Internal Fume Recirculation Burner for Compact, Low-NOx Operation
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Solution Overview
Problem
Existing burners with fumes recirculation systems are bulky and require substantial modifications to the flue structure, limiting their use to spacious environments and increasing costs, while also producing NOx and noise.
Innovation Solution
A compact burner design with a fumes return duct and suction means that reintroduces combustion gases into the comburent supply, reducing NOx emissions without additional flue modifications, using a heat exchanger to cool the gases and maintain a compact, silent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If external recirculation ducts are used to reintroduce combustion gases, then NOx emissions are reduced, but the system becomes bulky and requires substantial flue modifications
Solution Approach 1:
The patent merges the recirculation function directly into the burner assembly by integrating a recirculation chamber and duct within the burner structure itself. The recirculation duct (10) is positioned to draw combustion gases directly at the combustion head (8) and reintroduce them at the base of the combustion chamber, eliminating the need for separate external recirculation systems and flue modifications.
Solution Approach 2:
The patent changes the spatial arrangement by positioning the recirculation inlet at the combustion head level and the outlet at the base level, creating a vertical recirculation path within the burner assembly. This dimensional reorganization allows compact integration without requiring horizontal ductwork or substantial flue modifications.
2Productivity
If external recirculation ducts are installed, then combustion efficiency improves, but installation cost and complexity increase
Solution Approach 1:
The recirculation system is merged into the burner assembly as an integrated unit, allowing the entire system to be replaced as a single component. This eliminates the need for costly and complex modifications to existing flue structures, reducing installation costs while maintaining combustion efficiency improvements.
Solution Approach 2:
The burner assembly performs its own recirculation function through the integrated recirculation duct and chamber, drawing combustion gases directly at the combustion head and reintroducing them at the base. This self-contained system eliminates dependency on external recirculation infrastructure.
3Temperature
If combustion gases are recirculated through external ducts, then flame temperature is reduced, but the system produces noise
Solution Approach 1:
The recirculation path is reorganized vertically with the inlet at the combustion head and outlet at the base, creating a compact internal flow path that minimizes turbulence and noise generation compared to external horizontal ductwork.
Solution Approach 2:
The recirculation chamber (28) acts as an intermediary that gently introduces recirculated gases at the base of the combustion chamber, allowing for controlled mixing that reduces turbulence-induced noise while maintaining the temperature-lowering effect.
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 burner effectively reduces NOx emissions and noise, allowing easy installation in various environments by replacing the burner alone, without requiring extensive flue modifications, and maintaining a compact form factor.
Implementation Method 1
suction means, preferably defined by a fan, configured to draw at least an amount of comburent from an environment outside the burner and to move at least an amount of such comburent from the second inlet opening to the second outlet opening
Implementation Method 2
using a heat exchanger to cool the gases
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Burner (1) with fumes recirculation comprising a first supply duct (2) for supplying fuel, having at least a first inlet opening (3) and a first outlet opening (4) and a second supply duct (5) for supplying a comburent, having at least a second inlet opening (6) and a second outlet opening (7). The burner (1) further comprises suction means (9) configured to move said at least an amount of comburent from the second inlet opening (6) to the second outlet opening (7) and a fumes return duct (10) for fumes generated by the combustion of the flame and configured to promote a re- introduction of the fumes in the burner (1). In particular, the fumes return duct (10) has a third fumes inlet opening (11) arranged at the head (8) of the burner (1) and a third outlet opening (12) placed in fluid communication with the second inlet opening (6) for the comburent to promote an at least partial re-introduction of the combustion fumes in the second supply duct (5). Furthermore, the suction means (9) is configured to promote a movement of the combustion fumes from the fumes return duct (10) to the second supply duct (5).