The STP (Special Tube Plug) is a safe solution to isolate tubes in heat exchangers.
It is used to separate the tube from the heat exchange service when there is a defect that causes fluid mixing or when the tube joint to the tube plate no longer provides a good seal.
The most commonly used exclusion system is to use truncated cone plugs inserted by percussion into the tube to be excluded. However, the use of conical plugs wedged and/or welded into the tube risks creating a series of significant problems, including triggering a domino effect on the mandrels or welds of the tubes next to the excluded one.
The STP plug solves these problems thanks to the threaded connection that ensures a solid anchoring of the cap to the tube, preventing accidental projection due to pressure. In addition, the removal of installed STP is a simple and safe operation, even in the extreme case of a tube still under pressure.