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OPERATION, MAINTENANCE AND REPAIR OF AUXILIARY GENERATORS Episode 4

Tham khảo tài liệu 'operation, maintenance and repair of auxiliary generators episode 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | TM 5-685 NAVFAC MO-912 LUBE OIL IN WATER INLET METAL EDGE STRAINER WATER PUMP DRAIN WATER OUT LUBE OIL OUT S CT ON STRAINER CHECK VALVE SUMP Figure 3-9. Diesel engine lubrication system. LUBE OIL FILTER OIL COOLER comes up to speed and the auxiliary pump is shut down. The check valve also prevents loss of oil in case of leakage. g. Heating. Circulating lubricating oil absorbs heat from the engine. Frictional heat is absorbed from the bearings. The oil film on the cylinder walls absorbs heat from the combustion space before this oil film drains into the crankcase. Heat must be dissipated by a cooler if the temperature is to be kept below Fahrenheit. At higher temperatures oil oxidizes and sludge forms. An oil cooler is necessary when heat dissipated from the oil by conduction through the walls of the sump and by contact with water-cooled surfaces in the engine is insufficient to keep the temperature below manufacturer s recommendations. A cooler is particularly necessary for engines having oil-cooled pistons. h. Coolers. The oil cooler should be placed in the oil circuit after the lubricating oil filter. The filter then handles hot oil of lower viscosity than if it received cooled oil. The filter performance is better and the pressure drop through it is less with this arrangement. Coolers are usually mounted on the side of the engine or on the floor alongside of the engine base. Cooling water passes through the cooler before entering the engine jackets. Exceptions such as placing the oil-cooling coils in the water jackets at one end of the engine are permis sible. Also the coils may be placed in the side jackets. Some designs have the coil tubes in the cooling water header while in others water entering the cooler is bypassed around the jacket system. i. Oil filters. Proper installation and maintenance of oil filters and mechanical operation of the engine are equally important for treatment of oil. Prevention of contamination and removal of contaminants should be .