Heat Exchanger - Tubesheet (Confined or Extended)

[Angsi]

Are there any codes and rules that requires extended tubesheets (OD of the T/Sheet = OD of Girth Flange)to be used for certain cases or is confined tubesheets acceptable for all cases (Tema R).

The second question is, if lets say 10mm cladding thickness is required on the tubesheet, is it a standard practise to have one of the two expanded grooves in this cladded section?

 

[rmw]

The grooves should be in the base metal of the tubesheet, not in the cladding.

rmw

 

[metengr]

rmwis absolutely correct. The cladding serves as a corrosion barrier, and provides no structural integrity in this application.

 

[Christine74]

On exchangers where extended tubesheets are optional, such as "U" tube and floating head designs, the fixed tubesheet generally isn't designed as an extended type unless the customer specifically requests that be. A customer might specify an extended tubesheet to facilitate hydrotesting the bundle outside of the shell. But nothing in TEMA or API 650 requires that the tubesheet be extended for certain applications.

Looks like rmw has already answered the second question correctly.

-Christine

 

[Angsi]

Thanks.

 

[roca]

For integrally clad or weld overlaid tubesheets one groove should be in the centre of the cladding / overlay material layer. Check with your client.

rnw / meteng - if the grooves are in the base material how do you stop the tubeside fluid attacking the base material?

Extended tubesheets are again a client requirement.
If you use an extended tubesheet it is normally so that it can be used to hydro-test purposes (instead of using a test ring). In these case the tubesheet extension shall be calculated to withstand the bolt load during the hydrostatic test

 

[Angsi]

Roca, won't seal welding on both sides help i.e. prevent the tubeside fluid attacking the t/sheet base metal? Can this be considered as an adequate protection?

Thanks.

 

[roca]

How can you seal weld on both sides????
Why seal weld when you can put a groove in the 10mm cladding and one in the base material?
Some clients do not like seal welds – check with your client

I am not an expert in heat exchangers - but in my experience and with the clients I have used a groove is always put in the clad part of the tubesheet