Gas-Air Mixing Device with Selectable Outlets for Stable Combustion

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Solution Overview

Problem

Existing gas-air mixing devices in heating devices face challenges in achieving stable combustion mixture formation across a wide modulation range, particularly at high power levels, leading to issues like high noise emissions, large fan requirements, and risk of siphoning, while maintaining a simple and robust design.

Innovation Solution

A one-piece gas-air mixing device with a tubular mixing element inserted into the flow path of the heating device, featuring constant cross-section and adjustable gas outlet openings, which allows for precise fuel gas addition based on combustion air flow, reducing pressure drop and ensuring stable combustion across varying power levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas is added in the area of the smallest flow cross-section of the throttle point, then stable combustion mixture formation is achieved at low power levels, but excessive suction effect occurs at high power levels

Engineering Contradiction:
Improvestable combustion mixture formationVSAvoidexcessive suction effect
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by providing different gas outlet opening configurations in different regions of the mixing device. Specifically, it includes a first gas outlet opening in the area of the smallest flow cross-section for low power operation, and a second gas outlet opening in an area with larger flow cross-section for high power operation. This allows each region to have optimized characteristics for its specific operating condition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the gas outlet opening selectable between at least two different configurations depending on the power level. The system can dynamically switch between using the first gas outlet opening at low power levels and the second gas outlet opening at high power levels, adapting the mixing device's characteristics to match the current operating conditions.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If a large pressure drop is accepted at high power levels, then the mixing device can be simpler in design, but noise emissions increase and fan size must be larger

Engineering Contradiction:
Improvemixing device designVSAvoidnoise emissions
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by providing different gas outlet opening configurations in different regions of the mixing device. Specifically, it includes a first gas outlet opening in the area of the smallest flow cross-section for low power operation, and a second gas outlet opening in an area with larger flow cross-section for high power operation. This allows each region to have optimized characteristics for its specific operating condition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the gas outlet opening selectable between at least two different configurations depending on the power level. The system can dynamically switch between using the first gas outlet opening at low power levels and the second gas outlet opening at high power levels, adapting the mixing device's characteristics to match the current operating conditions.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the mixing device is designed for wide modulation range, then safe operation from 10% to 100% power is enabled, but device complexity increases

Engineering Contradiction:
Improvemodulation rangeVSAvoidmixing device structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing different gas outlet opening configurations in different regions of the mixing device. Specifically, it includes a first gas outlet opening in the area of the smallest flow cross-section for low power operation, and a second gas outlet opening in an area with larger flow cross-section for high power operation. This allows each region to have optimized characteristics for its specific operating condition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the gas outlet opening selectable between at least two different configurations depending on the power level. The system can dynamically switch between using the first gas outlet opening at low power levels and the second gas outlet opening at high power levels, adapting the mixing device's characteristics to match the current operating conditions.

Inventive Principle:
Principle #15Dynamics

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 safe and robust operation of heating devices across a wide modulation range, from 10% to 100% of rated power, without increasing complexity or manufacturing costs, and can be easily retrofitted to existing systems.

Implementation Method 1

The conveying device (2), in particular a fan, which can convey a mass flow (or volume flow) of combustion air

Methodology Applied
Scientific EffectSuction effect: Pressure Gradient

Implementation Method 2

The gas valve (5) adds a mass flow of fuel gas corresponding to a predetermined combustion air ratio to the mass flow of combustion air

Methodology Applied
Scientific EffectSuction effect: Pressure Gradient

Implementation Method 3

The fuel gas is often mixed with the mass flow of combustion air in the area of the throttle point

Methodology Applied
Scientific EffectGas mixing: Diffusion

Implementation Method 4

the mixing device (the throttle point) must generate sufficient intake pressure for mixture formation at low outputs, but at high outputs, the pressure drop at the throttle point must not be too high

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Data Source

PatentEP4596966A1Heating device with a gas-air mixing device
Publication Date: 2025.08.06 VAILLANT GMBH(DE)
  • EP4596966A1 patent drawingFigure 1
  • EP4596966A1 patent drawingFigure 2~3
  • EP4596966A1 patent drawingFigure 4

AI summary

The invention relates to a heating device (1) comprising a conveying device (2) which supplies a mixture of fuel gas and combustion air to a burner (3), and a one-piece gas-air mixing device (15) comprising a line element (19) which can be inserted into a flow path of the heating device (1) and at least one mixing element (20) which projects into a flow cross-section of the line element (19) and has at least one gas outlet opening (21).