Portable Reverse Osmosis Device Back Pressure Regulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current small handheld reverse osmosis (RO) water purification devices are overly complex and costly due to the need for pressure recovery mechanisms, which are not effectively implemented in portable systems and can lead to membrane damage from high-pressure brine flow.
Innovation Solution
A low-cost, portable RO device with a spiral wound membrane element that uses back pressure regulation and incorporates coarse filters at both ends, with metal biocides for disinfection, and a small diameter piston for pressurization, allowing for a straightforward flow path and reduced operational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pressure recovery mechanisms are used in handheld RO devices, then system efficiency is marginally improved, but device complexity increases significantly
Solution Approach 1:
The patent removes the pressure recovery mechanism entirely from the handheld RO device, extracting the complex energy recovery system that was present in larger RO systems. This simplification is appropriate for portable applications where the marginal efficiency gain does not justify the added complexity and size.
Solution Approach 2:
The patent employs a disposable membrane element that is replaced periodically rather than designing a complex system to recover and reuse brine pressure. This approach trades the complexity of pressure recovery for a simple replacement strategy, which is more suitable for portable devices.
2Loss of energy
If high-pressure brine flow is used to recover pressure energy, then energy efficiency improves, but membrane damage from high pressure increases
Solution Approach 1:
The patent eliminates the high-pressure brine flow path that causes membrane damage. By removing the pressure recovery mechanism, the system avoids subjecting the membrane to damaging high-pressure brine flow, thereby protecting membrane integrity while still achieving acceptable energy efficiency through simpler means.
Solution Approach 2:
The patent prevents membrane damage before it can occur by designing the flow path to avoid high-pressure brine contact with the membrane. The membrane is protected from the harmful effect of high-pressure brine flow by configuring the system so that brine does not flow at high pressure across the membrane surface.
3Loss of energy
If elaborate plumbing systems are used for pressure recovery, then energy efficiency improves, but device size and portability deteriorate
Solution Approach 1:
The patent removes the elaborate plumbing system required for pressure recovery, extracting the complex network of pipes, valves, and channels that would be needed to implement effective pressure recovery. This elimination is essential for maintaining device portability and compact size in handheld applications.
Solution Approach 2:
The patent replaces the complex, space-consuming pressure recovery plumbing with a simple disposable membrane element replacement strategy. This approach avoids the need for elaborate reusable plumbing systems, thereby maintaining compact device size suitable for portable applications.
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 device achieves efficient water purification with reduced operational effort and complexity, using back pressure regulation and metal biocides to prevent bio-fouling, while maintaining membrane integrity and producing safe drinking water within EPA standards.
Implementation Method 1
A typical reverse osmosis (RO) water purification system uses a high-pressure pump to provide high pressure raw water at a steady flow rate to the membrane element or elements
Implementation Method 2
using a straightforward flow path by way of back pressure regulation
Implementation Method 3
The upstream filter serves as a pre-filter for the RO membrane, while the downstream filter is back-washed by the exiting concentrated brine
Implementation Method 4
Metal biocides as taught in U.S. Pat. Nos. 5,632,904 and 6,303,039B1 are also able to be integrated into the present invention to disinfect the permeated and raw water contained in the device during prolonged storage
Implementation Method 5
A significant effort has been spent on improving the performance of RO membranes and their configuration. U.S. Pat. No. 3,367,504 describes an RO separation apparatus employing an envelope of semi-permeable membrane sheets
Data Source
AI summary
A lightweight, portable, water purification device can be used to recover potable water from any water source. The manually operated device, requires no external power, is very lightweight, and removes salt and other impurities from source water while also disinfecting it. A symmetrical reverse osmosis (RO) membrane coupled with a pre-filter is used to remove salt and impurities from the raw water. Metal biocides are integratable to disinfect the permeate, improve wet storage and to significantly reduce biofouling within the RO membrane.