Plastic Flange Connection Resists Wedge Expansion

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Solution Overview

Problem

Existing flange connections for plastic pipes and fittings face challenges in transmitting forces uniformly under high compressive and tensile stresses, leading to difficulties in maintaining a secure seal under internal pipe pressures, especially when the design requirements for ring collars with fillet grooves and inclined surfaces cannot be guaranteed.

Innovation Solution

A flange connection featuring a resilient plastic flange ring shaped like a plate spring, with a flange contact surface aligned at right angles to the pipe axis and an annular collar contact surface that forms an angle radially outward, which increases contact pressure and counteracts wedge-shaped expansion, utilizing a support collar and annular material reinforcements to maintain stability and resist deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional flange connections are used for plastic pipes, then the structure is simple and easy to manufacture, but the forces cannot be transmitted uniformly under high compressive and tensile stresses

Engineering Contradiction:
Improveforce transmission capabilityVSAvoidflange connection structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flange ring is designed with non-uniform thickness, being thicker in the radial inner area near the pipe and thinner in the radial outer area. This local variation in geometry allows the flange ring to concentrate force transmission where needed (near the pipe) while reducing material usage and complexity in less critical areas, thereby improving force transmission capability without proportionally increasing overall structural complexity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The flange ring's geometric parameters are specifically optimized with an inclined contact surface that forms an angle between 5-15 degrees with the pipe axis, and a thickness ratio (inner to outer) between 0.6-0.8. These parameter changes enable the flange ring to better distribute and transmit forces under high stress conditions while maintaining manufacturing feasibility

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If flange rings with wide axially sections are used to increase contact area, then force distribution improves, but the flange ring becomes more prone to tilting and deformation under internal pressure

Engineering Contradiction:
Improveflange ring stabilityVSAvoidresistance to tilting and deformation
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The flange ring employs local quality variation through non-uniform thickness distribution, being thicker radially inward where stability is needed and thinner radially outward where flexibility helps prevent tilting. This localized geometric optimization provides both stability and resistance to deformation without the drawbacks of uniformly wide flange rings

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The inclined contact surface of the flange ring forms a curved geometry relative to the pipe axis, creating a wedge-shaped profile that naturally resists tilting forces. This curved/spheroidal geometric feature distributes internal pressure forces more evenly and prevents the flat, wide flange rings from tilting and deforming under load

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If conventional ring collars without fillet grooves are used, then manufacturing is simpler, but they cannot withstand high internal pipe pressures due to plastic material flow

Engineering Contradiction:
Improvepressure resistanceVSAvoidcollar processing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The ring collar is designed with a localized fillet groove feature at the critical transition zone between the cylindrical pipe section and the collar body. This local geometric modification concentrates and controls plastic material flow in a specific area, enabling high pressure resistance without requiring complex processing of the entire collar structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fillet groove is pre-formed in the ring collar design to anticipate and control plastic material behavior under internal pressure. This preliminary geometric feature guides the plastic flow before pressure is applied, preventing uncontrolled material flow and maintaining structural integrity at high pressures while keeping manufacturing relatively simple

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

The solution effectively secures a flange connection under internal pressures of up to 25 bar by distributing forces uniformly and preventing plastic deformation, ensuring a reliable seal without excessive processing or tilting of the flange ring.

Implementation Method 1

the flange ring is formed from a resilient plastic, the flange ring is shaped like a plate spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3073166B1Flange connection
Publication Date: 2017.05.17 REINERT RITZ
  • EP3073166B1 patent drawingFigure 1~2
  • EP3073166B1 patent drawingFigure 3~4
  • EP3073166B1 patent drawingFigure 5

AI summary

A flange connection (10) for plastic pipes or fittings is shown and described, comprising a plastic ring collar (11) which forms an axially oriented sealing surface (12) and an axially oriented flange contact surface (13) and has a cylindrical pipe section (14), with a flange ring (16) which has a plurality of axial bores (18) for receiving screw bolts (17) and forms an axially oriented ring collar contact surface (19), wherein the ring collar contact surface (19) of the flange ring (16) forms an angle (α) with the flange contact surface (13) of the ring collar (11), which opens radially outwards from the cylindrical pipe section (14) of the ring collar (11).