RO Water Recirculation Control for Stable Purified Water Flow

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Solution Overview

Problem

Existing water purification systems face challenges in maintaining a consistent product water flow rate and pressure due to hardware deterioration over time, which can lead to uncertain throughput and potential risks such as bacterial contamination.

Innovation Solution

A water purification apparatus with a recirculation path and control mechanisms to regulate flow rate and pressure using sensors and a control unit, incorporating a reverse osmosis device, heater, and polisher to maintain stable fluid properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a water purification apparatus operates for an extended period, then it can continuously produce purified water, but hardware deterioration occurs leading to inconsistent flow rate and pressure

Engineering Contradiction:
Improvecontinuous operation timeVSAvoidflow rate consistency
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The control unit continuously monitors the actual flow rate using a flow sensor and compares it to the target flow rate. Based on this feedback, the control unit automatically adjusts the recirculation pump speed to maintain consistent flow rate and pressure throughout operation, resolving the reliability issue during continuous operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the recirculation pump operating parameters based on real-time flow rate measurements. The pump speed is continuously modified to compensate for hardware deterioration, ensuring that flow rate and pressure remain within target ranges even after extended operation periods.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the product water flow rate is increased to meet treatment demands, then productivity improves, but the risk of bacterial contamination and hardware damage increases

Engineering Contradiction:
Improvepurified water production rateVSAvoidbacterial contamination risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The flow sensor provides continuous feedback on the actual product water flow rate to the control unit. This enables the system to maintain the flow rate within a safe target range that satisfies treatment productivity requirements while preventing excessively high flow rates that could compromise system integrity and increase contamination risk.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system optimizes operating parameters including flow rate, pressure, and recirculation ratio to achieve the highest safe productivity. By dynamically adjusting these parameters within safe operational boundaries, the system maximizes purified water production while maintaining safety margins against contamination and hardware damage.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the product water flow rate is increased to overcome pressure drop from downstream filters, then throughput improves, but hardware stress increases leading to potential damage

Engineering Contradiction:
Improvewater throughputVSAvoidhardware durability
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The system uses pressure sensors to continuously monitor actual pressure levels in the water path. The control unit compares measured pressure against target pressure values and adjusts the recirculation pump and product water flow rate accordingly, ensuring throughput requirements are met while preventing pressure levels that could damage downstream filters or other hardware components.

Inventive Principle:
Principle #23Feedback

4Reliability

If a recirculation path is added to control flow rate and pressure, then flow consistency improves, but device complexity increases

Engineering Contradiction:
Improveflow rate stabilityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The recirculation pump serves multiple functions: it controls product water flow rate, maintains pressure, and enables feedback-based regulation. This multi-functionality justifies the added component by providing several control capabilities within a single system element rather than requiring separate mechanisms for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control unit automatically adjusts recirculation pump parameters based on real-time measurements from flow and pressure sensors. The system self-regulates to maintain target flow rate and pressure without requiring manual intervention, making the additional complexity manageable through automated control that compensates for the added components.

Inventive Principle:
Principle #25Self-service

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

Ensures a consistent and controlled product water flow rate and pressure, reducing the risk of hardware damage and bacterial contamination, thereby ensuring reliable and safe water production for dialysis treatments.

Implementation Method 1

a reverse osmosis device configured to produce purified water

Methodology Applied
Scientific EffectReverse osmosis: Reverse Osmosis

Implementation Method 2

a heater positioned in the permeate water path to heat purified water flowing in the purified water path

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a recirculation path configured to recirculate a proportion of the purified water from a first point downstream from the reverse osmosis device to a second point upstream of the reverse osmosis device

Methodology Applied
Scientific EffectFluid recirculation:

Data Source

PatentEP4219408B1A water purification apparatus
Publication Date: 2026.02.25 VANTIVE US HEALTHCARE LLC
  • EP4219408B1 patent drawingFigure 1
  • EP4219408B1 patent drawingFigure 2~3
  • EP4219408B1 patent drawingFigure 4a~4b

AI summary

The present disclosure relates to a water purification apparatus that comprises a reverse osmosis device, RO-device, producing a purified water flow and to a corresponding method. The proposed method comprises detecting at least one fluid property of purified water in the purified water path and regulating a flow rate of water in the recirculation path to fulfil one or more predetermined criteria of the purified water in the purified water path, based on the at least one detected fluid property. The present disclosure also relates to a computer program and a computer program product implementing the method.