Regarding Temperature
High-Temperature Conditions: Graphite packing features a temperature resistance range of -200°C to +455°C, whereas PTFE packing ranges from -200°C to +260°C (or 80°C to +260°C). Under high-temperature operating conditions, graphite packing demonstrates superior heat resistance. If the sealing environment involves elevated temperatures (exceeding 260°C), graphite packing is better able to maintain effective sealing performance. For instance, in the sealing of certain high-temperature steam pipelines where temperatures reach above 300°C, graphite packing constitutes the superior choice.
Low-Temperature Conditions: Both materials are suitable for use in low-temperature environments down to -200°C, and both can maintain a certain level of sealing performance under such conditions.
Regarding Pressure
Graphite packing can withstand pressures of up to 200 bar in rotary pumps, 100 bar in reciprocating pumps, and 400 bar in valves. While documentation for PTFE packing does not explicitly specify pressure limits for different types of equipment, it notes that the material is capable of providing effective seals in high-speed and high-pressure environments. In high-pressure settings-provided the pressure falls within the acceptable range for graphite packing-the latter demonstrates a distinct advantage in pressure resistance. However, if PTFE packing meets the specific requirements of a particular high-pressure device, either material can achieve an effective seal; the ultimate choice depends on the actual pressure values and the specific type of equipment involved.
Regarding Media
Chemically Corrosive Media: PTFE packing is capable of withstanding corrosion from a wide array of organic and inorganic chemical substances, maintaining its performance even in harsh chemical environments involving strong acids, strong bases, and similar agents. Consequently, PTFE packing holds a distinct advantage when sealing against highly corrosive chemical media. For example, in chemical manufacturing processes involving equipment seals exposed to highly corrosive substances-such as sulfuric acid or sodium hydroxide-PTFE packing is the more appropriate choice.
General Media: For media such as hot water, high-temperature steam, heat-transfer fluids, hydrogen, ammonia, organic solvents, hydrocarbons, and cryogenic liquids, graphite packing is widely utilized for sealing valves in industrial sectors including petroleum, power generation, chemical processing, and steel manufacturing; in these applications, graphite packing effectively demonstrates its superior sealing capabilities. PTFE packing is also suitable for sealing a wide variety of media-for instance, in valves, pumps, and pipelines within chemical processing equipment. Regarding the sealing of general media, both types of packing exhibit excellent applicability, with the specific choice ultimately depending on other operational parameters such as temperature and pressure.
