Heating Device Dual Flame Sensor Air Ratio Control

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Solution Overview

Problem

Existing heating devices face challenges in achieving precise control of the combustion air ratio, particularly in systems without dedicated sensors, leading to inefficient and unclean combustion.

Innovation Solution

A procedure that utilizes at least two flame sensors with different characteristics to record signals, which are then used to determine the mass flow and air ratio of the combustion mixture through multi-dimensional functions, enabling precise regulation of the heater.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single flame sensor is used to control air ratio, then the device complexity is reduced, but the measurement precision of combustion air ratio deteriorates

Engineering Contradiction:
Improvesensor quantityVSAvoidcombustion air ratio control precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from single-sensor control to dual-sensor control, adding another dimension of measurement. The first flame sensor provides primary air ratio information while the second flame sensor provides complementary data, enabling more precise determination of combustion air ratio through multi-dimensional signal evaluation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The control unit acts as an intermediary that receives signals from both flame sensors and processes them through multidimensional functions. This intermediary processing enables the system to derive precise air ratio and mass flow values by combining and analyzing signals from multiple sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If no mass flow sensor is installed, then the device complexity is reduced, but the measurement precision of mass flow deteriorates

Engineering Contradiction:
Improvesensor quantityVSAvoidmass flow determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control unit serves as an intermediary that derives mass flow information indirectly from flame sensor signals. By processing signals from both flame sensors through multidimensional functions, the system can determine mass flow without requiring a dedicated mass flow sensor, maintaining precision while reducing device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/electromechanical mass flow sensor with an optical/electrical measurement system using flame sensors. The mass flow is determined through signal processing and multidimensional function analysis rather than direct mechanical measurement, eliminating the need for additional sensors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conveying device power is used to determine mass flow, then the device complexity is reduced, but the measurement precision of mass flow deteriorates due to obstructions and inaccuracies

Engineering Contradiction:
Improvesensor quantityVSAvoidmass flow determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control unit acts as an intermediary that directly determines mass flow from flame sensor signals, bypassing the indirect method of using conveying device power. This direct signal-based determination avoids the inaccuracies introduced by obstructions in the flow path, providing more reliable mass flow data.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical measurement approach (using conveying device power) with an optical measurement approach (using flame sensor signals). This substitution eliminates the problem of flow path obstructions affecting measurement accuracy, as the optical sensors measure combustion characteristics directly rather than inferring flow from mechanical parameters.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach allows for permanent, precise control of the combustion air ratio, ensuring safe and efficient operation of the heater, and is suitable for various fuels without the need for additional sensors or structural changes.

Implementation Method 1

at least two flame sensors (6, 13) are provided, with both or all flame sensors having or generating signals (14, 15) with different characteristics related to the power and/or the air ratio (λ) of the heater

Methodology Applied
Scientific EffectFlame detection:

Data Source

PatentEP4279810B1Method for operating a heating device, heating device for carrying out the method, and computer program
Publication Date: 2025.04.09 VAILLANT GMBH(DE)
  • EP4279810B1 patent drawingFigure 1
  • EP4279810B1 patent drawingFigure 2
  • EP4279810B1 patent drawingFigure 3~4

AI summary

A method for operating a heating appliance (1) is proposed, comprising a burner (3) to which a combustion mixture of fuel gas and combustion air is supplied, and a first flame sensor (6) and a second flame sensor (13), wherein the first and second flame sensors (6, 13) generate signals (14, 15) with different characteristics with respect to the current power and/or air-fuel ratio (λ) of the heating appliance (1), comprising at least the following steps: a) acquiring a first signal (14) from the first flame sensor (6) and a second signal (15) from the second flame sensor (13), b) determining a mass flow rate (m) of combustion mixture supplied to the burner (3) and the air-fuel ratio (λ) of the combustion mixture taking into account the first and second signals (14, 15), c) adjusting the control of the heating appliance (1) taking into account the mass flow rate (m) and the air-fuel ratio (λ) determined in step b).A method proposed here enables precise control of a heating device (1) using two flame sensors (6, 13).