The total flow is divided by splitters in split-tube designs, and the resulting two streams do not have to be at exactly the same mass flow rate to maintain accuracy (they do, however, need to have the same density). The ability to extract data on total mass charged, solids rate, percent solids, and viscosity from a single instrument does lower the total cost of measurement, improves process control, and provides redundancy for other instruments.Ĭontinuous tube designs are generally preferred for slurry and other multi-phase fluid applications. On the other hand, they may not be competitive when used in simple flow measurement applications where volumetric sensors are sufficient and where repeatability is more important than precision. These mass flow meters provide short payback periods on applications where measurement accuracy lowers production costs (bathing, billing) or where multiple measurements (including density, temperature, pressure) are needed. The cost of an average-sized (under 2 in.) Coriolis flow meter is between $4,000 and $5,000. Gas content in low viscosity fluids, like milk, will separate at concentrations as low as 1%. Gas content in such highly viscous liquids can be as high as 20% with the small bubbles still remaining homogeneously dispersed. Liquids with viscosities as high as 300,000 centipoises can be metered with Coriolis meters. The amount of air in the process fluid that can be tolerated by a meter varies with the viscosity of the fluid. If a slug-flow recovery feature is provided in the transmitter, it will stop the measurement when slug flow is detected by the excessive drive power drawn, or by the drop in process density (reduction in sensor output amplitude). When fluid is unloaded from tank trucks, drums, or railroad cars, slug flow can occur, making the meter output unpredictable. Therefore, the amount of driving power that can be delivered to the flow tube is limited. Most meters are provided with intrinsically safe circuits between the flow tube and the transmitter. Self-draining designs are available for sanitary applications that meet clean-in-place requirements. Coriolis mass flow meters can detect the flow of all liquids, including Newtonian and non-Newtonian, as well as that of moderately dense gases.
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