What material is commonly used for modern compressor shaft seals?

The correct choice is metal or carbon because these materials provide the necessary durability and resistance to wear and tear that are crucial for the sealing function in compressors. In modern applications, metal and carbon seals are often utilized due to their ability to withstand high temperatures and pressures while maintaining a reliable seal to prevent gas or fluid leaks.

Carbon seals, in particular, are well-regarded for their low friction properties and ability to conform slightly to surfaces, which enhances sealing effectiveness. Metal seals offer excellent strength and longevity under extreme conditions.

While plastic and rubber are used in various sealing applications, they may not hold up as well under the demanding conditions often found in compressor operations, such as exposure to chemicals, high temperatures, or high pressures. Glass is not typically suitable for use in sealing applications due to its brittle nature. Therefore, metal or carbon is the most appropriate choice for compressor shaft seals.