Humidifier Membrane Stack Bracing Against Pressure Bulging
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Solution Overview
Problem
Conventional membrane stacks in humidifiers for fuel cell systems are prone to undesirable bulging under pressure, which can cause damage and destruction, particularly in the stacking direction, affecting the durability and efficiency of the polymer electrolyte membranes.
Innovation Solution
A membrane stack assembly is braced by two mechanically rigid end plates with a belt routed around the outside, acting as a tensioning belt to prevent pressure-induced expansion, using materials like glass fibers embedded in a thermoplastic matrix to provide high longitudinal strength and counteract bulging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressurized air flows through the membrane stack assembly in a humidifier, then the humidification function is achieved, but the membrane stack expands in the stacking direction causing damage or destruction
Solution Approach 1:
The belt is pre-tensioned around the membrane stack assembly before pressurized air flows through it. This preliminary tightening creates a constraining force that counteracts the expansion pressure generated when humidified air flows through the membrane stack, preventing membrane damage before it occurs
Solution Approach 2:
A flexible belt made of fiber-reinforced plastic material is used to constrain the membrane stack assembly. The belt wraps around the peripheral surface of the assembly, providing flexible yet effective restraint against expansion while allowing for some movement and pressure equalization
2Reliability
If a rigid constraint structure is added to prevent membrane stack expansion, then membrane durability is improved, but device complexity increases
Solution Approach 1:
Instead of a complex rigid constraint structure, a simple flexible belt is used to constrain the membrane stack assembly. The belt can be easily wrapped around the peripheral surface and tensioned to provide the necessary restraint, significantly reducing structural complexity while maintaining effectiveness
Solution Approach 2:
The belt is made from composite material consisting of fibers (such as glass fibers, carbon fibers, or aramid fibers) embedded in a plastic matrix. This composite construction provides high strength and stiffness to effectively restrain membrane expansion while keeping the belt thin and flexible for easy installation
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 effectively prevents membrane stack expansion, safeguarding against damage while maintaining gas separation and humidity equalization, thus enhancing the durability and efficiency of the fuel cell system.
Implementation Method 1
a belt (4) which rests with a first belt section (6a) on an outer side of the first end plate (3a) facing away from the membrane stack (1) and rests with a second belt section (6b) on an outer side of the second end plate (3b) facing away from the membrane stack (1)
Implementation Method 2
membranes (2) that are stacked on top of each other in a stacking direction (S), with each membrane being gas-tight and permeable to moisture
Data Source
AI summary
A membrane stack assembly for a humidifier in a fuel cell system is disclosed. The assembly includes a membrane stack having first and second fluid paths, allowing separate flow of two fluids while enabling moisture transfer through gas-tight, moisture-permeable membranes. The membranes are arranged in a spaced, stacked configuration along a stacking direction between two opposing end plates. At least one belt is provided, with a first belt section positioned on an outer side of the first end plate and a second belt section positioned on an outer side of the second end plate, securing the membrane stack between the end plates.