Cross-Pleated Membrane Cartridge Structure for Leak-Resistant ERVs
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Solution Overview
Problem
Existing heat and water vapor exchanger designs, such as planar plate-type and pleated membrane cartridges, face challenges with labor-intensive and expensive manufacturing, durability issues, and leakage due to numerous seals and edges, limiting their effectiveness in applications like energy recovery ventilators.
Innovation Solution
A cross-pleated membrane cartridge is developed using a method where two membrane strips are folded at 45° angles to form diagonal seams, creating a stack of layered passageways with reduced edge sealing needs, allowing for alternating fluid flow configurations and enhanced sealing characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If planar plate-type heat and water vapor exchangers are used, then scalability and adjustability are improved, but manufacturing complexity and cost increase due to large number of joints and edges requiring sealing
Solution Approach 1:
The membrane is divided into multiple pleated layers stacked together, with each layer forming a complete flow channel. This segmentation allows the exchanger to be scaled by simply adding or removing layers, while each individual layer maintains a simple structure with fewer sealing requirements compared to planar plate designs.
Solution Approach 2:
The membrane is folded into a three-dimensional pleated configuration rather than remaining flat. This dimensional transformation creates alternating flow channels between pleats, enabling cross-flow or counter-flow patterns while reducing the number of edges requiring sealing compared to planar plate assemblies.
2Adaptability or versatility
If planar plate-type heat and water vapor exchangers are used, then scalability is improved, but durability deteriorates due to potential delamination and seal failure
Solution Approach 1:
The exchanger is divided into multiple independent pleated layers, where each layer is self-supported and structurally complete. This segmentation eliminates the need for numerous inter-plate seals that are prone to delamination and failure in planar plate designs, thereby improving durability while maintaining scalability.
Solution Approach 2:
The membrane is formed into a rigid yet flexible pleated structure that maintains its shape and sealing integrity under pressure. The pleated configuration provides structural reinforcement to the thin membrane, preventing delamination and seal failure while allowing the exchanger to be scaled by adding layers.
3Ease of manufacture
If concertina-style pleated membrane cartridges are used, then manufacturing is simplified by reducing edges requiring bonding, but flow configuration flexibility is limited and pressure drop increases
Solution Approach 1:
The membrane is pleated in a specific three-dimensional configuration that creates alternating flow channels, enabling flexible flow patterns (cross-flow, counter-flow) while maintaining a simple manufacturing process. The pleated structure achieves flow configuration flexibility without requiring complex assembly or additional bonding steps.
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 cross-pleated design reduces leakage and cross-contamination, improves durability, and simplifies manufacturing by minimizing the number of seals, resulting in superior performance in pressurized applications compared to conventional designs.
Implementation Method 1
a water-permeable membrane via which water vapor and, provided there is a temperature differential across the membrane, heat is transferred between fluid streams flowing on opposite sides of the membrane
Implementation Method 2
heat is transferred between fluid streams flowing on opposite sides of the membrane
Data Source
AI summary
A membrane cartridge is manufactured by repeatedly folding and joining two strips of membrane to form a cross-pleated cartridge with a stack of openings or fluid passageways configured in an alternating cross-flow arrangement. The cartridge can be modified for other flow configurations including co-flow and counter-flow arrangements. Methods for manufacturing such cross-pleated membrane cartridges, as well as apparatus used in the manufacturing process are described. Cross-pleated membrane cartridges comprising water-permeable membranes can be used in a variety of applications, including in heat and water vapor exchangers. In particular they can be incorporated into energy recovery ventilators (ERVs) for exchanging heat and water vapor between air streams being directed into and out of buildings.