Electric Kettle Boiling Detection Using Temperature Rate Change
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Solution Overview
Problem
Existing electric kettles face challenges in accurately determining the boiling point of water, especially at high altitudes, due to insensitive steam switches and inaccurate temperature sensors, leading to unsafe operation and inefficiency.
Innovation Solution
A method utilizing a temperature sensor, microprocessor, and control circuit to detect and compare temperature rate changes, sending a control signal to cut off heating power when the rate change difference is minimized, ensuring accurate boiling point detection and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is used to detect water temperature, then the boiling point detection accuracy is improved, but the device becomes unsafe for operation at high altitudes where water boiling point is lower
Solution Approach 1:
The patent changes the detection parameter from absolute temperature to temperature rate of change. The microprocessor detects the rate of temperature increase (dT/dt) rather than just the temperature value itself. When water reaches boiling point, the temperature rate of change exhibits a characteristic pattern that can be detected regardless of the absolute boiling temperature, which varies with altitude. This allows the system to accurately detect boiling at any altitude without requiring altitude-specific calibration.
2Device complexity
If a steam switch is used to cut off power, then the boiling detection is simplified, but the switch is not sensitive enough and the structural configuration is complicated
Solution Approach 1:
The patent replaces the mechanical steam switch system with an electronic temperature sensing and processing system. Instead of using steam to mechanically actuate a dual-metal switch, the system uses a temperature sensor connected to a microprocessor that electronically monitors temperature changes and controls the heating element. This eliminates the need for complex steam channels and mechanical switch structures while improving detection sensitivity through electronic measurement.
3Extent of automation
If the temperature sensor triggers power cutoff at preset threshold, then the control is automated, but the heating source continues heating after water boils or stops before full boiling
Solution Approach 1:
The patent implements a feedback control system where the microprocessor continuously monitors the temperature rate of change and adjusts the heating control accordingly. The system measures dT/dt in real-time and uses this feedback to determine when boiling occurs. When the characteristic boiling pattern is detected in the temperature rate of change, the system automatically cuts off power. This closed-loop feedback mechanism ensures accurate boiling detection and appropriate power control without manual intervention.
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 method accurately determines the boiling point of water and safely cuts off heating power, enhancing user safety and operational efficiency across various altitudes and heating power settings.
Implementation Method 1
providing a temperature sensor, a microprocessor, and a control circuit to the electric kettle; detecting the interior temperature in the electric kettle, wherein the interior temperature is measured by either the water temperature, the temperature of the heating point contacting with the water, or the temperature of the interior wall of a kettle body
Implementation Method 2
The electric kettle has brought many conveniences for people in their living and work. The traditional method for electric kettle to determine and control the boiling water is to apply a 'steam' switch made of dual metal materials to switch off the power of the heating source
Data Source
AI summary
A water temperature calibration method for an electric kettle includes the steps of providing a temperature sensor, a microprocessor, and a control circuit; detecting an interior temperature from one of the temperatures of the water, a heating point contacting with the water, and an interior wall of the electric kettle; determining a temperature rate change by the microprocessor and comparing a current cycle of the temperature rate change with a previous cycle thereof; and sending out a control signal to the control circuit when the current cycle of the temperature rate change is close to the previous cycle thereof that a difference between the current cycle of the temperature rate change and the previous cycle thereof is minimized. Therefore, the process is adapted to accurately determine the water temperature and to cut off the heating power when the water is boiled.