What a Mass Flowmeter Really is

Mass flowmeters are also known as inertial flowmeters or coriolis flowmeters; they are a device that measures exactly how much fluid flows though a tube, but it doesn’t measure the volume of the fluid passing though the tube. It does measure the quantity of mass flowing though the device though. Mass flow rate is proportional to volumetric flow only when the density of the fluid is stable, and if the fluid has an unstable density, or contains any bubbles the volume flow rate multiplied by the density can not be calculated accurately of the mast flow rate.

What Are the Limitations? Mass flowmeters can easily sense the flow of all liquids, including Newtonian and non-Newtonian, and also moderately dense gases. Mass flowmeters have self-draining designs that are available for sanitary applications. Like ultrasonic flowmeters it also uses sensors to detect flow. Also, many mass flowmeters are provided with essentially harmless circuits between the flow tube and the transmitter. Consequently, the quantity of driving power that can be delivered to the flow tube is restricted, and when fluid is unloaded from tank trucks, drums, or railroad cars, slug flow can occur, which this can make the meter output unpredictable. That’s why it’s a good idea to obtain a mass flowmeters with a slug-flow recovery feature present in the transmitter. The slug-flow recovery feature will stop the measurement when slug flow is detected so you can properly remove the slug flow before harm is done to your mass flowmeter, and the density doesn’t drop. The quantity of air in the progression fluid that can be accepted by a meter will vary with the thickness of the fluid. Liquids with viscosities as high as 300,000 centipoises can be metered with mass flowmeters. Gas levels in such high thick liquids can be as high as 20% with small bubbles still remaining dispersed within. Gas levels in low thickness fluids such as in milk will divide at concentrations as low as 1%. What is the Price? On average the price of an average-sized mass flowmeter, which is less than two inches, costs anywhere between $4,000 and $5,000, but mass flowmeters present short reimbursement time on applications where measurement precision lessens productions costs. It lowers production costs in both simple measurement needs like bathing or billing, and multiple measurement needs like density, temperature, and pressure. But, they may not be gung ho when used in single flow measurement applications where volumetric sensors are adequate and where repeatability is more significant than accuracy. The capability to take out data on whole mass charged, solid rates, percent solids, and viscosity from a single device does lower the total price of measurement, and improves process control.