Calibrating multi-variable flowmeters
If you’re using more than one variable from a single device, you need to calibrate all of them sooner or later. Video: Beamex demonstrates dual pressure calibration.
One of the advantages of modern process sensor technology is that you can often measure more than one type of process variable with only one device and one penetration into the process. Probably the most common example of this is using a differential pressure (DP) sensor with an orifice plate or other device to measure flow. In most situations, the sensor can also give you a pressure reading of the line and probably a process temperature as well.
If you’re using all those readings, your quality assurance program will typically require you to calibrate all those functions as part of your larger sensor calibration routines. Some field calibration devices, such as the Beamex MC6, can handle the differential pressure, static pressure, and temperature devices in one operation.
In the attached video, Ned Espy discusses how this approach works, and demonstrates how it can be done on a Rosemount 3051S multi-variable transmitter. The test tools used in this case include two pressure gages, RTD simulator, mA meter, and HART communicator. The methods used for testing can be applied to calibration and verification of other flowmeters and complex smart instruments.
Peter Welander, pwelander(at)cfemedia.com