Air extraction fan with variable flow cross-section in case of fire
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Solution Overview
Problem
Existing air extraction fans in buildings, especially during fires, face challenges in maintaining sufficient airflow due to the restriction caused by turbines when they are stopped, leading to inadequate ventilation rates and increased pressure drops, which is critical for fire safety as they need to maintain a minimum ventilation rate of 30 minutes at 400°C.
Innovation Solution
An air extraction fan with a deformable part made of plastic material that deforms under high temperatures to increase the outlet passage section, complementing the normal passage and reducing pressure drops, allowing for enhanced airflow even when the turbine is stopped, thereby facilitating the escape of hot gases during fires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the turbine is stopped during a fire, then energy consumption is reduced, but the airflow is restricted and pressure drop increases
Solution Approach 1:
The patent applies the dynamics principle by making the outlet passage section variable through a deformable part that automatically changes shape in response to temperature variations. During normal operation, the passage maintains its standard configuration for efficient airflow. During a fire, the heat causes the deformable part to expand or change shape, automatically increasing the outlet passage section to maintain sufficient airflow without requiring turbine operation. This dynamic adaptation resolves the contradiction between energy savings from stopping the turbine and the need for maintained airflow during emergencies.
2Productivity
If the outlet passage section is increased during a fire, then airflow is improved, but the device complexity increases
Solution Approach 1:
The patent employs the self-service principle by designing a deformable part that automatically responds to thermal conditions without requiring external control systems, actuators, or additional mechanical components. The deformable part is made of material that inherently changes shape when exposed to high temperatures, such as heat-activated memory alloys or thermally responsive polymers. This self-actuating mechanism increases the outlet passage section during fires while avoiding the complexity of controlled systems, resolving the contradiction between improved airflow and device complexity.
3Productivity
If a deformable part is added to increase passage section, then airflow during fire is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by utilizing materials with inherent thermal response properties that change their physical state or dimensions in response to temperature variations. The deformable part is constructed from materials such as heat-activated shape memory alloys, thermally responsive polymers, or composites with differential thermal expansion coefficients. These materials are integrated into the existing outlet passage structure using conventional manufacturing techniques, allowing the passage section to automatically increase during fires without requiring complex assembly processes or specialized manufacturing methods, thus resolving the contradiction between improved fire-mode airflow and manufacturing ease.
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 deformable part automatically increases the outlet passage section, reducing pressure drops and ensuring sufficient airflow during fires, even if the turbine is not operational, thus improving safety by maintaining ventilation and reducing the risk of heat-related hazards.
Implementation Method 1
the passage of air or fumes at a higher temperature in this fan is accompanied by a heating of the deformable part, which deforms thereby automatically increasing the passage section
Implementation Method 2
a deformable part closing a passage to the outside, which deforms in temperature under the effect of hot gases in the fan during a fire, so as to form an additional exit passage adding to the normal exit passage
Data Source
Figure 1~3
Figure 4~6
AI summary
Air extraction fan intended to be placed on a building at the outlet of a ventilation circuit, having a normal passage for the air outlet to the outside, this fan being characterized in that it comprises a deformable part (30) closing a passage towards the outside, which deforms in temperature under the effect of a flow of hot gases in the fan during a fire, so as to form an additional exit passage being added to the normal exit passage to increase the total outward passage section.