Flexible Element Pipe Removal Assembly

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Solution Overview

Problem

Existing pipe replacement methods, such as pipe bursting, often result in fracturing of ductile pipes like lead or copper, making it difficult to remove the old pipe completely, especially when they have low tensile strength, and there is a need for a system that can consistently remove pipes without fracturing and replace them with new ones.

Innovation Solution

A pipe removal assembly that uses a spool with a mechanical advantage system, such as a chain drive or planetary gear, to pull a flexible element through the pipe, which engages with the pipe to pull it out in compression, preventing tensile failure, and simultaneously positions a replacement pipe for installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pipe bursting is used to replace underground pipe, then replacement can be done without complete excavation, but the old pipe may fracture and remain difficult to remove completely

Engineering Contradiction:

Improveease of pipe replacementVSAvoidcomplete pipe removal

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A flexible element acts as an intermediary between the pulling device and the old pipe. This flexible element is pulled through the old pipe first, then used to engage and pull the old pipe out in compression, ensuring complete removal without fracture while maintaining the minimally invasive approach of pipe bursting

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of pulling the old pipe directly in tension (which causes fracture), the system first pulls a flexible element through the pipe, then uses this element to engage the pipe and pull it out in compression. This inverts the traditional pulling approach, converting tensile failure into compressive extraction for complete removal

Inventive Principle:

Principle #13The other way round (Inversion)

2Force

If ductile pipe with low tensile strength is pulled to remove it, then extraction is attempted, but tensile failure occurs leaving pipe sections in the ground

Engineering Contradiction:

Improvepulling forceVSAvoidtensile strength of pipe

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

The system inverts the extraction approach by not pulling the pipe directly in tension. Instead, a flexible element is pulled through first, then used to engage the pipe and pull it out in compression. This converts the problematic tensile loading into compressive loading, allowing complete removal of low tensile strength ductile pipes without fracture

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The flexible element serves as a mediator that transfers the pulling force through compression rather than direct tension on the pipe. By engaging the pipe internally and pushing it out in compression, the system overcomes the pipe's low tensile strength limitation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a flexible element is pulled through the pipe to provide supplementary strength, then complete pipe removal is achieved, but the system complexity increases

Engineering Contradiction:

Improvecomplete pipe extractionVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A flexible element is introduced as an intermediary component that is pulled through the old pipe and then used to engage and extract the pipe in compression. This additional element enables reliable complete removal of ductile pipes, with the complexity offset by the simplicity of the extraction mechanism

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible element serves multiple functions: it is pulled through the pipe to engage it, provides supplementary tensile strength during extraction, and enables the pipe to be pulled out in compression. This multi-functionality justifies the added component by eliminating the need for multiple separate systems

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 system effectively removes pipes with low tensile strength without fracturing, ensuring complete extraction and efficient replacement, with the flexible element providing supplementary strength to withstand high pulling forces and the ability to wrap the pipe around a spool for easy disposal.

Implementation Method 1

A pipe removal assembly that uses a spool with a mechanical advantage system, such as a chain drive or planetary gear, to pull a flexible element through the pipe

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

which engages with the pipe to pull it out in compression, preventing tensile failure

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS9566675B2Method and device to remove pipe

Publication Date: 2017.02.14 TT TECHNOLOGY INC

AI summary

A pipe removal method includes navigating a flexible element through a first pipe. At least a portion of the flexible element is coupled with the first pipe. The flexible element and the first pipe are pulled as a composite assembly, and the flexible element reinforces the tensile strength of the first pipe. In one example, the first pipe is at least pulled in compression between the point of coupling between the flexible element and the first pipe and a proximal end of the flexile element. In another example, the method includes wrapping the composite assembly around a spool. The composite assembly is thereby removed from the ground surrounding the first pipe.