Centrifugal Folding Cutter Head for Pipe Lining Removal

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Solution Overview

Problem

The existing methods for renovating pipes by inserting a flexible casing pipe that stiffens inside old pipes often result in air-filled gaps and difficulties in removing the stiffened lining without damaging the pipe, especially when the lining has already hardened, making it challenging and time-consuming to reline the pipe without causing damage.

Innovation Solution

A device with a cutter head featuring articulately arranged folding cutting devices that are extended by centrifugal force during rotation, allowing for efficient milling of obstacles and removal of stiffened linings without damaging the pipe interior, and retracting inwardly to prevent getting stuck, enabling effective cleaning and lining removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible casing pipe is inserted and stiffened inside old pipes to create a lining, then the pipe renovation is achieved with a new stiff and hard pipe lining, but air-filled gaps may form between the casing pipe and the old pipe interior

Engineering Contradiction:
Improvepipe lining integrityVSAvoidair-filled gaps
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful air-filled gaps between the casing pipe and old pipe interior using a cleaning device with cutting elements that mill away the gaps, transforming the defective lining into a defect-free lining by removing the harmful portions

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If the casing pipe is removed before stiffening, then the pipe can be relined without damage, but the removal process becomes difficult and time-consuming when the lining has already hardened

Engineering Contradiction:
Improvelining removal easeVSAvoidremoval time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent applies preliminary action by removing the stiffened lining immediately after installation while it is still relatively soft and pliable, before it fully hardens and becomes difficult to remove, thereby facilitating easier removal and reinstallation without excessive time loss

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a drilling machine like device is used to twine the still soft lining to a thin stick for removal, then the lining can be pulled out, but the process may fail leaving a stiff stick of stiffened lining that is very difficult to remove

Engineering Contradiction:
Improvelining removal successVSAvoidremoval completeness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical twining and pulling system with a milling system that uses rotating cutting elements to mechanically mill away the stiffened lining material, converting the removal process from a pulling operation to a cutting operation that reliably removes the lining without leaving residual sticks

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If large feed force is applied to the cutter head for fast cleaning, then productivity increases, but the folding cutting devices may fold in even when obstructed, reducing cleaning effectiveness

Engineering Contradiction:
Improvecleaning speedVSAvoidcutting device reliability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the cutting devices foldable rather than fixed, allowing them to dynamically adjust their position - folding in when encountering obstructions to avoid damage and folding out under centrifugal force during normal operation to maintain cutting effectiveness, thus enabling high productivity without sacrificing reliability

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

Enables fast and efficient cleaning of pipes with a large feed force, allowing for the removal of stiffened linings without damaging the pipe interior, reducing the risk of the device getting caught and facilitating the renovation process.

Implementation Method 1

the in the cleaning direction arranged end of the respective folding cutting device is arranged under the influence of centrifugal force generated by rotation of the cutter head to be folded out in a direction away from the longitudinal axis of the cutter head

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2934774B1Device for cleaning of pipes
Publication Date: 2020.01.22 RENZORATO AB
  • EP2934774B1 patent drawingFigure 1
  • EP2934774B1 patent drawingFigure 2
  • EP2934774B1 patent drawingFigure 3

AI summary

The invention relates to a device for cleaning of pipes (1) with a substantially circular cross section, where the device (2) comprises a cutter head (4) which when the cutter head (4) in operation rotates about its longitudinal axis (X) fits within the inner diameter (d) of the pipe, where the cutter head (4) further is arranged during rotation of the same to be fed forward inside the pipe (1) in a cleaning direction (R) parallel to the longitudinal direction (L) of the pipe (1) and with the longitudinal axis (X) of the cutter head (4) substantially aligned parallel to and concentrically to the centre axis (C) of the pipe (1), where the cutter head (4) comprises a body (6) and at least three on the body (6) articulately arranged folding cutting devices (8, 10, 12, 14), where the in the cleaning direction (R) arranged end (16, 18, 20, 22) of the respective folding cutting device (8, 10, 12, 14) is arranged under the influence of centrifugal force (Fc) generated by rotation of the cutter head (4) to be folded out in a direction away from the longitudinal axis (X) of the cutter head (4), and where further the respective folding cutting device (8, 10, 12, 14) comprises at least one cutter (24, 26, 28, 30) which in the folded out position of the respective folding cutting device (8, 10, 12, 14) is arranged for milling in the cleaning direction (R). The invention also relates to use of a device (2) for cleaning of pipes (1) when removing stiffened lining (62) inside pipes (1).