Small Gas Component Detection using Ultrasonic Transmission-mode Tomography System

This paper presents the development of an ultrasonic transmission-mode tomography system for the detection of small gas components by using higher frequency ultrasonic transducers. The selection of the transducer is important and must be suitable to the application design. Consideration on the natural limitation of ultrasonic wave is also noted as the higher the frequency of the ultrasonic transducer, the better the sensitivity but lower penetration depth. 16-pairs of these ultrasonic sensors are installed and fixed inside a sensor jig which is designed to hold all the sensors while providing support for optimum angle sensor placement. The sensor jig is also mounted on the circumference of a vertical column which will be used as the investigated process vessel. The developments presented also include the non-invasive fabrication techniques, the electronic measurement circuits, image reconstruction technique, and finally on the imaging results of the proposed system.