DNV KEMA Inspection system for Retaining Rings.

ServiceInitially DNV KEMA will try to obtain asmuch information about the ring’sgeometryand the actual access tothe rotor aspossible; sometimes thereis hardly anyinformation available;the ring’sgeometry is then firstmeasured using an ultrasonic C-scanmapping technique. With thisinformation an inspection plan isissued. Inspection is conducted withinthe time limitsprovided (within 24 hours, if required).Ultrasonic crack detection is focusedon the shrunk connections and wallthickness steps. In addition, whenevernecessary, eddy current scanning isadded to accurately map the outersurface. The ring’s coating is left inplace. Geometry and flaw data are thenfed into a computer model. Theresidual life span is embedded in theanalysis. Furthermore, it is establishedwhen new measurements will have tobe undertaken in order to monitor theflaw indications found.SpecificationsThe KIRR system can be applied ongenerators with a ringdiameter from500-2,000 mm. In-situ test characteristics:• Minimum gap height between rotorand stator: 9 mm• Technique: UT and ET scanning• Surface: 360°C circle and 5-100mm pitch per step• Defects as small as 1 mm can bedetected: guaranteed• Test duration: 24 hours effectively.BenefitsKIRR will be of considerable benefit toyou:• Major savings, since rotor rings willnot have to be replaced• You will constantly be aware of thecondition of the retaining rings andyou can continue monitoring them• A cost reduction because the rotorand the retaining rings do not needto be disassembled• The measuring does not take long• The system has a short delivery time.For more information:DNV KEMAP.O. Box 90356800 ET ArnhemThe NetherlandsT +31 26 3 56 35 00F +31 26 4 42 87 13contact.tos@dnvkema.comwww.dnvkema.comTOS.7064R&H.05