公开(公告)号：US4992735A

公开(公告)日：1991-02-12

申请号：US387997

申请日：1989-08-01

申请人： William K. Cullen ,  Charles H. Roth, Jr. ,  Lee W. Burtner ,  Francis X. Gradich ,  David A. Chizmar ,  Lawrence Galata

发明人： William K. Cullen ,  Charles H. Roth, Jr. ,  Lee W. Burtner ,  Francis X. Gradich ,  David A. Chizmar ,  Lawrence Galata

IPC分类号： F22B37/00 ,  G01N27/90 ,  G21C17/003

CPC分类号： F22B37/003 ,  G01N27/902

摘要： An apparatus and a method for remotely inspecting the interior walls of a cavity having a circular cross section that varies in diameter, such as the interior of a hollow tube plug. The apparatus has an eddy current probe head having a distal and proximal end, wherein the distal end engages the cavity walls, an elongated support assembly connected to the proximal end of the probe that is insertable within the cavity, a radial extender mechanism for radially extending and withdrawing the distal end of the probe with respect to the longitudinal axis of the support assembly, and a probe driving and delivery system for inserting the support assembly into the cavity and helically moving the probe head to inspect the cavity walls for discontinuities. In the method of the invention, the radial extender mechanism radially retracts the probe head within the support assembly when it is inserted through the cavity prior to the inspection operation in order to avoid mechanical interference, and then radially extends the probe head into engagement with the cavity walls. The probe driving and delivery system then helically moves the probe head across the cavity walls to scan the walls for discontinuities that indicate cracks.