Dishwasher, method and computer program product
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Solution Overview
Problem
Existing dishwashers face issues with spray arm blockages due to items like knives or plates protruding, which can hinder cleaning efficiency and require manual intervention to resolve.
Innovation Solution
A dishwasher with a motor-driven spray arm system that includes a sensor to detect blockages based on motor speed fluctuations, allowing for automatic countermeasures such as reversing the spray arm direction or decoupling the drive mechanism to prevent damage and ensure thorough cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spray arm rotates at high speed to improve cleaning efficiency, then cleaning productivity increases, but the risk of blockage from protruding items increases
Solution Approach 1:
The control unit continuously monitors motor current and compares it against threshold values to detect blockages. When the motor current exceeds the threshold, the system automatically responds by reversing the spray arm rotation direction, creating a closed-loop feedback system that maintains reliable operation during high-speed cleaning cycles
Solution Approach 2:
The spray arm rotation direction is dynamically changed from continuous unidirectional rotation to periodic bidirectional rotation when blockages are detected. This dynamic adaptation allows the system to maintain high cleaning efficiency during normal operation while automatically adjusting to prevent damage when obstructions occur
2Device complexity
If manual intervention is required to clear blockages, then the system remains simple, but user intervention time and cleaning downtime increase
Solution Approach 1:
The dishwasher system automatically detects blockages through motor current monitoring and self-resolves them by reversing spray arm rotation direction. This eliminates the need for user intervention to clear blockages, reducing cleaning downtime while maintaining relatively simple system architecture through the use of existing motor control capabilities
3Adaptability or versatility
If the spray arm is actively driven by electric motor to enable speed control, then cleaning versatility improves, but the complexity of blockage detection and control increases
Solution Approach 1:
The motor control system serves multiple functions: it provides variable speed control for different cleaning programs and simultaneously acts as a blockage detection sensor through current monitoring. This multi-functionality enables speed control versatility while avoiding the need for separate detection hardware, thereby limiting the increase in control system complexity
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 system effectively detects and mitigates spray arm blockages, ensuring optimal cleaning results and resource conservation by preventing re-washing, while minimizing mechanical stress and user intervention.
Implementation Method 1
a sensor unit for detecting the motor speed of the electric motor
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a dishwasher (1), more particularly a domestic dishwasher, comprising: - at least one spraying device (20) which is actively driven by means of a drive apparatus (15) and intended for applying a washing liquor to items to be washed that can be placed in a washing container (2) of the dishwasher (1), the drive apparatus (15) comprising an electric motor (16) for actively driving the at least one spraying device (20) and a sensing unit (16A) for sensing a motor rotational speed (SIG) of the electric motor (16); and - a control device (25) which is designed to detect a blockage of the at least one spraying device (20) on the basis of the sensed motor rotational speed (SIG).