E-Zine November 2014
Click here to read "Introduction"
Click here to read "Calibration Complexity"
As previously discussed, some flowmeters require straight run, while others do not. Installation of control valves, thermowells and the like upstream of the flowmeter can cause hydraulic turbulences that can adversely affect many flowmeters.
While flowmeters within some technologies are installed similarly, many flowmeters have idiosyncrasies that apply only to a specific flowmeter model. For example, mounting requirements for Coriolis flowmeters vary widely -- some manufacturers recommend four supports for certain designs, while others do not recommend any supports.
With the notable exception of custody transfer installations, many flowmeters are not installed per manufacturer installation recommendations. These flowmeters will not necessarily achieve the level of performance claimed by the manufacturer. One of the most common causes of installation failure in flow measurement is not paying attention to the “details.”
Despite performance that may be significantly degraded, users typically believe that the flowmeter performs within its claimed performance. When important process diagnosis and operating adjustments are based on these measurements, the quality of these measurements could cause inappropriate results that could be detrimental to the process. For example, in one application, an improperly installed flowmeter performed over 50 times worse than its claimed accuracy. Had the quantity of the fluid not been clearly visible, the user would not have known about the error, nor would the user have suspected that an error existed.
Many have the mistaken impression that flowmeter selection, installation and operation is relatively easy. However, even individuals experienced in flow measurement often have reservations about the flowmeters they select for a particular application. Achieving the promise of superior flow measurement is not an accident -- it is paying attention to the details.
From Flow Control (August 2002)