FLEXIM's Disturbance Correction Overcomes Challenging Straight Run Requirements

In the often limited space of industrial process plants, recommended straight-run requirements can be challenging to find. Due to restricted pipework, it's not always possible to carry out the optimum installation as advised, away from valves, bends, and other inline components that could cause excessive and problematic turbulence. Clamp-on flow meters usually require an inlet length of at least ten diameters for accurate measurement. 

Thanks to FLEXIM's disturbance correction, good accuracy is achieved even at non-ideal in-flow conditions reducing the required inlet length from 10 diameters to just two diameters. This innovation means installation happens in even the tightest spaces without process interruption. The disturbance correction is applicable for all path configurations compensating for cross flow. These are reflect-path and cross-path configurations. 

As part of the development, FLEXIM collaborated with the highly respected PTB on a research project focusing on the exact determination of flow profiles and how they influence the measuring accuracy of clamp-on ultrasonic flowmeters. Calibration determined the disturbance corrections implemented in the meter, firstly under undisturbed conditions and then under disturbed conditions. This allowed the disturbance correction to be obtained from the ratio of the two results, and the procedure was repeated for all types of disturbance that require a correction function to be put in place. Following correction, the uncertainty depends on the number of measurement planes installed, the distance to the disturbance, and its character. 

Analyzed by CFD, the effect of different bend radiuses found in industrial piping is included in the uncertainty. The disturbance correction applies to all fluids, no matter their state of aggregation or the diameter of the pipe. And although the disturbance correction is optimized for 90-degree bends and double bends, it also improves the accuracy of other types of disturbances. Because FLEXIM's flow disturbance correction reduces the required inlet length from 10 diameters to just two diameters, accurate measurements are guaranteed, even with non-ideal installation conditions. Maximum flexibility and cost savings are delivered for both planners and users alike.

Classic Controls, Inc.
+1 863-644-3642