Sanitary Pipe Flushing Control Using Dual Temperature Sensing

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Solution Overview

Problem

Existing hygienic flushing systems are unreliable in determining complete water exchange in pipes due to temperature fluctuations, leading to unnecessary water waste and inefficiency.

Innovation Solution

A hygienic flushing system using two temperature sensors to measure temperature differences within a water pipe, closing the flushing valve when a threshold temperature difference is reached, ensuring complete water exchange without excessive water usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If flushing continues until a substantially constant water temperature is measured, then the flushing process is automated, but the criterion of constant temperature is highly unreliable for determining complete water exchange due to temperature fluctuations in fresh water

Engineering Contradiction:
Improveautomatic flushing controlVSAvoidreliability of flushing completion determination
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent changes the control parameter from absolute temperature (constant temperature criterion) to temperature difference (ΔT between inlet and outlet). This parameter transformation resolves the reliability issue by eliminating the influence of fresh water temperature fluctuations, as the difference remains stable and indicative of complete water exchange regardless of the actual temperature values

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the unreliable mechanical/thermal sensing approach (monitoring absolute temperature) with a differential measurement system that compares temperatures at two points. This substitution creates a more robust control mechanism that is insensitive to environmental temperature variations and fresh water source fluctuations

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

2Reliability

If flushing is run for a longer time as a precaution, then complete water exchange is ensured, but unnecessary water loss occurs

Engineering Contradiction:
Improveensurance of complete water exchangeVSAvoidwater loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a feedback control system using temperature sensors at the inlet and outlet of the pipe. The control unit continuously monitors the temperature difference and automatically stops flushing when the predetermined threshold is reached, providing real-time feedback that eliminates the need for precautionary over-flushing and optimizes water consumption

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses the thermal properties of the water itself as the sensing mechanism. The temperature difference between inlet and outlet water naturally indicates the flushing progress, eliminating the need for external measurement devices or human intervention to determine when flushing is complete

Inventive Principle:
Principle #25Self-service

3Measurement precision

If expensive sensors such as flow sensors are used, then precise water exchange detection is achieved, but the system cost increases

Engineering Contradiction:
Improveprecision of water exchange detectionVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, complex flow sensors with inexpensive temperature sensors. Temperature sensing is a mature, low-cost technology that provides sufficient precision for detecting water exchange completion, significantly reducing system cost while maintaining measurement accuracy

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the measured parameter from flow rate (requiring expensive flow sensors) to temperature (measurable with cheap temperature sensors). This parameter transformation achieves the same functional goal of detecting water exchange completion using much less expensive components

Inventive Principle:
Principle #35Parameter changes

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

Provides a reliable and cost-effective method for determining complete water exchange, reducing water waste by optimizing flushing volume based on temperature measurements.

Implementation Method 1

a first temperature sensor (6) for measuring a first water temperature T1, and a second temperature sensor (7) for measuring a second water temperature T2

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4256142B1Sanitary flushing system and method of flushing a pipe of the sanitary flushing system
Publication Date: 2026.01.07 GEBERIT INT AG
  • EP4256142B1 patent drawingFigure 1
  • EP4256142B1 patent drawingFigure 2
  • EP4256142B1 patent drawing

AI summary

The invention relates to a sanitary flushing system comprising a water line (1) in which water is guided in a flow direction (F), a flushing fitting (4) which can be actuated to flush the water line (1), a control unit (5) for actuating the flushing fitting (4), a first temperature sensor (6) for measuring a first water temperature (T1), and a second temperature sensor (7) for measuring a second water temperature (T2), wherein the measurement values of the measured temperatures can be transmitted from the temperature sensors (6, 7) to the control unit (5), wherein, during a flushing process during which the flushing fitting is open such that the water line (1) is flushed, a temperature difference (dT) between the first water temperature (T1) and the second water temperature (T2) can be determined by the control unit (5), and wherein the flushing fitting (4) is closed when the temperature difference (dT) reaches a threshold value (dTS).