Grill Gas Shutoff Circuit for Drift-Tolerant Flame Detection
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Solution Overview
Problem
Existing grill safety shutoff systems face reliability issues due to wear, degradation, or contamination of flame sensors, leading to inaccurate detection of flame presence, which can result in unintended gas flow and safety hazards.
Innovation Solution
A safety shutoff apparatus that uses a control circuit to monitor changes in the flame detection signal over time rather than relying on absolute values, ensuring accurate detection of flame presence or absence, and automatically shuts off gas flow if no flame is detected, incorporating a solenoid valve and igniter system with a separate flame sensor for independent ignition and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flame sensor is used to detect flame presence, then safety shutoff function is achieved, but sensor degradation or contamination causes detection accuracy to deteriorate over time
Solution Approach 1:
The system dynamically monitors changes in flame detection signal characteristics over time rather than relying on static threshold comparisons. The control circuit tracks signal drift and adjusts detection parameters accordingly, allowing the system to adapt to sensor degradation and maintain accurate flame detection despite component aging or contamination.
Solution Approach 2:
The control circuit continuously monitors the flame detection signal and provides feedback to determine whether a flame is present based on signal changes. This closed-loop feedback mechanism allows the system to compensate for sensor drift by comparing current signal characteristics against baseline measurements, maintaining reliable detection even as the sensor degrades.
2Extent of automation
If a solenoid valve is used to control gas flow, then automatic shutoff capability is achieved, but system complexity increases
Solution Approach 1:
The control circuit integrates multiple functions including flame detection, signal analysis, and solenoid valve control into a single integrated unit. By combining these functions rather than using separate independent components, the system achieves automatic shutoff capability while minimizing the increase in overall system complexity through functional consolidation.
Solution Approach 2:
The control circuit serves multiple purposes: it monitors the flame detection signal, determines flame presence based on signal changes, controls the solenoid valve, and provides safety shutoff functionality. This multi-functional approach reduces the need for additional dedicated components, achieving automation without proportionally increasing system complexity.
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 safety by reducing the impact of sensor degradation or contamination, ensuring reliable gas flow control and preventing accidents by accurately detecting flame presence or absence, thereby maintaining operational safety and efficiency.
Implementation Method 1
a flame sensor can include one or more components subject to wear, degradation, contamination, or a combination thereof (e.g., contamination of a sensor rod or a circuit board), which may impair functioning of the flame sensor
Implementation Method 2
A valve disposed along a gas line is operated to control a flow of gas to a burner
Data Source
AI summary
A system for igniting a grill can include a solenoid valve, a flame rectification sensor, an igniter, and a control circuit connected to the solenoid valve and the flame rectification sensor. The solenoid valve controls flow of gas to the grill's burner and includes a switch that closes when a handle connected to the switch opens the solenoid valve. The control circuit sends current to the solenoid valve when the switch is closed to hold the solenoid valve open. After the switch closes, the igniter is ignited. After ignition, the control circuit monitors the presence of a flame with a flame rectification sensor. If no flame is detected after a certain amount of time, the control circuit stops sending current to the solenoid valve to close the solenoid valve.