Dishwasher Camera Assembly for Spray Arm Blockage Detection
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Solution Overview
Problem
Dishwasher appliances face challenges in determining the proper functioning of fluid delivery devices, such as spray arm assemblies, due to blockages or improper positioning of articles, which can lead to inadequate cleaning, especially for larger loads, and existing sensing techniques are inadequate.
Innovation Solution
A dishwasher appliance equipped with a camera assembly that captures consecutive images of the wash fluid during cleaning cycles to determine if the fluid delivery devices are operating correctly by comparing these images to baseline references, allowing for corrective actions like user notifications or adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensing techniques are used to detect spray arm rotation, then the system can identify some operational issues, but the sensing is blocked by articles in the appliance and cannot reliably determine proper functioning
Solution Approach 1:
The patent replaces mechanical sensing techniques (rotational encoders, position sensors on spray arms) with an optical imaging system using cameras and image processing algorithms. This substitution eliminates the problem of mechanical sensors being blocked by articles, as the camera observes fluid motion patterns from a distance without physical contact with the spray components.
Solution Approach 2:
The patent introduces wash fluid motion patterns as an intermediary indicator to indirectly detect spray arm operation. Instead of directly sensing the spray arm's position or rotation, the system observes the fluid dynamics (spray patterns, flow characteristics) that result from proper spray arm operation, providing reliable detection without direct contact with potentially blocked components.
2Loss of information
If valve position sensing is used to determine fluid delivery, then the system can detect valve opening/closing, but it cannot identify improper fluid delivery when the valve is open
Solution Approach 1:
The patent implements a feedback mechanism where the camera continuously monitors wash fluid delivery patterns and compares them against expected patterns for properly functioning spray arms. This real-time visual feedback allows the system to verify actual fluid delivery performance and detect deviations indicating blockages or malfunctions, regardless of valve position.
Solution Approach 2:
The patent utilizes visual characteristics of the wash fluid (appearance, distribution patterns, flow characteristics visible in images) as indicators of proper fluid delivery. By analyzing these visual properties in captured images, the system can determine whether fluid is being delivered correctly without needing additional sensors in the fluid path.
3Productivity
If multiple fluid delivery devices are used to clean larger loads, then cleaning coverage is improved, but the failure of even one device significantly reduces cleaning efficacy
Solution Approach 1:
The patent implements a self-diagnosis capability where the camera system automatically monitors each spray arm's operation and identifies malfunctions without user intervention. When a blockage or malfunction is detected in one of multiple spray arms, the system can alert the user and potentially adjust operation to compensate, ensuring the other spray arms continue functioning to maintain adequate cleaning effectiveness.
Data Source
AI summary
A dishwasher appliance includes a tub defining a wash chamber for receipt of articles for washing, a fluid delivery device configured for delivering wash fluid into the wash chamber, and a camera assembly mounted with a view of the wash chamber including a location where the fluid delivery device is configured for delivering the wash fluid. A controller is configured to obtain consecutive images of the wash fluid in the wash chamber, determine whether the fluid delivery device is providing acceptable delivery of the wash fluid into the wash chamber, wherein the determining includes using the consecutive images of the wash fluid to determine whether there are differences in the wash fluid present in the wash chamber, and initiate corrective action if the fluid delivery device is not providing an acceptable delivery of the wash fluid into the wash chamber.