ULTRASONIC THICKNESS GAUGE

ULTRASONIC BASICS PRINCIPLES AND APPLICATIONS

Sound is a mechanical wave which travels with specific velocities depending on medium of propagation, which may be Solid, Liquid or Gases. Sound waves having very high frequencies reflect from boundaries of materials and produces distinct echo patterns. For transmitting sound waves and receiving echoes, ultrasonic sensors normally called as transceivers or transducers are used. The commonly used transducers are Contact, Angle beam, Delay line, Immersion and Dual element transducers. Propagation of sound waves through solid material are determined by Ultrasonic Transducers.

When an electric pulse of voltage is applied to ultrasonic Transducer it vibrates across a specific spectrum of frequencies and generate burst of sound waves. These sound waves get reflected back in form of echo and an electric pulse is generated. Based on these pulses, thickness can be calculated. The amount of time taken for sound to travel through medium and amplitude of received signal are the values to be measured,

The most common methods of Ultrasonic measurements utilizes either longitudinal waves or shear waves. The Longitudinal wave is a compression wave in which the particle motion is in the same direction of the propagation wave. The shear wave is a wave motion in which the particle is perpendicular to the direction of propagation. Ultrasonic measurement is a Non Destructive type technique. i.e. it introduces high frequency sound waves into the test object without altering or damaging it in any way.

Ultrasonic detection is most commonly used in Industrial Applications to detect hidden tracks, discontinuities, Thickness Measurement in metals, composites, plastics, and ceramics.