CALIBRATION METHOD UNDER OPERATING CONDITIONS OF ULTRASONIC FLOW METRES - COUNTERS OF FLOW RATE AND VOLUME OF LIQUID SINGLE-PHASE MEDIA Russian patent published in 2013 - IPC G01F25/00 

FIELD: measurement equipment.

SUBSTANCE: calibration method involves stages, at which a reference sound velocity in stationary medium is determined for the specified absolute pressure, absolute temperature and component composition (in case of natural gas). Then, using similarity parameters for developed turbulent streams, values of propagation time of ultrasonic signals along acoustic paths of a certain counter in flowing fluid medium are calculated by means of a programme at the specified value of averaged volume flow rate within the measurement range. In compliance with the received time (frequency) values of propagation, time measurement channels of that counter are checked and adjusted by means of a sound pulse generator; after that, fluid medium volume is measured as per the counter readings (actual volume) at the specified point of variation range of averaged volume flow rate (volume) of the medium flowing in the pipeline. By comparing the obtained result to the primary calibration data, correction (as per reference volume) to the counter readings at the specified point of the measurement range is obtained. Correction for the initially chosen averaged volume is determined in the same manner. If difference between corrections meets the established criterion, relative correction (in %) is entered to the counter computer.

EFFECT: performing a calibration procedure of flow meters - counters in field in a dynamic mode and reduction of costs owing to reducing the costs for calibration, and namely for flow metres - counter with inner diameter of more than 300 mm, due to refusal to use stationary calibration units of increased height and larger diameters.