Pipe Coupling Seal-First Assembly to Prevent Premature Gripping

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Solution Overview

Problem

The existing Aquafast pipe coupling products face issues with premature gripping during assembly and final bolt-torquing, leading to incorrect positioning and potential leakage due to the gripper ring engaging the pipe before the sealing gasket, especially when pipes are restricted from axial movement.

Innovation Solution

The pipe connection design incorporates supports that maintain a predetermined spaced relation between the intermediate and end rings until a specific torque is applied, ensuring the sealing gasket is compressed before the gripper ring engages, with features like radial projections and collapsing struts to control the torque distribution and prevent premature gripping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the gripper ring is designed to grip the pipe firmly, then the grip strength is improved, but premature gripping occurs during assembly preventing correct positioning

Engineering Contradiction:
Improvegrip strengthVSAvoidassembly positioning
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The support structure performs a preliminary action by maintaining the gripper ring in a non-gripping state during assembly, preventing premature engagement. Only after the sealing gasket is compressed does the support collapse, allowing the gripper ring to engage the pipe. This sequencing ensures correct positioning before gripping occurs.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the gripper ring engages the pipe early during torquing, then grip is established, but the sealing gasket is not properly compressed leading to leakage

Engineering Contradiction:
Improvegrip establishmentVSAvoidsealing reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The support structure ensures the sealing gasket is compressed first as a preliminary action before the gripper ring engages the pipe. The support maintains spacing between the gripper ring and pipe until the sealing gasket compression is achieved, then collapses to allow gripper engagement, ensuring proper sealing sequence.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the pipe is restricted from axial movement, then installation stability is improved, but premature gripping prevents proper assembly positioning

Engineering Contradiction:
Improveinstallation stabilityVSAvoidassembly positioning
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The support structure acts as an intermediary between the gripper ring and the pipe, preventing direct engagement during assembly. It maintains the gripper ring in a non-gripping state while allowing the pipe to be positioned correctly, then collapses to allow gripping once positioning is complete.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Force

If the gripper ring compresses immediately upon contact, then gripping force is maximized, but correct axial positioning cannot be achieved

Engineering Contradiction:
Improvegripping forceVSAvoidaxial positioning precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The support structure performs the preliminary action of preventing gripper ring compression during the positioning phase. It maintains the gripper ring in an uncompressed state while the pipe is being positioned axially, ensuring precise positioning before allowing compression and gripping to occur.

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

This design ensures the sealing gasket is fully compressed before the gripper ring engages, maintaining a tight seal and preventing leakage, while providing a visual indication of proper assembly and operation, thus overcoming the issues of premature gripping and leakage in existing products.

Implementation Method 1

a sealing gasket 111 which is seated on the annular seat 109... ensure that the intermediate ring 115 is displaced relative to the sleeve 103 in order to compress the sealing gasket 111

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the gripper ring 123... into tight gripping engagement with an outside diameter of a pipe... to resist end load forces as created typically by internal pressure, Poisson's effect and temperature changes

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

to resist end load forces as created typically by internal pressure, Poisson's effect and temperature changes

Methodology Applied
Scientific EffectPoisson's effect: Poisson's Effect

Implementation Method 4

a plurality of fixings 159... which engage the end rings 131 of the respective pipe connections 101a, b and act to displace the same axially towards one another on torquing

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP3047188B1Pipe connection
Publication Date: 2021.06.02 CRANE LTD
  • EP3047188B1 patent drawingFigure 1~1b
  • EP3047188B1 patent drawingFigure 2
  • EP3047188B1 patent drawingFigure 3

AI summary

A pipe connection (101a, 101b) for providing a connection to a pipe, the pipe connection comprising: a sleeve (103) which receives a pipe and has a seat (109); a first sealing or gripping element (111) which is disposed adjacent the seat; an intermediate member (115) which is disposed adjacent the first sealing or gripping element; a second sealing or gripping element (123) which is disposed adjacent the intermediate member; an end member (131) which is disposed adjacent the second sealing or gripping element; at least one fixing (159) which engages the end member and is configured to displace the same axially inwardly relative to the sleeve on torquing; and at least one support (151, 153) which is disposed between one of the sleeve (103) and the intermediate member (115) or the intermediate member (115) and the end member (131), wherein the at least one support is configured to maintain the sleeve and the intermediate member or the intermediate member and the end member with a predetermined spaced relation until application of a torquing force between the sleeve and the intermediate member or the intermediate member and the end member which exceeds a predetermined threshold, whereby the end member is displaced relative to the intermediate member to displace the second sealing or gripping element ahead of displacement of the intermediate member relative to the sleeve to displace the first sealing or gripping element or the intermediate member is displaced relative to the sleeve to displace the first sealing or gripping element ahead of displacement of the end member relative to the intermediate member to displace the second sealing or gripping element.