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In 1979 UAI was started to develop a sensor technology that would measure materials and products, made in process industries, to better than micrometer accuracy. Development requirements were such that the technology had to work on any material in most process environments. Conventional methods, including laser, optical, capacitive, nuclear, eddy current and contact were rejected because they did not meet one or more constraints. Ultrasound was attractive but science at the time, said that ultrasound could not be transmitted through air accurately and reliably. Traditional ultrasonic measuring devices create a sound wave using a piezo crystal. This method generates sound by electrically vibrating a crystal within the sensor. Because of the mass of the piezo crystal, ambiguous sound waves are generated--it takes an extended period of time for the signal to increase and then decrease. Distance/thickness measurements taken with this method are unreliable and inconsistent.
UAI pioneered a more accurate measurement method by tensioning thin conductive film on a conductive plate. Charging the film and plate and then removing the charge results in a distinct pulse --an unambiguous sound wave--providing a consistent basis to measure the speed of sound and produce accurate measurements.
Ultrasonic Arrays research and development produced an ultrasound-based non-contact measurement system and method. Unlike other measurement methods, non-contact ultrasonic gauges do not require recalibration. Because UAI gauges do not actually touch the product, they do not sustain material buildup or cause damage to the product surface. The non-contact nature of this technology simplifies fixturing as the gages can be mounted in a fixed position and make accurate measurements over a wide range of stand off distances and thicknesses.