Spiral Rectangular Ducting with Rounded-Die Corner Forming
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Solution Overview
Problem
Existing methods for manufacturing and assembling rectangular and square HVAC ducting are time-consuming and expensive, with limitations in length and structural integrity, and face challenges in forming large-sized ducting without excessive friction and deformation.
Innovation Solution
The use of lengthy variable length helical round duct sections transformed into square or rectangular cross-sections using an expansion apparatus with rounded die corners to reduce friction and prevent material failure, combined with flanged connectors for inner connection and reinforcing sections for enhanced structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If sharp-cornered dies are used to form rectangular ducting from round spiral ducting, then the ducting can be formed into rectangular shape, but excessive friction causes material to adhere to die corners and split at corners
Solution Approach 1:
The patent applies curved or rounded die corners instead of sharp corners when forming rectangular ducting from round spiral ducting. This curvature reduces friction between the die and ducting material, preventing material adhesion and corner splitting while still achieving the desired rectangular cross-section shape.
2Shape
If conventional bending methods are used to form rectangular ducting, then corners can be formed, but the ducting length is limited by brake press size and sheet metal stock length
Solution Approach 1:
The patent changes the manufacturing approach from bending flat sheet metal to expanding round spiral ducting. This parameter change allows production of much longer ducting lengths because spiral ducting can be manufactured in continuous long sections and then expanded in-place to rectangular shape, eliminating the length constraints of brake presses and sheet stock.
3Length of moving object
If face flange structures are used to connect ducting sections, then ducting sections can be joined end-to-end, but additional corner pieces and clips are required to seal corners
Solution Approach 1:
The patent merges the connection and corner sealing functions into a single integrated expansion process. By expanding round spiral ducting with pre-formed corner sections into rectangular shape, the corners are naturally formed and sealed as part of the main ducting body, eliminating the need for separate corner pieces and clips that are required with conventional face flange connections.
4Shape
If rectangular ducting is formed from bent sheet metal, then corners can be created, but reinforcing members are needed to prevent vibration and increase structural integrity
Solution Approach 1:
The patent uses the spiral-wound thin-gauge material itself to provide structural integrity. The helical spiral construction creates a naturally stiff and vibration-resistant structure that eliminates or reduces the need for additional reinforcing members, while still allowing the ducting to be expanded from round to rectangular cross-section.
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 method allows for the efficient and cost-effective production of large-sized rectangular or square ducting with improved structural integrity and airflow efficiency, reducing the need for intermediate reinforcements and minimizing air leakage, while enabling longer continuous ducting lengths.
Implementation Method 1
rounded die corners to reduce friction and prevent material failure
Data Source
AI summary
A duct structure (50), includes lengths of square/rectangular duct (52) manufactured by performing spiral duct in round cross-section (51) and then transforming the round cross-section into square and rectangular cross-sections utilizing expandable die structures (58). The duct (52) may be connected together end to end by flanged connectors (54) formed from strip stock (220), that is notched at locations that correspond to the corners of the formed flange connector. The cross-sectional profile of the flanged connector is then formed by roll forming and/or bending and/or other techniques. Thereafter, the strip stock is bent at its notched locations to define the corners (230) of the flange connector (54) and then the free ends of the strip stock are fixed together.