RO Water Purification Recirculation for Stored TDS Control

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Solution Overview

Problem

Conventional RO water purification devices suffer from increased total dissolved solid (TDS) concentration in stored drinking water due to pressure changes and time, leading to higher TDS levels in the RO filter and post-filter, which existing technologies fail to address effectively, causing user inconvenience and poor water quality.

Innovation Solution

A water purification apparatus with a recirculating mechanism that uses a water quality detector, control valve, and controller to recirculate and re-purify drinking water in the post-filter when TDS levels exceed a set standard, ensuring cleaner water output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If drinking water is stored in the post-filter for later use, then water availability is improved, but the TDS concentration increases over time due to pressure changes and storage duration

Engineering Contradiction:
Improvewater storage durationVSAvoidTDS concentration
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The system implements periodic recirculation of stored water through the RO membrane at predetermined intervals (e.g., every 24 hours) or when TDS threshold is exceeded. This periodic flushing action removes accumulated dissolved solids from the stored water without requiring continuous circulation, thereby maintaining water quality over extended storage periods while minimizing energy consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The water quality detector continuously monitors TDS concentration in the post-filter and provides feedback to the controller. When the detected TDS level exceeds the predetermined threshold, the controller automatically activates the recirculation pump to flush the stored water through the RO membrane, thereby dynamically maintaining water quality based on actual conditions rather than fixed timing.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If manual cleaning of the RO membrane is implemented, then TDS concentration control is improved, but user convenience deteriorates due to required manual operation and waiting time

Engineering Contradiction:
ImproveTDS concentrationVSAvoiduser convenience
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system automatically performs recirculation cleaning of the stored water without requiring user intervention. The controller autonomously activates the recirculation pump based on either predetermined time intervals or real-time TDS monitoring, and the recirculated water automatically flows through the RO membrane and post-filter to remove dissolved solids. Users simply access clean water whenever needed without manual cleaning operations or waiting periods.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The automated feedback mechanism detects when TDS concentration exceeds acceptable levels and automatically triggers the recirculation cleaning process, eliminating the need for users to manually initiate cleaning operations. The system self-regulates water quality maintenance based on actual conditions.

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If existing cleaning technologies are used, then some pipeline cleaning is achieved, but the post-filter water quality is not effectively improved

Engineering Contradiction:
Improvecleaning capabilityVSAvoidpost-filter TDS concentration
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The system extracts and addresses the specific problem of post-filter water quality by implementing a dedicated recirculation pathway that specifically targets the post-filter chamber. Unlike conventional cleaning that focuses on the RO membrane, this system routes recirculated water specifically through the post-filter to remove dissolved solids that accumulate in the stored water, thereby directly addressing the root cause of deteriorating water quality in the dispensing chamber.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The water purification system is segmented into distinct functional zones: the RO filtration zone, the post-filter storage zone, and the recirculation cleaning zone. The recirculation system specifically targets the post-filter storage zone for periodic flushing, separating the cleaning function from the primary filtration function. This segmentation allows independent optimization of water quality maintenance in the storage chamber without affecting the RO membrane operation.

Inventive Principle:
Principle #1Segmentation

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 apparatus intelligently maintains water quality by recirculating and re-purifying water when necessary, reducing waste and enhancing user experience by providing consistently clean drinking water.

Implementation Method 1

The RO filter (30) has an inlet (31) and an outlet (32). The inlet (31) is in fluid communication with the outlet (22) of the pump (20)... The post-filter (51) receives and then filters the water purified by the RO filter (30)

Methodology Applied
Scientific EffectReverse osmosis: Reverse Osmosis

Implementation Method 2

The pump (20) has an inlet (21) and an outlet (22)... The inlet (21) is in fluid communication with the pre-filter (11)... The outlet (22) of the pump (20) is in fluid communication with the inlet (31) of the RO filter (30)

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Data Source

PatentEP4596502A1Water purification apparatus
Publication Date: 2025.08.06 LAN SHAN ENTERPRISE
  • EP4596502A1 patent drawingFigure 1
  • EP4596502A1 patent drawingFigure 2
  • EP4596502A1 patent drawingFigure 3

AI summary

A water purification apparatus (1) receives raw water, which sequentially passes through a pre-filter (11), a pump (20), an RO filter (30), and a post-filter (51) and is stored in the post-filter (51) as drinking water. A recirculating water loop (60) is in fluid communication with the post-filter (51) and the pump (20) to facilitate flow of the drinking water. A water quality detector (61) generates a water quality signal corresponding to a quality value of the drinking water. A control valve (62) is in fluid communication with the recirculating water loop (60). A controller (70) receives the water quality signal and is stored with a water quality standard and a recirculation period. When a water discharging member (53) stops discharge of the drinking water and the quality value exceeds the water quality standard, the controller (70) activates the pump (20) and the control valve (62), such that the drinking water in the post-filter (51) recirculates through the recirculating water loop (60) and is re-purified.