Induction-Heated Dryer Drum Control for Uniform Laundry Drying
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Solution Overview
Problem
Conventional laundry treating apparatuses with hot-air drying functions face inefficiencies in heat transfer, leading to drying imbalances and mechanical stress on laundry, particularly with large or bulky loads, resulting in uneven drying and potential damage.
Innovation Solution
A laundry treating apparatus utilizing an induction heater to conductively heat the drum, with controlled drum motion cycles including conductive accelerating, space securing, and rearrangement motions, to ensure uniform drying and minimize mechanical stress on laundry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot-air drying is used with tumbling operation, then drying function is added to washing apparatus, but heat transfer efficiency is low and drying imbalance occurs
Solution Approach 1:
The patent replaces the mechanical hot-air drying system with an induction heating system that uses electromagnetic fields to directly heat the drum. This substitution eliminates the need for complex air circulation ducts and fans, while achieving more uniform and efficient heat transfer to the laundry through direct conductive heating from the drum surface.
Solution Approach 2:
The patent utilizes the phase transition of water from liquid to vapor through induction heating. The induction heater generates electromagnetic fields that induce eddy currents in the metallic drum, rapidly heating it to facilitate evaporation of moisture from laundry without requiring large volumes of hot air circulation.
2Productivity
If tumbling operation is performed at 40-60 RPM, then laundry is lifted and dropped for drying, but mechanical force causes shrinkage and deformation
Solution Approach 1:
The patent changes the operational parameters by using induction heating instead of mechanical tumbling for drying. The drum can rotate at lower speeds or remain stationary while induction heating provides the necessary thermal energy for drying, thereby reducing mechanical stress and preventing laundry shrinkage and deformation.
Solution Approach 2:
The patent replaces the mechanical tumbling action with electromagnetic induction heating. Instead of relying on gravitational lifting and dropping of laundry through drum rotation, the system uses electromagnetic fields to directly heat the drum, which then transfers heat to the laundry through conduction, minimizing mechanical damage.
3Loss of energy
If drum rotates at high speed for conductive heating, then heat transfer efficiency increases, but laundry may not spread evenly causing localized overheating
Solution Approach 1:
The patent employs periodic alternation between conductive heating phase (drum rotating at high speed for efficient heat transfer) and tumbling phase (drum rotating at low speed or stationary for laundry redistribution). This periodic action ensures that laundry receives uniform heat exposure over time, preventing localized overheating while maintaining overall drying efficiency.
Solution Approach 2:
The patent dynamically adjusts drum rotation speed based on the drying phase. During conductive heating, the drum rotates at high speed to maximize heat transfer efficiency. During tumbling redistribution, the drum slows down or stops to allow laundry to spread and reposition. This dynamic speed adjustment optimizes both heat transfer efficiency and drying uniformity.
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 achieves uniform drying of laundry, reduces shrinkage and deformation, and optimizes drying performance for various load types by adjusting drum motion cycles based on load conditions, enhancing heat transfer efficiency and reducing mechanical stress.
Implementation Method 1
an induction heater disposed on the tub and heating an outer circumferential face of the drum contacting the heater
Implementation Method 2
heating an outer circumferential face of the drum contacting the heater; drying the laundry in contact with the drum
Data Source
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AI summary
Disclosed are an object treating apparatus, and more particularly, an object treating apparatus for heating a drum using an induction heater and a control method thereof. The object treating apparatus includes a tub; a drum rotatably disposed within the tub and accommodating an object therein; an induction heater disposed on the tub and configured to heat an outer circumferential face of the drum contacting the heater; a motor to rotate the drum; and a processor configured to control an operation of the induction heater to dry the object, wherein the processor is configured to control revolution per minute (RPM) of the drum to perform, during drying,: a conductive accelerating motion having a target RPM in which the object rotates integrally with the drum while the object is in close contact with an inner circumferential face of the drum; and a rearrangement motion having a target RPM lower than the target RPM of the conductive accelerating motion.