Dryer Lint Filter Clogging Detection Using Airflow Rate Measurement
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Solution Overview
Problem
Conventional dryer appliances lack effective detection methods for lint filter clogging, leading to increased pressure drop, reduced airflow, longer drying times, and decreased energy efficiency, as well as potential overheating issues.
Innovation Solution
The appliance measures temperature and relative humidity of air before and after the drying compartment during a steady state condition to calculate the airflow rate, allowing for the detection of clogged lint filters and enabling corrective actions such as alerting the user or initiating an auto-cleaning cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature-based detection methods are used, then the system is simple to implement, but the detection sensitivity to gradual lint accumulation is insufficient
Solution Approach 1:
The patent replaces conventional temperature-based detection with an airflow rate measurement system. By measuring the actual airflow through the dryer using differential pressure sensors across a flow restriction element, the system achieves higher sensitivity to lint accumulation without requiring complex temperature monitoring arrays. The airflow measurement directly reflects filter clogging conditions, providing more precise detection than indirect temperature methods.
Solution Approach 2:
The patent introduces a flow restriction element (orifice plate or venturi) as an intermediary component in the airflow path. This element creates a measurable differential pressure that correlates with airflow rate and indirectly indicates filter clogging status. The intermediary transforms the difficult-to-measure airflow rate into an easily measurable pressure differential, enhancing detection sensitivity while maintaining system simplicity.
2Productivity
If lint filter cleaning is delayed, then the appliance structure remains simple, but the pressure drop increases and airflow is reduced
Solution Approach 1:
The patent implements a feedback control system that continuously monitors airflow rate through the dryer and compares it against predetermined thresholds. When the airflow rate indicates filter clogging (below threshold), the system automatically generates a notification to the user to clean the filter. This feedback mechanism maintains optimal drying efficiency by triggering timely filter maintenance without requiring complex predictive algorithms or additional hardware beyond the airflow sensor and control logic.
Solution Approach 2:
The system enables users to self-monitor and self-maintain the lint filter through automated airflow monitoring and user notifications. The control system automatically tracks airflow degradation and informs users when filter cleaning is needed, allowing users to perform simple maintenance tasks based on objective data rather than arbitrary schedules. This self-service approach maintains productivity while keeping the overall appliance structure relatively simple.
3Use of energy by moving object
If the airflow rate is not monitored, then the appliance is simpler, but the energy efficiency decreases and overheating risk increases
Solution Approach 1:
The patent replaces complex multi-parameter monitoring systems (temperature, humidity, power consumption) with a single airflow rate measurement system. By measuring differential pressure across a flow restriction element, the system directly quantifies airflow rate, which serves as a leading indicator for both energy efficiency and overheating risks. This mechanical measurement approach is simpler than electronic sensor arrays while providing more direct information about system performance and filter condition.
Solution Approach 2:
The patent changes the monitoring parameter from indirect indicators (temperature, power consumption) to a direct indicator (airflow rate). Airflow rate is a more fundamental parameter that directly reflects filter clogging status and system performance. By monitoring this single parameter with high sensitivity, the system can predict and prevent energy efficiency degradation and overheating before they occur, maintaining energy efficiency without requiring complex multi-parameter monitoring systems.
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 effectively detects clogged lint filters, preventing airflow restrictions, maintaining energy efficiency, and reducing the risk of overheating, thereby ensuring optimal drying performance.
Implementation Method 1
measuring temperature and relative humidity of air supplied to the compartment during the steady state condition; measuring temperature and relative humidity of air received from the compartment during the steady state condition
Implementation Method 2
measuring temperature and relative humidity of air supplied to the compartment during the steady state condition; measuring temperature and relative humidity of air received from the compartment during the steady state condition
Implementation Method 3
supply air to the compartment to vaporize moisture from articles in the compartment
Implementation Method 4
supply air to the compartment to vaporize moisture from articles in the compartment
Implementation Method 5
assessing a moisture extraction rate from the load or articles during the steady state condition; ascertaining an amount of moisture per unit volume of air removed from the load of articles
Data Source
AI summary
A laundry appliance uses a determination of volumetric airflow rate after a steady state condition is reached to determine the accumulation of lint in filter. Based on the determination, various actions can be taken including notifying the user, shutting off the appliance, initiating an automatic cleaning sequence for one or more lint filters, and combinations thereof. One or more temperature sensors, relative humidity sensors, and weight sensors are used to provide measurements for determining the volumetric airflow rate.