The main equipment for dry calibration testing includes water flow calibration device, bell jar gas flow calibration device, standard meter gas flow calibration device, sonic nozzle gas flow calibration device, and related electronic instruments.
1. Water flow calibration device
Two methods were used, namely static volume method and standard table method, with system uncertainties of ± 0.15% and ± 0.5% for the device. Two pipelines, DN50 and DN100, were selected for the experiment, with maximum flow rates of 37m3/h and 140m3/h, respectively. The dry calibration test of DN50 liquid vortex flowmeter was conducted on this device.
2. Bell type gas flow calibration device
The capacity of the device is 2000L, the working pressure is 5kPa, the system uncertainty is ± 0.5%, and the cumulative flow uncertainty is ± 0.2%; The maximum instantaneous flow rate is 350m3/h, and the dry calibration test of DN50 gas vortex flowmeter is mainly carried out on this device.
3. Standard method gas flow calibration device
This device can provide testing for gas vortex flowmeters with a diameter of DN100 or above under normal temperature and pressure conditions. In dry calibration testing, DN100 is used
Gas vortex flowmeterMainly carried out on this device.
The maximum flow rate of DN100 vortex flowmeter can reach 1200m3/h, and the system uncertainty of the device is ± 0.5%.
4. Sonic nozzle gas flow standard device
This device is a pressurized gas calibration device with a maximum working pressure of 0.6 MPa and a maximum flow rate of 2200 kg/h. This device provides validation tests for the Strouhal number of DN50 gas vortex flowmeter at different pressures. ．
The above four sets of verification devices have been certified and authorized by national technical supervision institutions. All experiments were conducted in accordance with the industry standard ZBN12 008 (now JB/79249-1999) and the methods specified in the national metrological verification regulation JJG 620-89, now JJG 198-94 "Metrological Verification Regulation for Velocity Flowmeters" at that time.