Heating Appliance Burner Door with Chicane Gas Preheating
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Solution Overview
Problem
Conventional doors with integrated burners in heating appliances suffer from significant thermal radiation losses and safety risks due to high external temperatures, leading to reduced efficiency and potential burns during maintenance.
Innovation Solution
A door design featuring a pair of metal sheets with a deflector plate in between, where the gaseous mixture follows a chicane trajectory, utilizing a heat shield effect to keep the outer sheet cool and preheat the mixture before combustion, improving efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional door with ceramic-based insulating material is used, then thermal insulation is provided, but the external face temperature still reaches 120-180°C causing energy loss and burn risks
Solution Approach 1:
A deflector plate is introduced as an intermediary component between the burner and the door sheets. This deflector plate redirects the gaseous mixture flow to follow a chicane trajectory, causing the cold currents to lick the inner face of the outer sheet and the outer face of the deflector plate, thereby shielding these surfaces from direct exposure to high-temperature combustion gases and reducing thermal radiation losses
Solution Approach 2:
The gaseous mixture is preheated by the thermal radiation from the burner before reaching the combustion zone. This preliminary heating action improves combustion efficiency while the deflector plate geometry ensures that the preheating occurs without directly exposing the outer door surface to extreme temperatures
2Object-affected harmful factors
If the door is made with thick insulating material to reduce heat transfer, then thermal protection is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The door is segmented into multiple functional layers: an outer sheet exposed to ambient air, an inner sheet facing the burner, and a deflector plate positioned between them. This segmentation allows each component to perform its specific function - the outer sheet remains cool for safety, the inner sheet handles thermal exposure, and the deflector plate controls flow patterns - thereby achieving thermal protection through functional distribution rather than simply increasing material thickness
Solution Approach 2:
Different regions of the door structure are assigned different thermal and functional properties. The deflector plate is positioned specifically to redirect flows where needed, the ceramic-based insulating material is applied locally on the inner face surrounding the burner, and the outer sheet is designed to remain thermally isolated. This localized optimization achieves protection without requiring the entire structure to be overly complex or thick
3Productivity
If the burner is positioned close to the tubes for efficient heating, then heating efficiency is improved, but the door temperature increases causing safety risks
Solution Approach 1:
The deflector plate serves as a mediator that allows the burner to be positioned close to the tubes for efficient heating while simultaneously protecting the door structure. By redirecting the gaseous mixture flow in a chicane pattern, the deflector plate ensures that hot combustion gases are directed toward the tubes for heating while the outer door surfaces are shielded from direct thermal exposure
Solution Approach 2:
The thermal radiation that would otherwise be a harmful loss is converted into a beneficial preheating mechanism. The deflector plate geometry is designed so that thermal radiation from the burner preheats the gaseous mixture before combustion, improving efficiency, while the same radiation pattern is controlled to avoid directly heating the outer door surface to dangerous temperatures
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 solution significantly reduces thermal radiation losses, maintains the outer door at a safe temperature, and enhances combustion quality, thereby improving the overall efficiency and safety of the heating appliance.
Implementation Method 1
the flow of gaseous mixture penetrating into the apparatus through said inlet opening is deviated towards the outside of the deflector plate, bypasses its peripheral edge from the outside inwards, and then flows on its internal face
Implementation Method 2
the streams of gaseous mixture penetrating into the apparatus follow a chicane trajectory; these cold currents first lick the inner face of the outer sheet and the outer face of the deflector plate
Implementation Method 3
This thermal radiation significantly lowers the overall efficiency of the device; thus, for a door of circular shape, with a diameter of 220 mm, the loss of energy can be of the order of 150 Wh, or 540 kJ
Implementation Method 4
these cold currents first lick the inner face of the outer sheet and the outer face of the deflector plate, which acts as a heat shield
Data Source
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AI summary
The invention relates to a door (1) provided with a gas burner (2) on the inner surface thereof and with a system (5) for carrying a combustible gas to the burner on the outer surface thereof, and which can be inserted and attached into a frame (61) of a wall of the device (AC); the door comprises a pair of metal sheets (10, 11) rigidly connected to one another at the edges thereof (100), with input openings (102) and output openings (103) for the gas mixture, respectively, and which are mutually separated, in order to leave an inner space receiving a deflector plate (3) serving as a thermal shield to be swept over on either side by the flow of the gas mixture supplying the burner. Said arrangement reduces heat loss through the door, making it possible to keep the outer surface cold, thus also avoiding the risk of burns, while at the same time preheating the gas mixture. The invention can be used in heating appliances.