The problem of overlapping heat exchanger supports
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We are currently designing three fixed-plate heat exchangers with a diameter of DN1500 (using saddles as supports). Due to limited space on site, the client has requested that the three units be installed one on top of another. I’m concerned that having them stacked so high might cause them to wobble; what if they fall over? I would like to ask everyone for any good methods for designing saddles, or whether it’s necessary to add supports on the periphery or something similar.
Heat exchangers can be arranged in an overlapping manner as needed, with generally no more than 3 units being overlapped. Heat exchangers with a shell diameter of ≥1.6m should not be arranged in an overlapping fashion. When heat exchangers handling different media are placed overlappingly, care must be taken to ensure that the installation height meets the requirements for piping.
How can I ensure that the device doesn’t shake after installation? Do I need to add supports nearby?
You can check by applying the loads of the two heat exchangers above to the supports of the heat exchanger at the bottom. You can add me on WeChat at shuiguowuhen330; I’m sure communication will go well.
It is a common design approach; one can consider treating the bottom heat exchanger as a horizontal vessel, and include the weight of the heat exchanger in the density of the medium inside the vessel. This allows for an initial assessment of the stability of the lowest support brackets and the shell. Additionally, the risk of overturning due to an increased center of gravity must also be taken into account.
Such a design should be avoided as much as possible. When three heat exchangers are connected through overlapping supports, the local stresses at the junctions between the supports and the cylinder become very complex due to differences in expansion within the shell side, as well as the weight of the equipment. Conventional design methods are unable to calculate these stresses. Moreover, the height resulting from this overlapping arrangement is quite high, so seismic loads and pipe stresses cannot be ignored. Our design features separate support frames; only those with a weight of 400 or less use an overlapping installation method, for reference only.