Composite Tank Dome Sealing With Metal Boss Press-Fit Assembly
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Solution Overview
Problem
Existing fibre composite tanks experience leaks around the dome area due to the deformation of plastic annular end fittings during thermal processing, leading to compromised fluid tightness and reliability.
Innovation Solution
The use of a metal boss assembled in a tight fit inside a metal end fitting, combined with a sealing arrangement that includes a metal boss and an annular sealing element, ensures a press-fit assembly that maintains seal integrity during resin solidification, using thermoplastic resins for the liner and composite tapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic annular end fitting is used to assemble the metal boss, then the assembly process is easier, but the end fitting deforms during thermal processing causing leaks and compromising fluid tightness
Solution Approach 1:
The patent changes the material parameter of the end fitting from plastic to metal. This material substitution prevents thermal deformation during resin solidification, eliminating the root cause of leaks while maintaining assembly feasibility through the press-fit design between the metal boss and metal end fitting.
2Manufacturing precision
If the resin is heated to solidify the composite shell layer, then the composite structure is formed, but the plastic end fitting deforms causing leaks between components
Solution Approach 1:
The patent changes the material parameter of the end fitting from plastic to metal. This material substitution prevents thermal deformation during resin solidification, eliminating the root cause of leaks while maintaining assembly feasibility through the press-fit design between the metal boss and metal end fitting.
3Reliability
If a press-fit assembly is used between the metal boss and end fitting, then the seal integrity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent utilizes thermal expansion and contraction principles to achieve the press-fit assembly. The metal boss is heated to expand, inserted into the metal end fitting, then cooled to contract and create a tight interference fit. This thermal method achieves reliable sealing without requiring complex mechanical fastening systems.
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 method enhances the tank's seal at the dome, ensuring improved fluid tightness and the ability to withstand overpressures of at least 2 bars, with the tank design suitable for containing pressurized gases or liquids.
Implementation Method 1
a step of shrinking a metal boss by cooling it to a negative temperature
Implementation Method 2
a step of expanding the metal boss by warming it to a positive temperature, the annular outer radial surface of the metal boss being in sealing contact with the annular inner radial surface of the opening
Data Source
Figure 1
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AI summary
The invention relates to a method for producing a fibre composite tank (1), comprising: - a step (S1) of assembling a removable moulding mandrel (8); - a step (S2) of applying an end fitting (11a,11b) to the moulding mandrel (8), said end fitting (11a,11b) being a metal ring having an opening (14a,14b); - a step (S3) of forming a first fibre composite shell layer (2) on the moulding mandrel (8) and on the end fitting (11a,11b); - a step (S4) of disassembling and removing the moulding mandrel (8) through the opening (14a,14b); - a step (S5) of shrinking a metal boss (10a,10b) by cooling; - a step (S6) of inserting the metal boss (10a,10b) in the opening (14a,14b) of the end fitting (11a,11b); - a step (S7) of expanding the metal boss (10a,10b) by warming. The invention also relates to a fibre composite tank (1).