Conductive Plastic Flange Sealing for Leak-Proof Pipe Joints

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Solution Overview

Problem

Existing flange connections for plastic pipes tend to become leaky over time due to plastic creep, requiring frequent re-tightening, which is difficult and often impossible when pipes are installed, and the sealing elements cannot be reused after maintenance.

Innovation Solution

A flange connection using a conductive plastic sealing element made of a single material, which can be heated electrically to ensure a strong bond with pre-weld collars, eliminating the need for additional parts and reducing assembly errors by being integrated into the welding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sealing elements are used in flange connections, then assembly is simple, but the connection becomes leaky over time due to plastic creep requiring frequent re-tightening

Engineering Contradiction:
ImprovetightnessVSAvoidre-tightening frequency
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the conventional mechanical sealing system with a welding-based sealing system. Instead of relying on mechanical compression of sealing elements that require periodic re-tightening, the sealing element is welded to the pre-weld collars, creating a permanent mechanical bond that eliminates the need for re-tightening and prevents leakage due to plastic creep.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state of the sealing element by heating it to its melting point during the welding process. This parameter change allows the sealing element to transition from a solid state to a molten state and back, creating a strong weld bond with the pre-weld collars that prevents leakage and eliminates the need for periodic maintenance.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If sealing elements with integrated heating wires are used, then heating capability is achieved, but additional assembly work and wire exits are required

Engineering Contradiction:
Improveheating capabilityVSAvoidnumber of parts
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the heating function and sealing function into a single integrated component. The sealing element itself is made of conductive plastic that can be heated electrically, eliminating the need for separate heating wires and reducing the number of parts. This integration simplifies the assembly process and reduces device complexity while maintaining heating capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the material property of the sealing element by using conductive plastic instead of conventional non-conductive sealing materials. This parameter change enables the sealing element to be heated electrically directly, eliminating the need for integrated heating wires and simplifying the overall device structure.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If mechanical clamping devices are used to counteract plastic creep, then tightness is maintained, but regular readjustment is required which is difficult when pipes are installed

Engineering Contradiction:
ImprovetightnessVSAvoidaccessibility for re-tightening
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces the mechanical clamping system that requires periodic adjustment with a welding-based system. The sealing element is welded to the pre-weld collars, creating a permanent bond that maintains tightness without requiring periodic mechanical adjustment. This substitution eliminates the accessibility problem associated with re-tightening installed pipes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs the sealing action in advance during the initial assembly by welding the sealing element to the pre-weld collars. This preliminary welding action creates a permanent seal that prevents future leakage due to plastic creep, eliminating the need for later maintenance or re-tightening operations.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If conventional sealing elements are used, then assembly is straightforward, but the same sealing element cannot be reused after maintenance

Engineering Contradiction:
Improveassembly simplicityVSAvoidreusability
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The patent replaces the conventional mechanical sealing system with a welding-based system. The welded sealing element can be removed and reused after maintenance because the welding process creates a clean, removable bond. This substitution enables both straightforward assembly and reusability, resolving the contradiction between ease of manufacture and ease of repair.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 long-lasting, leak-proof connection with reduced need for re-tightening and allows for the reuse of the sealing element after maintenance, ensuring consistent tightness and ease of assembly.

Implementation Method 1

the sealing element consists of a conductive plastic and exclusively of one material... Thanks to the conductive plastic, the sealing element can be heated using electricity supplied

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3985294B1Flange connection
Publication Date: 2023.09.27 GEORG FISCHER ROHRLEITUNGSSYSTEME AG
  • EP3985294B1 patent drawingFigure 1
  • EP3985294B1 patent drawingFigure 2

AI summary

Flange connection for joining two plastic pipe ends and method for assembly comprising two opposing plastic pipe ends (2), each having a weld collar (3), two loose flanges (4), each having a loose flange arranged at each pipe end, the loose flanges having bores (5) for clamping together, clamping means (6), the clamping means being arranged in the bores and serving to pull the loose flanges and the pipe ends together, and a sealing element (7), the sealing element being made of a conductive plastic and consisting exclusively of one material.