Ultrasonic Thickness Gauge
One of the tool used for measuring the thickness of the material from one side by using a nondestructive method. Rather than using micrometer or caliper it’s more fast and reliable than the manual methods.What Can Be Measured? In actual any type of #engineering material can be measured using this device, It is used to measure metallic, plastic, composite, fiberglass, ceramic and glass objects. Even if the material is rolled or curved or straight it’s thickness can be measured. This method is completely non-destructive and can also be used for liquid level and biological samples.Wood,foam and concrete are not recommended for measurement because of poor transmission of sound wave.How does it work? Sound energy is produced when an object vibrates. The sound vibrations cause waves of pressure that travel through a medium, such as air, water, wood or metal. Sound energy is a form of #mechanical energy. Ultrasound wave have higher frequency that is not audible, these are used for measurement of thickness by using minimum of 500KHz frequency to the maximum of 20 Mhz frequency. Ultrasonic thickness gauges work by very precisely measuring how long it takes for a sound pulse that has been generated by a small probe called an ultrasonic transducer to travel through a test piece and reflect back from the inside surface or far wall. Because sound waves reflect from boundaries between dissimilar materials, this measurement is normally made from one side in a "pulse/echo" mode.The transducer contains a piezoelectric element which is excited by a short electrical impulse to generate a burst of ultrasonic waves. The sound waves are coupled into the test material and travels through it until they encounter a back wall or other boundary. The reflections then travel back to the transducer, which converts the sound energy back into electrical energy.It is important to note that the velocity of sound in the test material is an essential part of this calculation. Different materials transmit sound waves at different velocities, generally faster in hard materials and slower in soft materials, and sound velocity can change significantly with temperature. Thus it is always necessary to calibrate an ultrasonic thickness gauge to the speed of sound in the material being measured, and accuracy can be only as good as this calibration.Measurement ModesThere are three common ways of measuring the time interval that represents the sound wave's travel through the test piece. Mode 1 is the most common approach, simply measuring the time interval between the excitation pulse that generates the sound wave and the first returning echo and subtracting a small zero offset value that compensates for fixed instrument, cable, and transducer delays. Mode 2 involves measuring the time interval between an echo returned from the surface of the test piece and the first backwall echo. Mode 3 involves measuring the time interval between two successive backwall echoes.Two Probe transducer PT-12 have been supplied to Pakistan Petroleum Limited