Flexible In-Trench Ballast Bag for Conduit Stability
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Solution Overview
Problem
Conduit emplacement techniques face challenges due to displacement forces, such as mechanical, hydrodynamic, and hydrostatic forces, leading to potential conduit rupture, and existing weighting methods are costly, labor-intensive, and require increased trench dimensions.
Innovation Solution
A conduit weighting device made of flexible sheet material with a container and flaps that can be filled onsite with ballast, featuring anchoring means and baffles to prevent bulging, allowing for conformal placement over the conduit and reducing installation costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If concrete arch structures are used for weighting conduits, then conduit stability against displacement forces is improved, but manufacturing cost, transportation cost, and installation complexity increase significantly
Solution Approach 1:
The patent uses flexible weighting bags made of fabric or plastic material instead of rigid concrete arch structures. These flexible bags can be easily transported, positioned over the conduit, and filled with ballast material on-site, eliminating the need for complex pre-fabrication and heavy machinery installation while providing sufficient weighting to prevent conduit displacement
Solution Approach 2:
The flexible weighting bags are made from inexpensive materials such as fabric or plastic that can be manufactured locally and disposed of or reused after serving their weighting function. This replaces expensive concrete arches that require significant manufacturing investment and complex installation procedures
2Ease of operation
If flexible weighting bags with single compartment are used, then ease of installation is improved, but reliability against ballast free flow deteriorates when damage occurs
Solution Approach 1:
The weighting bag is divided into multiple compartments by internal partitions or baffles. If one compartment is damaged, the other compartments remain intact and continue to contain ballast, preventing complete failure and ballast free flow. This segmentation maintains reliability while keeping the overall structure simple and easy to install
3Strength
If cords or cables are added to weighting bags to prevent compartment bulging, then structural integrity is improved, but ease of operation deteriorates due to cumbersome installation
Solution Approach 1:
The patent uses flexible fabric or plastic material for the weighting bag that inherently resists excessive bulging through its material properties and construction. The flexibility of the material allows it to conform to the ballast material while maintaining structural integrity without requiring additional rigid reinforcement elements like cords or cables that would complicate 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 device effectively counters displacement forces, reduces manufacturing and transportation costs, and allows for shallower trench depths by filling and installing the weighting device in-trench, enhancing conduit stability and installation efficiency.
Implementation Method 1
the weight of the bag holding the conduit in position
Implementation Method 2
prevent excessive compartment bulging when the bags are filled with ballast
Data Source
AI summary
A conduit weighting device has a container to contain ballast. The container is formed from flexible sheet material and has a top opening to receive the ballast. The device has flaps extending from respective opposite edges of the top opening of the container. The container forms an underside channel sized and shaped to receive a conduit for conforming placement of the conduit weighting device on the conduit to weight the conduit. The flaps are sized and shaped: when in an open arrangement, to extend beyond edges of a trench containing the conduit to hold open the top opening while receiving the ballast material; and when in a closed arrangement, to close the top opening of the container. The weighting device may be placed on an entrenched conduit before filling, and then filled in place with locally-available backfill. The device may be transported to the site in a collapsed compact form.