Which systems do not use corrugated ribbon packing?

The correct choice indicates that fuel oil (F/O) and lube oil (L/O) systems do not utilize corrugated ribbon packing. This is due to the specific operating conditions and requirements of these systems. In particular, F/O and L/O systems require packing that can effectively seal under varying temperatures and pressures without being compromised by the properties of the fluids being handled.

Corrugated ribbon packing is typically used in applications requiring flexibility and the ability to conform to irregular surfaces, which is often beneficial in high-pressure (HP) and low-pressure (LP) systems, hydraulic systems, and cooling systems, where a secure seal is crucial to prevent leaks and maintain system integrity. The materials used in these systems are often able to withstand the mechanical stresses encountered better than the packing materials used in F/O and L/O systems.

F/O and L/O systems prioritize materials that resist wear and provide reliable sealing for oils, which are generally denser and more viscous. Therefore, the use of alternative packing materials that are specially designed for these specific applications leads to enhanced performance and longevity in those systems.