Two-Stage Gas Burner with Segmented Baffles
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Solution Overview
Problem
Existing gas-fired air heaters face challenges in controlling flame shape and emission levels across varying firing intensities, leading to inefficiencies and excessive nitrogen dioxide and carbon monoxide emissions, particularly at high fire settings, and require retrofits to increase Btu output while maintaining emission standards.
Innovation Solution
A gas-fired burner assembly with a V-shaped combustion chamber and strategically arranged apertures in baffles creates a two-stage combustion system, maintaining a primary flame zone near the manifold and establishing a secondary flame zone, using air buffers and negative pressure zones to control flame characteristics and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the firing intensity is increased to raise Btu output, then the flame fills and exceeds the combustion chamber, but nitrogen dioxide emissions increase and flame stability decreases
Solution Approach 1:
The combustion chamber is segmented into multiple zones with progressively sized apertures in the baffles. The baffles are divided into sections with different aperture configurations - smaller apertures near the manifold for low-fire stability and larger apertures toward the exit for high-fire capacity. This segmentation allows the system to maintain flame stability across the entire firing range while controlling emissions.
Solution Approach 2:
Different regions of the combustion chamber are given different local qualities through varied aperture sizing and positioning in the baffles. The apertures are strategically placed with specific sizes at specific locations to control air-fuel mixing characteristics in each zone, enabling optimal combustion at both low and high firing intensities without excessive nitrogen dioxide formation.
2Productivity
If air inlets are enlarged to support high firing intensity, then enough air is admitted for proper air-fuel mixture, but the flame extends outside baffles exposing it to excess ambient air and increasing nitrogen dioxide
Solution Approach 1:
The baffle aperture configuration is designed to be dynamically effective across varying firing intensities. The progressive sizing of apertures from smaller near the manifold to larger toward the exit creates a dynamic air supply system that automatically provides appropriate air-fuel ratios for both low and high fire conditions, preventing flame blowout at high intensity while containing the flame within baffles to control emissions.
3Reliability
If air inlets are positioned to maintain low-fire stability, then the flame is maintained near the manifold, but at high fire the flame only establishes toward the end of baffles away from the manifold
Solution Approach 1:
The baffle system incorporates local quality variations with different aperture sizes at different locations. Smaller apertures near the manifold provide controlled air mixing for stable low-fire operation, while progressively larger apertures toward the baffle exit enable sufficient air supply for high-fire intensity, allowing the flame to establish and maintain itself throughout the combustion chamber including near the manifold at high fire.
4Productivity
If the burner is designed for high Btu output, then the flame fills the combustion chamber, but the products of combustion are not separated from the air stream and are delivered directly to occupied space
Solution Approach 1:
The design extracts and contains the combustion process within the bounded combustion chamber formed by the baffles. By properly sizing and positioning baffle apertures, the system ensures complete combustion occurs within the chamber while the flame is contained, preventing unburned combustion products from being directly delivered to occupied spaces and allowing high Btu output to be achieved safely.
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 two-stage combustion system enhances Btu output, maintains flame stability across firing rates, reduces nitrogen dioxide and carbon monoxide emissions, and allows for retrofitting existing manifolds without increasing footprint, adhering to emission standards and improving operational range.
Implementation Method 1
a gas conduit disposed within the manifold and linked to the trough by a plurality of gas ports that transport gas from the conduit to the trough
Implementation Method 2
at least one air port provided in each shoulder, each air port linking the trough to ambient air to transport air into the trough
Implementation Method 3
a gas-fired burner assembly with a V-shaped combustion chamber and strategically arranged apertures in baffles creates a two-stage combustion system
Implementation Method 4
The flame and its byproducts are mixed directly with the air stream and added to the space being heated
Data Source
AI summary
A direct gas-fired burner assembly is disclosed in which a two-stage flame is produced. A gas manifold is attached to two baffles with apertures disposed therein. The apertures are designed such that a fuel rich zone occurs near the manifold, while a lean zone occurs away from the manifold. At high fire, the apertures create a negative pressure zone which draws the gas away from the burner thereby allowing a primary flame to burn. The primary flame in the fuel rich zone ignites a secondary flame in the lean zone. Because a flame is burning throughout the entire combustion zone, the flame does not move out past the baffles, the flame remains smaller and cooler, and a lower output of pollutants is achieved.