Plate Fin Heat Exchanger Contingent Layer Leak Detection

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Solution Overview

Problem

Plate fin heat exchangers face challenges in predicting and detecting fluid leaks, especially in the cap sheets or outermost active layers, which can lead to operational issues and require timely repair or replacement.

Innovation Solution

Incorporating a contingent layer body with a sealed fluid space pressurized with inert gas and a pressure monitoring system that detects pressure changes, coupled with an emergency pressure relief device to vent excess pressure and signal operators of leaks, thereby preventing damage and facilitating timely maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a contingent layer body with sealed fluid space is added to detect leaks, then leak detection capability is improved, but device complexity increases

Engineering Contradiction:
Improveleak detection capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The contingent layer body is pre-filled with inert gas at a controlled pressure before the heat exchanger begins operation. This preliminary action establishes a baseline pressure state that enables subsequent leak detection through pressure monitoring, allowing the system to detect cap sheet or parting sheet failures without requiring complex external testing equipment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inert gas within the sealed contingent layer body serves as an intermediary medium for leak detection. Instead of directly monitoring the process fluid for leaks, the system uses the inert gas pressure as an indirect indicator - if the process fluid leaks into the contingent layer, it displaces the inert gas and changes the pressure, signaling a leak condition without contaminating the process fluid or requiring direct contact with hazardous materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If pressure monitoring system and emergency relief device are installed, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure monitoring system continuously monitors the pressure within the contingent layer body and provides feedback to the control system. When pressure deviations exceed predetermined thresholds, the system triggers an alarm or shutdown signal, enabling operators to detect and respond to leaks promptly. This feedback mechanism transforms the passive contingent layer into an active safety monitoring system.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The emergency pressure relief device is pre-configured to automatically activate when pressure within the contingent layer body exceeds safe thresholds. This beforehand cushioning prevents catastrophic failures by providing a predetermined pressure release path, protecting the heat exchanger from over-pressurization damage without requiring complex real-time decision-making systems.

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

3Measurement precision

If inert gas is used to pressurize the fluid space, then leak detection precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveleak detection precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The contingent layer body is filled with inert gas (such as nitrogen or air) at a controlled pressure during the manufacturing process. The inert atmosphere prevents chemical reactions with the process fluid, maintains stable pressure conditions for accurate leak detection, and allows the system to operate safely with flammable or reactive process fluids. The inert gas creates a controlled environment that enhances measurement precision while requiring only standard manufacturing procedures.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 solution effectively detects leaks in the cap sheets and parting sheets, allowing for proactive maintenance and extending the operational life of the heat exchanger by alerting operators to pressure deviations and providing a mechanism for pressure relief.

Implementation Method 1

A contingent layer body is positioned adjacent to the outermost active layer and includes a fin plate positioned between a parting sheet and a cap sheet. The contingent layer body has a fluid space that is sealed with respect to the atmosphere and that contains an inert gas at a predetermined pressure that is above or below atmospheric pressure.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

A pressure monitoring system is in communication with the fluid space of the contingent layer body

Methodology Applied
Scientific EffectPressure sensing:

Implementation Method 3

An emergency pressure relief device is configured to release a pressure within the fluid space if a preset pressure is exceeded

Methodology Applied
Scientific EffectPressure relief: Depressurisation

Data Source

PatentEP3704431B1Plate fin fluid processing device, system and method
Publication Date: 2022.08.10 CHART ENERGY & CHEMICALS INC
  • EP3704431B1 patent drawingFigure 1~2
  • EP3704431B1 patent drawingFigure 3
  • EP3704431B1 patent drawingFigure 4

AI summary

A plate fin fluid processing device includes active layers, where each active layer includes a fin plate sandwiched between parting sheets so that an active fluid space is defined between the parting sheets. The active layers include an outermost active layer having an inlet and an outlet. A contingent layer body is positioned adjacent to the outermost active layer and includes a fin plate positioned between a parting sheet and a cap sheet. The contingent layer body has a fluid space that is sealed with respect to the atmosphere. A pressure monitoring system is in communication with the fluid space of the contingent layer body. An emergency pressure relief device is configured to release a pressure within the fluid space if a preset pressure is exceeded.