Expandable Sewer Shaft Liner for Berm and Channel Rehabilitation

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Solution Overview

Problem

Existing lining technologies for sewer shafts with varying diameters are costly and labor-intensive, as they require separate mandrels for each design and manual rehabilitation of berms and channels, and conventional liners cannot accommodate large diameter differences without risking damage.

Innovation Solution

A radially expandable lining hose with a cylindrical inner film tube and a layer of helically wound fiber material impregnated with resin, featuring a predetermined breaking point for radial expansion, allowing adaptation to different sewer shaft diameters and simultaneous rehabilitation of berms and channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional liners are used for sewer shafts with large diameter differences, then the liner can be installed in the shaft, but the liner risks overstretching and damage to the inner film tube and fiberglass tape winding

Engineering Contradiction:
Improvediameter adaptation rangeVSAvoidliner integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The liner is divided into multiple longitudinal sections that can independently expand and adapt to different diameters. The inner film tube is segmented with tear lines that allow controlled expansion in steps, enabling the liner to accommodate large diameter differences without overstretching any single section beyond its elastic limit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The liner transitions from a static, fixed-diameter structure to a dynamic, multi-stage expansion system. The inner film tube expands in controlled stages through the tear lines, allowing progressive adaptation to varying diameters while maintaining structural integrity throughout the expansion process.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If separate winding mandrels are manufactured for each sewer shaft design, then lining tubes can accommodate different diameter changes, but production costs significantly increase

Engineering Contradiction:
Improvedesign-specific adaptationVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

A single universal liner design with segmented construction and controlled tear lines can be used for multiple sewer shaft designs with different diameters. The liner's ability to expand in controlled stages allows one standardized product to serve multiple applications, eliminating the need for custom mandrels for each shaft design.

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

Solution Approach 2:

The liner's effective diameter is changed through controlled expansion rather than through different manufacturing parameters. By using a single base diameter liner that expands to match the target shaft diameter via the tear line mechanism, the system achieves design-specific adaptation without requiring different manufacturing parameters or custom tooling.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If manual rehabilitation methods are used for berms and channels, then complete rehabilitation can be achieved, but labor intensity and costs increase significantly

Engineering Contradiction:
Improvecomprehensive rehabilitation coverageVSAvoidrehabilitation efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The liner design integrates coverage of multiple shaft components (cylindrical section, conical transition section, berm, and channel) into a single continuous structure. By extending the liner to cover all these areas and using the expansion mechanism to adapt to the varying geometries, the system combines what would traditionally require separate manual operations into one automated installation process.

Inventive Principle:
Principle #5Merging (Combining)

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 efficient rehabilitation of sewer shafts with varying diameters using a single lining hose, reducing production costs and labor, while maintaining airtightness and adhesion to the shaft walls, and preventing resin leakage.

Implementation Method 1

a radially expandable layer of fiber material, which is impregnated with a curable reaction resin

Methodology Applied
Scientific EffectRadial expansion: Elasticity

Implementation Method 2

a curable reaction resin

Methodology Applied
Scientific EffectResin curing: Photopolymerisation

Data Source

PatentEP4449000B1Lining tube for restoring defective sewer shafts including a berm and a channel, and method for producing same, and method for lining a defective sewer shaft
Publication Date: 2025.08.13 BRANDENBURGER LINER GMBH & CO KG
  • EP4449000B1 patent drawingFigure 1
  • EP4449000B1 patent drawingFigure 2a
  • EP4449000B1 patent drawingFigure 2b

AI summary

The invention relates to a lining tube (1) for restoring a defective sewer shaft which has a first shaft portion with a first diameter, an adjoining second shaft portion with an expanded diameter, and a berm and a channel, comprising an inner film tube (10) and a radially expandable tubular layer of fiber material (20) that is provided around the inner film tube and is impregnated with a curable reaction resin, wherein the inner film tube (10) has a connecting portion (12) which extends in the longitudinal direction thereof and which connects two circumferential portions (10a), (10b) of the inner film tube (10) that extend in parallel with one another to a circumferentially closed inner film tube (10) having a defined nominal diameter, and wherein the connecting portion (12) has a predetermined breaking point (14) that extends along the inner film tube (10) and can be separated in the circumferential direction by introducing a pressure medium into the inner film tube in order to radially expand the inner film tube (10) and the layer of fibrous material (20) provided thereon beyond the nominal diameter. The lining tube according to the invention is characterized in that the radially expandable tubular layer of fiber material (20) is closed by a seam at a first end that can be introduced into the channel of the sewer shaft (100), which seam extends orthogonally to the longitudinal axis of the tubular layer of fiber material (20) of the lining tube (1).