Fuel Cell Humidifier Membrane Tensioning via Fixing Elements
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Solution Overview
Problem
Existing humidifiers for fuel cells face challenges in securely fixing a stack of water-vapor-permeable membranes, leading to potential membrane contact under negative pressure and uneven moisture distribution.
Innovation Solution
A humidifier design featuring a stack unit with membranes fixed using complementary fixing elements that increase membrane tension, ensuring a defined distance and preventing undesirable contact, with options for adhesive or friction locking and hollow-cylindrical elements for additional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membranes are arranged in a stack with spacers and sealing elements, then moisture enrichment function is achieved, but membrane position stability deteriorates under negative pressure
Solution Approach 1:
The patent applies preliminary action by pre-tensioning the membranes using fixing elements that act on the membranes from different sides before negative pressure occurs. The fixing elements increase membrane tension in advance, ensuring that when negative pressure is applied, the membranes remain separated and maintain their defined relative distance, preventing harmful contact.
2Reliability
If fixing elements are used to increase membrane tension, then membrane position stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the fixing elements with the spacer structure, combining two functions into a single integrated component. The fixing elements are formed as one piece with the spacers, eliminating the need for separate fixing mechanisms and reducing overall device complexity while maintaining the tensioning function.
Solution Approach 2:
The fixing elements serve multiple functions simultaneously: they act as spacers to maintain distance between membranes, provide sealing surfaces for sealing elements, and apply tension to the membranes through their complementary projection-recess design. This multi-functionality reduces the number of separate components needed.
3Ease of manufacture
If membranes are placed directly on top of one another in the region of fixing elements, then manufacturing simplicity is improved, but membrane distance control deteriorates
Solution Approach 1:
The patent introduces sealing elements as intermediaries between the membranes and the fixing elements. These sealing elements are received by recesses in the fixing elements and provide a defined spacing, ensuring precise membrane distance control while allowing the membranes to be simply stacked directly on top of one another during assembly.
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 securely fixes membranes, maintaining a defined distance and preventing membrane contact under pressure, ensuring efficient moisture enrichment of air for fuel cells and other applications, such as aircraft humidification.
Implementation Method 1
Water molecules penetrate through the membrane from the moist to the dry air flow, which thereby is enriched with moisture
Data Source
AI summary
A humidifier has a stack unit having a plurality of water-vapor-permeable membranes which are arranged parallel one above the other and spaced apart from one another. Two adjacent membranes are connected to one another via fixing elements, wherein a first fixing element acts on the top membrane from above and a second fixing element acts on the bottom membrane from below.