Laundry Dryer Capacitive Humidity Sensor for Efficient Drying Control
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Solution Overview
Problem
Existing laundry drying appliances lack precision and accuracy in humidity measurement, leading to inefficient drying processes and excessive power consumption, as current systems are hindered by complex and unreliable humidity sensing arrangements.
Innovation Solution
A laundry appliance equipped with a humidity sensor featuring capacitance-sensing pads, protective packaging, and temperature sensors, which allows for differential humidity measurements and improved reliability through a structured electronic connector and potting encapsulation for moisture protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal plate is mounted on the door wall using bi-adhesive tape to measure humidity, then humidity sensing capability is provided, but the mounting becomes complex and time-consuming, reducing manufacturing yield
Solution Approach 1:
The patent integrates the humidity sensing functionality directly into the door assembly by incorporating a printed circuit board with sensing pads that are structurally integrated into the door wall. This eliminates the need for separate metal plate mounting using bi-adhesive tape, thereby simplifying the manufacturing process while maintaining humidity sensing capability.
2Ease of manufacture
If bi-adhesive tape is used to fix the metal plate, then the plate can be attached, but moisture and water can dissolve the adhesive leading to loose attachment or detachment
Solution Approach 1:
The patent replaces the bi-adhesive tape (which degrades in moisture) with a permanent structural integration method using a printed circuit board that is mechanically and electrically integrated into the door assembly. This eliminates the use of degradable adhesives while maintaining ease of manufacturing through standard PCB fabrication techniques.
3Reliability
If the drum or a metal plate on the drum is used as capacitor plate for humidity measurement, then humidity sensing is enabled, but complex electrical wiring harness and slip ring arrangements are required
Solution Approach 1:
The patent extracts the humidity sensing function from the rotating drum and relocates it to the stationary door assembly. By placing the sensing pads on the door rather than on the drum, the system eliminates the need for rotating electrical connections such as slip rings and complex wiring harnesses, while still enabling humidity measurement of the laundry load.
4Extent of automation
If predetermined drying program duration is used, then the drying process can be controlled, but the results depend strongly on laundry amount and type, leading to excessive power consumption
Solution Approach 1:
The patent implements real-time humidity sensing feedback through the capacitive sensing pads on the door. The control system continuously monitors the humidity level of the laundry load and dynamically adjusts the drying program duration and intensity based on actual moisture content, rather than relying on predetermined fixed-time programs. This enables the dryer to terminate the drying process as soon as the laundry reaches the desired dryness, significantly reducing excessive power consumption.
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 solution enhances the accuracy and precision of humidity measurements, enabling more efficient and optimized laundry drying processes while reducing power consumption and manufacturing complexity.
Implementation Method 1
A sensor (400) is provided which comprises an operating support (405), at least one pad (425, 430) made of an electrically conductive material and being adapted to operate as a plate of a capacitor and a sensing arrangement (410)
Data Source
AI summary
A laundry appliance having a laundry drying chamber and a sensor for measuring the humidity of laundry items contained in the laundry drying chamber. The sensor includes an operating support having a first surface and a second surface opposite to the first surface. The sensor also has at least one first pad provided on the first surface of the operating support and at least one second pad provided on the second surface of the operating support, both the first pad and the second pad being made of an electrically conductive material and being adapted to operate as a plate of a capacitor. Methods for detecting humidity of laundry items are also provided.