In 1997, Sierra Instruments took proven vortex shedding technology to the next level with the launch of the Innova-Mass® Model 240 & Model 241 Multivariable Mass Vortex Flow Meter. Sierra was the first to offer this unique solution for measuring the mass flow of gases, liquids and steam.
Vortex shedding flow meters have been in use for many years. The typical device is a flanged in-line unit. Most vortex meters measure only one variable (the velocity of the flowing fluid). Effectively, this makes the typical vortex meter a volumetric unit. While mass flow can be calculated for a constant density fluid, it becomes problematic for gases and steam. A multivariable mass vortex meter builds upon the current generation and offers improved accuracy, lower installed cost, and enhanced functionality, including multiple outputs of process conditions. These features reduce total cost of ownership and provide a reliable, accurate instrument for monitoring mass flow rate and other process variables.
The multivariable mass vortex monitors mass flow rate by directly measuring three variables: fluid velocity (v), temperature (T), and pressure (P). The built-in flow computer calculates mass flow rate (ṁ), density (ρ) and volumetric flow rate (Q) based on these three direct measurements (see Figure 1).