2 - Machinery service systems and equipment

Abstract

This chapter focuses on various marine auxiliary machinery systems, equipment, and their services. It explains machinery such as air compressors, oil fuel transfer, centrifuges, and lubricating systems. Air at a pressure of 20 to 30 bars is required to start the main and auxiliary diesel engines in motor ships and for the auxiliary diesels of steamships. A starting air system for main diesels normally has two air compressors and two reservoirs with sufficient capacity for 12 main engine starts (six if a nonreversible engine). Receivers must store sufficient air for the starts without the need of top-up from compressors. Safety valves are normally fitted to air receivers, but in some installations, reservoirs are protected against overpressure by those of compressors. If safety valves are isolated from reservoirs, the latter must have fusible plugs fitted to release air in the event of fire. Reservoirs are designed, built, and tested under similar regulations to those of boilers. The low-pressure control air-system receiver is supplied ideally from a low-pressure and oil-free compressor. The supply may be obtained from the main air-start reservoirs through reducing valves or pressure regulators, driers, oil traps, and filter. In steamships, the starting air arrangements for diesel auxiliary engines are similar to those in motor ships. The low-pressure air for instrumentation and remote-control devices is likely to be supplied from a low-pressure and oil-free compressor.