Duct
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Solution Overview
Problem
Existing duct configurations that absorb electromagnetic waves to prevent radiation noise from entering indoor spaces often hinder fluid flow and do not allow for selective transmission of specific frequency electromagnetic waves.
Innovation Solution
A duct design featuring an electromagnetic wave inhibiting sloped surface and a Frequency Selective Surface (FSS) inner peripheral member, which reflects unwanted electromagnetic waves while allowing specific frequencies to pass through, minimizing fluid flow obstruction and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an electromagnetic wave absorbing member is provided on the inner surface of the duct to absorb radiation noise, then electromagnetic wave shielding is improved, but fluid flow is inhibited and pressure loss increases
Solution Approach 1:
The invention extracts the electromagnetic wave absorbing member from the fluid flow path by positioning it on the outer surface of the duct rather than the inner surface. This allows the member to maintain electromagnetic shielding functionality while eliminating its negative impact on fluid flow and pressure loss.
Solution Approach 2:
The invention transitions the electromagnetic wave absorbing member from a two-dimensional inner surface configuration to a three-dimensional outer surface configuration. This dimensional change allows the member to be positioned outside the fluid flow path while still providing effective electromagnetic wave shielding through the duct wall.
2Object-affected harmful factors
If an electromagnetic wave absorbing member is used to absorb all frequencies of electromagnetic waves, then comprehensive shielding is improved, but selective transmission of specific frequency bands is lost
Solution Approach 1:
The invention applies different electromagnetic wave interaction properties to different parts of the system: the outer surface electromagnetic wave absorbing member provides broadband absorption, while the inner surface configuration (or specific frequency selective structures) allows selective transmission of desired frequency bands. This local differentiation of properties enables both comprehensive shielding and selective transmission.
Solution Approach 2:
The invention segments the electromagnetic wave control function into separate components: one component handles broadband absorption of unwanted frequencies, while another component handles selective transmission of desired frequencies. This segmentation allows each component to be optimized for its specific function without compromising the other.
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 duct achieves smooth fluid flow and selective electromagnetic wave transmission, effectively reducing radiation noise intrusion while maintaining air flow efficiency.
Implementation Method 1
an electromagnetic wave inhibiting sloped surface that is formed on an inner surface of the tube and extends to be sloped to approach an axial line of the tube from the outside toward the indoor in an axial direction of the tube and that reflects an electromagnetic wave
Implementation Method 2
an electromagnetic wave selecting inner peripheral member that has a tubular shape covering the electromagnetic wave inhibiting sloped surface from an inner peripheral side and is capable of selectively transmitting only an electromagnetic wave of a specific frequency incident on the tube
Data Source
AI summary
A duct includes: a tube that is formed to extend from an indoor of a building or a movable body and that allows an outside and the indoor to communicate with each other; an electromagnetic wave inhibiting sloped surface that is formed on an inner surface of the tube and extends to be sloped to approach an axial line of the tube from the outside toward the indoor in an axial direction of the tube and that reflects an electromagnetic wave; and an electromagnetic wave selecting inner peripheral member that has a tubular shape covering the electromagnetic wave inhibiting sloped surface from an inner peripheral side and is capable of selectively transmitting only an electromagnetic wave of a specific frequency incident on the tube.