As a result, the processor selects one of four target moisture values from these conditions.