Composite Thief Hatch Sealing Against Corrosion and Venting
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Solution Overview
Problem
Thief hatches in oil and gas tanks are prone to corrosion and seal failure due to dissimilar metals, leading to uncontrolled venting of hydrocarbon gases, which violates regulations and poses safety risks.
Innovation Solution
A composite material-based thief hatch system with a flange body and lid, featuring a gasket, hinge, and optional sensors, designed to resist corrosion and maintain seal integrity, using polymers and fiber-reinforced materials to prevent degradation and enhance sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dissimilar metals are used in thief hatch construction, then manufacturing flexibility and strength are improved, but corrosion and seal degradation occur leading to loss of seal integrity
Solution Approach 1:
The patent applies composite materials by constructing the thief hatch from multiple materials including a metal flange body, a polymer lid, and a gasket seal element. This composite approach allows each material to contribute its strengths (metal for structural strength, polymer for corrosion resistance, gasket for sealing) while avoiding the corrosion problems of dissimilar metal contacts through proper material selection and interface design.
2Ease of manufacture
If dissimilar metals are used in thief hatch construction, then ease of manufacture is improved, but corrosion occurs leading to gasket sealing degradation
Solution Approach 1:
The patent extracts the problematic dissimilar metal contact by replacing the metal lid with a polymer lid, eliminating the galvanic corrosion pathway between dissimilar metals while maintaining the functional requirements of the hatch assembly.
3Object-generated harmful factors
If hatches remain closed to prevent emissions, then environmental compliance is improved, but access for gauging fluid levels becomes difficult
Solution Approach 1:
The patent applies dynamics by designing the lid with a hinge connection that allows it to be opened for access when needed, while the gasket seal and latch mechanism enable it to be securely closed to prevent emissions during normal operation. This dynamic design allows the system to switch between operational states (open for access, closed for emission prevention) as needed.
Data Source
AI summary
The present disclosure refers to a system and components for a thief hatch. The thief hatch may include a flange body comprising a first composite material. The flange is configured to attach to a tank roof. A lid is operably connected to the flange body. The lid comprises a second composite material. The lid comprises a hinge operably connected to allow for at least partial opening and closing of the lid. The first composite material and the second composite material are the same material or different materials.