Patent ID: 11885663
Assignee: ENDRESS+HAUSER FLOWTEC AG
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method of calibrating a flowmeter device under test, the method comprising:
establishing a steady state flow of a calibration fluid through a flowpath of a calibration rig comprising at least one bank of flowmeters including one or more flowmeters;
switching the calibration rig to an open loop mode for a period, wherein in the open loop mode the flowpath includes a primary reference standard such that calibration fluid flowing through the at least one bank of flowmeters during the period flows into the primary standard;
measuring a first flow rate of the calibration fluid through the at least one bank of flowmeters during the period;
determining a second flow rate of the calibration fluid based on the mass of calibration fluid that flows into the primary reference standard during the period;
comparing the first flow rate and second flow rate to determine an accuracy of each flowmeter of the at least one bank of flowmeters;
when the accuracy of the one or more of the flowmeters of the at least one bank of flowmeters does not meet a first maximum uncertainty requirement, calibrating the one or more of the flowmeters relative to the second flow rate;
switching the calibration rig to a closed loop mode, wherein in the closed loop mode the flowpath includes the at least one bank of flowmeters and the device under test and does not include the primary reference standard such that calibration fluid flowing through the at least one bank of flowmeters and the device under test does not flow into the primary reference standard;
establishing a steady state flow of the calibration fluid through the flowpath of the closed loop mode;
measuring a third flow rate of the calibration fluid through the device under test;
comparing the first flow rate and the third flow rate to determine an accuracy of the device under test; and
when the accuracy of the device under test does not meet a second maximum uncertainty requirement, calibrating the device under test relative to the first flow rate.