Helical Corrugated Pipe Connection with Deformable Sealing Ring

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Solution Overview

Problem

Existing connections for helically corrugated metal pipes to connecting pieces often require complex assembly and do not reliably seal at high pressures, such as over 25 bar, especially in gas applications.

Innovation Solution

A connection method using a clamping nut, union nut, and a rubber sealing ring with an expanding wedge, where the sealing ring is deformed radially to create a tight seal between the corrugated pipe and the connecting piece, facilitated by a wedge-shaped expanding ring and annular groove, allowing easy assembly and high-pressure sealing without the need for open flames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a support ring and pressure ring with graphite seal are used to connect the corrugated pipe to the connecting piece, then the connection can withstand high pressure, but the assembly process becomes complex and requires precise alignment of multiple components

Engineering Contradiction:
Improvehigh-pressure sealing capabilityVSAvoidnumber of components and assembly steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the support ring, pressure ring, and sealing element into a single integrated connecting piece. This connecting piece has an integrated sealing groove and sealing bead structure, eliminating the need for separate graphite seals and multiple rings, thus simplifying assembly while maintaining high-pressure sealing capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connecting piece serves multiple functions simultaneously: it provides structural support, creates pressure sealing through the integrated sealing bead, and guides proper alignment. This multi-functional design replaces the separate functions previously performed by multiple distinct components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a graphite seal is deformed radially to seal the corrugated pipe, then high-pressure sealing is achieved, but the assembly requires precise positioning and alignment

Engineering Contradiction:
Improvesealing performance at high pressureVSAvoidassembly simplicity and alignment requirements
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sealing bead is pre-formed as an integral part of the connecting piece with the correct geometry and elasticity properties. This preliminary preparation ensures that when the connecting piece is installed, the sealing bead automatically deforms radially to create the seal without requiring complex alignment procedures during assembly

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sealing mechanism utilizes elastic deformation of the sealing bead material, changing its physical state from rigid to flexible during installation. The sealing bead deforms radially under installation pressure to conform to the corrugated pipe surface, creating an effective seal, then maintains this deformed state under operating pressure

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If traditional screw connections are used without additional sealing components, then assembly is simple, but the connection cannot reliably seal at pressures over 25 bar

Engineering Contradiction:
Improveassembly simplicityVSAvoidsealing capability at high pressure
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The sealing bead acts as a flexible sealing element that deforms under pressure to create a tight seal. This flexible sealing mechanism is integrated into the rigid connecting piece, combining the simplicity of a basic screw connection with the sealing capability of flexible materials, enabling reliable sealing at pressures over 25 bar while maintaining ease of assembly

Inventive Principle:
Principle #30Flexible shells and thin films

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 provides a reliable, easy-to-assemble seal that withstands pressures over 25 bar, is suitable for gas applications, and can be installed by non-professionals, ensuring high tightness and safety in explosion-proof areas.

Implementation Method 1

a sealing ring (6) made of elastically or plastically deformable material, with which the end of the corrugated metal tube (1) is sealed against the connecting piece (3) in an axially directed manner

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

an expanding ring (7) made of elastically or plastically deformable material, having a wedge-shaped cross section

Methodology Applied
Scientific EffectMechanical advantage through wedge shape: Wedge

Data Source

PatentEP1783413B1Arrangement for connecting the ends of a metal pipe with helical corrugations with a connecting piece
Publication Date: 2011.10.12 BRUGG ROHR AG HLDG
  • EP1783413B1 patent drawingFigure 1~1a
  • EP1783413B1 patent drawingFigure 2

AI summary

The arrangement has a clamping nut (4) on an end of a metal pipe (1). A circular sealing ring (6) that is made of deformable plastic material e.g. rubber, is provided on the end of the metal pipe. The sealing ring comprises a circular groove at its front surface, and two concentric ring parts are provided in the sealing ring. The clamping nut and a connecting piece are braced with each other in an axial direction by a connecting nut (5).