Patent attributes
A mass flow verifier (MFV) that is space-efficient and can verify flow rates for unknown fluids over a wide range of flow rates includes a chamber configured to receive a fluid, a critical flow nozzle connected to the chamber, and first and second pressure sensors that, respectively, detect fluid pressure in the chamber and upstream of the critical flow nozzle. A controller of the MFV is configured to verify flow rate of the fluid by, (i) at a first flow range, measuring a first flow rate based on a rate of rise in pressure of the fluid as detected by the first pressure sensor and determining a gas property function of the fluid based on pressures as detected by the first second pressure sensors, and (ii) at a second flow range, measuring a second flow rate based on pressure detected by the second pressure sensor and the determined gas property function.
