Plate Heat Exchanger Leak Testing via Pressure Differential
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Solution Overview
Problem
Existing methods for leak testing assembled plate heat exchangers are inadequate in detecting small faults like fatigue cracks or corrosion pinholes, leading to unnecessary disassembly and waste, as they fail to accurately identify small cross-flows between fluid paths.
Innovation Solution
A method and apparatus that create a pressure differential between fluid paths by evacuating one path to a low pressure and introducing a test gas into the other, allowing for the detection of leaks without disassembly, using a test gas and optional tracer gas to identify leaks in the heat exchanging portions of the exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional leak testing methods are used on assembled plate heat exchangers, then the testing can be performed without disassembly, but small faults such as fatigue cracks or corrosion pinholes cannot be reliably detected
Solution Approach 1:
The invention changes the physical parameters of the testing environment by evacuating one fluid path to create a vacuum condition and introducing a test gas to the other path at elevated pressure. This creates a significant pressure differential that forces even small amounts of leaking gas through faults, making them detectable. The parameter change from atmospheric pressure to vacuum/pressurized conditions enables reliable detection of small faults that would be invisible under normal operating conditions.
Solution Approach 2:
The invention introduces a test gas as an intermediary substance to facilitate leak detection. This test gas, when pressurized in one path, acts as a mediator that reveals leaks by migrating through faults into the vacuum path where it can be detected. The intermediary test gas makes invisible small faults visible without requiring disassembly of the heat exchanger.
2Reliability
If the heat exchanger is disassembled to find and repair faults, then small faults can be located and repaired, but time is lost and food product is wasted
Solution Approach 1:
The invention performs preliminary leak detection on the assembled heat exchanger before disassembly is required. By using the vacuum and pressurized test gas method, all faults are identified and their locations are determined while the heat exchanger remains assembled. This preliminary action prevents unnecessary disassembly and enables targeted repair only when and where needed, saving time and preventing food product waste.
Solution Approach 2:
The invention provides feedback about the location and presence of leaks through detection of test gas in the vacuum path. This feedback mechanism allows operators to identify exactly where faults exist without disassembling the heat exchanger, enabling informed decisions about whether disassembly and repair are actually necessary or if the unit can continue operation.
3Reliability
If the heat exchanger is disassembled to repair faults, then leaks can be fixed, but assembly/disassembly is time consuming
Solution Approach 1:
The invention performs preliminary fault identification and location while the heat exchanger is assembled. By detecting test gas migration through leaks in the vacuum path, the exact locations of faults are identified before any disassembly occurs. This preliminary action eliminates unnecessary disassembly for units without leaks and enables rapid, targeted repair only when needed, significantly improving maintenance productivity.
4Ease of operation
If conventional leak testing is used, then the testing process is simple, but small cross-flows between fluid paths cannot be detected
Solution Approach 1:
The invention maintains ease of operation by using a straightforward process of evacuating one path and pressurizing the other with test gas. The parameter change to vacuum conditions dramatically increases the sensitivity of leak detection, as even tiny leaks become visible when gas is forced through faults by the pressure differential. The method remains operationally simple while achieving high detection sensitivity.
Solution Approach 2:
The invention replaces complex disassembly-based mechanical inspection methods with a pneumatic field-based detection system. By using vacuum and pressurized test gas, the system substitutes mechanical disassembly and visual inspection with a field-based method that detects leaks remotely through gas migration, maintaining simplicity while dramatically improving detection capability.
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 the reliable detection of small faults such as hairline cracks or pinholes in assembled heat exchangers, reducing unnecessary disassembly and improving the efficiency of leak testing by allowing for in-situ identification of leak locations.
Implementation Method 1
a vacuum pump for evacuating said first and second fluid paths
Implementation Method 2
introducing a test gas to said first fluid path so that a pressure differential is created between said first fluid path and said second fluid path
Implementation Method 3
a leak detector for detecting the presence of test gas in said second fluid path
Data Source
AI summary
A method for detecting the presence of a leak between two fluid paths of an assembled plate heat exchanger by evacuating one or both fluid paths to a low pressure, introducing a test gas to one of the fluid paths to create a pressure differential between the fluid paths, and testing for the presence of test gas in the second fluid path.