Vortex flowmeters are mainly used for flow measurement of industrial pipeline media, such as gas, liquid, steam and other media. How to judge the performance of vortex flowmeter?
It can be reflected by several important indicators such as accuracy, reproducibility, sensitivity, response time, zero drift and range drift. The following is an introduction for you.
Accuracy
Accuracy is also called precision, which is the degree of accuracy of the measurement result of the vortex flowmeter close to the true value. It is generally expressed by absolute error or relative error:
Absolute error = measured value – true value
Relative error = absolute error / true value
Any type of flowmeter cannot measure the true value of the measured parameter absolutely accurately during measurement, and can only strive to make the measured value close to the true value.
In practical applications, we generally use the indication value of a standard instrument with higher accuracy as the true value of the measured medium, and the difference between the indication value of the measuring flowmeter and the indication value of the standard instrument is the measurement error. The smaller the error value, the higher the reliability of the measuring flowmeter.
Repeatability
Repeatability refers to the percentage of the difference between each measured value and the average value relative to the maximum scale range when the same vortex flowmeter is used for repeated measurements under the condition that the pipe diameter, medium flow, temperature, pressure and other measurement conditions remain unchanged.
This is an important indicator of the stability of the vortex flowmeter, and it is generally necessary to check it when the instrument is put into operation and daily calibration.
Sensitivity
Sensitivity refers to the sensitivity of the vortex flowmeter. The industry often uses the ratio of the change in the output of the vortex flowmeter to the change in the measured parameter that causes these changes to express it.
We know that the integrated vortex flowmeter with temperature and pressure compensation function can measure temperature, pressure, and flow at the same time. The sensitivity of multiple parameters is often easier to reflect the performance of the flowmeter.
Response time
When the parameters of the measured medium change, the display value of the vortex flowmeter will always take a period of time to be accurately displayed.
The time lag between this period and the change of the measured parameters is the response time of the vortex flowmeter. In fact, other instruments also have response time, some of which are expressed by time constants, such as thermal resistance temperature measurement, and some are expressed by damping time, such as ammeter resistance measurement, etc.
Zero drift and range drift
Zero drift and range drift refer to the percentage of the average change value relative to the range after multiple measurements of the relative zero point and maximum range confirmed by the vortex flowmeter.