How It Works
Mass Extraction is a gas flow measurement technology that utilizes a laminar flow element for leak testing. This Intelligent Mass Flow Sensor (IMFS) is an ATC patented design that measures the mass flow rate. It does this by measuring the flow rate or a gas that is in the molecular flow regime. In the molecular flow regime, gas molecules are more likely to collide with the side walls rather than with other molecules.
While in this state, flow through an annular gap in a laminar flow element will incur pressure changes. The change in pressure is due to Brownian motion rather than friction loss that we see in the IGLS.
The design and high precision machining of the IGLS allows for a more consistent annular gap. This is not possible with a tube or plate style laminar flow element. The design also enables precision control of the measurement gap. Allowing a more fine-tuned sensor for custom-type applications with greater repeatability.
The stand-alone test systems integrate an IMFS with a test circuit. This circuit then maintains a flow of stable air through the IMFS on its way to the Unit Under Test (UUT).
To achieve this sequence a series of evacuation steps bring the UUT down to test pressure. After stabilizing at the correct test pressure measurement steps can take place. These steps force air leaking from the UUT to flow through the IMFS on the way to the vacuum reservoir. The measured loss in flow is then compared to a specified rejection limit.
Mass Extraction Technology differs from Micro-Flow Technology.