Auxiliary steam systems supply steam at the pressures and temperatures required cooperate many systems and machinery, both inside and outside engineering spaces. As discussed previously, auxiliary steam is often called saturated steam or desuperheated steam.

Many steam systems and machinery receive their steam supply from auxiliary steam systems on most steam-driven ships. Some typical examples are constant and intermittent service steam systems, steam smothering systems, ships' whistles, air ejectors, forced draft blowers, and a wide variety of pumps. Some newer ships use main steam instead of auxiliary steam for the forced draft blowers and for some pumps. Aboard some ships, turbine gland sealing systems receive their steam supply from an auxiliary steam system. Other ships may receive their supply from the auxiliary exhaust system. Gland sealing steam is supplied to the shaft glands of propulsion and generator turbines to seal the shaft glands against leakage. This leakage includes air leaking into the turbine casings and steam leaking out of the turbine casings. More use of electrically driven (rather than turbine-driven) auxiliaries has simplified auxiliary steam systems on newer ships.

SUMMARY

In this chapter, you have learned about the main steam system, the auxiliary steam system, and the use of steam after it leaves the boiler. Remember, steam and feedwater are recycled over and over again to provide heat and power to operate machinery. It is important that you understand the terminology associated with steam and feedwater systems. You will use these terms in your day-to-day routine aboard ship. Some of the subjects will be discussed in greater detail in later chapters. All of these areas are important in their own right. As you learn this information, you will become a more proficient and reliable technician.