Compact Heat Exchangers

7Manufacturing and Qualification Testing of Compact Heat Exchangers

7.1 Construction of Brazed Plate‐Fin Heat Exchanger

The heat exchanger is assembled from a series of flat sheets/separating sheets and corrugated fins in a sandwich construction. Tube plates (i.e. parting sheets) provide the primary heat transfer surface. Parting sheets are positioned alternately with the layers of fins in the stack to provide containment between individual layers. These elements are built into a complete core and then vacuum brazed to form an integral unit. A section through a typical plate‐fin heat exchanger core is shown in Figure 7.1. The heat transfer fins provide the secondary heating surface for heat transfer. Fin types, densities and heights can be varied to ensure that exchangers are tailor‐made to meet individual customer requirements in terms of heat transfer performance versus pressure drop. Distributor fins collect and distribute the heat transfer fluid from the header tank to the heat transfer fins at the inlet and reverse the process at the outlet. Distribution fins are taken from the same range as the heat transfer fins, but tend to be less dense.

Figure 7.1 Core structure of brazed aluminium plate‐fin heat exchanger. (Hesselgreaves [1])

The heat exchanger core is then encased in a welded structure that incorporates headers, support plates and feed/discharge pipes. Most plate‐fin ...