LEAKLAB · TESTING AND ENGINEERING
The evacuated object is connected to a mass-spectrometer detector while external seams and joints are exposed to helium.
Local leak detection
A pumping system evacuates the object and establishes the required detector operating conditions. Helium is applied sequentially to external regions. A repeatable detector response helps locate a through-defect in the exposed boundary.
Control the exposure and response
The spray route, gas flow, dwell time and background recovery are established for the actual geometry. Line conductance, auxiliary pumping and the leak’s position can delay the response or reduce the fraction reaching the detector.
Before testing, check the background and response to a suitable reference leak in the working arrangement. The applicable ASTM edition, acceptance criterion and system detection limit are agreed. A low nominal analyser detection limit does not by itself establish the product-test threshold.
Preparing and verifying the test
- Review the drawing, materials, internal volumes, test boundary and required result.
- Agree the document edition, allowable pressure difference, vacuum and temperature, acceptance criterion and required system sensitivity.
- Clean and dry the object, prepare fixtures and exclude leakage from the test connections.
- Check instrument metrological status and the working characteristics of the complete arrangement; use an appropriate reference response for the selected method.
- Perform the agreed scan or measurement cycle and record the actual conditions. Confirm suspected leaks by repeat tracer-gas exposure where applicable.
- Check system stability after the test and report the result against the agreed criterion.
What the customer receives
The agreed scope can include a test programme, operating or inspection instructions, measured results, a map of located leaks and a technical conclusion. The report identifies the object and tested regions, applicable programme, instruments and metrological status, pressure and temperature, response checks, observations and limitations.
Define your task
Send a drawing or sketch, material, dimensions and volume, working pressure, allowable vacuum and temperature, leak-tightness requirement, number of items, site and schedule. These inputs determine the method, fixture, equipment and reporting scope.
Discuss a test programme