Pipe Connecting Device With Flared Inner Ring And Inclined Pressing Surface

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Solution Overview

Problem

Conventional pipe-connecting devices using inner rings face challenges with repeated use, requiring strong fastening efforts, leading to stress on components, deformation, and potential loosening, especially in high-temperature or long-term applications, and are difficult to reassemble for maintenance.

Innovation Solution

The pipe-connecting device features an inner ring with a tip-contracted outer-circumferential flared surface and an inclined inner circumferential surface in the union nut, reducing surface pressure and stress concentration by using a wide surface for pressing, allowing for a satisfactory seal while enabling more repeated uses and easier reassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If strong fastening work using a tool is performed to achieve seal performance and prevent tube slipping, then sealing reliability is improved, but worker burden increases and work difficulty in confined spaces arises

Engineering Contradiction:
Improveseal performanceVSAvoidworker burden
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The union nut is designed with a tube pressing portion that automatically presses the tube in the axial direction during screw advancement, eliminating the need for separate fastening operations. The system performs its own sealing and securing function through the integrated pressing mechanism, reducing worker burden while maintaining reliability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The fastening function and sealing function are merged into a single operation. The union nut simultaneously performs both the fastening (by screwing onto the external thread) and sealing (by pressing the tube through the tube pressing portion), reducing the number of steps and tools required

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If strong fastening is applied to ensure seal performance, then sealing reliability is improved, but stress on components increases causing deformation and potential loosening

Engineering Contradiction:
Improveseal performanceVSAvoidcomponent stress
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The pressing force is concentrated at the tube pressing portion which is specifically designed to contact the tube. This localized pressing approach ensures adequate sealing force is applied where needed without distributing excessive stress throughout the entire component structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tube pressing portion is designed to dynamically adjust the pressing force based on the screw advancement distance. As the union nut is screwed on, the pressing force increases progressively, allowing the system to achieve adequate sealing without applying excessive static stress that could cause deformation

Inventive Principle:
Principle #15Dynamics

3Reliability

If strong fastening work is required for seal performance, then sealing reliability is improved, but work time and complexity increase

Engineering Contradiction:
Improveseal performanceVSAvoidfastening operation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The tube pressing portion is pre-configured on the union nut to automatically perform the pressing action during screw advancement. The sealing function is prepared in advance as part of the fastening mechanism, eliminating the need for separate sealing operations and reducing total work time

Inventive Principle:
Principle #10Preliminary action

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 configuration enhances seal performance, reduces deformation, and increases the number of repeated uses by distributing pressure evenly, improving workability and extending the device's lifespan.

Implementation Method 1

an outer circumferential portion in which a tip-contracted outer-circumferential flared surface is insertable from a tip end into a tube end portion of a fluid transfer tube made of a resin to flare the tube end portion

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the tube pressing portion is formed into an inclined inner circumferential surface which is inclined in a same direction as the tip-contracted outer-circumferential flared surface, reducing surface pressure and stress concentration by using a wide surface for pressing

Methodology Applied
Scientific EffectPressure distribution: Pressure Increase

Implementation Method 3

a seal element portion and a seal forming portion are pressed against each other

Methodology Applied
Scientific EffectSealing by compression: Pressure Increase

Data Source

PatentEP2995839B1Pipe connecting device
Publication Date: 2019.08.07 NIPPON PILLAR PACKING CO LTD
  • EP2995839B1 patent drawingFigure 1
  • EP2995839B1 patent drawingFigure 2
  • EP2995839B1 patent drawingFigure 3

AI summary

A pipe-connecting device is provided which is of the type using an inner ring, and which, while maintaining a satisfactory seal performance, is improved so as to be repeatedly used times larger than those in the conventional art, by revising the structure. A pipe-connecting device includes: an inner ring 3 having an outer circumferential portion 3G having, at a tip end, a tip-contracted outer-circumferential flared surface 3a that flares a tube end portion 4C; a pipe joint body 1 that has a tubular screwing portion 1A having an external thread 7; and a union nut 2 having an internal thread 13. The inner ring 3 flares the tube end portion 4C, and is inserted into the tubular screwing portion 1A. The tip-contracted outer-circumferential flared surface 3a is clamped and pressed through the tube 4 by the union nut 2 which is screw-advanced by screwing with the tubular screwing portion 1A. A tube pressing portion 12b which is in the union nut 2, and which presses the tube 4 against the tip-contracted outer-circumferential flared surface 3a is formed into an inclined inner circumferential surface which is inclined in the same direction as the outer-circumferential flared surface 3a with respect to the axis Y of the tubular screwing portion 1A.