Ice Maker Harvest Control Using Temperature Confirmation
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Solution Overview
Problem
Existing ice makers lack reliable methods to determine if all ice has been harvested from the freeze plate, leading to potential 'freeze-up' issues, flooding, and excessive wear due to incomplete harvest cycles, especially in high water hardness areas and winter months.
Innovation Solution
Incorporating both a harvest sensor and a temperature sensor to confirm that all ice has been harvested, with the temperature sensor providing additional feedback to the controller to ensure accurate termination of the harvest cycle and prevent incomplete ice removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only a harvest sensor is used to detect ice harvest completion, then the device complexity is low, but the reliability of harvest completion detection is insufficient leading to freeze-up issues
Solution Approach 1:
The patent implements a feedback mechanism where the temperature sensor continuously monitors evaporator temperature and provides feedback to the controller. The controller compares the temperature reading against a predetermined threshold to determine harvest completion, creating a closed-loop control system that reliably detects when all ice has been harvested without causing freeze-up conditions.
Solution Approach 2:
The temperature sensor serves as an intermediary element between the physical state of ice on the evaporator and the control system. Rather than directly detecting ice presence, the sensor measures temperature as an intermediate parameter that indirectly indicates harvest completion status, enabling reliable detection without complex direct ice sensing mechanisms.
2Productivity
If the harvest cycle is terminated early based on incomplete detection, then productivity is maintained, but harmful factors increase due to flooding and freeze-up
Solution Approach 1:
The temperature sensor is positioned to detect temperature changes that occur just before complete ice harvest. By monitoring temperature trends in advance, the system can predict harvest completion and terminate the cycle at the optimal moment, preventing both early termination (which causes freeze-up) and delayed termination (which causes flooding).
Solution Approach 2:
The system uses temperature as a critical parameter to control the harvest cycle termination. By monitoring temperature changes in the evaporator and comparing against predetermined thresholds, the system dynamically adjusts the harvest cycle timing to match actual ice melt conditions, preventing harmful effects while maintaining productivity.
3Measurement precision
If temperature monitoring is added to confirm harvest completion, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
The temperature sensor serves multiple functions: it monitors evaporator temperature during operation, detects harvest completion by comparing temperature against thresholds, and provides data for controller decision-making. This multi-functionality allows high measurement precision without proportionally increasing device complexity, as a single sensor handles multiple detection tasks.
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
Enhances the reliability of the ice making process by preventing freeze-ups, flooding, and reducing wear on system components, ensuring complete ice harvest and maintaining system integrity.
Implementation Method 1
a temperature sensor for measuring a temperature that indicates that all of the ice has been harvested from the freeze plate
Implementation Method 2
a hot gas valve which is adapted to be opened during a harvest cycle to direct warm refrigerant from the compressor to the evaporator through a hot gas bypass line
Implementation Method 3
The refrigeration system uses a refrigerant capable of transitioning between liquid and gaseous states
Implementation Method 4
a compressor for pressurizing the refrigerant
Implementation Method 5
a condenser for receiving the pressurized refrigerant and condensing the refrigerant into a substantially liquid refrigerant
Implementation Method 6
an evaporator for receiving the low pressure liquid refrigerant from the thermal expansion valve and discharging low pressure, substantially gaseous refrigerant
Data Source
AI summary
An ice maker for forming ice having a refrigeration system, a water system and a controller. The refrigeration system includes a freeze plate in which ice is formed and a hot gas valve for harvesting the ice therefrom. A harvest sensor is triggered when at least a portion of the ice is harvested from the freeze plate and at least one temperature sensor measures a temperature that indicates that all of the ice has been harvested from the freeze plate. The temperature sensors may include a temperature sensor for measuring the refrigerant temperature at the evaporator outlet, the refrigerant temperature at the evaporator inlet, and/or the temperature of the freeze plate. The controller closes the hot gas valve in response from the triggering of the harvest sensor and the temperature measured by the temperature sensor(s) indicating that all of the ice has been harvested from the freeze plate.