Boiler Tube Plugs
When to Plug Tubes
Boiler Tube Plugs
When suspected tubes in a boiler are leaking and boiler efficiency is down. Carry out a vacuum test on all tubes. Completion of tests will show the validity of each tube. If there is evidence of feed water running out of the tube. Then a compromised tube is evident and boiler tube plugs are required.
When feed water runs down the face of the tube sheet from the tube joint and the inside of the tube is dry. The leak is from the tube joint itself. This can be a matter of re-rolling a compromised tube joint. This type of leak is more evident when a hydrostatic test is complete. Re-rolling the tube joint may seal the tube. However, over-rolling a tube can make the problem worse. Over-rolling the tube can stretch the ligature between tubes making others leak.
Piercing tubes before inserting Tube Plugs
Before welding, end users need appropriate material certification for the plugs. This certification ensures that the correct type of plug is being used. Allowing for traceability in the event of any issues. Heat lot numbers are available SA-105 plugs. This extra documentation further verifies the integrity and quality of the plugs.
Before insertion of the plug in the defective tube. The tube needs piercing top and bottom so no air gets trapped in the tube after plugging.
This is very important! Allowing water to run through the tube to avoid internal pressurization.
Take care to have the welding completed with the appropriate welding procedure. Ignoring proper procedures can lead to damage to the tube sheet. This in turn will add costs in the long run. Furthermore, welding ensures that the plug has the best seal possible. This is especially important in cases where the tube is more corroded. Welding can create a tight seal, preventing any leaks or dislodging of the plug.
The best tool to do this is the One Revolution Internal Tube Cutter. As displayed on the left this tool is operated manually by the socket and T bar method. As the tool is turned, the cutter comes out of the tool and cuts completely through the tube wall. Only a short cut of about 20mm is needed at both ends. It is better to have the cuts at the top and bottom of the tube so no air is trapped.
If plugging Heat exchangers consult the link below: