Ovalized Air Jet Fire Fighting Blower for Backflow Prevention
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Solution Overview
Problem
Conventional fire fighting blowers often fail to effectively evacuate hot fumes from buildings during fires, leading to 'flash-over' phenomena and reduced visibility for firefighters, as they create air jets with free spaces on the door surface that allow backflow, potentially endangering firefighters and prolonging evacuation times.
Innovation Solution
A fire fighting blower with a propeller and tubular casing that generates an ovalized air jet by using a combination of first and second deflectors, directing airflow in opposite directions to cover the entire door surface, preventing backflow and enhancing fume expulsion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fire fighting blower generates an axial air jet, then the air jet can be produced with a simple tubular casing, but the air jet creates free spaces on the door surface that allow backflow of hot fumes
Solution Approach 1:
The invention transforms the symmetric circular air jet into an asymmetric ovalized air jet by introducing deflectors that modify the flow distribution. The ovalized section is oriented such that its major axis is perpendicular to the door plane, ensuring complete coverage of the rectangular door surface and eliminating free spaces where backflow could occur.
Solution Approach 2:
The invention adds a dimensional transformation by converting the circular cross-section air jet into an ovalized cross-section jet. This dimensional change allows the air jet to match the rectangular geometry of the door, providing complete surface coverage and preventing backflow through proper geometric alignment.
2Productivity
If the air jet is directed to cover the entire door surface, then backflow is prevented, but the conventional axial jet creates free spaces that reduce effectiveness
Solution Approach 1:
The ovalized air jet creates an asymmetric flow distribution that specifically targets complete door surface coverage. The major axis of the ovalized section is perpendicular to the door plane, ensuring that the entire rectangular door is covered by the high-velocity air stream, thereby preventing backflow and protecting firefighters while maximizing fume evacuation efficiency.
3Productivity
If jet rectifying deflectors are used to concentrate the air jet, then the air flow is focused towards the door, but the conventional circular jet cannot cover the rectangular door surface completely
Solution Approach 1:
The invention transforms the circular cross-section of the concentrated air jet into an ovalized cross-section, changing the geometric dimensions to match the rectangular door surface. This dimensional adaptation allows the concentrated air jet to cover the entire door area, combining jet concentration with complete surface coverage.
Solution Approach 2:
The deflectors are specifically designed to create localized modifications in the air flow, concentrating the jet in certain directions while expanding it in others. The first deflectors concentrate the air axially, while the second deflectors create the ovalized shape, providing different flow characteristics in different spatial directions to match the door geometry.
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 blower effectively evacuates hot fumes more quickly and safely by ensuring the entire door surface is covered, reducing the risk of backflow and improving firefighter visibility and intervention speed.
Implementation Method 1
a propeller (2) and a tubular casing (3) for producing an axial airflow
Implementation Method 2
an assembly of first deflectors for concentrating the axial airflow and generating a concentrated axial air jet
Implementation Method 3
a second direction reversing deflector which directs this part of the airflow in the opposite direction of rotation of the propeller
Implementation Method 4
project a jet of air through the door in order to push the hot fumes outwardly of the building
Data Source
AI summary
A fire fighting blower (1) comprises a propeller (2) coaxially mounted in a tubular casing (3) for generating an axial airflow. The blower comprises an airflow guiding device (9) in the casing (3) for obtaining a concentrated air jet having a substantially ovalized section, it comprises within the tubular casing (3) an assembly of first deflectors (4) for concentrating the axial airflow and generating a concentrated axial air jet and an assembly of second deflectors (16, 17) for generating an air stream deflected from the concentrated axial air jet so that the concentrated air jet having an ovalized section is a combination of the concentrated axial air jet and the deflected air stream.