Ferrule Fitting Assembly for Flexible Duct Connection Without Sealants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rigid sheet metal fittings for HVAC ductwork are labor-intensive and costly due to inconsistency, leakage, and difficulty in sealing, especially in tight spaces and when connecting large-diameter ducts, which requires additional materials and tools.
Innovation Solution
A fitting assembly with a ferrule that includes a sidewall with varying diameters and a radial thread, featuring a tab and recess system for secure engagement without the need for sealants, allowing for easy assembly and airtight connections using a ferrule thread that stretches the flexible duct for secure retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sheet metal fittings are used, then rigid connection is achieved, but labor intensity and material cost increase due to mastic and mechanical fasteners
Solution Approach 1:
The patent extracts and eliminates the need for mastic and mechanical fasteners by integrating the sealing function directly into the fitting's stamped construction. The fitting's design inherently provides both structural connection and air-tight sealing, removing the separate sealing step and materials.
Solution Approach 2:
The patent merges the structural connection function and sealing function into a single integrated fitting component. The stamped metal fitting simultaneously provides rigid support and creates an air-tight seal with the ductwork, combining multiple functions that were previously separated.
2Strength
If conventional sheet metal fittings with sharp edges are used, then structural strength is maintained, but ductwork stretching becomes difficult
Solution Approach 1:
The patent applies different surface qualities to different parts of the fitting. The internal surface that contacts the ductwork is formed with a smooth, rounded profile that facilitates easy stretching, while the external structure maintains the necessary strength and rigidity for structural support.
3Quantity of substance
If large diameter ducting is used, then airflow capacity is improved, but connection difficulty increases due to tension and handling
Solution Approach 1:
The patent segments the connection process into distinct functional zones: the duct end, the fitting interface, and the sealing surface. This segmentation allows each component to be optimized independently, making it easier to handle and connect large diameter ducting by focusing the connection effort at specific locations rather than requiring manipulation of the entire duct.
4Reliability
If conventional fittings require mastic application, then sealing is achieved, but access to obscured sides becomes challenging
Solution Approach 1:
The fitting is designed to be self-sealing through its stamped construction that inherently creates an air-tight interface with the ductwork. The fitting's geometry automatically provides the sealing function without requiring external application of mastic or other sealants, making the installation process independent of difficult-to-reach areas.
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 solution simplifies the installation process by providing a secure, airtight connection without additional sealants, reducing labor and material costs, and allowing for easy assembly without specialized tools, while maintaining airtight integrity.
Implementation Method 1
The pitch of the ferrule thread is less than a pitch of a helix structure of the flexible duct when the flexible duct is fully elongated. An outer diameter of the ferrule thread is larger than an inner diameter of a helix structure of the flexible duct when a pitch of the ferrule thread is equal to a pitch of the helix structure of the flexible duct when the flexible duct is fully elongated.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fitting assembly for connection to a flexible duct includes a ferrule configured for insertion into an open end of the flexible duct a fitting removably connected to the ferrule. The ferrule includes a sidewall defining a minor diameter and a major diameter spaced apart from the minor diameter, and a ferrule thread extending radially outward from the sidewall. One of the fitting and the ferrule defines a recess. Another of the fitting and the ferrule comprises a tab configured to extend into the recess. One of the recess and the tab comprises an edge. Another of the recess and the tab comprises a ramped surface extending in a circumferential direction of the ferrule, such that rotation of the ferrule relative to the fitting causes the ramped surface to engage the edge, thereby radially deflecting the tab and disengaging the tab from the recess.