Our metal gauge thickness meters
An ultrasonic metal thickness meter measures using the multiple echo technology for fully accurate error-free data. A gauge with a single crystal probe will use the time taken for echoes of sound to travel through a material, then convert these into a thickness measurement. The name comes from multiple sounded pulses being used during this process. First, a short pulse of sound is generated and coupled into the material. The gauge will then listen for back-wall echoes as it is in receiving mode. When three consecutive echo signals of equal pacing are detected, it will proceed to measure the time between them.Then it will calculate the thickness of the material. Any coating will be automatically ignored due to three echoes being used. Because the spacing between the three consecutive echoes has to be equal, measurements are thoroughly checked and vastly more reliable than they would be using single echo methods. You can rest assured knowing that the metal gauge thickness measurement displayed will be accurate – if the timings do not match, then a measurement will not be displayed at all.In order to illustrate the timing method, the travel of the beam will be depicted in the diagram found on our multiple echo information page. The path of the beam is straight, at 90 degrees to the surface with the ultrasonic energy reverberating up and down within the metal. Every time the echo is reflected back down, a portion of the energy comes up through the coating striking the probe (that now acts as a receiver). The delay between the echoes at the face of the probe will be exactly equal to the time it takes to pass through the material which means that any coatings like paint will be ignored. The final measurement displayed will only be of the thickness of the metal.The biggest advantage of the multiple echo system that a Cygnus Instruments gauge uses is that paint or coating will not have to be removed – it will not be included in the displayed measurement. Our gauges will be able to read through coatings of up to 6 millimetres which can be increased to 20 millimetres using the deep coat function. A single crystal probe that has a straight sound beam can be used to measure on surfaces that are curved. Because the timings between the second and third echoes have to match, a verified accurate measurement is ensured.