Radiatronics: nondestructive testing instruments for inspectors and quality control

The Current State-of-the-Art

     Ultrasonic thickness gauging has changed significantly over the past few years. There are new requirements for repeatability, data recording and through coating measurements that we did not even think about when we first started selling these instruments, nearly thirty years ago.
     The ultrasonic thickness gauges we offer today are well constructed, reliable instruments. They are available from the barest of basic gauges to fully loaded, feature packed, computer interfaceable instruments. Even the most basic gauges now have many new and useful features. The typical U.S. made instrument is superior in both features and reliability, to any of the imports we have seen.
     We advise you to be cautious in buying, as there are many cheap instruments from third world countries being advertised in catalogs, post card packs, and trade magazines. They are rarely identified as to where they came from or who actually made them. Buyer beware!!
     We do not object to imports in general, but we have little tolerance for poorly made or unreliable instruments being sold for applications involving safety and quality. There may be places to cut corners - this is not one of them!
     Today's prices are lower, the quality higher, and you have more models and features to choose from than at any time in the past.

How Ultrasonic Thickness Gauges Work

Corrosion & General Purpose Gauges
(D-Meters & T-Mikes)

     Corrosion and general purpose ultrasonic thickness gauges measure the elapsed time from the instant the sound beam leaves the probe until it is returned as a result of reflection from the opposite surface.
     Thickness is equal to this time value divided by two and then multiplied by the material's sound velocity.
     Corrosion and General Purpose Gauges use "dual" probes that are capable of getting a useable echo on materials with corroded and pitted back walls.
     This class of thickness gauge can also be used on attenuative, large grained materials such as casting and plastics.

Precision and Through Coating Thickness Gauges

Precision and "through coating" thickness gauges use a "multiple echo" technique. These instruments measure the time between the first and second or subsequent reflections. Some require three "multiple echoes".
To have "multiple echoes", you must have parallel walls. This is not what you find on corroded pipes and tanks! This type of gauge can only measure where the material is not severely corroded.