Pressure Vessel Foot Design for Blow Molding Reinforcement
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Solution Overview
Problem
Existing pressurized vessels, particularly those made through blow molding, suffer from thin spots and weak areas around the corners and foot regions due to material stretching, leading to reduced stress resistance and performance.
Innovation Solution
The design incorporates a foot with a narrow neck and a wider head, allowing for more extensive coverage by longitudinal windings and minimizing material migration during molding, thereby reducing thin spots and enhancing structural reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a foot is molded onto the liner during the blow molding process, then the manufacturing process is simplified and cost is reduced, but thin spots develop at the inside corners and center of the foot creating weak areas
Solution Approach 1:
The foot geometry is pre-designed with a narrow neck and wider head configuration before molding to control material flow and prevent thin spot formation during the blow molding process
Solution Approach 2:
The foot cross-sectional dimensions are varied along its length, with a narrow neck portion and a wider head portion, to optimize material distribution and eliminate thin spots while maintaining structural integrity
2Strength
If fibers are wound around the liner to reinforce it, then the stress resistance and strength are improved, but the foot area remains unreinforced creating a potential weak spot
Solution Approach 1:
The foot is designed with asymmetric geometry (narrow neck, wider head) to enable comprehensive fiber coverage of the entire foot area, eliminating the unreinforced weak spot while maintaining overall vessel strength
Solution Approach 2:
Fibers are wrapped around the foot in multiple directions including longitudinal windings that encircle the foot, providing reinforcement in previously unreinforced areas and eliminating weak spots
3Shape
If the liner material is stretched around corners of the mold during blow molding, then the liner conforms to the mold shape, but thin spots are created that weaken the liner
Solution Approach 1:
The foot cross-sectional dimensions are varied along its length with a narrow neck and wider head to control material flow and prevent excessive stretching that causes thin spots
Solution Approach 2:
Different portions of the foot have different cross-sectional dimensions (narrow neck vs. wider head) to locally optimize material distribution and prevent thin spot formation in critical areas
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 design results in a stronger pressure vessel with reduced unreinforced areas and increased stress resistance by ensuring consistent liner thickness and comprehensive reinforcement, outperforming prior art vessels in terms of strength and performance.
Implementation Method 1
Air is then forced into the center of the plastic, thereby forcing the soft plastic outward against the walls of the mold
Implementation Method 2
Once the fibers are wrapped, the resin is cured to provide a strong pressure vessel
Data Source
AI summary
An improved molded, reinforced pressure vessel having a winding foot on the liner tank which includes a head, disposed away from the tank and a narrowed neck extending between the head and the tank wherein outer radial dimensions of the head are greater than outer radial dimension of the neck. The improved foot design allows windings to cover more of the liner tank that maximizes the reinforcement provided by the winding and in blow molded liner tanks, the narrow neck restricts the migration of material out of and away from the foot, thus producing a stronger liner tank.