Dual-Chamber Burner Assembly for Wide-Range Heat Modulation

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Solution Overview

Problem

Conventional single chamber burners for water heating appliances face limitations in achieving continuous modulation of heat input over a wide range of heat demands, leading to inefficiencies and increased complexity when trying to achieve high turndown ratios.

Innovation Solution

A dual-chamber burner assembly with separate inlet passages for each chamber, utilizing multiple blower assemblies to provide premixed fuel and air independently to each chamber, allowing for a turndown ratio of at least 25:1 and enabling continuous modulation without the need for large, customized blower and gas valve components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single chamber burner is used with fixed flow rate, then the appliance structure is simple, but the turndown ratio is limited and cannot achieve continuous modulation over wide range

Engineering Contradiction:

Improveturndown ratioVSAvoidburner structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The burner is divided into multiple independent chambers (first burner chamber, second burner chamber, etc.), each capable of independent operation with separate fuel and air supplies. This segmentation allows each chamber to be controlled independently, enabling continuous modulation of total heat output by adjusting the number and intensity of active chambers, thereby achieving high turndown ratio without requiring a single complex modulating burner.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple single chamber burners are used to achieve wide range modulation, then the turndown ratio increases, but the plumbing and control system complexity increases

Engineering Contradiction:

Improveheat input rangeVSAvoidplumbing and control

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple burner chambers are merged into a single integrated burner assembly with a common header that distributes fuel and air to all chambers. This merging eliminates the need for separate plumbing runs to multiple independent burners and allows for simplified centralized control of fuel and air flow to all chambers, reducing overall system complexity while maintaining the ability to modulate heat input across a wide range.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common header and fuel distribution system serve multiple burner chambers simultaneously, making the system multi-functional. The same fuel line and air supply infrastructure supports operation of one or multiple chambers depending on heat demand, eliminating redundant plumbing and control components that would be required if separate single-chamber burners were used.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If flame sensor is exposed to flame from adjacent chamber, then the flame detection is simple, but false detection occurs and reliability decreases

Engineering Contradiction:

Improveflame detection accuracyVSAvoidflame sensor positioning

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flame sensor for each burner chamber is extracted and positioned within its own chamber, isolated from flames in adjacent chambers. This extraction ensures that each flame sensor detects only the flame from its associated burner chamber, preventing false detection and improving reliability of flame monitoring and safety control.

Inventive Principle:

Principle #2Taking out (Extraction)

4Adaptability or versatility

If large customized blower and gas valve components are used, then high turndown ratio can be achieved, but the component size and cost increase

Engineering Contradiction:

Improveturndown ratioVSAvoidblower and valve size

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The total fuel and air flow requirement is segmented across multiple smaller burner chambers, each served by appropriately sized standard blower and valve components. This segmentation allows the use of smaller, off-the-shelf components rather than requiring one large customized blower and valve system, reducing component size, cost, and lead time while achieving the same overall turndown ratio capability.

Inventive Principle:

Principle #1Segmentation

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

The dual-chamber burner assembly achieves a high turndown ratio of at least 25:1, enabling continuous modulation of heat input over a wide range while maintaining efficiency and reducing complexity, and includes safety features to prevent backflow and condensation issues.

Implementation Method 1

a flame sensor located adjacent the flame sensor portion of the second burner chamber need not be exposed to flame from the first burner chamber

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9097436B1Integrated dual chamber burner with remote communicating flame strip

Publication Date: 2015.08.04 LOCHINVAR LLC

AI summary

A dual chamber burner assembly provides a header, a first burner chamber adjacent the header, and a second burner chamber on an opposite side of the first burner chamber from the header. The second burner chamber is provided with a flame sensor portion extending back through the first burner chamber toward the header so that first and second flame sensors may be utilized to detect flame in the first and second chambers, respectively.