Apparatus for accurately positioning heat exchanger tube within steam generator tube sheet

摘要

Apparatus for positioning either one of a pair of automatically controlled remote mechanisms (12) for properly positioning the two opposed ends (30a, 30b) of a common heat exchanger tube (18) within a tube sheet (20) of a steam generator and having a tool (26) for securing the tube therein. The apparatus includes a pair of microswitches (73, 90) precisely positioned closely adjacent the tool on each of said pair of mechanisms. The first switch (73) is actuated upon initial engagement of the tube end (30) and the tool (28) to indicate which of the opposed tube ends is first engaged, and the second switch (90) is actuated upon proper positioning of the tube end within the tube sheet. In operation, the tube end nearest the tube sheet of the two opposed tube ends to be engaged is the first tube end to be positioned and secured within the tube sheet. Conventionally, this has been a manual operation. This apparatus permits automatic positioning of heat exchanger tubes within a tube sheet, reducing worker exposure to radioactivity.