The plate heat exchanger plates are divided into parallel flow and diagonal flow according to the flow pattern of the heat exchange medium.Correspondingly,the plate heat exchanger gaskets are divided into single-sided flow and diagonal according to the flow pattern of the heat exchange medium. The quality of the heat exchanger channel gasket is a important factor that affects the life of the plate heat exchanger.Compression set rate is an important basis for measuring the elastic recovery ability of gasket materials and determining the temperature limit of use. At the allowable use temperature, the smaller the value, the better the elastic recovery performance, and the better the sealing performance and the average life of the gasket. The compression set rate will increase with increasing temperature and time, and is related to the molecular weight of the rubber, vulcanizing agents, reinforcing agents and other additives. Under the premise of raw rubber, it mainly depends on the type of vulcanizing agent and the optimum amount of formula. The phenolic compound vulcanizing agent has the lowest compression set ratio; the amine compound vulcanizing agent is the worst.