Expandable Sewer Shaft Lining Tube for Variable Diameters
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Solution Overview
Problem
Existing lining tubes for restoring sewer shafts with varying diameters face challenges in achieving maximum mechanical strength and seal-tightness due to limitations in stretchability, which leads to logistical and cost issues in producing and installing these tubes.
Innovation Solution
A cross-sectionally circular, cylindrical lining tube designed to adapt to different sewer shaft diameters through radial expansion, featuring an inner film tube with a predetermined breaking point and a radially expandable layer of fiber material impregnated with a curable reactive resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lining tube is produced with an outer diameter 5 to 10% smaller than the inner diameter of the sewer pipe to be restored, then the surface quality of the cured laminate is improved and slight changes in diameter are compensated, but the stretchability is limited to maximum 10% to avoid damaging the inner film tube
Solution Approach 1:
The inner film tube is segmented into two functional zones: a first zone with high stretchability (at least 10%, preferably 20-50%) made from elastic material, and a second zone with limited stretchability (maximum 10%) made from less elastic material. This segmentation allows the lining tube to achieve both high overall expandability for adapting to different sewer diameters and controlled localized stretching to maintain surface quality and prevent resin blowout.
2Reliability
If more than 40 different basic types of lining tubes with respective nominal diameters are produced to provide optimally adapted lining tubes for each sewer diameter, then the mechanical strength and seal-tightness are maximized for each specific diameter, but the logistical effort and production costs increase greatly
Solution Approach 1:
The lining tube design with the first zone of elastic material and second zone of less elastic material creates a universal product that can adapt to multiple sewer diameters (DN 150-1000 mm) through controlled expansion. The high stretchability zone enables the tube to expand to match different target diameters while the limited stretchability zone ensures quality control, making a single design suitable for various applications rather than requiring 40 different types.
Solution Approach 2:
The invention changes the material parameter (stretchability) along the circumference of the inner film tube, creating zones with different elastic properties. This parameter variation allows the same lining tube design to achieve optimal performance across a range of sewer diameters by controlling where and how much the tube expands during installation.
3Ease of operation
If the lining tube is produced with a diameter greater than the inner diameter of the sewer pipe to be restored, then the installation is simplified, but the laminate and outer film tube develop creases that cause shadowing during UV curing and prevent complete curing through of the reactive resin
Solution Approach 1:
The lining tube employs dynamic expansion characteristics through the first zone of elastic material that can stretch significantly during installation to accommodate larger diameters, then stabilizes when the expansion force is removed. This dynamic behavior allows the tube to be installed easily on larger diameters without permanent creases, as the material returns to its optimal configuration, ensuring complete UV curing while maintaining ease of installation.
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 solution allows for the use of a single lining tube to restore sewer shafts with varying diameters, ensuring maximum mechanical strength and seal-tightness while reducing production and installation costs by eliminating the need for multiple tube sizes.
Implementation Method 1
The connecting portion (12) comprises a predetermined breaking point (14) which can be broken open in the circumferential direction by introducing a pressure medium, in particular compressed air
Implementation Method 2
a radially expandable layer of fiber material, which is impregnated with a curable reactive resin
Data Source
AI summary
A lining tube for restoring a defective sewer shaft which has a first shaft portion of a first diameter and an adjoining second shaft portion of an larger diameter. The lining tube has inner film tube and a radially expandable layer of fibrous material around the inner film tube and impregnated with a curable reactive resin. The inner film tube has a connecting portion which extends in the longitudinal direction and which connects two mutually parallel circumferential portions of the inner film tube to a circumferentially closed inner film tube. The connecting portion has a predetermined breaking point which extends along the inner film tube 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 and the layer of fibrous material beyond their nominal diameter.