RO Membrane Pressure Control for Stable Ultrapure Water Supply
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Solution Overview
Problem
Existing methods for controlling reverse osmosis membrane devices in ultrapure water production systems face issues such as decreased permeate water amount due to fouling and membrane damage from frequent starting and stopping, leading to water quality deterioration and increased cleaning frequency.
Innovation Solution
A method involving a flow adjustment mechanism and pressure control to stabilize water supply pressure, allowing the reverse osmosis membrane to operate continuously by adjusting water supply based on demand, reducing the need for stopping and minimizing membrane degradation and cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the reverse osmosis membrane device is frequently started and stopped to match water usage demand, then water supply can be matched to demand, but membrane damage occurs and water quality deteriorates
Solution Approach 1:
The reverse osmosis membrane device operates continuously without frequent starting and stopping. The water supply mechanism adjusts its output to match demand while the membrane remains in operation, preventing membrane damage and water quality deterioration associated with frequent start-stop cycles
Solution Approach 2:
The water supply mechanism's output parameters (flow rate, pressure) are dynamically adjusted to match water usage demand. This allows the system to adapt to varying demand while maintaining continuous operation of the membrane device, resolving the contradiction between adaptability and reliability
2Ease of operation
If the reverse osmosis membrane device operates at constant flow rate and pressure, then operation is simple, but it cannot respond to fluctuations in water usage demand
Solution Approach 1:
The water supply mechanism transitions from constant operation to dynamic operation, continuously adjusting its output parameters (flow rate, pressure) in response to water usage demand. This allows the system to maintain ease of operation while gaining adaptability to fluctuating demands
Solution Approach 2:
The system incorporates feedback from water usage demand to dynamically adjust the water supply mechanism's output. This feedback loop enables the membrane device to respond to demand fluctuations while maintaining simple operational control through automated adjustment
3Productivity
If the water supply pressure varies with demand, then water supply matches demand, but membrane performance deteriorates due to pressure fluctuations
Solution Approach 1:
The water supply mechanism dynamically adjusts its output parameters (flow rate, pressure) to match water usage demand. By controlling both parameters simultaneously, the system maintains productivity while ensuring the membrane operates under stable conditions that preserve its performance
Solution Approach 2:
The system transitions from static to dynamic operation where the water supply mechanism continuously adapts its parameters. This dynamic adjustment allows the membrane to operate continuously at optimal conditions while the supply amount varies to meet demand, resolving the contradiction between productivity and reliability
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
Stable water delivery is achieved with reduced membrane degradation and cleaning frequency, ensuring consistent water quality by maintaining constant pressure through demand-based operation.
Implementation Method 1
a reverse osmosis membrane device 33
Data Source
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Figure 5~6
AI summary
A method for controlling a reverse osmosis membrane device in a pure water production device according to the present invention includes reducing the opening degree of a control valve 62 to reduce the amount of primary pure water W2 being supplied to a sub-tank 41 if the amount of ultrapure water being used at a use point decreases and a measured value for a water level obtained by a water level meter 63 increases. In such an instance, on the basis of a measured value obtained by a pressure meter 61, a control means reduces the output of a high pressure pump 32A so that the measured value obtained by the pressure meter 61 remains substantially constant at a predetermined pressure. However, if the amount of ultrapure water being used at the use point increases and the measured value for the water level of the sub-tank 41 decreases, then the opening degree of the control valve 62 is increased to raise the amount of water being supplied to the sub-tank 41. In such an instance, on the basis of the measured value obtained by the pressure meter 61, the control means increases the output of the high pressure pump 32A so that the measured value obtained by the pressure meter 61 remains substantially constant at the predetermined pressure. Adopting such a configuration yields a feature in which water is stably fed even if the flow rate changes in a manner that follows the amount of water being used or another such parameter.