Single Ferrule Pipe Fitting for Strong Sealing With Fewer Parts
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Solution Overview
Problem
Double ferrule-type fittings achieve efficient sealing but have a larger number of parts, while single ferrule-type fittings have fewer parts but struggle to efficiently generate the necessary force for sealing, presenting a trade-off between part count and sealing effectiveness.
Innovation Solution
A fitting design featuring a ferrule with a rising portion, intermediate portion, and pressed portion, where the ferrule is accommodated in a space formed by the fitting body, nut, and pipe, allowing the rising portion to increase its angle and generate a biting force into the pipe upon tightening, leveraging a tapered surface for efficient sealing with fewer parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double ferrule-type fitting is used, then sealing property is improved, but the number of parts increases
Solution Approach 1:
The patent combines the functions of two ferrules into a single ferrule structure. The single ferrule integrates the sealing function and the pipe-biting function that were previously distributed across two separate ferrules, thereby reducing part count while maintaining sealing effectiveness through the lever mechanism and geometric design
Solution Approach 2:
The single ferrule is divided into distinct functional zones: a first end portion for pipe contact and biting, an intermediate portion with larger inner diameter for structural leverage, and a second end portion for nut engagement. This segmentation allows each zone to perform its specific function efficiently while being part of a unified component
2Device complexity
If a single ferrule-type fitting is used, then the number of parts is reduced, but the force for biting into the pipe is insufficient
Solution Approach 1:
The ferrule is designed to dynamically change its geometry during tightening. As the nut is tightened, the ferrule deforms elastically, causing the first end portion to rotate and bite into the pipe. The intermediate portion's larger inner diameter allows this dynamic deformation and lever action to occur, converting axial compression into radial biting force
Solution Approach 2:
The ferrule utilizes curved and tapered surfaces, particularly at the first end portion where a tapered outer circumferential surface contacts the pipe. This geometric design concentrates the applied force and directs it efficiently into the pipe wall, enhancing the biting action while maintaining structural integrity
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 design efficiently generates a biting force into the pipe, achieving a sealing property comparable to double ferrule-type fittings while reducing the number of parts, providing a strong and reliable seal that resists vibrations and loosening.
Implementation Method 1
the rising portion rises to rotate, with an outer circumference of the first end portion serving as a fulcrum and an inner circumference of the first end portion serving as a point of load, thereby implementing a drive to bite into an outer circumference of the pipe
Data Source
AI summary
A fitting to be connected to a pipe includes: a first member; a second member coupled by screw coupling with the first member; and a ferrule placed in an accommodation space formed by an inner circumferential surface of the first member, an inner circumferential surface of the second member, and an outer circumferential surface of the pipe. The ferrule has a rising portion including a first end portion, a pressed portion located closer to a second end portion than the rising portion, and an intermediate portion including a portion where an inner diameter is greater than the first end portion and the second end portion, the intermediate portion connecting together the rising portion and the pressed portion. The first member has a first tapered inner circumferential surface, which is an inner circumferential surface having a tapered shape, to be in contact with the first end portion of the ferrule. The second member has a pressing portion for pressing at least a portion of the pressed portion of the ferrule. The accommodation space has a first clearance space for accommodating the ferrule therein and allowing the rising portion to rise so as to increase an angle of the rising portion with respect to the outer circumferential surface of the pipe.