Resilient Seal for Pressure Vessel Valve Interface
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Solution Overview
Problem
Existing pressure vessels for storing compressed natural gas (CNG) face challenges in maintaining reliable sealing under high pressure conditions and are prone to leaks, particularly at the interface between the mouthpiece and resin liner, which can be difficult to repair and are affected by deformation of the resin liner.
Innovation Solution
A pressure vessel design featuring a resin liner with a tubular extension and a stiffer tubular member, both with threaded connections, a valve with a resilient seal member, and a fiber-reinforced resin layer, ensuring mechanical attachment and sealing performance through annular projections and a thermally welded or bonded interface, along with a skirt portion for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a resin liner is used to reduce weight, then the weight of the pressure vessel is reduced, but the sealing performance deteriorates due to deformation under pressure
Solution Approach 1:
The sealing system is divided into multiple segments: the resin liner, the rigid tubular extension, the mouthpiece, and the resilient seal member. Each segment performs a specific function, with the rigid tubular extension and mouthpiece providing structural stability and the resilient seal member providing sealing, thereby resolving the contradiction between weight reduction and sealing reliability
Solution Approach 2:
A resilient seal member (O-ring) is introduced as an intermediary element between the rigid mouthpiece and the resin liner. This intermediary compensates for the deformation of the resin liner under pressure, maintaining reliable sealing while allowing the use of lightweight resin material
2Reliability
If a rigid mouthpiece is used to ensure sealing, then the sealing performance is improved, but the deformation compatibility with resin liner deteriorates
Solution Approach 1:
Different parts of the system have different rigidity properties tailored to their specific functions. The mouthpiece and tubular extension are made rigid for structural stability and sealing, while the resin liner is made more compliant to accommodate pressure-induced deformation. The resilient seal member provides localized compliance at the sealing interface
Solution Approach 2:
The system utilizes changes in material properties and geometric parameters. The resilient seal member changes its cross-sectional dimension under pressure to maintain sealing contact, while the rigid mouthpiece maintains its geometric parameters. This parameter change allows the rigid and compliant components to work together effectively
3Strength
If the fiber reinforced layer is applied to protect the resin liner, then the mechanical strength is improved, but the accessibility for repair deteriorates
Solution Approach 1:
The pressure vessel is segmented into a removable mouthpiece assembly and the main body with fiber reinforced layer. The mouthpiece can be detached independently for repair or replacement without damaging the fiber reinforced layer or the resin liner, thereby maintaining mechanical strength while improving repair accessibility
Solution Approach 2:
The threaded connection between the mouthpiece and tubular extension is designed to allow easy assembly and disassembly. This preliminary design consideration enables maintenance personnel to access and repair the sealing components without requiring specialized equipment or damaging the protective fiber reinforced layer
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 ensures reliable sealing performance across various pressure conditions, reduces the risk of leaks, and facilitates easy assembly, maintaining the structural integrity and fuel efficiency of the pressure vessel.
Implementation Method 1
a resilient seal member is placed in the gap... the sealing performance of the resilient seal member can be ensured under all pressure conditions
Data Source
AI summary
In a pressure vessel (1) comprising a resin liner (2) provided with a tubular extension (22) defining a through hole therein for receiving and expelling the gas or liquid, a tubular member (100, 200, 300) fitted in the through hole of the tubular extension, a mouthpiece (4) threaded into the tubular extension, a fiber reinforced resin layer (3) placed around an outer surface of the resin liner, and a valve (60) fitted into the central bore of the tubular member, the valve include a section (62) having a smaller outer diameter than an opposing inner circumferential surface of the tubular member defining a gap between the valve and tubular member, and a resilient seal member (80) is placed in the gap. The tubular member is made of a material such as metallic material which is stiffer than the resin liner. Thereby, the resilient seal member is interposed between the tubular member and valve which are both highly stiff or free from deformation when the interior of the pressure vessel is placed under various pressure conditions so that the sealing performance of the resilient seal member can be ensured under all pressure conditions.