Underground Splice Box Using Diving Bell Air Entrainment

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Solution Overview

Problem

The current methods for splicing and maintaining underground fibre optic cables are time-consuming and costly, requiring skilled labor, precise sealing to prevent moisture ingress, and often involve complex procedures for locating and excavating splice boxes, which can be inaccurate and expensive.

Innovation Solution

An assembly comprising a holder with a splice box that utilizes the 'diving bell' principle, where the splice box is placed with its bottom side turned downwards, forming an airtight and watertight unit, and is accessible via a top cover, allowing for easier installation and maintenance, with optional features like a removable cover, drainage passages, and a bottom plate for supporting splices, reducing the need for precise sealing and simplifying the splicing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the splice box is made watertight to protect optical fibres against moisture, then protection against moisture is improved, but the sealing procedure becomes accurate and time-consuming, increasing costs

Engineering Contradiction:
Improveprotection against moistureVSAvoidsealing procedure time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Instead of making the splice box watertight by sealing all surfaces, the invention inverts the approach by leaving the bottom side open and using the diving bell principle. The airtight and watertight unit is formed by the holder with open bottom side and the splice box with airtight ceiling and housing wall, allowing air to be trapped inside to prevent water ingress without requiring complex sealing procedures on all surfaces.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention introduces air as an intermediary substance between the splice box interior and the external environment. By trapping air inside the splice box through the diving bell principle, the air acts as a barrier that prevents moisture and water from reaching the optical fibres, eliminating the need for time-consuming waterproof sealing procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the splice box is placed in a protective holder buried in the ground, then protection against damage is improved, but space shortage problems occur when the holder is buried in its entirety

Engineering Contradiction:
Improveprotection against damageVSAvoidspace requirement
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The invention segments the protective structure into two parts: the holder that is buried in the ground and the splice box that remains accessible. The holder provides protection against damage while the open bottom side allows the splice box to be accessed without burying the entire holder, thus reducing space requirements and avoiding space shortage problems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the dimensional arrangement by positioning the splice box vertically within the holder with the open bottom side facing downward. This vertical arrangement allows the splice box to be accessed from the top while the holder extends downward into the ground, optimizing space utilization and providing protection without requiring the entire structure to be buried at the same depth.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the splice box and excess cable length are kept at a certain distance from the original cable route according to regulations, then cable damage during excavation is prevented, but work costs increase due to strict regulatory compliance requirements

Engineering Contradiction:
Improveprevention of cable damageVSAvoidwork complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention creates an equipotential working environment by providing a protected space (the holder with splice box) that maintains safe distances from the cable route while allowing all splicing operations to be performed in a controlled manner. This eliminates the need for workers to repeatedly excavate and relocate equipment, simplifying the work process while maintaining safety margins.

Inventive Principle:
Principle #12Equipotentiality

4Ease of operation

If the splice box is accessible for maintenance work, then ease of operation is improved, but protection against moisture may be compromised

Engineering Contradiction:
Improveaccessibility for maintenanceVSAvoidprotection against moisture
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention creates a dynamic system where the holder can be accessed for maintenance work by removing the top cover, while the splice box maintains its airtight and watertight properties through the diving bell principle. The open bottom side allows access and cable installation, while the trapped air provides continuous moisture protection during both operation and maintenance phases.

Inventive Principle:
Principle #15Dynamics

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 solution reduces the complexity and cost of splicing operations by allowing less skilled personnel to perform tasks more quickly, minimizes the need for precise sealing, and enhances the protection of splice boxes against moisture while maintaining accessibility and ease of use, thereby lowering overall operational costs.

Implementation Method 1

the splice box is delimited by a bottom side, a ceiling and a housing wall which extends between the bottom side and the ceiling, wherein the ceiling and the housing wall form an airtight and watertight unit

Methodology Applied
Scientific EffectDiving bell principle: Air Entrainment

Data Source

PatentEP2166392B1Splice box in an underground vault
Publication Date: 2018.01.24 ATTEMA BV
  • EP2166392B1 patent drawingFigure 1
  • EP2166392B1 patent drawingFigure 2
  • EP2166392B1 patent drawingFigure 3~4

AI summary

The invention relates to a holder for a(n optical fibre) cable, which holder can be buried in the ground, and an associated splice box. The splice box has a ceiling, a bottom side and a housing wall extending therebetween. The housing wall and the ceiling are airtight and watertight. The bottom side of the splice box is open. The splice box is arranged with the open bottom side pointing downwards. The holder has vertical side walls which widen, viewed from top to bottom. The holder is provided with one or more resilient stems as marking elements tracing the buried holder. The holder has a cover at the top side for allowing access to the interior of the holder. A slab assembly is provided around the access opening for covering the area surrounding the access opening when the latter is open.