Elastic Outlet Seal for Aluminum Electrolytic Cell Cathode Bars

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Solution Overview

Problem

Existing outlet seals for aluminum electrolytic cells are gas permeable, fail to compensate for cathode bar displacements due to thermal and sodium expansion, leading to seal disruption, oxidation of the carbon lining, and increased labor and material costs for installation and maintenance.

Innovation Solution

An elastic, gas-proof, and heat-proof sealing sleeve that synchronously or asynchronously moves with the cathode bar, filled with an elastic, fire-proof sealant, ensuring tightness and resistance to aggressive gases, and allowing the cathode bar to slide relative to the cathode shell, while minimizing material usage and installation complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a sealing gland and layer of alumina are used, then the structure is simple, but the seal is gas permeable and cannot maintain tightness during thermal expansion and sodium expansion

Engineering Contradiction:
Improveseal structureVSAvoidseal tightness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses a flexible sealing element made of gas-proof material that can deform and move with the cathode bar during thermal expansion and sodium expansion, maintaining seal tightness while accommodating dimensional changes. This flexible membrane approach replaces the rigid alumina layer that failed to maintain tightness.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing system combines multiple materials with complementary properties: a flexible gas-proof outer layer for tightness, an inner sealing element for adaptability, and support structures for mechanical strength. This composite construction achieves both simplicity and reliability by integrating multiple functions into a unified seal assembly.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the sealing gland is rigid, then the structure is stable, but it cannot compensate for transverse displacement of the cathode bar

Engineering Contradiction:
Improveseal structure stabilityVSAvoidcompensation for displacement
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The sealing system incorporates dynamic elements that can move and deform in response to cathode bar displacement. The flexible sealing element and movable plate structure allow the seal to adapt to transverse and axial movements while maintaining its sealing function, transforming a static rigid structure into a dynamic adaptive system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Flexible sealing elements replace rigid components, enabling the seal to accommodate transverse displacement of the cathode bar through elastic deformation and controlled movement, while maintaining structural integrity and sealing effectiveness.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a sylphon is used, then hermetic connection is achieved, but the developed surface area and internal space volume increase sealant outlay and cost

Engineering Contradiction:
Improvehermetic connectionVSAvoidsealant consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and eliminates the sylphon component entirely, replacing it with a simpler sealing arrangement using a flexible element and plate structure. This removes the unnecessary developed surface area and internal volume that consumed excessive sealant, achieving hermetic connection more efficiently.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A flexible sealing element replaces the complex sylphon structure, providing hermetic connection with minimal material consumption. The thin film approach creates an effective seal without the volumetric inefficiencies of folded sylphon structures.

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of manufacture

If the cathode bar surface is irregular, then manufacturing is easier, but aggressive gases pass through gaps during firing and startup

Engineering Contradiction:
Improvecathode bar productionVSAvoidgas penetration
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A flexible sealing element conforming to the irregular cathode bar surface creates a gas-tight barrier during firing and startup. The flexibility allows the seal to adapt to surface irregularities while maintaining hermetic properties, preventing aggressive gas penetration without requiring a perfectly smooth cathode bar.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing system is designed to accommodate surface irregularities in advance, creating a cushioning effect that prevents gas leakage paths. The flexible element compensates for manufacturing tolerances and surface imperfections before aggressive gases can penetrate through gaps.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution enhances the service life of aluminum electrolytic cells by preventing air and aggressive gas penetration, reducing leakage and maintenance costs, and improving ecological safety through a durable and adaptable seal that maintains integrity during thermal expansion and sodium expansion.

Implementation Method 1

the cathode bar shifts along its axis due to thermal expansion, and the cathode bar shifts transversely to its axis as a result of sodium expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

An elastic, gas-proof, and heat-proof sealing sleeve that synchronously or asynchronously moves with the cathode bar

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

filled with an elastic, fire-proof sealant, ensuring tightness and resistance to aggressive gases, and allowing the cathode bar to slide relative to the cathode shell

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

An elastic, gas-proof, and heat-proof sealing sleeve... ensuring tightness and resistance to aggressive gases

Methodology Applied
Scientific EffectGas-proof barrier:

Implementation Method 5

in the form of a sleeve that is hermetically connected by one end to the cathode shell, narrows in a direction away from the cathode shell, and hugs the cathode bar around the perimeter of its cross section

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentUS9994963B2Outlet seal for the cathode bars of an aluminum electrolytic cell
Publication Date: 2018.06.12 MID MOUNTAIN MATERIALS INC

AI summary

Sealing devices are provided as configured for use with cathode devices of an electrolytic cell for production of aluminum. In particular, the seals are specifically configured to provide an outlet seal for the cathode bars. The sealing devices are made of a material that is elastic, gas-proof, and heat-proof, and can create a hermetic seal around the cathode bar in such a way as to be able to move synchronously or asynchronously with the movement of the cathode bar as it undergoes thermally induced movement during aluminum production.