RU2217704C2 - Method for graduating and testing liquid meters and flow meters (variants) - Google Patents

Abstract

FIELD: measuring processes and equipment, possibly metrological equipment for measuring flowrate and volume of water at operation condition. SUBSTANCE: method comprises steps of placing on pipeline near zone for testing metering device sample unit; successively passing through them the same flow and comparing readings; using as sample unit group of n certified ultrasonic flow meters with outer arrangement of pickups; selecting number of devices in group equal to quotient of division of squared value of root-mean-square deviation of one device of group by squared value of preset root-mean-square deviation of sample unit; according to first variant of invention measuring liquid flowrate by means of tested device and successively by means of each sample device of group; determining mean value of readings of sample devices; comparing said mean value with readings of tested device for determining its graduation characteristics; according to second variant of invention placing on pipeline pickup of one of sample devices, namely of reference device; simultaneously measuring liquid flowrate by means of tested device, namely by means of reference device and successively by means of each other device of group; determining mean value of readings of group of devices and relating it to reference device; comparing said related mean value with readings of tested device for determining its graduation characteristics. EFFECT: realization of graduation and testing of working metering device without demounting it and without interrupting operation of pipeline with use of devices whose accuracy is less than that of tested device. 4 cl, 1 dwg

Description

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Claims (4)

1. The method of graduation and verification of meters and liquid flow meters installed in the pipeline, using sequential transmission of the same stream through the calibrated and exemplary measuring means and comparing their readings, characterized in that as a standard measuring means using a group of n exemplary flow meters with external arrangement of sensors, in operating conditions without violating water pipes and their operating mode, and the number of devices in the group is selected from the ratio

Where

- standard deviation of the model means; σ is the standard deviation of one device in the group, at the same time, the fluid flow in the pipeline is simultaneously measured by a verified means and sequentially by each sample device from the group, the average value of the indications of the standard devices is determined and, comparing this average value with the readings of the verified means, its calibration characteristic is determined. 2. The method according to claim 1, characterized in that sensors of two exemplary devices from the group are installed on the pipeline at a distance of 0.5-2 m from each other along its generatrix and, moving the sensor of one of the devices along the pipeline in a plane perpendicular to its axis at fixed angles, simultaneously measure the fluid flow, comparing the readings of both instruments, determine the value of the axial asymmetry of the flow, which is taken into account in the calibration characteristic of the calibrated measuring instrument by multiplying the volume obtained during the measurement a group measure of the hydrodynamic coefficient K to obtain the actual value of the volume of fluid passing through the pipeline. 3. A method for calibrating and verifying liquid meters and flowmeters installed in a pipeline using sequential transmission of the same stream through a calibrated and exemplary measuring instrument, and comparing their readings, characterized in that a group of n exemplary flowmeters with external arrangement of sensors, in operating conditions without violating the water pipes and their operating mode, while the number of devices in the group is selected from the ratio

Where

- standard deviation of the model means; σ is the standard deviation of one device in the group, a sensor of one of the exemplary devices is installed on the pipeline near the calibrated measuring instrument and taken for reference, then simultaneously verified by the reference and sequentially, each of the remaining exemplary instruments in the group measures the fluid flow rate, determines the average value of the readings of the group of instruments and assigns it to the reference instrument, comparing this is the assigned value with the testimony of the verified means, determine its calibration characteristic. 4. The method according to claim 3, characterized in that along the generatrix of the pipeline at a distance of 0.5-2 m from the sensor of the reference device, a sensor of one of the devices of the group is installed and, moving the installed sensor through the pipeline in a plane perpendicular to its axis at fixed angles, at the same time measure the fluid flow, comparing the readings of both instruments, determine the value of the axial asymmetry of the flow, which is taken into account in the calibration characteristic of the calibrated measuring instrument by multiplying the value of the volume obtained when measuring the groups oic measure for the hydrodynamic coefficient K to obtain the actual value of the volume of fluid passing through the pipeline.

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