| 摘要 |
<p>The invention concerns flow metering equipment and can be used for calibration of ultrasonic flow meters for single-phase liquids (gases) used in the petroleum, oil, gas and other industries. The technical effect consists in that the flow meter calibration is carried out in the dynamic mode on site, which minimizes the calibration costs, especially for flow meter calibration with an internal diameter of more than 300 mm, due to needless of stationary verification facilities of large diameter and height. At the first stage of the calibration the reference standard velocity of sound is determined in non-flow medium for the set absolute pressure, absolute temperature and composition (in case of natural gas). Then, using similarity criteria for a fully- developed turbulent stream, and using the meter's software program, the transit time values are found of ultrasonic signals along acoustic paths, of a particular meter, in the flowing liquid medium at the chosen value of the averaged volumetric flow rate within the flow measurement range. Next, based on the obtained values of the transit time (frequency) the measurement channels of time are checked and adjustment is made for the given meter, using sound impulses generator. After that, in accordance with the meter's registration data (real volume) the volume rate of flow liquid is measured at the chosen point within the measurement range of the averaged volumetric rate (volume) of the stream in the pipeline. The obtained measurement result is compared with the primary calibration data and the correction to the meter's indications (in accordance with the reference standard of volume) at the chosen point within the measurement range is found. In the same way the correction is found for the initially chosen averaged volume. If the difference between the corrections is in agreement with the set criteria, the relative correction (in %) is entered in the meter's calculator.</p> |
