Laundry Dryer Fan Speed Control Using Electrode-Based Load Sensing
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Solution Overview
Problem
Laundry dryers often operate at reduced capacity, leading to inefficient energy consumption and prolonged drying cycles due to suboptimal load utilization, as existing methods fail to adapt drying cycles effectively to varying loads.
Innovation Solution
A method that detects electric resistance and conductivity between electrodes in the laundry drum to estimate the load, adjusting the rotation speed of the drying air stream fan accordingly, with higher speeds for lighter loads to enhance drying performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the drying cycle operates at full capacity settings, then the drying power is sufficient for maximum load, but energy consumption increases and drying time extends for reduced loads
Solution Approach 1:
The patent applies dynamics by making the drying air stream fan rotation speed variable rather than fixed. The control unit adjusts the fan speed dynamically based on the detected load amount, increasing speed for lighter loads and decreasing for heavier loads. This dynamic adjustment ensures sufficient drying power for any load size while avoiding excessive energy consumption that would occur with fixed full-capacity settings.
Solution Approach 2:
The patent changes the operational parameter of the drying air stream fan speed based on load conditions. By detecting the load amount and correspondingly adjusting the fan rotation speed, the system adapts the drying power parameter to match actual needs, preventing energy waste while maintaining effective drying performance across different load sizes.
2Power
If the drying cycle operates at full capacity settings, then the drying power is sufficient for maximum load, but drying time extends for reduced loads
Solution Approach 1:
The system dynamically adjusts the drying air stream fan speed based on detected load amount. For reduced loads, the fan operates at higher speeds to intensify drying airflow, thereby reducing drying time. For maximum loads, the fan operates at lower speeds appropriate for the capacity, preventing unnecessarily extended drying cycles. This dynamic adaptation optimizes drying time across all load conditions while maintaining sufficient drying power.
3Measurement precision
If stationary electrodes are used to detect laundry weight through electrical resistance, then load detection is achieved, but measurement precision is affected by signal noise
Solution Approach 1:
The control unit continuously monitors the electrical resistance between stationary electrodes and uses this feedback to determine load amount. The system processes the resistance signals to compensate for noise effects, converting the electrical measurements into accurate load detection information that guides subsequent drying cycle adjustments.
Solution Approach 2:
The patent replaces direct mechanical weight measurement with an electrical field-based detection method. By using stationary electrodes to measure electrical resistance caused by laundry contact, the system achieves load detection without mechanical sensors, improving reliability while the control unit processes the electrical signals to overcome noise interference.
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 approach optimizes energy use and reduces drying time by correlating electric signal noise and fluctuations with load levels, ensuring the dryer operates at maximum performance even with partial loads.
Implementation Method 1
detecting an electric resistance and/or an electric conductivity between two or more electrodes (12, 14) at least partly contacting the laundry inside the laundry drum (16)
Implementation Method 2
detecting an electric resistance and/or an electric conductivity between two or more electrodes (12, 14)
Implementation Method 3
controlling a rotation speed (v) of a drying air stream fan (30) for conveying a drying air stream through the laundry drum (16)
Implementation Method 4
a method for controlling a drying cycle of a laundry dryer in dependence of the amount of load inside a laundry drum
Data Source
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AI summary
The present invention relates to a method for controlling a drying cycle of a laundry dryer (10) in dependence of the amount of load inside a laundry drum (16), comprising the steps of: detecting an electric resistance and/or an electric conductivity between two or more electrodes (12, 14) at least partly contacting the laundry inside the laundry drum (16) and, estimating the amount of load inside the laundry drum (16) by evaluating the noise and/or fluctuation of the detected electric resistance and/or conductivity, and controlling a rotation speed (v) of a drying air stream fan (30) for conveying a drying air stream through the laundry drum (16) in response to the estimated amount of load inside the laundry drum (16), wherein the rotation speed (v) of the drying air stream fan increases with a decreasing amount of load in the laundry drum (16). Further, the present invention relates to a corresponding laundry dryer (10).