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Measuring Flow: What's Right and What's Not

Flow meters are used in all sorts of facilities such as sewage plants, laboratories, semiconductor manufacturing, industrial plants and HVAC operations, as well as engine fuel cells. The choice of which particular flow meter to employ is determined by use, footprint and budget. At the opposite ends of the flow meter spectrum are devices that use high-end means to accomplish their tasks, or are low-end mechanical devices to measure the flows.
           
The Coriolis flow meter uses what is known as the Coriolis effect to directly measure mass flow. They have broad use, from measuring hydrogen gas to a viscous mass, such as peanut butter, without the need of recalibration. A Coriolis measurement is extremely accurate. The ultrasonic flow meter is a device used where ultra-pure liquids are in use, such as in semiconductor operations where cleanliness is definitely next to Godliness. Ultrasonic flow meters for use in the semiconductor industry are usually assembled in at least a Class 100 Clean Room. These units can operate under increased pressures (PSI) as well as within high temperature environments. Sensing of liquid flow is managed through the use of an ultrasonic transmitter and a receiving device mounted just behind the deal at each end of a flow tube. Thanks to the technology used, an instantaneous flow rate is obtained and a total flow volume calculated.
           
With mechanical flow meters, the fluid within the conduit passes over a rotary device, such as a turbine or an anemometer. The flow rate is calculated as the fluid flows over the device. Another mechanical device is called a venturi meter and harkens back to use centuries ago during the time of the Roman Empire. This meter constricts the flow of the liquid and the differential pressure resulting from this constriction is then measured. Gas running through a pipeline often has its flow rate calculated in this fashion. Another flow meter device called an orifice plate also uses flow constriction for the measurement data.
           
The magnetic flow meter is common in use and uses the principle of magnetic induction to calculate the data. Magnetic induction is simply the production of voltage across a conductor that’s situated in a changing magnetic flux, which itself is a measure of the quantity of magnetism. A magnetic field is applied to the metering tube. The result is a measurable difference proportional to the flow velocity perpendicular to the flux lines, or the lines of force passing through a specified area in a magnetic field. Back in 1831, Michael Faraday is believed to have discovered the phenomenon known as induction used for these modern-day calculations.
           
Flow meters accomplish their tasks through the use of a variety of unique technologies. Some are based upon centuries-old technologies while others rely on high-tech methodology for their results. Whatever the system in use, accurate readings and measurements of liquids and gases are critical to the safety and ultimate productivity of facilities.

Sierra Instruments is a leading manufacturer of mass flow meters, mass flow controllers, and partial flow sampling systems.  This successful business is family-owned and is constantly striving towards perfection in terms of quality, price, delivery, innovation, and customer support.

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