Forced Flue Heater Cooling Layout for Burner Fan Motor Heat
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Solution Overview
Problem
Forced flue heaters that draw out combustion gas using a burner fan installed downstream from the heat exchanger face the challenge of the burner fan motor being heated to high temperatures, which can lead to inefficiencies and potential damage.
Innovation Solution
The forced flue heater design includes an air outlet upstream from the heat exchanger to direct cooling air towards the burner fan motor, creating a pressure difference that cools the motor efficiently without affecting the warm air output or heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a burner fan is installed downstream from the heat exchanger to draw out combustion gas, then combustion gas leakage is prevented when the heat exchanger cracks, but the burner fan motor is heated to high temperature
Solution Approach 1:
The patent extracts the burner fan motor from the high-temperature combustion gas environment by positioning it outside the air channel, while the burner fan itself remains inside to draw out combustion gas. This separation allows the motor to be cooled by ambient air while the fan continues to prevent gas leakage.
Solution Approach 2:
The patent introduces a partition wall with an air outlet as an intermediary structure. This partition separates the air channel into upstream and downstream sides, allowing cool air to pass through the air outlet and cool the burner fan motor, while maintaining the fan's position in the combustion gas path.
2Temperature
If cooling air is directed to the burner fan motor, then the motor temperature is reduced, but the amount of warm air blown may be reduced
Solution Approach 1:
The patent segments the air channel using a partition wall, creating separate upstream and downstream regions. The air outlet is positioned on the partition to allow cooling air to be extracted from the upstream side (before the heat exchanger) and directed to the motor, while the downstream side maintains full warm air flow to the outlet.
Solution Approach 2:
The patent takes preliminary action by positioning the air outlet upstream from the heat exchanger, where the air is still cool. This allows cooling air to be obtained before the air is heated, ensuring that the cooling process does not interfere with the warm air generation and output.
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 design effectively cools the burner fan motor without reducing the amount of warm air blown through the outlet, maintaining the heater's performance while preventing overheating.
Implementation Method 1
a heat exchanger, through which the combustion gas generated by the burner passes... The air is warmed by the heat exchanger
Implementation Method 2
The burner fan installed downstream from the heat exchanger draws out the combustion gas to create negative (vacuum) pressure inside the heat exchanger
Implementation Method 3
a difference in pressure between an inside and an outside of the partition causes air upstream from the heat exchanger to flow through the air outlet as cooling air to cool the burner fan motor
Data Source
AI summary
A forced flue heater draws out combustion gas using a burner fan installed downstream from a heat exchanger to prevent a burner fan motor from being heated to high temperature. The forced flue heater blows air to an air channel using a blower fan, and warms the air using the heat exchanger contained in the air channel. The pressure upstream from the heat exchanger is higher by a value corresponding to the resistance of the heat exchanger. The blower fan contained in an outer case draws in the surrounding air to lower the pressure inside the outer case. A partition separating between the inside and the outside of the air channel has an air outlet located upstream from the heat exchanger. This allows the cool air upstream from the heat exchanger to flow outside the partition. The air is then used as cooling air for cooling the burner fan motor. This structure prevents the burner fan motor from being heated to high temperature when the burner fan is heated to high temperature.