Team has successfully combined its high pressure (HTHP) tapping procedures with the company's tube plugging technologies to successfully seal tube and plug leaks on fin fan exchangers -- online.

Prior attempts at online repair of fin fan leaks by other contractors were limited only to specific leaks such as thread leaks at header plugs. Tube leaks could not be sealed externally because the tubes were so close together and there was no room for repair clamps or access to the leaking tube.

Team has successfully engineered a method to seal both. Tube leaks are sealed at the header by utilizing specialty plugs. The plugs are placed inside the tube and torqued to expand and seal against the header wall. Tube leaks are successfully repaired by plugging the leading tube at both ends to isolate the leaking tube from the process.

Both methods sound simple, but are complex and require precise application when performed online with the fin fan in full operation.

Setting and torquing the tube plugs is accomplished by utilizing a machine with a special fixture - designed and fabricated by Team - mounted on the fin fan header. The header plug then can be removed with the fin fan online utilizing Team's expertise.

With the header plug removed, the specialty plug is inserted into the tube end and header wall and torqued securely in place. Leaks past the rolled area can be successfully and effectively sealed in this manner, also.

Isolation of a tube with a through-wall leak is accomplished by repeating the above procedure at the opposite end of the leaking tube, thus effectively plugging the leaking tube and removing it from service with the fin fan in operation.

Header plugs are reinstalled once these procedures are complete.

Thread leaks on header plugs are similarly repaired by removing the plug and coating the threads with Team's HiProSeal^® thread sealant and reinstalling the plug into the header wall while the fin fan is in service.

At no time are plant operations interrupted during these procedures. The initial difficulty in the development of the above procedures lay in designing an effective, adjustable fixture that could be assembled onto a fin fan header and used as support for Team's special machine.

Several fixture designs were tested at Team. Two were selected; one of which - depending upon the location of the leaking tube - can reach about 75% of the leaking tubes.

Once the repairs are completed, nothing is left permanently attached to the fin fan. All tooling, fixtures and hardware are removed from the headers. Only the tube plugs remain in place inside the tubes.

Fin Fan leaks have been successfully repaired online at major chemical plants and refineries.

For more information visit the Specialty Maintenance Page