The plate heat exchanger is a high-efficiency heat exchange device composed of a plurality of corrugated heat transfer plates at a certain interval by welding or pressing by a rubber gasket. According to the processing technology, it is divided into detachable heat exchanger and fully welded non-removable heat exchanger. The welded heat exchanger is a structure between the two, that is, the two fluids are assembled as relatively independent structures. . When the welding or assembly of the plates is assembled in accordance with the principle of alternating two-two, the two groups are alternately arranged. In order to increase the area and rigidity of the heat exchange plate, the heat exchange plate is stamped into various corrugated shapes. Currently, it is mostly a v-shaped groove. When the fluid forms a turbulent flow at a low flow rate, the heat transfer effect is enhanced to prevent scale formation on the sheet. The four corner holes on the plate are designed as a fluid distribution pipe and a discharge pipe, and the two heat exchange mediums respectively flow into the respective flow paths to form a countercurrent or a parallel flow through each of the plates for heat exchange.