Gas Burner Flame Control Using Dual Thermocouple Voltage Thresholds
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Solution Overview
Problem
Conventional gas appliances rely on thermocouples to sense flames, leading to delayed identification of successful ignition and prolonged gas leakage when flames are extinguished, posing safety risks due to incomplete magnetic field stabilization and slow voltage decay.
Innovation Solution
A control method for gas appliances that uses a thermocouple to determine successful ignition by setting a first voltage threshold for continuous gas supply and a higher second voltage threshold for extinguished flames, enabling earlier gas pipe closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermocouple-based flame sensing is used, then the gas appliance can detect flames, but the identification of successful ignition is delayed and gas leakage occurs when flames are extinguished
Solution Approach 1:
The control device performs preliminary actions by continuously monitoring the sensing voltage during the ignition process and comparing it against threshold values. When the voltage exceeds the first threshold, the system proactively determines successful ignition and activates the gas valve, rather than waiting for traditional delayed detection methods
Solution Approach 2:
The system implements continuous feedback monitoring of the thermocouple sensing voltage and dynamically adjusts gas valve control based on real-time voltage comparisons against predefined thresholds. This feedback mechanism enables rapid response to ignition status changes and flame extinction events
2Reliability
If the thermocouple heating time is extended to ensure sufficient sensing voltage, then reliable flame detection is achieved, but the ignition process becomes slower and user experience deteriorates
Solution Approach 1:
The invention changes the detection parameter from waiting for fixed thermocouple heating completion to monitoring real-time sensing voltage levels against dynamic thresholds. This parameter transformation enables earlier detection while maintaining reliability, as the system responds to voltage threshold crossings rather than fixed time intervals
Solution Approach 2:
The control device performs preliminary voltage threshold evaluation during the thermocouple heating process itself, enabling ignition confirmation before traditional completion criteria are met. This preliminary detection action accelerates the overall ignition process while preserving detection reliability
3Object-affected harmful factors
If the electromagnetic valve is kept closed during ignition to prevent gas leakage, then safety is improved, but the ignition process cannot complete successfully
Solution Approach 1:
The system uses feedback control by continuously monitoring sensing voltage and dynamically adjusting gas valve state. The valve remains closed initially, then opens automatically when voltage exceeds the first threshold confirming ignition, and closes when voltage drops below the second threshold indicating flame extinction - creating a self-regulating safety mechanism
Solution Approach 2:
The control device performs preliminary safety preparation by keeping the gas valve closed before ignition confirmation, then executes preliminary ignition testing with controlled gas flow once voltage thresholds are met. This preliminary safety action prevents gas leakage while enabling successful ignition under controlled conditions
4Device complexity
If a single voltage threshold is used for both ignition confirmation and flame extinction detection, then the control logic is simplified, but gas leakage occurs during flame extinction due to slow voltage decay
Solution Approach 1:
The invention segments the voltage threshold into two distinct levels: a first threshold for ignition confirmation and a second threshold for flame extinction detection. This segmentation enables differentiated response strategies - opening the gas valve at the first threshold and closing it at the second threshold - thereby preventing gas leakage during flame extinction while maintaining manageable control logic
Solution Approach 2:
The system changes the detection parameter from a single static threshold to two distinct voltage levels with different functional meanings. This parameter differentiation enables the system to distinguish between ignition confirmation events and flame extinction events, allowing appropriate gas valve control for each scenario
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 accelerates ignition, reduces power consumption, and enhances safety by promptly blocking gas flow when flames are extinguished, minimizing gas leakage and potential hazards.
Implementation Method 1
the thermocouple 18 is disposed adjacent to the burner 10, and is adapted to sense the flames and output a corresponding sensing voltage
Implementation Method 2
the electromagnetic valve would have a constant magnetic field and remain in an open state for the gas to pass through
Data Source
AI summary
A gas appliance includes a burner, a gas valve, an ignitor, a thermocouple, and a control device, wherein the control device is adapted to execute a control method comprising the following steps: controlling the ignitor to ignite and the gas valve to open; receiving a sensing voltage output from the thermocouple; stop the ignitor from igniting and controlling the gas valve to keep a gas pipe be in an open state when the sensing voltage increases to a first voltage; receiving the sensing voltage output from the thermocouple continuously, and controlling the gas valve to block the gas pipe when the sensing voltage decreases from higher than a second voltage to lower than the second voltage, wherein the second voltage is higher than the first voltage. Whereby, an ignition procedure could be speeded up and the gas could be blocked earlier as the flames are extinguished.