The life of the gasket directly affects the use of the plate heat exchanger. The heat exchange medium has low viscosity at high temperature and strong permeability, which is easy to cause leakage. Wax oils and heavy oils with high viscosity have strong permeability at high temperatures and corrosive effects on gaskets. At high temperatures situation, flanges, bolts and gaskets may undergo creep and stress relaxation, resulting in loose seals and reduced seal specific pressure.Some non-metallic gaskets accelerate aging or deterioration at high temperatures, and even burn out, the amount of rebound will decrease, which will affect the seal.Due to the different temperatures of the various parts of the sealing assembly, the thermal expansion is not uniform, which increases the possibility of failure of the gasket seal. If the temperature changes repeatedly, the seal is more likely to fail. The plate heat exchanger should be repaired and replaced with a new one in case of leakage.