Manhole Electronic Assembly With Sacrificial Anode Corrosion Protection

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Solution Overview

Problem

Manholes with electronic devices and ground bars experience galvanic and electrolytic corrosion due to dissimilar metals immersed in accumulated water, leading to device damage and reduced lifespan, as existing de-couplers fail to effectively prevent corrosion in both direct and alternating current scenarios.

Innovation Solution

An electronic device assembly is designed with a grounding device and an anode member, where the anode member is made of a second metal with a lower potential than the device's housing, acting as a sacrificial anode to protect the device from corrosion, and is connected using a split cable for easy installation and maintenance, with multiple anode members and rod members for prolonged service and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If multiple anode members and rod members are used, then service life and stability are prolonged, but device complexity increases

Engineering Contradiction:
Improveservice life of anode memberVSAvoidstructure complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the protective anode system into multiple independent anode members (first anode member, second anode member, etc.) that can be individually installed and replaced. Each anode member is associated with specific rod members, creating modular units that simplify maintenance and extend overall service life through progressive replacement rather than replacing the entire system at once.

Inventive Principle:
Principle #1Segmentation

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 assembly effectively protects the electronic device from galvanic and electrolytic corrosion by allowing the anode member to corrode instead of the device, prolonging its lifespan and preventing damage, while the rod members ensure stable fastening and easy replacement, maintaining the device's functionality in moist environments.

Implementation Method 1

A metal potential of the second metal is less than a metal potential of the first metal. In the manhole, galvanic corrosion or galvanic corrosion and electrolytic corrosion occur on the anode member to protect the electronic device

Methodology Applied
Scientific EffectGalvanic corrosion:

Implementation Method 2

When a potential difference of the two is greater than 50 millivolts (minimum potential difference triggering galvanic corrosion), galvanic corrosion occurs between the communications device and the ground bar once both the communications device and the ground bar are immersed in the accumulated water (electrolyte solution) in the manhole. Further, there is not only galvanic corrosion but also electrolytic corrosion on a communications device that is cable-supplied with an alternating current.

Methodology Applied
Scientific EffectElectrolytic corrosion: Electrolysis

Data Source

PatentEP3498885B1Arrangement comprising an electronic device assembly in a manhole
Publication Date: 2023.10.04 HUAWEI TECH CO LTD
  • EP3498885B1 patent drawingFigure 1
  • EP3498885B1 patent drawingFigure 2
  • EP3498885B1 patent drawingFigure 3

AI summary

An electronic device assembly, fastened in a manhole is disclosed. The electronic device assembly includes an electronic device, a grounding device, and an anode member. A base material of a housing of the electronic device is a first metal. The grounding device is electrically connected to the housing. The anode member is electrically connected to the housing, a base material of the anode member is a second metal, and a metal potential of the second metal is less than a metal potential of the first metal. When the electronic device assembly is applied to a manhole with accumulated water or another moist environment, the accumulated water is equivalent to an electrolyte solution. The metal potential of the second metal is less than the metal potential of the first metal. Therefore, in a remote direct current supply scenario, galvanic corrosion occurs on the anode member to protect the electronic device from galvanic corrosion. In an alternating current cable-supply scenario, the anode member protects the electronic device from galvanic corrosion; in addition, electrolytic corrosion occurs on the anode member to protect the electronic device from electrolytic corrosion, so as to prolong a lifetime of the electronic device.