Progressive Cutter Liner Removal System

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Solution Overview

Problem

Existing devices lack the necessary cutting and grinding power to efficiently remove structural liners, such as cured-in-place and cement-mortar liners, from conduits, especially when these liners are hardened and deformed, and often fail to maintain the desired geometry and smoothness of the conduit after removal.

Innovation Solution

A device with a set of cutters mounted on a shaft, capable of providing at least 1000 ft lbs of torque, and a system of guides and supports to maintain axial centering and control during the removal process, featuring progressively larger circular cutters with carbide tips and cutouts for debris passage, along with spring-loaded rollers for flexibility and radial adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If existing cleaning devices are used to remove structural liners, then the device can move through the conduit, but it lacks the necessary cutting and grinding power to efficiently remove hardened and deformed liners

Engineering Contradiction:

Improvecutting and grinding powerVSAvoiddevice structure

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The device divides the cutting function into multiple progressive cutters of increasing diameter, each handling different stages of liner removal. This segmentation allows the system to build up cutting power progressively while maintaining manageable individual component sizes and complexities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The multiple cutters are arranged in a nested configuration where smaller cutters are positioned inside larger ones, all mounted on the same shaft. This nesting approach maximizes cutting power within a compact device envelope, allowing the system to deliver high power without proportionally increasing overall device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If high torque is applied to remove hardened liners, then cutting efficiency improves, but the device may lose axial centering and control in the conduit

Engineering Contradiction:

Improveliner removal efficiencyVSAvoidconduit geometry and smoothness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Guide means are introduced as intermediary elements that mediate between the high-torque cutting action and the conduit wall. These guides maintain axial centering and directional control of the shaft, ensuring that the aggressive cutting action remains precisely controlled and does not compromise conduit geometry.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guide means are positioned at specific locations along the shaft to provide localized centering and control. This distributed guidance approach ensures that high torque can be applied for efficient liner removal while maintaining precision in critical areas where geometry control is most important.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If multiple progressive cutters are used to maintain conduit geometry, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:

Improveconduit geometry and smoothnessVSAvoidcutter arrangement and control

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple progressive cutters are merged into a single integrated assembly mounted on one shaft, all driven by a common power source. This combining approach achieves the manufacturing precision benefits of multiple cutters while avoiding the complexity of multiple independent drive systems, as all cutters are driven together through the single shaft.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If the device is designed for high cutting power, then productivity improves, but the device size and weight increase

Engineering Contradiction:

Improveliner removal speedVSAvoiddevice weight

Core Design Contradiction:

ProductivityVSWeight of moving object

Solution Approach 1:

The device employs a dynamic, modular shaft assembly with multiple progressive cutters that can be engaged or disengaged as needed. This dynamic configuration allows the system to deliver high cutting power when required while maintaining a more compact and lighter overall structure when the full cutting capacity is not needed, optimizing the weight-power ratio.

Inventive Principle:

Principle #15Dynamics

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

Effectively removes structural liners and service connections, maintaining the conduit's geometry and smoothness, enabling efficient rehabilitation and preventing turbulence or contamination.

Implementation Method 1

a set of cutters mounted on a shaft for rotation about an axis of the conduit... drive means for rotating the set of cutters about the axis... providing at least 1000 ft lbs of torque

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

capable of providing at least 1000 ft lbs of torque... effectively removes structural liners... maintaining the conduit's geometry and smoothness

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS10012339B2Liner removal system

Publication Date: 2018.07.03 FER PAL CONSTR

AI summary

A system for removing structural liners (whether cured-in-place liners or cement-mortar liners) from a dry conduit is disclosed. The system uses a set of cutters of progressively larger diameters, front and rear supports designed for this purpose, and a drive means for driving the system down the conduit where the structural liner is to be removed.