Removable Cover Seal Assembly for Galvanic Corrosion Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fasteners in multi-component structures, particularly in marine environments, are prone to corrosion due to galvanic action and retention of corrosive liquids, leading to increased maintenance costs and downtime for repairs.
Innovation Solution
A seal assembly using resilient seals, non-conductive plastic bushings, and gaskets is integrated between fasteners to prevent galvanic action and water ingress, comprising a pair of resilient gaskets on either side of a radial flange, a stainless steel washer, and an O-ring to ensure a tight seal and maintain the stud's spacing from the hole, while a corrosion-resistant coating is applied to all components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fasteners are used to secure components in marine environments, then structural assembly is achieved, but corrosion and galvanic action occur due to dissimilar materials and water retention
Solution Approach 1:
A non-conductive bushing is introduced as an intermediary component between the metallic stud and the hole in the component. This bushing prevents direct electrical contact between dissimilar metals, eliminating galvanic action, while also preventing water retention that would cause corrosion. The bushing maintains the structural fastening function while adding corrosion protection.
Solution Approach 2:
Resilient seals and gaskets are used to create flexible sealing barriers that prevent water ingress into the fastener assembly. These elastic components conform to surfaces and maintain sealing under vibration and thermal expansion, preventing water from reaching and corroding the fastener components.
2Adaptability or versatility
If dissimilar materials are used in fasteners, then galvanic action occurs leading to corrosion, but material selection is constrained by functional requirements
Solution Approach 1:
The non-conductive bushing acts as a mediator that electrically isolates dissimilar materials (such as stainless steel studs with aluminum or carbon fiber components). This allows engineers to continue using dissimilar materials for functional reasons (strength, weight, corrosion resistance) without suffering from galvanic corrosion, as the bushing breaks the electrical circuit.
3Ease of manufacture
If conventional fasteners are used without sealing, then assembly is simple, but water ingress causes corrosion and maintenance issues
Solution Approach 1:
The sealing components are nested within the fastener assembly structure. The resilient seal sits in a groove on the stud, the non-conductive bushing is inserted into the hole, and gaskets are placed between components. This nested arrangement provides comprehensive sealing and corrosion protection while maintaining a compact, integrated fastener assembly that remains relatively simple to install.
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 effectively inhibits corrosion and galvanic action, reducing maintenance costs and downtime by providing a reliable seal that prevents water ingress and electrical contact between dissimilar materials, thus enhancing the durability of the fastener assembly in corrosive environments.
Implementation Method 1
Upon tightening of the nut on the stud, the gaskets are compressed to provide a seal between adjacent surfaces
Implementation Method 2
a non conductive bushing on each of the studs and located in respective ones of the annular voids
Data Source
AI summary
A watertight seal is provided between a pair of components by providing a clearance between studs on one of the components and holes on the other. A non-conductive bushing is located in the void between the stud and hole and has a flange at one end. A first pair of resilient gaskets is located on opposite sides of the flange. A rigid washer overlies one of the resilient gaskets and a further resilient gasket is located on the opposite side of the washer. A nut having a blind bore extending from an end face is threaded to receive the stud and an O ring is located on the fastener between an end face of the nut and the second resilient gasket to effect a seal therebetween. Upon tightening of the nut on the fastener, the gaskets are compressed to provide a seal between adjacent surfaces and the bushing maintains the fasteners spaced from the holes.