Give Your Flow Meter a Happy Home

摘要

Increased emphasis on the need to improve process performance and reduce variability mean many control loops today are optimized. This is done through digital adaptive control and predictive control algorithms in distributed control systems or programmable logic controllers. These advanced control routines make it easy to linearize control valve performance and get the most out of assets. They do not, however, guarantee accurate and repeatable input values from all the primary measuring instruments. That's why when measuring flow, one of the easiest and most economical ways to ensure that process improvements are what we expect is to make sure our flow devices have a happy home. Let me explain: Flow meter manufacturers, in accuracy statements for volumetric flow measurement technologies, assume an ideal, fully developed flow profile at the meter inlet. This ideal flow stream is a symmetric, swirl-free, turbulent flow profile. The actual shape of the velocity profile is determined by the viscosity of the fluid, the pipe wall roughness and the Reynolds number. Flow technologies, such as orifice, vortex, ultrasonic and turbine meters, have the same requirements.