Plastic Pipe Welding Flash Reservoir and Reinforcement

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Solution Overview

Problem

The existing welding processes for plastic pipes, such as infrared and rotation welding, result in the formation of weld flash, which affects the stability and flow characteristics of the pipe, leading to stress concentrations and potential material damage due to the bulge created by the sweat flash.

Innovation Solution

A plastic pipe design featuring an internal weld flash reservoir and a reinforcing section with a continuously increasing outer diameter, a wedge-shaped inner sweat expulsion reservoir, and reinforcement ribs and rings, which absorb and distribute stress evenly, preventing sweat flash from reaching the outside and enhancing the connection strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If recesses are arranged on the contact surface to accommodate welding debris, then cleanliness requirements can be met in the interior of the plastic pipe, but the stability of the connection is affected

Engineering Contradiction:
Improvecleanliness requirementsVSAvoidstability of the connection
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The invention extracts the harmful weld flash from the pipe interior by providing a dedicated receiving space (recess or reservoir) on the welding surface. This allows the weld flash to be contained in a controlled location rather than being pushed into the pipe interior, thus meeting cleanliness requirements while preserving connection stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The recess or reservoir acts as an intermediary structure between the welding process and the pipe interior. It provides a buffer zone that captures weld flash before it can enter the pipe interior, resolving the contradiction between cleanliness and connection stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the plastic pipe is welded using conventional processes, then the welding process can be carried out, but weld flash forms on the inside of the plastic pipe affecting flow characteristics

Engineering Contradiction:
Improvewelding processVSAvoidweld flash affecting flow characteristics
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the weld flash from the pipe interior by providing a dedicated receiving space (recess or reservoir) on the welding surface. This allows the weld flash to be contained in a controlled location rather than being pushed into the pipe interior, thus meeting cleanliness requirements while preserving connection stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The recess or reservoir is pre-formed on the welding surface before the welding process takes place. This preliminary preparation ensures that when welding occurs and flash is generated, the flash has a predetermined space to accumulate rather than entering the pipe interior, thus preventing flow characteristic degradation.

Inventive Principle:
Principle #10Preliminary action

3Strength

If the outer diameter of the plastic pipe is increased continuously toward the welding surface in the reinforcement section, then stresses are reduced and evenly distributed, but the device complexity increases

Engineering Contradiction:
Improvestress distributionVSAvoidpipe geometry complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention applies local quality by providing a reinforcement section with continuously increasing outer diameter only in the specific area where welding occurs and stresses are concentrated. The rest of the pipe maintains its normal uniform geometry. This localized geometric modification strengthens the stress-prone welding area without unnecessarily complicating the entire 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 design reduces stress concentrations, maintains cleanliness inside the pipe, and improves the stability and strength of the weld seam, ensuring effective absorption of internal and external loads, including high pressures, while maintaining smooth flow characteristics.

Implementation Method 1

The welding process is carried out, for example, by infrared welding, rotation welding or hot gas welding

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

in rotation welding, plasticization is achieved through frictional energy by the rotating upper mold part is pressed by a carrier ring with a defined, variable contact pressure against the lower molded part

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Data Source

PatentEP2730829B1Plastic pipe
Publication Date: 2017.09.06 VERITAS AG
  • EP2730829B1 patent drawingFigure 1~2
  • EP2730829B1 patent drawingFigure 3
  • EP2730829B1 patent drawingFigure 4

AI summary

The plastic pipe (100) has a tube wall that is provided with a welding surface for welding the plastic pipe main portion to a plastic tube (200). An inner welding waste reservoir configured for receiving an inwardly pressed welding shoot. A reinforcing portion configured for reinforcing the tube wall in the region of the welding waste reservoir in which an outer diameter of the plastic pipe main portion is increased to the welding surface. The inner diameter of the plastic pipe main portion in the reinforcement portion is constant.