Calibration of differential pressure flowmeter and its error analysis

- Nov 28, 2017 -

Abstract: Differential pressure flowmeter is widely used in the field of flow measurement. The high-precision calibration system was used to calibrate the differential pressure flowmeter, and the outflow coefficient of the flowmeter was obtained. The error of the outflow coefficient was analyzed by scientific analysis, and the calibration result and experimental error were obtained. Through the analysis of the results can be determined, the flowmeter measurement error in line with the standard, can be used in the actual field measurement.

Key words: differential pressure meter calibration effluent coefficient error analysis measurement


Differential pressure flowmeter is widely used in industrial production flow measurement, flow measurement plays an important role. The flowmeter needs to be calibrated at the factory to determine whether its measurement accuracy meets the standard.


In this paper, taking the long-diameter nozzle flowmeter as an example, through the calibration experiment and experimental data analysis, introduced the differential pressure flowmeter calibration process and measurement principle, combined with scientific and reasonable error analysis method, obtained a reliable outflow coefficient, identified The flowmeter in the actual measurement of the reliability.

1, differential pressure flowmeter calibration process


Differential pressure flow meter calibration process shown in Figure 1. Before starting the centrifugal pump, open the drain valve I and the drain valve II, vent the standard tank II and close the drain valve II, and fully open the flow control valve I and the flow control valve II to divert the commutator switch to the standard tank I;


Start the centrifugal pump, calibration medium - water in a closed pipe flow through the flow control valve I, was calibrated long-diameter nozzle flow meter, flow control valve II, flow to the standard tank I into the underground pool cycle; until the flow rate is stable, Move the commutator control switch, quickly switch the commutator through the electric valve, the water flow to the standard tank II, the flow of water to the standard tank II at the same time the experiment began;


When the water level reaches the standard volume height, quickly switch the commutator, the water flow through the standard tank I into the underground pool, and open the drain valve II, the standard tank II water emptying, a calibration experiment ends. Repeat several times to get more experimental data. After all the calibration experiments, open the drain valve II and drain the water from the standard tank II.

During the calibration experiment, the differential pressure signal measured by the intelligent differential pressure transmitter is transmitted to the PLC module in the control cabinet and converted into a signal automatically controlled by a computer program, so as to obtain calibration experiment data. During the calibration experiment, the water in the underground pool is recycled, and the water resources are reasonably used, so there is no waste problem.

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