example,
of an 3 Layer gasoline hose, with its echo signal display from an
oscilloscope.
There is a wide range of Coex Pipes, with extreme differences, from thin automotive hose up to thick PVC foam pipe.
In general there is no statement available, whether ultrasonics can measure the total or the layer thickness. It is depend upon the layer thickness and the kind of materials, wether it is possible to do an evaluation. Each individual case has to be investigated.
example,
of an 3 Layer gasoline hose, with its echo signal display from an
oscilloscope.
For so-called multilayer foamed PVC pipes the first layer can be measured. The second Layer also, but not for all thickness and density conditions. Usually be the last (inner) thin PVC layer cannot be measured.
For 2-layer shrink hoses, all measurement are possible.
For gasoline pipes it is possible to measure the total thickness and some of the layers.
If good echo signals can be gained, for further success a sophisticated ultrasonic hardware/software is necessary. Each transducer channel is to be evaluated due to rapid multiplexing. At the moment there is only one system available for this. The system supports 32 channels and can, in theory evaluate one transducer with 32 different adjustments. A practical would be to evaluate 8 transducers with 4 different adjustments.
Rolf Diederichs 19. Dec 1995, dieder@teuto.de