Reverse Osmosis Membrane Element With Water Division Structure
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Solution Overview
Problem
Current reverse osmosis membrane elements have a short use life due to concentration polarization, scaling, and reduced efficiency caused by a wide water flow channel and short contact time with the membrane, leading to increased saltiness and precipitation on the membrane surface.
Innovation Solution
A full-effective reverse osmosis membrane element with a central tube and reverse osmosis membrane assembly wound around it, featuring a water division structure that increases the flow distance and area contact, and includes water inlet and outlet configurations to enhance flow rates and turbulence, reducing polarization and scaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If raw water flows parallel to the central tube through a wide water flow channel, then the device structure is simple, but the contact time with the reverse osmosis membrane is short and concentration polarization occurs
Solution Approach 1:
The water feed channel is divided into multiple flow channels by water division structures (baffles), segmenting the single wide channel into several narrower parallel channels. This increases the contact time between raw water and the reverse osmosis membrane while maintaining structural simplicity. The segmentation allows water to flow through a longer path along the membrane surface without requiring a complex overall device configuration.
2Device complexity
If the water flow channel is wide, then the device structure is simple, but water flows at low speed causing concentration polarization and scaling
Solution Approach 1:
By dividing the wide water feed channel into multiple narrower flow channels using water division structures, the linear flow velocity of water increases for the same flow rate. This higher flow speed reduces concentration polarization and prevents scaling on the membrane surface, while the overall device structure remains relatively simple through the use of straightforward baffles.
Solution Approach 2:
The water division structures create localized flow conditions with higher velocity in specific channels, optimizing the flow characteristics at the membrane interface. This local modification of flow quality addresses the scaling issue without requiring a complete redesign of the overall device structure.
3Use of energy by stationary object
If raw water continuously osmoses into the membrane bag, then the filtration process is continuous, but the water concentration increases and precipitation and scaling become more serious
Solution Approach 1:
The water feed channel is segmented into multiple flow channels, which distributes the continuous osmosis process across several parallel paths. This segmentation prevents excessive concentration buildup in any single location, reducing precipitation and scaling while maintaining continuous filtration operation throughout the membrane 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 design increases the use rate and efficiency of the reverse osmosis membranes by maintaining constant water flow speed, eliminating lamination, and scouring pollutants, thereby prolonging the membrane's life and improving water flux and salt rejection.
Implementation Method 1
raw water inflows from one end and flows in a direction parallel to a central tube; purified water enters a membrane bag of a reverse osmosis membrane to flow into the central tube
Implementation Method 2
full-effective reverse osmosis membrane element... raw water inflows from one end and flows in a direction parallel to a central tube; purified water enters a membrane bag of a reverse osmosis membrane
Implementation Method 3
the water feed channel has a water inlet formed in front edges of the two reverse osmosis membranes and water outlets formed in rear edges... the flow rate on the surface of the reverse osmosis membrane in this area is reduced
Data Source
AI summary
A full-effect reverse osmosis membrane element includes a central tube and a reverse osmosis membrane assembly wound around the central tube. The reverse osmosis membrane assembly includes a pair of reverse osmosis membranes attached at front surfaces thereof and wound around the central tube. A water feed channel has a water inlet formed at front edges of the reverse osmosis membranes and a water outlet formed at rear edges of the reverse osmosis membranes. A water division structure is arranged in the water feed channel, and includes a first water division band forming a preset space with the central tube when the reverse osmosis membranes are in an unfolded state. The first water division band divides the water feed channel into a first flow channel having a gradually decreasing cross-section and a second flow channel in communication with the first flow channel.