Although the plate heat exchanger is durable, after long-term use, it is difficult to maintain the original performance due to deterioration of the seal ring, adhesion of the stain. and various problems such as liquid leakage may occur. In order to make the plate heat exchanger more durable, stable and in the best condition, regular maintenance is indispensable. The marine heat exchanger gasket is the main sealing accessory of the heat exchanger, and the quality of the rubber pad determines the service life of the heat exchanger..The tear strength reflects the sensitivity of the gasket to the gap and the ability to resist cracking under a certain pressure. The gasket with low tear strength is easy to crack at the corners when the plate is pressed, which is especially important for the non-stick gasket. After the rubber is aged (aging), the degree of change in physical properties has a significant effect on the temperature resistance and service life of the gasket. For example, the EPDM rubber produced by a certain company meets the requirements of GB16409 at room temperature, but after 180 °C and 72 hours aging, the compression permanent crucible rate reaches 82.3% (75.6% increase); The hardness is 87 degrees (increased by 12 degrees); after the PHE equipped with the gasket is tested for 72 hours and hot steam (180C to 200 °C), the elasticity is almost completely lost.