Embedded Optical Waveguide in Plate Heat Exchanger Separating Plates

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Plate heat exchangers face mechanical damage and leakage due to thermal stresses from differential temperature expansions, and external temperature measurements are influenced by environmental factors, limiting precision and reliability.

Innovation Solution

Integrating an optical waveguide within the separating plates of the plate heat exchanger allows for precise temperature and strain measurements directly inside the exchanger, reducing the risk of damage and environmental interference, while maintaining a minimal installation footprint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature measurement is performed on the outer skin of the plate heat exchanger, then temperature data can be obtained, but the measurement is influenced by environmental factors and only provides local values that require assumptions to infer internal temperatures

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidenvironmental influence on measurement
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The optical fiber is embedded within the separating plate structure itself, nesting the measurement device inside the heat exchanger components. This allows the fiber to be positioned directly in the thermal field of interest while being protected by the plate structure, eliminating environmental influences on the measurement

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The optical fiber acts as an intermediary element that can sense temperature internally without being exposed to external environmental factors. The fiber transmits measurement data from the protected internal location to external monitoring systems, solving the contradiction between internal measurement accuracy and environmental protection

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the optical fiber is positioned in an open groove in a fin or separating plate, then temperature measurement is possible, but the optical fiber is vulnerable to mechanical damage

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidoptical fiber damage risk
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The optical fiber is nested within the separating plate structure rather than positioned in open grooves. The fiber is embedded in the material itself or in protected channels within the plate, using the plate structure as a protective enclosure that prevents mechanical damage while maintaining measurement capability

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The optical fiber is surrounded by and integrated with the separating plate material that serves as a protective cushion against mechanical stresses and thermal expansion forces. This pre-established protection prevents damage before it can occur during operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If additional space is provided for temperature measurement devices, then measurement capability is improved, but the compact structure of the plate heat exchanger is compromised

Engineering Contradiction:
Improvetemperature distribution measurementVSAvoidadditional space requirement
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The measurement function is merged with the separating plate structure itself. The optical fiber becomes an integral part of the plate rather than an separate component requiring additional space, combining the structural and measurement functions in a single integrated element

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The measurement capability is added in the dimensional space already occupied by the separating plate thickness, rather than requiring additional external volume. The fiber is positioned within the existing plate geometry, utilizing the available cross-sectional area without increasing the overall heat exchanger footprint

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This solution enhances the safety and reliability of the plate heat exchanger by providing high-resolution temperature and strain measurements, reducing the risk of mechanical damage and leaks, and isolating measurements from environmental influences.

Implementation Method 1

an optical fiber (35), in particular a fiber optic sensor cable, is integrated into the at least one separating plate (6)

Methodology Applied
Scientific EffectOptical fiber sensing: Optical Fibre

Implementation Method 2

The separating plates separate adjacent heat transfer passages in such a way that material transfer between the heat transfer passages is prevented, but heat transfer is enabled

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

Thermal stresses resulting from varying thermal expansions caused by differential temperature differences

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3784974B2Plate heat exchanger, process engineering system and method
Publication Date: 2025.01.15 LINDE AG
  • EP3784974B2 patent drawingFigure 1
  • EP3784974B2 patent drawingFigure 2
  • EP3784974B2 patent drawingFigure 3

AI summary

The invention relates to a plate heat exchanger (1) for a process engineering system (2), having a plurality of lamellae (3, 4) and a plurality of separating plates (5-7), which are arranged alternately, wherein at least one separating plate (6) has an optical waveguide (35) that is embedded in the at least one separating plate (6) in such a way that the optical waveguide (35) is covered on both sides by material of the at least one separating plate (6) in a first direction (R1) and in a second direction (R2), which are each oriented perpendicular to a plane (E) defined by the at least one separating plate (6) and in opposite senses with respect to one another.