Bladder System for Composite Curing with Integrated Vent Bolt
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Solution Overview
Problem
Existing bladder systems used in autoclave curing of composite resin parts with internal cavities often experience inconsistencies due to inadequate pressurization and potential leaks, which can lead to part collapse or uneven curing, and require vacuum bag vent holes for external pressure venting.
Innovation Solution
A bladder system featuring a flexible bladder with a bladder end fitting and vent bolt that allows direct exposure to external autoclave pressure through a pressure passageway, eliminating the need for vacuum bag vent holes and ensuring consistent pressurization by using a vent bolt to connect the bladder to the cure tool, thereby maintaining a closed system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vented bladder system is used to react autoclave pressure, then the bladder can be pressurized to support the part, but leaks in the bladder or improper venting can lead to insufficient pressurization and part collapse
Solution Approach 1:
The invention extracts the venting function from the vacuum bag system and integrates it directly into the bladder assembly through the end fitting and vent bolt mechanism. This allows the bladder to be pressurized independently through the autoclave atmosphere without relying on vacuum bag vent holes, thereby improving reliability while reducing overall system complexity.
Solution Approach 2:
The end fitting acts as an intermediary component that mediates between the autoclave atmosphere and the bladder interior. The vent bolt with its internal passage and sealing surfaces provides a controlled interface that allows pressure equalization while maintaining system integrity, eliminating the need for external venting through the vacuum bag.
2Reliability
If vacuum bag vent holes are used for bladder venting, then external pressure can be applied to the bladder, but sealant failure at vent holes can cause leaks and inconsistent pressurization
Solution Approach 1:
The invention removes the dependency on vacuum bag vent holes and their associated sealant applications. The venting function is extracted and built into the bladder assembly itself through the end fitting and vent bolt, eliminating the sealing interface problems associated with applying sealant at vent holes in the vacuum bag.
Solution Approach 2:
The vent bolt assembly is self-contained with its own sealing mechanism. The vent bolt threads into the end fitting and creates a sealed passage internally, allowing the system to self-regulate pressure without requiring external sealing materials or complex assembly procedures.
3Stress or pressure
If the bladder is sealed as a closed system, then pressurization can be maintained, but the bladder cannot be vented to external autoclave pressure
Solution Approach 1:
The vent bolt provides a dynamic sealing solution. When the vent bolt is installed, it creates a sealed passage that allows pressure equalization between the autoclave atmosphere and the bladder interior. The system can transition between sealed and vented states, providing adaptability while maintaining the ability to hold pressure when needed.
Solution Approach 2:
The sealing capability is localized to specific interfaces within the vent bolt assembly rather than requiring a complete seal throughout the entire bladder system. The vent bolt creates localized sealed passages at critical interfaces, allowing pressure control at specific locations while maintaining overall system flexibility.
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
This solution ensures consistent and reliable pressurization of composite parts during curing, reducing the risk of leaks and part collapse, while eliminating the need for vacuum bag vent holes, thus improving the quality and consistency of cured composite resin parts.
Implementation Method 1
a flexible bladder adapted to be placed in the cavity for applying pressure on the composite charge during autoclave curing
Implementation Method 2
Composite resin parts may be cured within an autoclave that applies heat and pressure to the part during a cure cycle
Implementation Method 3
Composite resin parts may be cured within an autoclave that applies heat and pressure to the part during a cure cycle
Data Source
Figure 1~2
Figure 3~4
Figure 5~6D
AI summary
Method and apparatus for use in curing of a composite charge having an internal cavity. Apparatus includes a flexible bladder (55) adapted to be placed in the cavity (45) for applying pressure on the composite charge during curing. An end fitting (200) is operatively coupled to the flexible bladder. The end fitting defining a bolt bore and a horizontal bore. When a vent bolt (300) is operatively coupled to the bolt bore of the end fitting, the vent bolt and the horizontal bore define a pressure passageway that allows an interior of the bladder to become subjected to external pressure.