Listen in: Ultrasonic technology offers versatility, economy

New electronic capabilities make for economy, simpler operation.
By Control Engineering Staff May 22, 2008


New family of ultrasonic flowmeters offers a useful combination of application versatility, simple operation, reliability, and economy for many general process applications. ( Click here to hear comments from Don Tyler, president of Clark Solutions .)

Clark Solutions ClarkSonic ultrasonic flowmeters are reportedly well suited for measuring flow in most clean liquids and many liquids with entrained solids. Applications include monitoring flow rates of chilled or heated water for HVAC installations, as well as in municipal, process, and industrial systems. The company says the family frees users from having to calibrate the transmitter to fluid temperature, viscosity, or density, making them very easy to deploy and very reliable. Output is standard 4-20 mA with user definable flow units.

ClarkSonic family has two main operating ranges. Model CSLFC ultrasonic transmitters are designed for flows to 400 GPM in

The company says the heart of the ClarkSonic flowmeters is a proprietary mixed signal ASIC, (application specific integrated circuit,) which allows sophisticated timing, control and transducer driver circuitry to be combined on a single integrated circuit. The ASIC uses a special algorithm that improves on standard single-path measurement techniques. ClarkSonic transmitters use the sing around method, where the ultrasonic transducer alternates between transmitting and receiving to measure differences in flight time between upstream and downstream transmissions. The flight time of the sound pulse from the transmitting transducer to the receiving transducer will be shortened if the pulse is launched in the direction of flow, and increased if launched opposite to the direction of flow. By alternating the transmitting and receiving transducers, the difference in these transit times can be used to calculate the velocity of the flow, which when multiplied by the area of the pipe results in a measure of volumetric flow rate. The primary advantage of the sing around method is that the velocity of the fluid is being measured independent of the relative speed of sound in that given fluid. That way, the output is unaffected by changes in fluid temperature, density and viscosity.

—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
Process Instrumentation & Sensors Monthly
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