Icemaker with thermoformed ice tray providing heating and phase change sensing
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Solution Overview
Problem
Conventional icemakers in household refrigerators face inefficiencies in energy consumption and ice release mechanisms, particularly in systems using high-power heating for ice removal and mechanical distortion during ice ejection.
Innovation Solution
A lightweight, thermoformed ice tray with integrated electrical heaters and capacitive sensing elements, allowing for low-wattage operation and precise control of ice ejection through mechanical warpage and capacitive sensing, reducing energy usage and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a highly conductive material such as aluminum and a central calorie rod heater are used to heat the tray for ice removal, then ice release is effective, but electrical power consumption exceeds 100 watts
Solution Approach 1:
The heater is divided into multiple independent heating zones corresponding to different sections of the ice tray. Each zone can be independently controlled and activated only when needed for specific pockets, rather than heating the entire tray simultaneously. This segmentation allows effective ice release while significantly reducing overall power consumption by activating only the necessary heating portions.
Solution Approach 2:
Different regions of the ice tray are equipped with heating elements of varying power levels based on local ice formation characteristics and ejection requirements. Areas requiring more aggressive ice release have higher power density, while other areas use lower power. This localized quality optimization ensures effective ice removal where needed while minimizing unnecessary energy consumption in areas where less heating is required.
2Strength
If the ice tray is constructed of robust injection molded plastic material to resist substantial cycling and distortion, then mechanical durability is improved, but the tray weight increases and flexibility for ice ejection is reduced
Solution Approach 1:
The ice tray is constructed from thin-walled flexible plastic material that can elastically deform during the ice ejection cycle. The flexibility allows the tray to bend and flex under cam action for effective ice release, while the material composition and wall thickness are optimized to maintain sufficient structural strength and durability over repeated cycling. This approach achieves both light weight and mechanical durability simultaneously.
3Weight of moving object
If the ice tray is constructed of thin thermoformed material for light weight and flexibility, then ice ejection flexibility is improved, but the tray may suffer from mechanical distortion during cycling
Solution Approach 1:
The ice tray design incorporates pre-calculated elastic deformation zones and reinforcement ribs positioned strategically to prevent permanent distortion during cycling. The thin-walled structure is engineered with appropriate wall thickness variations and support elements that cushion and distribute mechanical stresses during flexing, preventing cumulative distortion while maintaining the light weight and flexibility needed for effective ice ejection.
4Reliability
If a cam mechanism is used to flex the ice tray for ice release, then ice ejection is improved, but mechanical complexity increases
Solution Approach 1:
The cam mechanism for flexing the ice tray is integrated directly into the rotation drive assembly, combining the rotational motion drive with the flexing action in a single mechanical unit. The cam is positioned such that its profile naturally produces the required tray flexing during the rotation cycle, merging two functions (rotation and flexing) into one mechanism rather than requiring separate actuation systems, thereby reducing overall mechanical complexity while maintaining effective ice ejection.
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 enables efficient ice release with minimal mechanical distortion, lower energy consumption, and improved ice clarity by using low-wattage heating and capacitive sensing for precise control of the ice ejection process.
Implementation Method 1
heating a substantially planar sheet of thermoplastic to a pliable forming temperature
Implementation Method 2
formed by being drawn into a mold using vacuum or plugs corresponding to the mold recesses
Implementation Method 3
a central calorie rod ('cal-rod') heater may be attached to the tray, for example, along its centerline to heat the tray
Implementation Method 4
positioning the mold in a first upright position for filling the pockets with water and a second inverted position for ejecting frozen water from the pockets
Implementation Method 5
a cam rotating about the rotational axis when the ice tray is facing upward to receive water within the pockets and rising off the rotational axis when the ice tray is facing downward to flex the ice tray to release ice
Data Source
AI summary
An icemaker employs a thermoformed ice tray that may have preprinted conductors providing for heating elements in capacitive sensing. Capacitive sensing may be used to control a water fill level and/or to detect complete freezing of the ice cubes and/or to detect complete ejection of the ice cubes.