Regarding the selection of valve packing

What is a valve gasket?

It depends on the conditions under which the valve is to be used. Graphite is used for steam applications, PTFE for environments prone to corrosion, and rubber gaskets are used in special cases. Asbestos packing is employed for providing anti-corrosion sealing in environments involving acids, alkalis, liquid ammonia, water, oils, as well as for valves, pumps, pistons, and rods. Materials used for asbestos silicone oil packing: asbestos, tetrafluoroethylene emulsion, silicone oil. Operating temperature: -20–280°C. Operating pressure: 20 Mpa. Suitable for sealing devices such as petroleum and chemical industry containers, pumps, and valves. Graphite packing is used for sealing valves, pumps, and reaction vessels in environments with high temperatures, high pressures, and corrosive media. Tetrafluoroethylene-graphite interwoven packing is used to seal pump shafts and valve stems in applications involving various types of media. Jute packing is primarily used in pumps, refining equipment, filters, valves, propellers, and other applications where wear resistance is required. Polytetrafluoroethylene packing is widely used in industries such as food processing, pharmaceuticals, and paper and textile manufacturing, where high cleanliness standards are required, as well as on valves and pumps exposed to highly corrosive media. PTFE slitted wire gaskets are commonly used in rotating parts with lower linear speeds (less than 4 m/s). Scope of application: Maximum operating temperature: 260°C; Maximum operating pressure: 6.3 MPa; pH value: 0–14. Expanded polytetrafluoroethylene packing (black PTFE) has a maximum operating temperature of 280°C, a maximum operating pressure of 4.0 MPa, and a pH value of 0–14

Packaging material is the common term for the valve stem sealing filler. Regarding the selection, the technician above has already explained it.