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The gasket of a plate heat exchanger is a key component of the heat exchanger. As the application areas of plate heat exchangers continue to expand, different requirements are imposed in terms of temperature resistance, pressure resistance, and corrosion resistance for various media and processes. The operating temperature of a plate heat exchanger is actually the temperature that the gasket can withstand. It is obviously impossible to use a “universal” gasket to suit all situations. Instead, gaskets made of different materials should be used depending on the specific situation, and such gaskets must possess heat resistance, elasticity, and corrosion resistance. The commonly used gasket cross-sectional shape is hexagonal. Plate heat exchanger gaskets can be divided into 3 types based on the way they are installed on the heat exchange plates: (1) Direct bonding type: In this case, sealant is applied to the gasket before it is directly bonded to the installation grooves of the heat exchange plates. This type of gasket has a simple structure and is easy to manufacture, but its installation and removal are relatively troublesome; it is not suitable for situations where plate heat exchangers need to be frequently disassembled and reassembled. (2) Glue nail inlay type: This involves designing mounting holes on the heat exchange plates, with glue nails provided on the edges of the gaskets. After placing the gasket in the installation groove, the glue nails are inserted into these mounting holes. (3) Snap-fit type: This type features buckles designed on the edge of the gasket, which are used to snap the gasket onto the heat exchange plate. Inlaid and snap-fit gasket structures are complex and require tedious processing, but they are relatively easy to install and remove, making them suitable for plate heat exchangers that need to be disassembled and reassembled frequently. The common types of gaskets, their temperature resistance, and suitable media are as follows: Nitrile rubber NBR (–10~+110°C): water, seawater, mineral oil, saline. Ethylene propylene diene monomer EPDM (–25~+150°C): hot water, steam, acids, bases. Hydrogenated nitrile HNBR (–10~+150°C): high-temperature mineral oil, high-temperature water, and applications similar to those of nitrile rubber. Fluorocarbon rubber FKM (–5~+180°C): acids, bases, fluids. Perfluoroalkoxy rubber (0~+160°C): concentrated acids, bases, high-temperature oils, steam. If leakage, cracking, aging, or other issues occur in the gaskets of plate heat exchangers during use, they should be replaced promptly. The sequence for replacing the gasket is as follows: ① Remove the old gasket. Be careful not to cause scratches in the gasket groove during disassembly. ② Use propylene glycol, butyl glycol, or other similar solvents to thoroughly remove any residual glue from the gasket grooves. ③ Wipe the gasket groove and gasket clean with a clean cloth or cotton yarn. ④ For adhesive gaskets, the adhesive must be applied evenly inside the gasket groove. ⑤ Attach clean new gaskets to the board. ⑥ The plate with the gaskets applied to it should be placed in a flat, shaded, and well-ventilated area to dry naturally before it can be installed and used.