PVC Pipe Bell Testing System for Seal Integrity

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Solution Overview

Problem

The Rieber system for forming outside sleeves for PVC-type plastic material pipes faces issues such as incorrect positioning of the seal ring, leading to misshapen bells and compromised joint tightness, as well as potential seal damage during the forming process, which can result in irregularities and failure of the seal's tightness function.

Innovation Solution

A method is introduced to test the correct operation of the seal and bell by creating a closed chamber and applying a predetermined air pressure after the bell has cooled, using the forming mandrel and seal components to ensure the seal's integrity and proper positioning, with pressurized air being introduced through a controlled flow rate to verify the chamber's tightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the seal ring is positioned on the mandrel during the forming process, then the joint tightness function is improved, but the risk of incorrect positioning (180° rotation or wrong location) increases, leading to misshapen bells and compromised tightness

Engineering Contradiction:
Improvejoint tightness functionVSAvoidseal positioning accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing a test pressurization before the actual forming operation. The mandrel is pressurized with air or gas to verify seal positioning and bell shape correctness before the hot pipe is introduced. This preliminary check prevents the harmful effects of incorrect seal positioning (180° rotation or wrong location) from affecting the final product, thereby resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the seal ring is introduced at a later stage, then the risk of incorrect positioning is reduced, but the guarantees of correct positioning and prevention of foreign matter contamination are worsened

Engineering Contradiction:
Improveseal positioning accuracyVSAvoidjoint tightness function
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces a preliminary testing phase before the actual forming operation. The mandrel is pressurized with air or gas to verify seal positioning and bell shape correctness before the hot pipe is introduced. This preliminary check ensures that the seal is correctly positioned and the bell shape is correct before committing to the forming operation, thereby maintaining both manufacturing precision and reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the test pressurization results to determine whether to proceed with the forming operation. If the test reveals incorrect seal positioning or bell shape defects, the process can be corrected before the actual forming takes place. This feedback mechanism ensures that only correctly positioned seals and properly formed bells proceed to the next stage, maintaining both precision and reliability.

Inventive Principle:
Principle #23Feedback

3Reliability

If the seal ring is used during the forming process, then the positioning guarantees are improved, but the risk of seal breakage or cracking during mandrel introduction increases

Engineering Contradiction:
Improveseal positioning guaranteesVSAvoidseal integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies preliminary action by performing a test pressurization before the actual forming operation. The mandrel is pressurized with air or gas to verify seal positioning and bell shape correctness before the hot pipe is introduced. This preliminary check allows detection of seal positioning issues without subjecting the seal to the full stress of the forming process, thereby reducing the risk of seal breakage while maintaining positioning guarantees.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by using a test pressurization to identify potential seal positioning problems before the actual forming operation. This preliminary test acts as a cushioning measure that prevents incorrect seal positioning from leading to seal breakage during the high-stress forming process, thereby protecting seal integrity while maintaining positioning accuracy.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Measurement precision

If a test method is introduced to verify seal and bell correctness, then the detection of positioning errors and defects is improved, but the process time and complexity increase

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidforming process time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing a test pressurization before the actual forming operation. Although this adds a preliminary step, it prevents costly rework and defects in the final product, thereby reducing overall process time when considering the avoidance of defects. The test quickly verifies seal positioning and bell shape, providing rapid feedback without significant time penalty.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the test pressurization results to immediately determine whether to proceed with forming. This rapid feedback mechanism allows for quick correction of any issues before the actual forming takes place, preventing defects rather than detecting them after the fact. The feedback loop is designed to be efficient, minimizing the time added to the overall process while maximizing defect prevention.

Inventive Principle:
Principle #23Feedback

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 method effectively verifies the seal's intactness and correct positioning, ensuring the bell's shape and tightness are maintained, preventing defects and ensuring the seal's functionality before the mandrel is removed.

Implementation Method 1

applying a predetermined air pressure after the bell has cooled, using the forming mandrel and seal components to ensure the seal's integrity and proper positioning, with pressurized air being introduced through a controlled flow rate to verify the chamber's tightness

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2793011B1Testing system for the operation of the tightness seal and bell of a pvc-type plastic material pipe, obtained by a forming process with integrated seal
Publication Date: 2017.10.11 IPM
  • EP2793011B1 patent drawingFigure 1
  • EP2793011B1 patent drawingFigure 2~3

AI summary

The invention relates to a system to test the correct operation of the tightness seal (3) and outside sleeve of the bell joint (7) of a PVC-type plastic material pipe (2) in which the seal is positioned, obtained by a forming process with integrated seal, according to which the plastically deformed end of the pipe is inserted into a forming mandrel (1) bearing said tightness seal (3); said system implying the performance of the testing function by achieving and testing a pre-determined pressure by the controlled influx of air into a chamber (11) delimited by a portion of the outer surface (9) of the forming mandrel, by a section of the inner surface (10) of the pipe (2), by the same tightness and forming seal (3), and by a further seal (8) located on the pipe, the above-mentioned pressure tightness being obtained if the seal is working and the bell has been correctly formed, and being performed after forming and cooling of the bell (7) and before removal of the mandrel.