Spiral Reverse Osmosis Membrane Edge Sealing
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Solution Overview
Problem
Conventional spiral reverse osmosis membrane elements suffer from micro-leaks due to inadequate impregnation of sealing resins, leading to incomplete separation of feed-side and permeation-side fluids, and excessive adhesive usage results in uneven thickness and wrinkles during membrane winding.
Innovation Solution
A spiral reverse osmosis membrane element with a non-woven fabric layer having a specific pore diameter ratio and thickness, impregnated with a sealing resin up to the vicinity of the skin layer, using a porous support to enhance sealing and prevent micro-leaks, and a method involving interfacial polymerization of polyfunctional compounds to form a polyamide skin layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of adhesive is used to prevent raw water permeation, then sealing effectiveness is improved, but adhesive thickness becomes ununiform and wrinkles occur during membrane winding
Solution Approach 1:
The patent applies porous materials (non-woven fabric with controlled pore structure) as an intermediate layer to enable uniform adhesive impregnation. The porous structure allows the adhesive to penetrate evenly throughout the membrane assembly, achieving reliable sealing without excessive adhesive application that would cause thickness variation and wrinkles.
Solution Approach 2:
The patent changes the physical parameters of the non-woven fabric (pore diameter, thickness) to optimize adhesive impregnation. By controlling the pore diameter to be 1/10 to 1/5 of the adhesive molecule size and setting specific thickness ranges, the adhesive can uniformly penetrate the sealing portion without creating uneven thickness or wrinkles.
2Reliability
If adhesive is applied to seal membrane edges, then feed-side and permeation-side fluids are prevented from mixing, but adhesive does not sufficiently impregnate into the separation membrane causing micro-leaks
Solution Approach 1:
The patent uses a non-woven fabric with controlled porosity as an intermediate layer between the membrane and adhesive. The porous structure facilitates deep and uniform adhesive impregnation into the sealing portion, ensuring complete fluid separation without micro-leaks while maintaining consistent adhesive distribution.
Solution Approach 2:
The non-woven fabric acts as an intermediary layer that mediates between the adhesive and the membrane assembly. It provides a controlled pathway for adhesive impregnation, ensuring uniform penetration to the required depth without direct application issues, thereby achieving reliable fluid separation.
3Reliability
If adhesive is applied to seal edges, then sealing portion is formed, but excessive adhesive causes ununiform thickness and winding difficulties
Solution Approach 1:
The patent optimizes the physical parameters of the non-woven fabric (thickness: 10-50 μm, pore diameter: controlled relative to adhesive molecules) to regulate adhesive impregnation. This control ensures sufficient sealing performance while preventing excessive adhesive accumulation that would cause thickness variation and winding difficulties.
Solution Approach 2:
The porous non-woven fabric layer acts as a controlled medium that absorbs and distributes adhesive uniformly. This prevents excessive adhesive from creating ununiform thickness, thereby maintaining ease of manufacture and successful membrane winding while achieving reliable sealing.
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 micro-leaks and improves separation performance by ensuring uniform impregnation of the sealing resin, achieving good salt rejection and permeate water quality, particularly in separating NaCl aqueous solutions under high pressure.
Implementation Method 1
the separation membrane is impregnated with the sealing resin at least up to the vicinity of the skin layer through the porous support
Implementation Method 2
a non-woven fabric layer having a structure capable of sufficiently impregnating therein a sealing resin
Data Source
AI summary
A spiral reverse osmosis membrane element that improves impregnation property of a sealing resin at edges of a membrane leaf and can effectively prevent micro-leaks. The spiral reverse osmosis membrane element comprises a cylindrically wound body comprising a perforated core tube and, spirally wound therearound, a separation membrane, a feed-side passage material and a permeation-side passage material in a laminated state, and a sealing portion for preventing a feed-side liquid and a permeation-side liquid from being mixed together, wherein the separation membrane facing the permeation-side passage material has a structure that a porous support and a skin layer are successively laminated on a non-woven fabric layer, and the sealing portion sealed with a sealing resin is provided at the edges of the separation membrane, wherein the separation membrane is impregnated with the sealing resin at least up to the vicinity of the skin layer through the porous support.