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Application reports
# 1 : Leak testing of heat exchangers
The leak test on shell-and-tube heat exchangers combines quantitative leak detection ...
Application
The leak test on shell-and-tube heat exchangers combines quantitative leak detection using a hard vacuum method with leak location of leaky elements or tubes.
Benefits of Adixen tracer gas methods
• Integral test with clear quantitative result - no operator interpretation
• Easy calibration of test result and response time during test
• Fast pin-pointing of leak position and identification of leaking part
• Selective repair of sites only that are leaking above reject level
Specification
Any type of heat exchanger must be leak tight under operational conditions. The tightness criteria are determined by temperature, pressure and media and can be converted into a tracer gas leak rate. Current method and reason for change
In many cases the leak test is combined with a pressure burst test. The tests often are made with liquids that may contaminate the sample or require additional cleaning steps after the test.
With soap sprays leaks can be missed since the soap is blown off at large leaks. In case of small leaks the method is too slow to react.
In most cases the sample volume is too large for use of pressure decay methods within a reasonable time scale.
Tracer gas methods are the only methods with a sufficient sensitivity and dynamic range for all heat exchanger applications.
How to use the tracer gas method
The heat exchanger is sealed off at both ends using a special flange adapter with a connection to a pumping group and the leak detector. The tube section is evacuated and the shell area is pressurised with tracer gas. The gas will penetrate through a leak and can be detected by a Helium leak detector. Audio and visual alarms are used to indicate a leak and data can be recorded. Alternatively or in addition a Helium or Hydrogen sniffer probe can be used for pinpointing leaks.
Tracer gas methods - the most sensitive and versatile NDT methods
An unrivalled sensitivity and a wide dynamic range are the key characteristics for tracer gas leak detection methods. Easy operation, high acceptance and regulation conformity have made tracer gas leak detection methods the optimum solution for quality control.
Equipment used
Helium leak detector ASMGraphThe ASMGraph is a rugged and versatile leak detector which combines high hardware performance with a touch screen operator interface. The advanced features at your fingertip make Helium leak detection a simple and user friendly method. The universal unit can be used both for quantitative measurement and leak locating.
Hydrogen leak detector H2000 PlusThe H2000 PLUS is virtually maintenance free making it the ideal detector for mobile use on the production floor. A sensor that responds to Hydrogen only ensures fast and easy pinpointing of leaks.
