Laundry treating apparatus having induction heater and control method thereof
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Solution Overview
Problem
Conventional laundry treating apparatuses without a circulating duct face challenges in accurately detecting dryness and determining the end of the drying process due to sensor malfunctions caused by detergents, washing-water, condensed water, or lint, and require multiple temperature sensors, making them complex to manufacture and operate.
Innovation Solution
A laundry treating apparatus using a single temperature sensor to detect dryness by measuring the temperature difference between the space around the drum and the condensed water, allowing for accurate determination of drying completion without direct contact with the drying target, and employing an induction heater to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a humidity sensor is used to detect dryness, then drying end detection is enabled, but the sensor is contaminated by detergent, washing-water or lint making it difficult to sense accurate humidity
Solution Approach 1:
The patent uses temperature sensors as intermediaries to indirectly detect drying status. Instead of placing a humidity sensor directly in the drum where it contacts detergent and lint, the system measures temperature of the drum and surrounding air, then infers moisture content from temperature differences and heat exchange patterns. This mediator approach avoids direct contamination while still enabling accurate dryness detection.
Solution Approach 2:
The patent replaces the electrical humidity sensing mechanism with a thermal measurement system. By using temperature sensors to measure heat exchange between the drum, air, and condensed water, the system substitutes direct humidity measurement with indirect thermal inference, eliminating the contamination problem inherent in electrical sensors exposed to washing chemicals.
2Measurement precision
If temperature sensors are installed near inlet and outlet of condensing duct to detect dryness, then drying end detection is enabled, but three or more temperature sensors are required increasing manufacturing complexity
Solution Approach 1:
The patent merges the functions of multiple temperature sensors into a single integrated measurement system. By placing one temperature sensor in the drum and another near the condensing duct inlet, the system combines temperature differential measurement with the existing circulation duct structure to achieve dryness detection without requiring separate sensors at multiple locations including the outlet.
Solution Approach 2:
The temperature sensors serve multiple functions: they monitor drum temperature for heating control, measure air temperature for drying detection, and enable calculation of temperature differentials for moisture content inference. This multi-functionality eliminates the need for dedicated sensors at each measurement point, reducing the total sensor count while maintaining detection accuracy.
3Adaptability or versatility
If air circulation system with condensing and drying ducts is used for drying, then drying function is enabled, but the apparatus requires separate circulation ducts making it difficult to manufacture
Solution Approach 1:
The patent merges the drying function with the existing washing machine structure by utilizing the tub and drum as the heating and drying chamber. The induction heater mounted on the tub exterior provides heating, while the drum rotation and natural convection handle air circulation. This eliminates the need for separate circulation ducts and condensing chambers, simplifying manufacturing while maintaining drying capability.
Solution Approach 2:
The system uses the drum's rotation and natural convection currents to circulate air throughout the drum and tub space. The heated air naturally rises and circulates without requiring mechanical fans or complex ducting. Condensed water collects at the bottom of the tub where it can be drained, eliminating the need for separate condensing ducts and making the system easier to manufacture.
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 identifies the drying end timing and determines the drying target load amount using one or two temperature sensors, reducing sensor malfunctions and manufacturing complexity, while ensuring accurate dryness detection and efficient energy use.
Implementation Method 1
an induction heater disposed on the tub and configured to heat an outer circumferential face of the drum contacting the heater
Implementation Method 2
humid steam evaporated in heat exchange between the heated drum and the object is condensed into the condensed water inside the tub
Data Source
AI summary
An object treating apparatus includes a tub, a rotatable drum for receiving an object, an induction heater for heating an outer circumferential face of the drum, a motor for rotating the drum, an upper temperature sensor, a lower temperature sensor, and a processor. The upper temperature sensor detects a temperature of a space between the tub and the drum. The upper temperature sensor is disposed inside the tube at an upper portion of the tub. The lower temperature sensor detects a temperature around condensed water at a bottom of the tub. The lower temperature sensor is disposed inside the tub at a lower portion of the tub. The processor can determine a drying ending timing based on the temperatures detected by the upper and lower temperature sensors.