Non-Uniform Air Vent Cross Section for EMI Shielding and Cooling

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Solution Overview

Problem

There is a conflict between electromagnetic interference (EMI) shielding and thermal management in computing systems, as EMI engineers prefer smaller air vent openings for better shielding, while thermal engineers require larger openings for efficient cooling, leading to a balance that becomes increasingly difficult with more powerful and faster systems.

Innovation Solution

The design of air vents with varying cross-sections, where the diameter increases non-linearly from a smaller first opening to a larger second opening, allowing for improved EMI shielding without compromising airflow, by maintaining the smallest opening size for shielding effectiveness and increasing the second opening for enhanced airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If smaller air vent openings are used, then EMI shielding performance is improved, but airflow and cooling efficiency deteriorate

Engineering Contradiction:

ImproveEMI shielding performanceVSAvoidairflow and cooling efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The air vent structure employs different opening sizes at different locations: smaller openings at the first opening (shielding side) for EMI protection and larger openings at the second opening (airflow side) for cooling efficiency. This local differentiation allows each side to optimize for its specific function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention transitions from a two-dimensional cross-sectional view to a three-dimensional non-linear tapered structure. By varying the diameter non-linearly along the length of the air vent, the design adds a dimensional aspect that simultaneously satisfies both shielding and airflow requirements that cannot be met by uniform cross-section designs.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If larger air vent openings are used, then airflow and cooling efficiency are improved, but EMI shielding performance deteriorates

Engineering Contradiction:

Improveairflow and cooling efficiencyVSAvoidEMI shielding performance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If straight through holes are used, then manufacturing simplicity is maintained, but the ability to balance EMI and thermal requirements is limited

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidability to balance EMI and thermal requirements

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention changes the geometric parameters of the air vent from a uniform cylindrical shape to a non-linear tapered shape with varying diameter along its length. This parameter change enables the structure to achieve both EMI shielding and thermal management performance that cannot be obtained with simple straight through holes, while still being manufacturable using conventional techniques.

Inventive Principle:

Principle #35Parameter changes

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 approach provides effective EMI shielding while maintaining or improving airflow and cooling efficiency, balancing the inverse requirements of EMI shielding and thermal management.

Implementation Method 1

Air vents on a computing system chassis are designed to shield unwanted electromagnetic energy

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

allow efficient air flow to cool the system

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS20230156983A1Air-vent with non-uniform cross section for EMI shielding

Publication Date: 2023.05.18 CISCO TECHNOLOGY INC

AI summary

Embodiments herein describe air vents that provide air flow for cooling but still provide EMI shielding. In one embodiment, the air vents have a first opening on a first side of a body of a chassis and a second opening on a second, opposite side of the body. These openings form an aperture through the side of the chassis. In addition, the first opening has a smaller diameter than the second opening.