On-site Manhole Casting System with Plastic Liners
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Solution Overview
Problem
The current industry standard for manhole components is limited by the need for pre-casting plants, high production and transportation costs, long curing times, and susceptibility to corrosion, which results in increased costs and reduced service life.
Innovation Solution
An on-site casting system using lightweight, thin-walled plastic forms fabricated at a production facility, assembled on-site, and filled with concrete, which cures in place, providing a stronger and more durable manhole assembly with enhanced corrosion resistance through a plastic liner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pre-casting plants are used to manufacture manhole components, then manufacturing precision and structural strength are improved, but device complexity and production costs increase
Solution Approach 1:
The system divides the manhole assembly into separate components (base, walls, top section) that are cast independently in simple on-site molds and then assembled together. This segmentation allows each component to be manufactured using simple, low-complexity molding techniques while maintaining overall structural integrity through proper joining methods.
Solution Approach 2:
The patent introduces a grout mixture as an intermediary material that fills the cavities within the hollow-chamber blocks during assembly. This grout acts as a bonding agent and structural filler, providing the necessary strength and stability to the assembled manhole without requiring complex pre-casting plant equipment.
2Manufacturing precision
If pre-casting plants are used to manufacture manhole components, then manufacturing precision is improved, but loss of time in production and delivery increases
Solution Approach 1:
The system performs preliminary preparation by creating simple reusable molds from flexible material (such as a shower curtain) that can be stored and reused multiple times. These pre-prepared molds enable quick on-site assembly and casting operations, eliminating the need for time-consuming transport from distant pre-casting plants while maintaining adequate manufacturing precision for on-site conditions.
3Strength
If traditional concrete structures are used for manholes, then structural strength is achieved, but susceptibility to corrosion increases
Solution Approach 1:
The patent applies different material properties to different parts of the manhole structure. The hollow-chamber blocks are made from concrete with embedded plastic bottles that provide local corrosion resistance at critical areas, while the grout mixture provides additional protective filling. This local quality approach addresses corrosion susceptibility without compromising overall structural strength.
4Device complexity
If on-site casting with simple molds is used, then device complexity is reduced, but manufacturing precision may deteriorate
Solution Approach 1:
The system uses a flexible material (such as a shower curtain) as a template or copy to create the mold shape. This flexible template can be conformingly shaped and reused to create consistent, precise molds on-site without requiring complex precision manufacturing equipment. The template copying method ensures adequate dimensional accuracy for on-site casting applications.
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
This system significantly reduces production and delivery time, eliminates the need for large pre-cast plants, and offers a structurally stronger, longer-lasting manhole assembly resistant to environmental exposure, while lowering costs and maintenance requirements.
Implementation Method 1
plastic liner. These servicing methods, though, are not permanent, and require regular maintenance intervals.
Implementation Method 2
The concrete is then allowed to cure for a required length of time.
Data Source
AI summary
A permanent on-site manhole casting system comprising a top, a main barrel, and a base. Each component consists of a ribbed plastic outer barrel and a ribbed plastic inner barrel with a plurality of plastic tie strips used to connect the said outer and inner barrels. A coupling mechanism consisting of a plastic outer coupling ring and a plastic inner coupling ring is welded to the coupling ends of the top, main barrel and base which connects the top, main barrel and base components. A concrete mixture is poured into the space between the coupled outer and inner barrels where the concrete is then allowed to set and cure and the filled form is then completely buried.