Dual Chamber Burner Assembly for Wide Turndown Modulation
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Solution Overview
Problem
Conventional water heating appliances with single chamber burners face limitations in achieving continuous modulation of heat input over a wide range of demands, leading to inefficiencies and increased complexity when trying to maintain high turndown ratios.
Innovation Solution
A dual blower system with separate low range and high range blower assemblies supplies premixed fuel and air to a multiple chamber burner assembly, allowing for continuous variable heat input with a turndown ratio of at least 25:1, utilizing existing smaller capacity blowers and gas valves to achieve high inputs without the need for large, customized components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single chamber burner with fixed flow rate is used, then the device complexity is low, but the turndown ratio is limited and cannot achieve continuous modulation over wide range
Solution Approach 1:
The burner is divided into multiple independent chambers (first chamber and second chamber) that can operate independently or simultaneously. Each chamber has its own fuel and air inlet passages, allowing separate control of heat input from each chamber. This segmentation enables continuous modulation over a wide turndown ratio by adjusting the operation of individual chambers while maintaining relatively simple individual chamber structures.
2Adaptability or versatility
If multiple staged burners are used to achieve variable input, then the turndown ratio is improved, but the system can only change input in substantial increments rather than continuously
Solution Approach 1:
The burner system incorporates variable speed blowers that dynamically adjust the flow rate of combustion air to each chamber. By continuously varying the blower speed and corresponding air flow rate, the system achieves continuous modulation of heat input rather than discrete stepped changes. The fuel flow is similarly varied to maintain proper fuel-air ratios across the entire operating range.
3Adaptability or versatility
If a variable flow blower is used to achieve continuous modulation, then the turndown ratio is improved to 4:1, but physical limitations prevent achieving higher turndown ratios
Solution Approach 1:
The burner is divided into multiple independent chambers (first chamber and second chamber) that can operate independently or simultaneously. Each chamber has its own fuel and air inlet passages, allowing separate control of heat input from each chamber. This segmentation enables continuous modulation over a wide turndown ratio by adjusting the operation of individual chambers while maintaining relatively simple individual chamber structures.
Solution Approach 2:
Multiple chambers are merged into a single burner assembly that shares common structural elements and control systems. The chambers operate in parallel, with their heat inputs combining to provide the total required heat output. This merging approach multiplies the effective turndown ratio capability while maintaining reliable operation across the extended range.
4Adaptability or versatility
If multiple single chamber burners are used to achieve wide range modulation, then the turndown ratio is improved, but the plumbing and control system complexity increases
Solution Approach 1:
Multiple chambers are merged into a single burner assembly that shares common structural elements and control systems. The chambers operate in parallel, with their heat inputs combining to provide the total required heat output. This merging approach multiplies the effective turndown ratio capability while maintaining reliable operation across the extended range.
Solution Approach 2:
The burner design uses universal components and configurations across chambers, with each chamber being substantially identical in structure. This multi-functionality allows the same basic chamber design to serve different operating ranges, simplifying both plumbing and control systems while achieving wide turndown capability through coordinated operation of multiple chambers.
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 blower system enables a wide range of heat input modulation with improved efficiency and reduced complexity, providing a high turndown ratio and limitless input capacity while preventing backflow and condensation issues through independent blower operation and supplemental air management.
Implementation Method 1
a first foraminous outer wall portion and a second foraminous outer wall portion
Data Source
AI summary
A dual chamber burner assembly is provided for use with a heater apparatus having dual combustion air premix blowers. The burner assembly includes first and second interior zones communicated with first and second foraminous outer wall portions. First and second fuel and air inlet passages are communicated with the first and second interior zones, respectively.