Leak testing of shell and tube heat exchangers
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Dear sea friends: There are various methods for testing the leakiness of shell-and-tube heat exchangers, such as ammonia testing and helium testing. Which of these methods has more advantages – ammonia testing or helium testing?
Could you explain in detail how to perform an ammonia leak test?
Ammonia has strong permeability and an irritating odor
To increase air pressure, can’t compressed air be used? I don’t understand. If the compressed air doesn’t leak, conduct a hydraulic pressure test for leakage detection.
Ammonia and helium are mainly used for leak detection; compressed air cannot be used
Ammonia leaks are detected using phenolphthalein, while helium leaks are detected with instruments; helium leak detection is the most stringent method for detecting leaks
Helium leak testing can only determine whether a heat exchanger is leaking or not; it requires simple preparation and takes little time. However, if a leak occurs, helium testing cannot identify the location of the leak ； Ammonia leak testing is more complicated than helium leak testing, requiring more preparation work; the interior of the heat exchanger needs to be purged with nitrogen 3-4 times. Its advantage is that it allows for the accurate identification of the location of the leak
I don’t understand why helium testing cannot detect leaks. Please advise; thank you!