Double Wall Plate Heat Exchanger Sensor Probe Leakage Detection

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Solution Overview

Problem

In plate heat exchangers with double wall plates, it is difficult to detect which plate is leaking, and the time to detect leakage can be excessively long due to the thin space between the plates, making it challenging to identify the source of the leak.

Innovation Solution

Incorporating a sensor probe between the adjoining plates, which senses parameters such as capacitance, impedance, or temperature, using an insulated electrically conducting material to detect changes in dielectric properties caused by moisture, allowing for immediate detection of leaks and identification of the affected plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If double wall plates are used to prevent media mixing, then leakage protection is improved, but leakage detection difficulty increases

Engineering Contradiction:
Improveleakage protectionVSAvoidleakage detection difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

An insulated sensor probe is introduced as an intermediary element between the adjoining plates. The sensor probe detects leakage by sensing changes in dielectric properties (capacitance, impedance, or temperature) when moisture enters the space between the plates, thereby solving the detection difficulty while maintaining the leakage protection of double wall plates.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical detection methods (relying on fluid accumulation visible on the floor) with an electrical sensing system. The sensor probe measures electrical parameters (capacitance, impedance, temperature) to detect leakage, substituting mechanical observation with electrical measurement for faster and more reliable detection.

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

2Reliability

If the space between adjoining plates is made thin, then media mixing prevention is improved, but leakage detection time increases

Engineering Contradiction:
Improvemedia mixing preventionVSAvoidleakage detection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The sensor probe is pre-installed between the plates before they are compressed together. This preliminary placement ensures that the sensor is ready to detect leakage immediately when it occurs, eliminating the time delay associated with post-leakage detection methods. The sensor starts monitoring from the moment the plates are assembled.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces delayed mechanical detection (waiting for fluid to accumulate and become visible) with immediate electrical sensing. The sensor probe continuously monitors dielectric properties, providing real-time detection of leakage as soon as moisture enters the thin space between plates, thereby reducing detection time while maintaining the thin space design for media mixing prevention.

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

3Device complexity

If no sensor is installed, then device complexity is reduced, but leakage location identification is lost

Engineering Contradiction:
Improvedevice complexityVSAvoidleakage location information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The plate heat exchanger is segmented into multiple independently monitorable sections, with each section containing its own sensor probe. This segmentation allows the system to identify which specific plate or section is leaking, providing location information without requiring a single complex centralized detection system. Each sensor is a simple, identical unit that monitors its local environment.

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

Enables immediate detection of leaks in individual heat exchanger plates, reducing the time to identify the source of leakage and providing precise location information, even in large systems, with a thin insulated metallic wire demonstrating good response to small fluid amounts.

Implementation Method 1

the sensor probe is configured to sense at least one parameter between the electrically conducting material of the sensor probe and the adjoining plates. The parameter comprises one of the capacitance, the impedance, the electrical resistance and the temperature.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

using an insulated electrically conducting material to detect changes in dielectric properties caused by moisture

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

The parameter comprises one of the capacitance, the impedance, the electrical resistance and the temperature.

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 4

the sensor probe is made of an electrically conducting material in the shape of wire, a strip or a foil

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2630432B1A heat exchanger plate and a plate heat exchanger
Publication Date: 2019.06.26 ALFA LAVAL CORP AB
  • EP2630432B1 patent drawingFigure 1~2
  • EP2630432B1 patent drawingFigure 3~4
  • EP2630432B1 patent drawingFigure 5~7

AI summary

The invention refers to a plate heat exchanger and a heat exchanger plate (1). The heat exchanger plate for a plate comprises a heat transfer area (10) and an edge area (11), extending around the heat transfer area. The heat exchanger plate is a double wall plate formed by two adjoining plates compressed to be in contact with each other. The heat exchanger plate comprises a sensor (20) which is configured to sense at least one parameter and to produce a signal depending on the parameter and that the sensor comprises a sensor probe (21) that is provided between the adjoining plates.