Modular GRP Manhole Lining for Tapered Geometry
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Solution Overview
Problem
Sewer manholes face significant damage due to thermal, chemical, and hydrological loads, leading to surface corrosion and structural damage, with existing rehabilitation methods failing to provide long-term resistance and stability, especially in complex geometries and tapered sections.
Innovation Solution
A method and device for producing a glass fiber reinforced plastic (GRP) lining that can be molded to fit standard and custom manhole shapes, featuring a modular winding process with adjustable segments and a resin-impregnated textile composite, which is inflated and cured in place to provide a durable, chemically resistant seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement-bound coating materials are used for plastering, then the surface can be sealed, but the coating lacks permanent resistance and the load-bearing capacity is not restored
Solution Approach 1:
The patent uses glass fiber reinforced plastic (GRP) composite material that combines the strength of glass fibers with the bonding properties of resin. This composite structure provides both permanent chemical resistance and restored load-bearing capacity, overcoming the limitations of simple cement coatings by integrating multiple material properties into a single rehabilitation layer.
2Reliability
If reaction resin coatings are used, then the surface can be sealed, but the coating detaches from the substrate with the formation of bubbles
Solution Approach 1:
The patent employs a flexible GRP lining that conforms to the substrate surface, creating a continuous seal without air pockets. The fibrous composite structure allows the lining to adapt to surface irregularities while maintaining strong adhesion, preventing the bubble formation and detachment issues experienced with rigid reaction resin coatings.
3Reliability
If GfK panels are fitted, then chemical resistance and dimensional stability are achieved, but the panels require complex assembly and cannot be easily installed in existing sewage systems
Solution Approach 1:
The patent divides the GRP lining into modular segments that can be individually manufactured and then assembled in the existing sewage system. This segmentation allows the complex GRP structure to be produced using simpler, more manageable components while maintaining the overall chemical resistance and dimensional stability of the complete lining system.
4Ease of manufacture
If a hose liner is inserted and cured with UV light, then the lining can be produced, but the method is unsuitable for junctions and manholes with tapered geometries
Solution Approach 1:
The patent uses a dynamic inflation process where the lining is introduced in a collapsed state, then inflated to expand and conform to the specific geometry of the manhole or junction. This dynamic transformation allows the same lining material to adapt to various geometries including tapered sections, eliminating the limitation of fixed-geometry UV-cured hose liners.
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 GRP lining effectively seals leaks, enhances manhole stability, and allows for easy cleaning, while maintaining structural integrity and accommodating various load stresses, ensuring long-term durability and resistance to aggressive substances.
Implementation Method 1
curing it with a UV light source
Implementation Method 2
infrared radiation source
Data Source
Figure 1~2
Figure 3~6
Figure 7~8
AI summary
The method serves to renovate a sewer manhole and comprises the following steps: a. pulling of an inflatable film tube (40) onto a mould (38) which corresponds to the sewer manhole profile, b. wrapping and/or placing of at least one stretchable, textile strip (46, 46') of the film tube (40) which has been pulled onto the mould (38), wherein at least one non-stretchable longitudinal strip (48) which has tensile strength is also introduced in the axial direction between the strips (46, 46'), c. attaching a protective cover (52) which encloses the lining (50) which has been produced in this way, d. pulling of the lining (50) from the mould (38) which is reduced in the radial direction, e. inserting of the lining (50) into a sewer manhole (10) to be renovated and introducing a pressure-tight sack (66) into the inner film tube (40) of the lining (50), f. sealing of the lining (50) at the upper end and inflation until it bears against the manhole wall (34), g. curing of the lining (50) which is impregnated with resin. A variable mould (38) which is composed of modules (38-1, 38-2, 38-3) of different shape and size in accordance with the sewer manhole (10) to be renovated serves to produce the lining (50).