Vortex shedding flow meter calibration

Vortex flow meter is an extremely useful device which helps in determining the flow of a fluid. It is however versatile enough and can also be applied to natural gases and general gases. It is particularly useful in determining mass flow rates but is use friendly and can be applied to custom flow as well. The entire hassle of the flow determination will however become pointless if the measurements are not done accurately. Accuracy of flow meter is determined by its calibration. Calibration is a useful index and tells about the possible deviation a particular device has from a standard.

How to measure flow meter calibration?

Vortex flow meter calibration can be measured by two widely used procedures. These include:
1. Using a flow meter whose calibration is extremely high. Such a flow meter is known as master flow meter. Calibration of master flow meters is determined by the National Institute of Standards and Technology, commonly known as NIST, and is used as a standard to determine the accuracy of other flow meters. Hence, this procedure of flow measurement is a relative one.
2. Second important method for accuracy determination is galvimetric weighing. The amount of flowing fluid is measured by a very accurate weigh scale whose accuracy too is a standard one like master flow meter and is determined by equal competency byhe National Institute of Standards and Technology.

What is the Rationale for Properly Calibrating the Vortex Flow Meter?

Once a problem in calibration is determined, the next step is to get rid of that problem. It may seem easier to adjust the flow meter to read zero when there is no fluid flow, it is an in fact a very complex task probably because flow of any liquid or solid medium has been never ideally equal to zero. Practically speaking, flow rate is measured by the vortex flow meter and master flow meter (or galvimetric weighing), the two readings plotted on the graph and compared. Deviation is then noted and written in device manual to ensure that the customer gets desired and accurate results.

It is specifically important to determine the flow meters which have moving parts because these parts are likely to reduce calibration by undergoing wear and tear. Vortex flow meter has to be repeatedly checked for accuracy errors because the bar which is immersed in water continuously generates vortices and the vibrations may damage it. Moreover, this rod is of metal and is likely to give different results with climatic changes due to expansion and contraction.