Gas Burner Flame Detection with IR Sensing and Relay Protection
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Solution Overview
Problem
Existing cooking units face issues with inaccurate heat regulation due to infrared sensor placement, risk of sensor damage, and frequent false positives in gas shutdown detection, leading to inefficient and unsafe cooking processes.
Innovation Solution
A cooking unit design featuring a thermocouple connected through an oversized relay to the safety electrovalve, with an infrared sensor positioned above the cooking zone to detect food temperature, and a single variable-pitch regulating electrovalve for each burner, allowing precise control and minimizing signal loss, while a protective germanium glass screen safeguards the sensor from high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the infrared sensor is positioned closer to the cooking zone for better temperature detection, then measurement precision is improved, but the risk of sensor damage from high temperatures increases
Solution Approach 1:
A germanium glass screen is introduced as an intermediary element between the infrared sensor and the cooking zone. This screen allows infrared radiation to pass through while blocking direct exposure to high temperatures, flames, and splashing oils, thus protecting the sensor while maintaining temperature detection capability
Solution Approach 2:
The infrared sensor is positioned in a horizontal plane rather than directly above the cooking zone, detecting temperature from the side. This spatial reconfiguration allows the sensor to be closer to the cooking action without being exposed to direct heat and flames
2Device complexity
If the thermocouple signal is directly connected to the safety electrovalve without amplification, then device complexity is reduced, but the reliability of flame detection decreases due to signal loss
Solution Approach 1:
An oversized relay is introduced as an intermediary component between the thermocouple and the safety electrovalve. The relay amplifies the weak thermocouple signal (0.25A, 5mV) to reliably activate the safety electrovalve, eliminating false positives while maintaining system simplicity
Solution Approach 2:
The relay is specifically designed with oversized parameters (higher current and voltage ratings than minimum requirements) to minimize signal loss and ensure reliable activation of the safety electrovalve even with the weak thermocouple signal
3Manufacturing precision
If multiple fixed-pitch electrovalves are used for gas flow regulation, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
A single variable-pitch electrovalve replaces multiple fixed-pitch electrovalves, providing continuous gas flow regulation across the entire range from minimum to maximum. This single component performs the function previously requiring multiple discrete components, reducing complexity while maintaining precision
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 configuration enhances heat regulation accuracy, reduces false positives, and ensures safe operation by minimizing signal loss and protecting the infrared sensor, resulting in a more efficient and reliable cooking experience.
Implementation Method 1
an infrared sensor located above the cooking zone and focused towards the cooking zone for remote detection of the temperature of a food cooked in said cooking zone
Implementation Method 2
a thermocouple in thermal contact with the flames that apply heat to the cooking zone
Data Source
AI summary
Food cooking unit composed of gas burners (1), regulation electrovalves (3) of the supplied gas; an infrared sensor (5) focused towards the cooking zone; a thermocouple (6) in thermal contact with the flames and in connection with a safety electrovalve (4) through a relay (10) and an electronic control device (7) connected to said infrared sensor (5), to said at least one regulating electrovalve (3) and the relay (10) and that stores different regulation programs and that regulates the regulating electrovalve (3) and/or interrupts the thermocouple connection with the safety electrovalve in response to the signals obtained from the infrared sensor (5) and/or the thermocouple (6), and issues warnings in response to signals from the thermocouple (6).