Ultrapure Water Bypass Recirculation for Accurate Volume Dispensing
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Solution Overview
Problem
Existing water purification and dispensing systems struggle to accurately dispense ultrapure water at a wide range of flow rates, from drop-by-drop to full rate, due to limitations in DC motor speed control and pressure management, leading to inaccuracies and inefficiencies in dispensing volumes.
Innovation Solution
A closed water recirculation loop system with a bypass passage and three-way valves for controlling flow rates, allowing for constant pumping and precise dispensing across various modes, including recirculation, manual, and automatic dispensing, independent of motor speed and pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If DC motor speed control is used to adjust dispensing flow rate, then the system can operate at different throughput rates, but very low flow rates like drop-by-drop cannot be achieved due to insufficient motor control precision
Solution Approach 1:
The patent replaces the DC motor mechanical speed control system with a valve-based flow control system. The first valve (recirculation valve) and second valve (dispensing valve) use solenoid actuation and spring-loaded mechanisms to control flow distribution, eliminating the need for precise low-speed DC motor control and enabling drop-by-drop dispensing through valve positioning rather than motor speed modulation.
Solution Approach 2:
The system changes the control parameter from motor speed to valve opening degree and recirculation ratio. By adjusting the recirculation flow rate through the first valve and dispensing flow through the second valve, the system achieves precise control over dispensing flow rate independent of pump speed, allowing flow rates from drop-by-drop to full throughput.
2Speed
If recirculation solenoid valve is opened to achieve very low dispensing flow rates, then drop-by-drop dispensing becomes possible, but the flow rate cannot be precisely controlled as it depends on final filter pressure drop
Solution Approach 1:
The patent segments the flow control function into two independent valves: the first valve (recirculation valve) controls the recirculation flow path, and the second valve (dispensing valve) controls the dispensing flow path. This segmentation allows independent control of recirculation and dispensing flows, decoupling the dispensing flow rate from filter pressure drop dependencies and enabling precise volumetric control.
Solution Approach 2:
The recirculation valve acts as an intermediary that regulates the recirculation flow to maintain stable pressure conditions in the purification loop. By controlling the recirculation rate, the system stabilizes the pressure environment, which in turn enables the dispensing valve to achieve precise flow control independent of filter pressure variations.
3Productivity
If the system is designed for high throughput purification, then maximum treatment capacity is achieved, but accurate dispensing across a wide range of flow rates from drop-by-drop to full rate becomes difficult
Solution Approach 1:
The patent implements dynamic flow control through electronically controllable solenoid valves that can adjust their opening degree in real-time. The recirculation valve and dispensing valve can dynamically redistribute the purified water flow between recirculation and dispensing paths, allowing the system to adapt from high throughput recirculation mode to precise low-rate dispensing mode while maintaining the same pump and purification infrastructure.
Solution Approach 2:
The purification system is designed with multi-functionality: the same pump and purification means serve both high-volume recirculation for water treatment and precise low-volume dispensing for applications. The valve system enables a single infrastructure to perform multiple functions across a wide range of flow rates, from drop-by-drop dispensing to full throughput operation.
4Extent of automation
If automated volumetric dispensing is implemented, then predetermined volumes can be dispensed automatically, but the system complexity increases with additional control mechanisms
Solution Approach 1:
The patent incorporates flow sensors and control logic that monitor the actual dispensing volume and provide feedback to the valve control system. The microcontroller adjusts the opening degree and duration of the dispensing valve based on feedback from flow measurements, enabling automated volumetric dispensing with compensation for variations in flow conditions, achieving high accuracy despite the added control complexity.
Data Source
AI summary
The invention provides a water purification and dispensing system, preferably for producing ultrapure water and offering the purified water at one or more dispensing sites in a desired volume. The water purification and dispensing system comprises a (closed) water recirculation loop including a water inlet for introducing water to be purified, pumping means for pumping water through said water recirculation loop in a flow direction, water purification means for purifying water downstream of said water inlet, a dispensing portion of the water recirculation loop including one or more outlet(s) for purified water branched from said water recirculation loop downstream of said water purification means, a first valve arranged between each outlet and said water recirculation loop, for controlled dispensing of the purified water from said recirculation loop through the respective outlet, a second valve arranged in said dispensing portion of the water recirculation loop downstream of said first valve(s) and upstream of said pumping means, a bypass passage branched from said water recirculation loop and bypassing said dispensing portion of the water recirculation loop including said first valve(s) and said second valve, and a third valve for controlling the flow rate through said bypass passage.