The plate heat exchanger is a new type of high efficiency heat exchanger which is assembled from a series of metal sheets with a certain corrugated shape. Plate heat exchangers are usually assembled from thin plates. A wide variety, such as: sealed, welded, spiral plate, shell and shell. In the early days, plate heat exchangers were only used in light industrial sectors such as high temperature sterilization of milk, juice processing and beer brewing. With the improvement of manufacturing technology, corrosion-resistant sheet materials and gasket materials resistant to high temperature and corrosion have gradually appeared, and the sheets have also been gradually enlarged. Currently. Plate heat exchangers have been widely used in various chemical industries, food industry, metallurgical industry, petroleum industry, power station, machinery, sewage treatment and so on.