Pliable-Wall Air Duct Structure That Stays Expanded When Depressurized
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Solution Overview
Problem
Metal ducts in buildings can cause condensation issues leading to mold and bacteria growth, uncomfortable drafts, and unsightly sagging when deflated, and produce noise when re-inflated, posing problems in environments where air quality and aesthetics are critical.
Innovation Solution
A pliable-wall air duct system with an internal framework made of rigid materials like plastic or fiberglass that maintains the duct's shape and tension, preventing sagging and noise when the blower is inactive, and includes radial support members and adjustable end caps to ensure consistent airflow and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal ducts are used for conveying conditioned air, then structural strength and durability are improved, but condensation formation and mold/bacteria growth occur due to thermal conductivity issues
Solution Approach 1:
The patent replaces rigid metal ducts with flexible fabric ducts that have low thermal conductivity. The fabric material acts as a thermal insulator, preventing condensation formation on the duct surface while maintaining structural integrity through the flexible shell design. This resolves the contradiction by eliminating the thermal conductivity issue that causes condensation while preserving the duct's structural function.
2Object-affected harmful factors
If fabric ducts are used to prevent condensation, then thermal insulation and mold prevention are improved, but the duct sags and creates noise when the blower is inactive
Solution Approach 1:
The patent divides the continuous fabric duct into segments by inserting rigid support ribs at regular intervals. These ribs act as internal structural elements that maintain the duct's cylindrical shape and prevent sagging when air pressure is absent, while the fabric segments between ribs retain their thermal insulation properties for condensation prevention.
Solution Approach 2:
The patent creates a composite structure combining flexible fabric material with rigid support ribs. The fabric provides thermal insulation and condensation resistance, while the rigid ribs provide structural support and shape stability. This composite design resolves the contradiction by integrating materials with complementary properties.
3Shape
If rigid support structures are added to maintain duct shape, then shape stability and noise reduction are improved, but device complexity increases
Solution Approach 1:
The patent applies rigid support ribs only at specific locations along the duct length where structural support is needed, rather than making the entire duct rigid. This localized application of rigidity maintains shape stability and reduces noise while minimizing the overall complexity of the support structure.
Data Source
AI summary
Example air ducts comprising pliable tubular sidewalls are provided with example internal frameworks that hold the duct in a generally expanded shape even when the duct is depressurized. The framework tensions the pliable sidewall material along the length of the ducts to keep the material taut. In some examples, the framework is restrained within the duct such that the duct's sidewall, being in tension, holds the framework in compression longitudinally. Thus, in the longitudinal direction, the duct is in tension and the framework is in compression. To prevent the framework from buckling under the compressive force, some example frameworks comprise a central longitudinal shaft with a plurality of radial spokes and rings that help hold the shaft straight. In some examples, the rings also help hold the duct radially expanded.