What is a Tube Heat Exchanger?

Among many different heat exchangers’ designs, Tube Heat Exchanger is a class. Oil refineries & other major & other major chemical processing units use this type of heat exchanger, and that’s because it is better suited for high-pressure applications. According to the sound of the name, this is a type of heat exchanger that consists of a large vessel for pressure and a bunch of tubes that work cohesively for smooth & convenient functioning of the unit. Subzero Solutions is one of the best Tube Expander manufacturer in India. 

As the normal operations go by and the tubes heat & cool down with the process, the heat exchanger’s tubes tend to contract & expand simultaneously with the process. 

Retubing? Let’s Get A Hang Of It!

Deterioration of these tubes depends on multiple factors, like, application, calcium, saltwater scale, Lyme, and other contaminants. As time goes by, all these factors contribute towards an inevitable result, which is a failure. And when that happens, replacing the tubes becomes a necessity. The process & efforts that go into the replacement of tubes is what retubing of the heat exchanger means.

Now, How Do We Retube?

When it comes to retubing methods in Tube Heat Exchangers, we have two different methods used by the majority of the industry. We have already learned why retubing is such an important process, now let’s learn about the methods of retubing, the difference between them, and what the process is. 

The two well-known methods of Retubing a Heat Exchanger are Retubing by Tube Sheet Cutting Method and Retubing without Tube Sheet Cutting Method. Over the years we have perfected one method from the other, but the two major differences between them are the time difference & internal inspection. If we do not cut the tube sheet, it would lead to us not being able to inspect the internals of the heat exchanger like baffles, tie rods, spacers, etc, but, it will also help in reducing the time duration by 50% when compared to when we cut the tube sheet.

Heat Exchanger Retubing by Tube Sheet Cutting Method

• • Start by removing the channel cover and its end flange on both sides, after which you are required to carry out a thorough visual inspection and record areas of damage, corrosion effects on the tube sheet surface, gasket areas, and any other affected areas.
  • Now remove the existing weld metal with the bevelling tool, after that the shell to tube sheet weld joint on the fixed side tube sheet, if you find any dispensary found against drawing, inform the end-user.
  • Perform cleaning of shell internals after pulling out bundle and carryout sweep blasting on bundle skeleton, now perform 100% Dye Penetrant Testing on tube sheet holes after machining contour radius. 
  • Now Reassemble the new tube and inspect the whole tube all around.

Heat Exchanger Retubing without Tube Sheet Cutting Method

• • Start by removing the channel cover and its end flange on both sides, after which you are required to carry out a thorough visual inspection and record areas of damage, corrosion effects on the tube sheet surface, gasket areas, and any other affected areas.
  • Now, cut & remove old plugs, and remove the weld metal were required for welded tubes using standard cutters and clean the hole. Perform the sweep blasting on both corroded tube sheet faces before the removal. Now, cut the tubes from one end to the fixed side, Pull out the tubes from the fixed side. 
  • Perform cleaning of shell internals after pulling out bundle and carryout sweep blasting on bundle skeleton, now perform 100% Dye Penetrant Testing on tube sheet holes after machining contour radius.
  • Now Reassemble the new tube and inspect the whole tube all around.