In heat exchanger design, the requirement for the perpendicularity between the tube holes in the tube sheet and the sealing surface of the tube sheet serves the purpose of
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In heat exchanger design, why is it necessary to ensure that the tube holes in the tube sheet are perpendicular to the sealing surface of the tube sheet, and why must this be done in accordance with GB/T1184-1996? It is difficult for conventional drilling processes to achieve the required precision; what is the purpose of the specified tolerance for perpendicularity?
In my opinion, the vertical precision is high; compared to lower precision levels, this reduces the restraining stresses associated with assembly during the manufacturing process. During operation, the tensile and compressive stresses between the individual tubes and the tube sheet are relatively similar, which prevents stress concentration from causing damage to certain tubes
The 2nd floor is correct. It shouldn’t be difficult to meet these requirements with today’s level of processing technology
The standard requirements are set according to 1184; that is the minimum requirement. For tube bundles with high alignment precision, the requirement for verticality is more stringent than that specified in 1184. The requirement for the verticality of tube holes is first to ensure the proper assembly of the tube bundle, and secondly, as mentioned on the second floor, to make the pulling force on the tubes uniform and reduce stress concentration in the tubes during operation. With the improved precision of the tube bundles in model 151, the verticality of the tube holes should also increase accordingly. Given the current level of machining technology, even for deep hole processing, as long as the manufacturing process is appropriate, achieving the required verticality precision is not a difficult task :)
The clearance between the heat exchange tubes and the holes in the tube sheet is very small, making it difficult to install the heat exchange tubes at an angle; moreover, it is hard to achieve a good seal when expanding the tubes, and their tensile strength is also affected.