Immersion Filter Probe Clogging Detection

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Solution Overview

Problem

In process water analyzer arrangements, determining the clogging condition of an immersion filter probe without a pressure sensor is challenging, as it affects pumping performance, and existing methods rely on transmembrane pressure or flow rate measurements.

Innovation Solution

A method using a bidirectional peristaltic hose sample pump with a flow sensor and an electronic filter clogging condition determination module, which controls the pump to measure motor rotations for defined filtration and non-filtration volumes, allowing for clogging condition assessment without direct pressure measurement, utilizing the difference in motor rotations to indicate filter membrane resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transmembrane pressure measurement is used to determine filter clogging condition, then measurement precision is improved, but device complexity increases due to requiring pressure sensors

Engineering Contradiction:
Improvefilter clogging condition detectionVSAvoidpressure sensor requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/physical pressure sensor measurement system with an electrical motor rotation counting system. The motor rotations required to pump a defined volume are measured and used to infer filter clogging condition, eliminating the need for direct pressure sensing while maintaining measurement capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces motor rotations as an intermediary parameter to indirectly measure transmembrane pressure. Instead of measuring pressure directly, the system measures the motor rotations required to pump a known volume through the filter, which correlates to the pressure differential across the membrane.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If flow rate measurement is used to detect membrane clogging, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvemembrane clogging detectionVSAvoidflow rate measurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the flow measurement function with the existing pumping system by using the motor rotation counter already required for dosing control. The same motor rotation data serves dual purposes: controlling the pump dosing and detecting filter clogging, eliminating the need for separate flow measurement instrumentation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor rotation measurement system serves multiple functions: it controls the peristaltic pump dosing operation and simultaneously detects both filter membrane clogging and pump hose wear conditions. This multi-functionality reduces overall system complexity while maintaining detection precision.

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

3Reliability

If peristaltic pump is used for robustness against clogging, then reliability is improved, but pumping performance decreases due to hose friction and resistance

Engineering Contradiction:
Improveclogging resistanceVSAvoidpumping efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent performs preliminary assessment of pump hose condition by measuring motor rotations for non-filtration pumping. This allows detection of hose wear and friction issues before they significantly impact filtration performance, enabling preventive maintenance to restore optimal pumping efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring motor rotation counts and comparing them against reference values. When deviations indicate hose wear or filter clogging, the system can trigger alerts or adjustments to maintain optimal pumping performance and reliability balance.

Inventive Principle:
Principle #23Feedback

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

Enables accurate determination of filter clogging conditions, differentiating between hose condition and membrane clogging, and provides a hose condition value for wear detection, improving pumping efficiency and reducing maintenance needs.

Implementation Method 1

a peristaltic pump rotor (44) for providing a peristaltic deformation of the deformable flexible pump hose (42)

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Implementation Method 2

The flow sensor precisely detects and determines a total flow volume in the range of several milliliters and with an accuracy of preferably at least 0.1 ml

Methodology Applied
Scientific EffectFlow detection:

Implementation Method 3

the sample filter membrane is distally not perfectly mechanically supported and is bulged with a membrane distal bulging volume when water is pumped in backward direction

Methodology Applied
Scientific EffectMembrane elasticity: Elasticity

Data Source

PatentEP4180792B1A method for determining a sample filter clogging condition value
Publication Date: 2024.06.12 HACH LANGE HACH LANGE
  • EP4180792B1 patent drawingFigure 1
  • EP4180792B1 patent drawingFigure 2

AI summary

The invention is directed to a method for determining a sample filter clogging condition value (C) of an immersion filter probe (20) of a process water analyzer arrangement (10), with the method steps provided by a filter clogging condition determination module (60): driving the sample pump (40) for pumping a defined filtration volume (FV) flowing through the filter membrane (24) and detected by the water flow sensor unit (50), memorizing the filtration motor rotations value (FR) generated by the motor speed control (61) for pumping the defined filtration volume (FV), driving the sample pump (40) for pumping a defined non-filtration volume (NV) detected by the water flow sensor unit (50), wherein the non-filtration volume (NV) is smaller than the membrane distal bulging volume (MV), memorizing the motor rotations value (NR) generated by the motor speed control (61) for pumping the defined non-filtration volume (DV), and determining the sample filter clogging condition value (C) with the filtration motor rotations value (FR) and the non-filtration motor rotations value (NR).