Auxiliary Heating Duct for Cold-Start Indirect Fired Heaters
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Solution Overview
Problem
Indirect fired heaters used in cold climates face performance issues due to unheated burner assemblies and components, leading to potential fuel gelation and poor operation.
Innovation Solution
An auxiliary heating duct is designed to direct a portion of heated air from the heating air passage back to the burner assembly and related components, preventing combustion fumes from entering the heated air passage, thereby providing heat to the fuel lines, blower motor, fuel filter, and fuel pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heated air is recycled to the heating air inlet, then temperature control of heated air is improved, but the burner assembly and related components remain unheated resulting in poor performance in cold climates
Solution Approach 1:
The invention divides the air circulation system into two separate loops: the primary loop recycles heated air to the heating air inlet for temperature control, while the auxiliary duct creates a secondary loop that directs heated air to the burner assembly. This segmentation allows both functions to operate independently without interfering with each other.
Solution Approach 2:
The auxiliary heating duct acts as an intermediary component that transfers heated air from the heating air passage to the burner assembly. This mediator enables heat delivery to the burner components without disrupting the existing heated air recycling system.
2Object-affected harmful factors
If separate heated air and combustion passages are used, then combustion gas contamination is prevented, but the burner assembly remains unheated in cold climates
Solution Approach 1:
The invention maintains the separation between the heating air passage and combustion passage to prevent contamination, while adding a dedicated auxiliary duct that provides a separate pathway for delivering heated air to the burner assembly. This segmented approach preserves the integrity of both air streams.
Solution Approach 2:
The auxiliary duct extends the heating system into a new spatial dimension by routing heated air from the heating air passage (one dimension) to the burner assembly (another dimension), thereby providing thermal protection to components without compromising the separation between air streams.
3Device complexity
If burner assembly components are located at the inlet end, then compact design is achieved, but components are exposed to cold temperatures causing fuel gelation
Solution Approach 1:
The auxiliary heating duct delivers heated air to the burner assembly components before cold temperatures can cause fuel gelation. This preliminary heating action prevents fuel viscosity increase and ensures reliable fuel flow from the start of operation in cold climates.
Solution Approach 2:
The invention changes the temperature parameter of the environment surrounding the burner assembly components by introducing heated air through the auxiliary duct. This parameter change from cold to warm temperatures prevents fuel gelation while maintaining the compact inlet-end location of components.
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
This solution improves the operation of indirect fired heaters in cold climates by effectively heating the burner assembly and related components, preventing fuel gelation and maintaining performance.
Implementation Method 1
the heating air passage and the combustion passage being adjacent one another so as to be arranged to exchange heat from the combustion passage to the heating air passage
Implementation Method 2
the inlet end of the duct being arranged to be supported adjacent to the heating air discharge so as to be arranged to direct a portion of a flow of heated air from the heating air passage into the auxiliary passage
Data Source
AI summary
An auxiliary duct is supported on the housing of an indirect fired heater of the type having separate heated air and combustion passages. The auxiliary duct extends between an inlet end at the heated air discharge to an outlet end adjacent a burner assembly at the combustion inlet so as to be arranged to direct a portion of the flow of air heated by the heater towards components of the burner assembly including fuel lines, a fuel pump, a fuel filter and a combustion air intake blower for heating the burner assembly and associated components to improve the operation thereof in colder climates.