Spring-Loaded Reject Valve for Stable RO Pressure
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Solution Overview
Problem
Existing reverse osmosis systems face challenges in maintaining consistent system pressure and membrane yield due to variations in water salinity, temperature, and membrane aging, particularly in small devices using manual throttle valves which require constant monitoring and are prone to salt scaling.
Innovation Solution
An automatically operating reject valve with a compression spring mechanism that dynamically adjusts the flow channel cross-section, maintaining a pre-set system pressure and reject flow volume, similar to a check valve structure but optimized for pressure regulation and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual needle valve is used to throttle reject flow, then the system can be started and operated, but the pressure requires constant monitoring and adjustment, and salt scale accumulates on the valve
Solution Approach 1:
The reject valve is designed to automatically maintain system pressure without manual intervention. The valve self-regulates the reject flow based on the pressure differential between the RO module and atmospheric pressure, eliminating the need for constant monitoring and adjustment by the operator.
Solution Approach 2:
The manual mechanical adjustment system is replaced with an automatic pressure-regulating mechanism. The valve uses the pressure differential itself to control the throttling action, substituting manual mechanical adjustment with an automated pressure-responsive system.
2Device complexity
If a constant throttle is used, then the structure is simple, but the system pressure changes when the number of modules, water salinity, or temperature changes
Solution Approach 1:
The valve transitions from a static constant throttle to a dynamic pressure-regulating device. The reject flow cross-section automatically adjusts based on the pressure differential, allowing the valve to adapt to changing operating conditions such as varying module numbers, salinity, and temperature while maintaining stable system pressure.
Solution Approach 2:
The valve changes its flow resistance parameter dynamically in response to pressure differential changes. As the pressure differential varies with different operating conditions, the valve automatically adjusts its effective opening to maintain constant system pressure, rather than maintaining a fixed throttle position.
3Productivity
If membrane yield changes due to temperature variation or membrane aging, then the reject volume changes, but with a constant throttle the system pressure becomes unstable
Solution Approach 1:
The valve incorporates inherent feedback through the pressure differential between the RO module and atmospheric pressure. When membrane yield changes alter the reject volume, the resulting pressure change is immediately sensed by the valve, which automatically adjusts its opening to maintain stable system pressure, creating a self-correcting control loop.
4Ease of operation
If a manually adjustable needle valve is used, then initial pressure setting is possible, but the valve requires constant monitoring and adjustment throughout operation
Solution Approach 1:
The valve performs its own pressure regulation function continuously without requiring operator attention. After initial setup, the valve automatically maintains optimal system pressure throughout operation, eliminating the time loss associated with constant monitoring and manual adjustment.
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 valve ensures stable system pressure and efficient water production, allowing for the use of solar or wind energy with an inverter-driven pump, reducing manual adjustments and minimizing salt scaling by maintaining uniform pressure and flow.
Implementation Method 1
a reject valve (3) of a reverse osmosis device that throttles the reject flow and maintains the system pressure at a pre-set level and substantially constant... comprising a compression spring (6)
Implementation Method 2
As the flow of salt water passes through the module, the membrane separates fresh water from it... In order for the membrane to separate fresh water from salt water, the prevailing pressure in the module must be higher than the osmotic pressure of the concentrate flowing through the module
Data Source
AI summary
A reject valve of a reverse osmosis device, which is especially suited for brackish water reverse osmosis devices, which require a low system pressure less than 15bar. The valve keeps the system pressure substantially constant in a pre-defined range of the reject volume. The size of the inflow channel is adjusted by a spring-operated cone, which never entirely closes the channel, which forms a constant throttle until the pressure of the inflow has risen to approximately three quarters of the pressure arranged by the spring and prevailing at maximum volume of the reject flow. This operation is arranged structurally such that onto the shaft of the cone is fixedly supported a transverse plate abutting the inner wall of the body, which as pressed by the compression spring is supported by the end of an element connected to the end of the body, wherein the cone is in its lowest position.