Screw Fitting for Smooth Pipe Sealing

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Solution Overview

Problem

Existing pipe fittings that join a threaded end member with a smooth surface often damage the pipe during assembly, fail to provide sufficient mechanical and hydraulic sealing, and are complex and expensive to manufacture, with the risk of twisting the pipe and losing sealing integrity.

Innovation Solution

A screw fitting assembly comprising a ring nut, a pressing member, a rigid ring, and an elastomeric gasket, where the pressing member is snap-coupled with the rigid ring and gasket to form a unitary assembly that minimizes pipe damage, ensures high sealing efficiency, and simplifies assembly and manufacturing, with the pressing member's radial compression design preventing twisting and enhancing sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the ring nut is screwed onto the threaded end with conventional fittings, then the mechanical joining is achieved, but the pipe may be damaged or twisted during the screwing process

Engineering Contradiction:
Improvemechanical joining strengthVSAvoidpipe damage and twisting
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The pressing member is divided into multiple independent teeth that can flex and deform separately during the screwing process. This segmentation allows each tooth to adapt to the pipe surface independently, distributing the compression forces evenly and preventing concentrated stress that would cause pipe damage or twisting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressing member utilizes elastic deformation of its teeth during installation. The teeth are designed to flex elastically under compression, changing their shape temporarily during screwing, then maintaining a controlled compressive force on the pipe without causing permanent damage or twisting.

Inventive Principle:
Principle #35Parameter changes

2Ease of repair

If conventional fittings with separate components are used, then the assembly can be disassembled for maintenance, but the assembly process becomes complex and time-consuming

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidassembly complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The pressing member, rigid ring, and elastomeric gasket are combined into a single unitary pressing assembly. This merging eliminates the need for separate installation steps for each component, simplifying the assembly process while maintaining the ability to disassemble for maintenance by removing the entire assembly as one unit.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the pressing ring radially compresses the pipe to provide sealing, then hydraulic sealing is improved, but the pipe structure is weakened due to twisting

Engineering Contradiction:
Improvehydraulic sealing reliabilityVSAvoidpipe structural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The pressing member applies compression forces locally at multiple discrete tooth contact points around the pipe circumference rather than uniform radial compression. This localized distribution of pressure achieves effective hydraulic sealing while preventing the concentrated twisting forces that would weaken the pipe structure.

Inventive Principle:
Principle #3Local quality

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 effectively prevents pipe damage, ensures high mechanical and hydraulic sealing, simplifies assembly and manufacturing, and allows for easy maintenance and replacement, while reducing the risk of twisting and maintaining sealing integrity during screwing.

Implementation Method 1

an elastomeric gasket (50)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the pressing member's radial compression design preventing twisting and enhancing sealing

Methodology Applied
Scientific EffectRadial compression: Compression

Data Source

PatentEP3379124B1Unitary assembly and screw fitting for the reciprocal connection of a threaded end member and a pipe with a smooth surface
Publication Date: 2019.09.18 TAPEL DI MASTROMATTEO CIRO & C S A S
  • EP3379124B1 patent drawingFigure 1
  • EP3379124B1 patent drawingFigure 2~3
  • EP3379124B1 patent drawingFigure 4~5

AI summary

A screw fitting for the mutual joining of a threaded end member (T) and a pipe (P) with a smooth surface, comprising a tubular ring nut (20) defining an axis (X) having an outer surface (20') designated to be grasped by an operator to promote the screwing thereof on the threaded end member (T); a pressing ring (30) deformable upon the screwing of said ring nut (20) having an inner area (31") comprising a plurality of projections (34) designated to interact with the outer surface (P1) of the pipe (P) to provide a local mechanical sealing and an outer surface (36') designated to interact with the rear portion (21) of the ring nut (20); an elastomeric gasket (50) having an inner surface (50") designated to come into contact with the outer surface (P1) of the pipe (P) to provide the local hydraulic sealing; a rigid ring (40) interposed between the elastomeric gasket (50) and the pressing ring (30) for mutually separating them and for integrally coupling with both so as to form a unitary assembly. The rigid ring (40) includes a rear portion (41) susceptible to act a stop for a front portion (32) of the pressing ring (30) upon the radial compression thereof. The rigid ring (40) further includes a front portion (42) opposite to the rear portion (41) susceptible to be coupled with a corresponding rear portion (51) of the elastomeric gasket (50).