Ice Maker Capacitive Water Level Sensing for Harvest Control
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Solution Overview
Problem
Existing ice making machines face challenges in accurately detecting ice thickness without sensors in the food zone, avoiding contamination, and requiring precise mechanical adjustments, which can lead to incorrect harvesting and potential water leaks, causing issues with ice quality and machine performance.
Innovation Solution
A capacitive fluid level sensor is positioned externally to monitor the water level in the sump tank, allowing for accurate detection of ice thickness and failure modes, such as water leaks, without direct contact with water, eliminating the need for mechanical adjustments and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is placed in the food zone to directly measure ice thickness, then measurement precision is improved, but contamination risk and reliability deteriorate
Solution Approach 1:
The patent uses water level as an intermediary parameter to indirectly measure ice thickness. Instead of placing a sensor in the food zone to directly measure ice, the system monitors water level changes in the sump tank, which correlate to ice formation. This intermediary approach allows accurate measurement without contamination risk.
Solution Approach 2:
The patent replaces mechanical/physical sensors that would contact ice with an electrical capacitive sensor that measures water level. The capacitive sensor detects changes in capacitance based on water level position, eliminating the need for mechanical contact with the food zone while maintaining measurement capability.
2Measurement precision
If a hinged sensor is used to detect ice thickness, then measurement precision is improved, but device complexity and ease of operation worsen due to mechanical adjustments
Solution Approach 1:
The patent replaces the mechanical hinged sensor system with an electrical capacitive sensing system. The capacitive sensor has no moving parts and requires no mechanical adjustment, eliminating the complexity associated with hinged mechanisms while maintaining the ability to detect ice formation through water level monitoring.
Solution Approach 2:
The capacitive sensor system is self-adjusting and requires no manual calibration or mechanical tweaking. The sensor automatically adapts to different ice formation conditions through electrical signal processing, eliminating the need for operator intervention that would be required with mechanical sensors.
3Measurement precision
If direct water contact sensing is used, then measurement precision is improved, but reliability deteriorates due to scale accumulation and contamination
Solution Approach 1:
The patent positions the capacitive sensor to measure water level indirectly through the tank wall or at a position that minimizes direct water contact. The sensor detects capacitance changes caused by water level position without requiring the sensing element to be in direct, continuous contact with water, thereby preventing scale accumulation while maintaining detection accuracy.
Solution Approach 2:
The system creates an electrical copy or representation of the water level condition through capacitive coupling, rather than requiring direct physical contact between the sensor and water. This electrical field-based measurement replicates the water level information without the harmful effects of direct contact.
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 provides reliable and long-term performance by accurately controlling the ice harvest cycle, detecting failures, and automatically initiating cleaning cycles, ensuring consistent ice quality and machine efficiency.
Implementation Method 1
the sensor generates a capacitance signal that varies in response to a level of water within the sump
Data Source
AI summary
An ice maker comprising a refrigeration system, a water system, and a control system. The control system includes a controller comprising a processor and a water level sensor. The water level sensor is adapted to externally sense a capacitance corresponding to a sump water level. The controller is adapted to control the operation of the refrigeration system and the operation of the water system based upon the sump water level and to detect one or more failure modes of the water system based upon the sump water level.