Scaner is a device which consist of two elements: data gathering system and convert system. Gathering can be manual or automatic depend on particular situation. But the most importing thing about the scaner is not how to gather the data but how to convert them. The examples of displaying scaning data are digital flow detectors with B-Scan and C-Scan and so on. Sometimes can happen situations that for creating this displays a very complicated gathering data mechanism is used. The idea of B-Scan and C-Scan is very usefull but has a serious simplification. Man can find examples of flow detectors with a scaner which gives more usefull results than B and C-Scan. This flow detectors besides displaying can evaluate testing welds according to different standards. One of that flow detectors is Digital Flow Detector called CUD manufactured by ULTRA Institute.