What material are packing gland seals commonly made of?

Packing gland seals are specifically designed to prevent the leakage of fluids in various industrial applications, particularly in rotating equipment like pumps and valves. The correct material used for these seals is often a semi-metallic material impregnated with graphite.

This choice is essential because semi-metallic materials provide a combination of strength, durability, and flexibility, which is critical for maintaining a secure seal under varying temperatures and pressures. The addition of graphite enhances the material's ability to withstand friction and heat, allowing it to perform effectively in high-stress environments. This ensures a longer lifespan and better performance in preventing leaks.

Other materials, while they may provide sealing capabilities, do not offer the same performance characteristics. Rubber seals can become brittle over time, especially under heat and pressure, leading to failure. Plastic materials may not withstand high temperatures or pressures as effectively as semi-metallic seals. Fiberglass, on the other hand, does not have the necessary flexibility or sealing capability required for packing glands, making it less suitable for this specific application.