lesson 5　Text Fuel oil system 轮机英语课件.ppt

The fuel oil system for a diesel engine can be considered in two parts—the fuel supply and the fuel injection systems. Fuel supply deals with the provision of the fuel oil suitable for use by the injection system. The whole fuel system will then embody two almost entirely separate systems, one for diesel fuel and one for high viscosity fuel. The latter will embody heating arrangements and means to control the temperature of the fuel to ensure that it is adequately fluid when stored, transferred, cleaned and injected. In a typical fuel installation on board a ship for a modern diesel engine, separate filling connections for the diesel and heavy fuel tanks are provided. In use, the filling connections on deck are connected to shore hoses and the fuel oil bunkers(燃料舱) are then distributed to various double bottom, deep, wing and side tanks(双层底舱，深舱，舷侧舱和边舱） as necessary. Steam heating coils(蒸汽加热盘管) are installed in the various tanks to ensure that the temperature of the oil can be raised to reduce the viscosity to a level that will ensure easy pump-ability. Pipes used for transferring high viscosity fuel should be well lagged(加保温层) and long runs of piping(管道系统) should have steam-tracing pipes(蒸汽伴热管) fitted. The fuel oil is drawn from the bunker tanks through a duplex strainer(双联过滤器) by a transfer pump and thence to dirty oil storage or setting tanks. Leaving the fuel in the setting tanks whilst keeping it hot to reduce its viscosity allows the heavier impurities and any water present to settle to the bottom of the tank. The sediment(沉淀物) and water are drawn off leaving the remainder ready for cleaning. It is then passed to a purification(净化) system for treatment and from there to the clean heavy fuel tank, which known as the service tank. From the clean heavy fuel tank the oil gravitates through a heated buffer(缓冲柜)、 or balance tank to the booster pumps(增压泵) and is discharged through a fuel heater and filter to a viscosity regulator and from there to a duplex