Dryer appliance nuisance trip detection
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Solution Overview
Problem
Conventional dryer appliances experience nuisance tripping of thermostats due to false positives, leading to increased drying time as the secondary heat control system takes longer to reset, necessitating improved heat control systems and methods to minimize such events.
Innovation Solution
A dryer appliance equipped with a primary heat control system using a thermistor and a secondary heat control system with a thermostat, where a controller monitors temperature gradients, waits to verify the absence of a heating call, and determines a nuisance trip by comparing peak and present temperatures to prevent unnecessary thermostat deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secondary heat control system with thermostat is used to prevent excessive heating, then safety is improved, but nuisance tripping increases causing longer drying time
Solution Approach 1:
The controller performs preliminary actions by monitoring temperature trends and detecting nuisance trips before the thermostat actually trips. By identifying when the temperature is approaching the trip threshold and taking preventive actions (such as adjusting heating cycles), the system avoids the nuisance tripping that would otherwise cause drying time extensions while maintaining the safety function.
2Productivity
If thermostat trips are minimized to reduce drying time, then productivity is improved, but temperature monitoring precision must increase
Solution Approach 1:
The controller implements continuous feedback monitoring of temperature trends by reading temperature values at regular intervals and calculating the rate of temperature change. This feedback mechanism allows the system to detect when temperature is rising too quickly toward the thermostat trip threshold and take corrective heating adjustments, thereby preventing nuisance trips and maintaining productivity without requiring excessive measurement precision.
3Measurement precision
If the controller monitors temperature continuously to detect nuisance trips, then detection accuracy is improved, but energy consumption increases
Solution Approach 1:
The controller employs periodic temperature monitoring by reading the temperature sensor at predetermined time intervals rather than continuously. The system calculates temperature gradients based on these periodic readings and compares them against thresholds to detect nuisance trips. This periodic approach maintains adequate detection accuracy for identifying abnormal temperature rise patterns while significantly reducing energy consumption compared to continuous monitoring.
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
This approach reduces the likelihood of thermostat tripping, minimizing drying time by accurately identifying nuisance trips and optimizing the operation of the heating system, thereby enhancing the efficiency of the dryer appliance.
Implementation Method 1
A controller monitors a temperature with a thermistor of the primary heat control system
Data Source
AI summary
Dryer appliances and related methods are disclosed. Such methods may include, or such appliances may be configured for, monitoring a temperature with a thermistor of a primary heat control system of the dryer appliance. The present disclosure also includes determining a relay signal is calling to close a relay and thereby activate a heating system of the dryer appliance and verifying that the relay is closed. The present disclosure further includes allowing a minimum relay on time to elapse after verifying that the relay is closed. The present disclosure also includes determining a temperature gradient of the monitored temperature based on a change in the monitored temperature over the minimum relay on time. The present disclosure further includes detecting a nuisance trip because the determined temperature gradient is negative.