Retaining Ring Prevents Seal Displacement in Plastic Pipe Fittings

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Solution Overview

Problem

Existing methods for connecting plastic pipes to connection nipples risk impermissible displacement of the sealing ring due to insufficient chamfering, leading to a compromised seal and potential disconnection.

Innovation Solution

A receiving groove in the connection nipple for a resilient retaining ring, which is radially supported and has specific dimensions to prevent the connection of inadequately chamfered plastic pipes by forming a stop surface, while allowing properly chamfered pipes to be connected by compressing onto the inner diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the plastic pipe end is chamfered to allow the sealing ring to be pressed into the recess, then the connection process is simplified, but pipes without adequate chamfering can still be pushed onto the nipple causing seal displacement

Engineering Contradiction:
Improveconnection easeVSAvoidseal displacement hazard
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The retaining ring provides a self-checking function by automatically preventing insertion of improperly chamfered pipes. The pipe operator does not need to verify chamfer quality manually; the retaining ring itself serves as the verification mechanism by blocking insertion when the chamfer is insufficient to compress the ring adequately.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The retaining ring provides preliminary opposition to the insertion force when the chamfer is inadequate. By being radially resilient and positioned in the receiving groove, it counteracts the forcing action before the sealing ring can be displaced, preventing the harmful effect before it occurs.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If a retaining ring is added to prevent seal displacement, then the seal reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveseal protectionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retaining ring serves multiple functions simultaneously: it prevents seal displacement, verifies proper pipe chamfering, and provides mechanical stopping for improper connections. This multi-functionality justifies the addition of a single component that addresses multiple potential failure modes without requiring multiple separate devices.

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

Solution Approach 2:

The retaining ring is designed with specific dimensional parameters (outer diameter between the inner diameter of the plastic pipe and the outer diameter of the chamfer) that enable it to perform its protective function. By carefully controlling these parameters, the component achieves reliable seal protection without requiring complex structures or additional adjustment mechanisms.

Inventive Principle:
Principle #35Parameter changes

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

Prevents the connection of plastic pipes without adequate chamfering, ensuring a secure seal by preventing further insertion and requiring re-chamfering before connection, thus maintaining the integrity of the seal between the nipple and pipe.

Implementation Method 1

the chamfer represents a contact surface for the retaining ring, which is thus radially compressed onto the inner diameter of the plastic pipe

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the retaining ring, due to its correspondingly selected dimensions, forms a stop surface with its end face facing the connection end of the plastic pipe, which prevents the plastic pipe from being pushed further onto the connection nipple

Methodology Applied
Scientific EffectMechanical force: Force

Data Source

PatentEP2154411B8Device for attaching a plastic tube to a connection nipple
Publication Date: 2012.03.14 KE KELIT KUNSTSTOFFWERK GMBH

AI summary

The device connects a plastic pipe (1) to a connection fitting (2), where connecting ends (4) of the pipe have a front side chamfer (8) in an inner diameter region. The ends are axially retained between the fitting and a clamping piece (3). The pipe overlaps a sealing ring (5) that is retained in the fitting. The fitting in a connecting position of the pipe on a side of the ring opposite a front side (7) of the ends has a receiving groove (9) for a locking ring (10). Outer diameter of the locking ring is larger than inner diameter of the pipe, and smaller than outer diameter of the chamfer.