LEAK TESTING · ENGINEERING CALCULATOR
Compare four detector connections, the time to reach 95% of a step signal and the fraction of helium reaching the detector.
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Model
Calculate
Assumptions and use
Assume a well-mixed volume and constant effective speeds. Transport delays, instrument filtering and internal volumes are not included. Air-to-pure-helium conversion assumes molecular flow. Verify response and flow division with a reference leak connected at the test object.
Worked example
For 5 m³, detector speed 1 L/s and parallel high-vacuum pumping 1000 L/s, 95% response takes about 15 s; approximately 0.0999% of helium reaches the detector.
Record the units, gas, temperature, background and instrument settings with every result. Confirm the model assumptions before applying a calculated limit to a real test.
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