Cable Joint Backfilling Structure With Sand-Filtering Grid Openings
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Solution Overview
Problem
Existing backfilling protection structures for underground power cable joints are complex and costly, requiring special fine grain sand or chemicals for filling voids, and involve a time-consuming assembly process, with no need for sealing after installation.
Innovation Solution
A backfilling protection structure comprising a lower and upper casing part forming an elongated body with a channel for the power cable joint, featuring grid-covered top openings that filter out solid objects while allowing sand to enter, eliminating the need for special sand and simplifying the filling process, and allowing the structure to remain open after installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex protective structure is used to follow the contours of the power cable joint and accommodate breakouts, then the protection reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The protective structure is divided into multiple modular components: a base element with channel, a covering element, and multiple grid elements that can be separately positioned and attached. This segmentation allows each component to perform its specific function while simplifying the overall assembly process and reducing manufacturing complexity.
Solution Approach 2:
The base element serves multiple functions: it provides structural support, defines the protective channel, and offers attachment points for both the covering element and grid elements. The grid elements simultaneously protect against mechanical damage and filter backfill material, combining multiple protective functions in a single component.
2Reliability
If the protective structure is sealed and filled with special fine grain sand or chemicals, then the protection reliability is improved, but the ease of manufacture and installation are worsened
Solution Approach 1:
Instead of sealing the protective structure and using special fine grain sand to fill voids, the invention inverts the approach by using grids that actively filter out unwanted material while allowing standard sand to pass through. This eliminates the need for sealing and special materials, simplifying both manufacture and installation.
Solution Approach 2:
The grid elements automatically perform the filtering function during backfilling, allowing the structure to self-regulate the filling process without requiring manual sealing or special materials. The grids enable the system to use locally available sand while automatically excluding rocks and other harmful objects.
3Reliability
If the protective structure is sealed and requires filling of all internal voids, then the protection reliability is improved, but the productivity and installation time are reduced
Solution Approach 1:
The invention eliminates the need for sealing and void filling by inverting the protective mechanism from a sealed containment approach to an open filtering approach. The grids allow air and sand to pass through freely while blocking rocks, dramatically reducing installation time and eliminating the labor-intensive sealing process.
Solution Approach 2:
The invention extracts the sealing requirement entirely from the system by replacing it with a filtering mechanism. This removes the time-consuming steps of sealing internal voids and using special materials, allowing rapid installation while maintaining protection through the grid filtering system.
4Reliability
If grids with small mesh size are used to filter out rocks, then the protection reliability is improved, but the ease of operation during backfilling is worsened
Solution Approach 1:
The grid elements are positioned at specific locations where rock filtration is most needed, such as at the top of the backfilling process. The mesh size is optimized locally to balance rock filtration with sand passage, allowing easy backfilling operation while maintaining protection reliability at critical points.
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 simple and cost-effective backfilling of power cable joints by using locally available sand, protecting fragile components while filtering out large objects, and eliminating the need for sealing, thus reducing installation time and costs.
Implementation Method 1
each grid being configured to filter out solid objects larger than a predetermined size from entering through the respective top opening into the channel but enabling sand to enter the channel
Data Source
AI summary
A backfilling protection structure for underground installation of a power cable joint, including: a lower casing part forming a base of the backfilling protection structure and configured to be laid on soil, an upper casing part configured to be arranged on top of the lower casing part, wherein the lower casing part and the upper casing part are configured to be attached to each other to form an elongated body, wherein the body defines a channel for receiving a power cable joint, wherein the channel extends through the backfilling protection structure from a first end opening at a first axial end of the backfilling protection structure to a second end opening at a second end of the backfilling protection structure opposite to the first end, wherein the upper casing part is provided with a plurality of top openings distributed along the length of the body and extending into the channel, and a plurality of grids covering a respective top opening, each grid being configured to filter out solid objects larger than a predetermined size from entering through the respective top opening into the channel but enabling sand to enter the channel to bury the power cable joint inside the backfilling protection casing.