Issues with vertical fixed-tube-sheet drain ports
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For the drain ports on vertical fixed-tube-sheet designs, we weld a semi-circular cutout made from a pipe fitting to the tube sheet. Now, the inspection agency is asking whether there are any standards that explicitly permit such a design I showed them the \"Structural Design Manual for Steel Shell and Tube Heat Exchangers with Fixed Tube Sheets,\" but they still didn’t agree.
If specific guidelines for the design of vertical fixed-tube-sheet drain ports cannot be found in relevant industry standards or **standards, it may be necessary to verify them through other methods. It is recommended to provide a design scheme for the welded joint along with its mechanical analysis report, or to demonstrate its feasibility and safety by citing actual application cases of similar structures. At the same time, it is also possible to consider conducting technical exchanges with the special inspection agency to understand the specific concerns, and adjust the design plan or provide additional supporting documents based on their feedback. If an agreement still cannot be reached, modifications may be necessary by referring to the design schemes or standards recommended by the special inspection agency. .
Although this structure has been used in the industry, those who have conducted finite element analysis or mechanical analysis know that the stress on the edges of the semi-circular tube is much greater than that on the body of the circular tube. Therefore, strictly speaking, finite element analysis is necessary to calculate the stresses in this structure; conventional calculation formulas are not appropriate. If nothing goes wrong, it’s fine, but if problems arise, the designers are held responsible.
Indeed, sometimes the sealing on the welded side of the tube sheet is prone to problems
If standard support is necessary, then use a orifice plate flange, or a device flange equipped with leak detection holes; however, these leak detection holes are used for evacuation