The plate heat exchanger has a strong heat exchange capacity, and its heat transfer coefficient is several times that of a conventional heat exchanger. The heat exchange area per unit volume is large, compact and light. Therefore, it has always been favored by scientific researchers and users.However, the pressure resistance of the plate heat exchanger is not good and the sealing performance is poor, which restricts the application of the plate heat exchanger in engineering.In the past, plate heat exchangers were mainly used for cleaner working media, the working pressure was not too high and the leakage requirements were not too harsh. After the leakage, the equipment will not have a large impact on the environment and the working mediumsuch as Civil hot water delivery system and steam hot water exchange system.Now the use of plate heat exchangers in the use of refrigeration equipment using plate heat exchangers are mainly small equipment, mainly imported brazed plate heat exchangers. It is also feasible to use separate plate heat exchangers on the condensers and evaporators of large chiller units.