Ultrasonic sensing technology has become a key method for detecting level in tanks where intrusion into the tank is not desired. Its a good solution when the material being measured is caustic or volatile, under high pressure, at very high temperatures, or the environment is sanitary.
Using ultrasonic devices to sense through the metal tank walls also renders moot material compatibility issues, since there is no direct contact with the media. Further, these units are not affected by stirring devices. Perhaps the only catch has been in applications involving high-viscosity media, such as yogurt or ketchup, which form a film inside the container wall and can throw off ultrasonic sensors.
To address this shortcoming, Turck has developed a new version of its Levelprox line of level measurement systems. The dual-mode version features Echo Mode, an addition to the reverberation technology of the original sensor. In normal mode, this sensor determines the level of the media by evaluating the amplitude of the signal resonating inside the tank, just as the earlier generation of Levelprox units did. Whereas film and other residue on the side of the tank could distort the resonance, and thereby throw off the earlier generation Levelprox sensor, Echo Mode allows the sensor to also factor in the echo as it returns from the opposite tank wall. Using both readings, an accurate level measurement can be determined.
By changing the dip-switch setting, the user will be able to select the appropriate operating mode for the application. But the unit also has the intelligence to know when it gets a bad reading, and it will take its own reading in Echo Mode.
The new Levelprox is suitable for breweries, dairies, food or beverage production facilities, wastewater treatment, chemical handling, oil or lubricant storage, and pharmaceutical applications.
Levelprox largely opened a market for non-invasive level measurement when it was introduced last July, says Grant Bistram, marketing services manager. Levelprox sensors are constructed of high-grade 316L stainless steel and can sense through walls from 1 mm (.040 in.) to 15 mm (.590 in.) in thickness. A 1Â½" Tri-clamp fitting is incorporated into the sensor and can be used with the optional mounting kit, which includes the clamp. The mount is welded to the tank, and the sensor is fastened to the mount with the Tri-clamp. This positions the sensor face in the ideal detection position and ensures a sanitary, leak-proof fitting. Levelprox is completely self-contained with no need for an additional amplifier.
For more information call 800/544-7769 or see www.turck.com.