Motor-Driven Chimney Draft System with Separated Motor Compartment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor-driven chimney draft systems increase flow resistance due to forced direction changes of flue gases and expose motors to excessive heating, which is undesirable and costly to mitigate.
Innovation Solution
The system separates the motor compartment from the flue gas compartment with a vertical air space and a transverse motor shaft, minimizing heat transfer and flow disturbance, with a screen on the separating wall directing flue gases radially and preventing reverse flow, while allowing ambient air for cooling and convection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the motor compartment is placed in the flow path of flue gases, then the motor can be compactly integrated, but the motor will be exposed to excessive heating
Solution Approach 1:
The system is divided into separate functional compartments: a motor compartment housing the motor and a flue gas compartment for gas flow. These compartments are physically separated by a separating wall, allowing the motor to be protected from hot flue gases while maintaining a compact integrated structure. The separation enables independent optimization of each compartment's function.
Solution Approach 2:
The motor is extracted from the direct flue gas flow path and placed in a separate motor compartment. This extraction removes the motor from the harmful thermal environment while preserving its functional connection to the flue gas flow through the separating wall and shaft arrangement.
2Power
If the motor shaft extends through the separating wall, then the motor can drive the impeller effectively, but heat transfer from flue gas to motor increases
Solution Approach 1:
The separating wall acts as an intermediary element that allows mechanical power transmission from the motor shaft to the impeller while blocking direct thermal contact between hot flue gases and the motor. The wall serves as a thermal barrier that maintains mechanical connectivity without compromising thermal isolation.
Solution Approach 2:
The separating wall has different properties at different locations: it is thermally insulating to block heat transfer, but mechanically permeable to allow the motor shaft to pass through and transmit power. This local differentiation of wall properties enables simultaneous achievement of thermal protection and mechanical drive function.
3Productivity
If the impeller is positioned to efficiently move flue gases, then draft performance improves, but flow resistance increases due to direction changes
Solution Approach 1:
The impeller blades are designed with curved surfaces that smoothly guide flue gases through the system. The curved geometry allows the impeller to change the direction of flue gases more gradually, reducing flow separation and turbulence, thereby minimizing flow resistance while maintaining effective draft performance.
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 maintains minimal flow resistance and protects the motor from excessive heating, ensuring efficient operation and reduced maintenance costs by minimizing heat transfer and flow disturbance.
Implementation Method 1
access by the ambient air to the space will give rise to thermally induced convection, in particular when the space is oriented vertically and is open upwardly
Implementation Method 2
The distance between the separating walls reduces heat transfer from the flue gas compartment to the motor compartment
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention provides a motor-driven chimney draft system with a flue gas inlet, a flue gas outlet, a flue gas compartment in fluid communication with the flue gas inlet and with the flue gas outlet, the flow of flue gases in the flue gas compartment having a flow direction from the flue gas inlet to the flue gas outlet, a motor compartment with motor having a motor shaft extending through a separating wall of the flue gas compartment, the motor shaft carrying an impeller for driving the received flow of flue gases in the flow direction; each of the separating wall of the flue gas compartment and the separating wall of the motor compartment extends parallel to the flow direction of flue gases, and they are arranged facing each other so as to define an air space therebetween, where the air space has openings allowing ambient air to flow through the air space.