New ultrasonic flowmeter family for process applications

Clark Solutions sensor family uses spool-section configuration for permanent mounting.

03/12/2010


Clark Flowmeter

Clark Sonic flow transmitter

 

Clark Solutions has released its new line of CSLFC ultrasonic flow transmitters aimed at permanent mounting applications in process systems. Clark says these transmitters are easy to install, do not impact the flow, pressure, or transit times of fluids, and are unaffected by fluid temperatures or viscosities, making them suitable for measuring flow ranges from 4.5 to 3,000 gpm in 4 to 10 in. pipe.

The company describes this product family as featuring no moving parts, with excellent long-term stability, no pressure drop, and high accuracy at a lower cost than similar instruments. Each sensor is built into a section of schedule 40 epoxy coated carbon steel pipe with Ultem encapsulated ultrasonic transducers and a choice of EPDM, Buna-N, Neoprene, FKM, or other seals. Device transmitters provide a continuous 4-20 mA flow signal. Optional configurations include direction of flow capability, NEMA 4 and 8 pin connector receptacles for simplified installation, and a DP/DS panel meter display.

Clark says its transmitter uses a proprietary mixed signal ASIC (application specific IC), which allows sophisticated timing, control, and transducer drive circuitry to be combined on a single chip. The ASIC uses a special algorithm that is an improvement upon standard single-path measurement techniques. The transmitters use the sing-around method, where each 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 this method is that the velocity of the fluid is being measured independent of the relative speed of sound in that given fluid. The measurement is also unaffected by changes in water temperature, density, and viscosity.

Read a tutorial on ultrasonic flowmeter technology.

-Edited by Peter Welander, process industries editor, peter.welander@cfemedia.com
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