Washing Machine Pumping Control for Heating Element Protection
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Solution Overview
Problem
Existing washing machines face issues with the heating element being damaged during the pumping process, and previous solutions involve complex technical means.
Innovation Solution
A laundry care appliance with a control device that activates the pumping device only when the laundry drum speed exceeds a first speed threshold and deactivates it below a second speed threshold, ensuring sufficient washing liquid and protecting the heating element by maintaining liquid coverage, and using a pressure sensor to further prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pumping device is activated during drum rotation at low speeds, then washing liquid can be recirculated, but the heating element becomes exposed and damaged due to insufficient liquid coverage
Solution Approach 1:
The control device monitors drum rotational speed and uses this feedback to determine when to activate or deactivate the pumping device. When speed exceeds the first threshold, pumping is activated; when it drops below the second threshold, pumping is deactivated. This feedback mechanism ensures the heating element remains protected while maintaining pumping productivity when conditions are appropriate.
Solution Approach 2:
The system dynamically adjusts pumping device operation based on real-time drum speed conditions. Rather than operating the pump continuously or at fixed intervals, the system adapts pump activation to the dynamic rotational state of the drum, activating only when speed thresholds indicate sufficient liquid coverage and deactivating when thresholds indicate risk of exposure.
2Reliability
If the pumping device operates continuously, then washing liquid is consistently recirculated, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The control device uses simple parameter thresholds (first speed threshold and second speed threshold) to govern pump operation. By monitoring whether drum speed exceeds or falls below these predetermined values, the system achieves reliable washing liquid recirculation control without requiring complex algorithms or multiple sensors, thus maintaining relatively simple device architecture.
3Reliability
If the pumping device is deactivated at low drum speeds, then the heating element remains protected, but washing liquid recirculation efficiency decreases
Solution Approach 1:
The pumping device operates periodically rather than continuously, activating during high-speed phases when liquid coverage is sufficient and deactivating during low-speed phases when coverage is insufficient. This periodic operation pattern protects the heating element while maintaining adequate recirculation efficiency during appropriate operational windows.
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 ensures efficient operation of the pumping device without air draw and protects the heating element from damage, maintaining uniform temperature distribution and efficient laundry care without complex technical efforts.
Implementation Method 1
a heating element for heating the washing liquid
Implementation Method 2
a drive motor for rotating the washing drum
Data Source
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AI summary
Disclosed is a laundry care apparatus (100) which comprises a rotatably mounted inner tub (106) for accommodating items of laundry (108), a drive motor (105) for rotating the inner tub (106), a pumping device (120) for recirculating the washing liquid, a heating element (132) for heating the washing liquid, and a control device (118) for controlling the drive motor (105), the pumping device (120) and the heating element (132) in accordance with a laundry care program running on the control device (118) during operation of the apparatus. The control device (118) is designed to activate, during increase of the rotational speed of the inner tub (106), the pumping device (120) when the rotational speed of the inner tub (106) exceeds a rotational speed threshold value.