THERMAL EXPANSION

[Tato]

I´m spanish engineer and i´ll try to find when a expansion join has to been used in heat exchangers. I find somethig in T.E.M.A. but it is not clear.
The shell has 80 Kg/cm2 but the tubes are in vacuum, so I know that a thermal expansion has to been noticed, however i don´t know if this difference is enough to require a expansion join.
Can anybody help me?

Eduardo

 

[prex]

The pressure differential has little to do with the need for an expansion joint: the basic datum is the difference of average wall temperatures.
Anyway the final decision on the nedd for an expansion joint is the result of the calculation procedure that is indeed fully detailed in TEMA: you should follow it to get a reliable answer. prex
motori@xcalcsREMOVE.com

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[MJCronin]

Tato,

Prex is correct, the issue is the maximum temperature difference between the two streams. I would like to add a couple of comments, though....

Some companies decide to include the expansion joint as an additional feature on any appropriate TEMA heat exchanger operating above a certain temperature ( say 300F) This policy is usefull in a facility where the process may change or where a heat exchanger may be used for another duty....

Secondly, you should consider having an experienced vendor help you by quoting a proposed HX two ways.... both with and without the expansion joint. He would be able to give you an operating temperature range difference where the EJ is required for your particular geometry/materials.

Good Luck

MJC