Heating Device Flame Control Through Temperature-Sensor Power Switching
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Solution Overview
Problem
Existing methods for controlling the composition of gas mixtures in hydrogen combustion heaters are prone to sensor drift and interference, leading to inaccurate combustion control and increased risks of backfiring or unburned hydrogen in the exhaust gas, as conventional sensors like optical and temperature sensors are susceptible to aging and contamination.
Innovation Solution
A method utilizing a temperature sensor with a temperature-dependent electrical resistance to determine a relative increase in a power parameter, allowing for precise combustion control by deriving the combustion air ratio, independent of sensor drift, through a control unit that regulates the electrical power of the temperature sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors or optical sensors are used for flame monitoring and combustion control during hydrogen combustion, then flame monitoring capability is improved, but sensor drift and contamination interference occur over time leading to incorrect temperature measurements
Solution Approach 1:
The patent implements a feedback mechanism where the measured flame temperature is continuously compared against expected values, and the gas mixture composition is automatically adjusted to compensate for sensor drift. The control system modifies the lambda value based on temperature deviations, creating a closed-loop system that maintains accurate combustion control despite sensor aging.
Solution Approach 2:
The patent changes the measurement parameter from direct temperature sensing to ionization current measurement. By detecting the ionization current generated by charged particles in the hydrogen flame, the system achieves reliable flame monitoring without the drift problems associated with traditional temperature sensors. This parameter change fundamentally resolves the reliability issue.
2Measurement precision
If conventional temperature sensors with temperature-dependent resistance are used, then temperature measurement capability is improved, but aging effects and oxidation cause resistance drift leading to incorrect temperature measurements
Solution Approach 1:
The patent replaces the mechanical/electrical resistance-based temperature sensing system with an optical/electrical ionization detection system. Instead of measuring resistance changes in a physical sensor exposed to harsh combustion conditions, the system measures ionization current generated by the flame itself, eliminating the aging and oxidation problems inherent in conventional temperature sensors.
Solution Approach 2:
The patent introduces ionization current as an intermediary measurement parameter. Rather than directly measuring flame temperature with a physical sensor that degrades, the system uses ionization current - a property of the flame itself - as a proxy indicator that correlates with combustion conditions but does not suffer from sensor aging or contamination.
3Measurement precision
If reference state at lambda value of 1 is used for combustion control, then stoichiometric combustion control is improved, but increased risk of backfiring occurs
Solution Approach 1:
The patent uses real-time ionization current feedback to dynamically adjust the lambda value away from the dangerous stoichiometric point. The control system continuously monitors combustion conditions and modifies the air-fuel ratio to maintain a safe margin from backfiring conditions while still achieving precise combustion control through adaptive adjustment rather than fixed reference operation.
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
Enables long-term stable combustion control by compensating for sensor drift and maintaining accurate gas mixture composition, reducing the risk of backfiring and unburned hydrogen, with the method applicable to heaters using hydrogen or hydrogen-containing fuels.
Implementation Method 1
a temperature sensor with a temperature-dependent electrical resistance for determining a temperature of a flame of the gas mixture combusted by the burner
Implementation Method 2
Gas-fired heaters fueled by fossil fuels often utilize the ionization effect, which can be measured based on freely available charge carriers in the flame and at least one electrode in the flame
Implementation Method 3
a burner for combusting a gas mixture supplied (to the burner or the combustion chamber)
Data Source
Figure 1
Figure 2~4
AI summary
A method is proposed for operating a heating device (1) which has at least one combustion chamber (2) with a burner (3) for burning a supplied gas mixture (4) and a heatable temperature sensor (5) for determining a temperature of a flame (6) of the gas mixture (7) burned by the burner (3) with a temperature-dependent resistance;wherein a relative increase in a power parameter is used for combustion control, and the relative increase in the power parameter is determined based on a first power parameter value (28) and a second power parameter value (30), wherein the second power parameter value (30) is detected while an electrical power of the temperature sensor (5) is being controlled to a predetermined electrical power, and the first power parameter value (28) is detected before switching on (21) or after switching off (22) the electrical power of the temperature sensor (5) to the predetermined power. In addition, a heater (1) and a computer program (33) are proposed. The method enables particularly precise and long-term stable combustion control of the heater (1). In addition, a heater (1) and a computer program (33) are proposed.;