The plate heat exchanger is an efficient and compact heat exchange device. It is widely used in refrigeration systems and is an indispensable equipment in refrigeration systems. It can be used as a condenser, evaporator, regenerator and intercooler. Compared with the traditional shell-and-tube heat exchanger, the heat equipment is only 1/3~1/6 of the shell-and-tube type, and the weight is only 1/2~1/5 of the shell-and-tube type. The injection volume is only 1/7 of the shell-and-tube type, and the heat transfer efficiency is 2 to 5 times higher than that of the shell-and-tube heat exchanger. It has the advantages of energy saving, economy, compact structure and convenient disassembly, and it is widely used in the refrigeration industry. For example: The chiller and the air-cooled heat pump water-cooling unit are used as heat exchangers for evaporators, condensers, heat recovery heat exchangers (superheaters), liquid subcoolers and oil coolers for screw compressors.