66.  State general requirement of fuel oil system?

- The system must ensure normal working of all engines even when the ship rolling 15o and pitching 5o.

- Fuel pipe must not be arranged near exhaust pipe, silencer, electric panel, and cabin or through fresh water tanks.

- Fuel is normally stored in double bottom tanks or wing tanks. Capacity of all tanks must be enough for continuing operation of the ship in estimated time with some percentage of fuel for stand by.

- There must be interconnection between tanks. The valves should be arranged so that it is easy for operation, checking and repairing.

- There must be separated pipes for receiving and delivering fuel on each tank. Besides this, vent pipe, drainpipe, overflow pipe (with sight glass), sounding pipe (or sounding device), manhole for inspection and repairing must be installed.

- Diameter of vent pipe is normally equal to receiving pipe. The upper end of vent pipe is placed on upper deck with a copper net to prevent dust and fire from falling into fuel tanks. On the other hand, a coaming for vent head must be arranged to prevent leaking or spilling of the fuel. Diameter of vent pipe in any case must not be smaller than 50 mm.

- The system must be provided with international flanges for receiving and discharging pipe and placed on both sides of the ship (Port & Starboard side).

- The system must be equipped with remote control device for emergency shit down of delivery valves of each fuel tank in case of fire or flooding in the engine room

- There must be indicators, alarm devices such as: pressure gauge, thermometer, viscometer, flow meter, and low-high level alarm to increase the safety of the system

- In case of using FO, FO purifier must be provided in the system. FO must be heated in storage tanks, settling tank, service tank before transferring and purifying. Heating coil of the tanks should be arranged about 25 cm from bottom of the tanks. If use steam for heating, steam pressure must be smaller than 7 kg/cm2. Fuel pipe must be heated and insulated to maintain FO temperature. The heating temperature of FO before entering the engine depends on kind of fuel and engine.

67.   State requirement of fuel oil heater?

Heavy fuel oil must be heated in the tank and pipe line. Steam or electric power can be used for heating. If steam is used, pressure must be smaller than 8kg/cm2. There must be fuel oil temperature regulator and high temperature alarm device or low flow alrm device, except heating temperature is smaller than flash point 10. Further more, fuel oil must be heated to suitable viscosity before injection. Three way valve should be arranged to change over from DO to FO and vice versa.

Do not apply electric heater for double bottom tank and deep tank.

Electric heater has to meet the following requirements

+ There must be automatic temperature regulator

+ There must be device for auto cut – off power supply with temperature sensor. This device must switch off power then heating temperature over 200 and manual device must be equipped.

68.  State requirements of fuel oil system for diesel engine?

- The system must ensure normal working of all engines even when the ship rolling 15o and pitching 5o.

- Fuel pipe must not be arranged near exhaust pipe, silencer, electric panel, and cabin or through fresh water tanks.

- Fuel is normally stored in double bottom tanks or wing tanks. Capacity of all tanks must be enough for continuing operation of the ship in estimated time with some percentage of fuel for stand by.

- There must be interconnection between tanks. The valves should be arranged so that it is easy for operation, checking and repairing.

- There must be separated pipes for receiving and delivering fuel on each tank. Besides this, vent pipe, drainpipe, overflow pipe (with sight glass), sounding pipe (or sounding device), manhole for inspection and repairing must be installed.

- Diameter of vent pipe is normally equal to receiving pipe. The upper end of vent pipe is placed on upper deck with a copper net to prevent dust and fire from falling into fuel tanks. On the other hand, a coaming for vent head must be arranged to prevent leaking or spilling of the fuel. Diameter of vent pipe in any case must not be smaller than 50 mm.

- The system must be provided with international flanges for receiving and discharging pipe and placed on both sides of the ship (Port & Starboard side).

- The system must be equipped with remote control device for emergency shit down of delivery valves of each fuel tank in case of fire or flooding in the engine room

- There must be indicators, alarm devices such as: pressure gauge, thermometer, viscometer, flow meter, and low-high level alarm to increase the safety of the system

- In case of using FO, FO purifier must be provided in the system. FO must be heated in storage tanks, settling tank, service tank before transferring and purifying. Heating coil of the tanks should be arranged about 25 cm from bottom of the tanks. If use steam for heating, steam pressure must be smaller than 7 kg/cm2. Fuel pipe must be heated and insulated to maintain FO temperature. The heating temperature of FO before entering the engine depends on kind of fuel and engine.

69.  State requirements of boiler burner?

Main boiler burner:

These must be at least 2 pumps and heating devices for boiler which has high pressure injection firing device. Pump capacily can be able to supply enough amount of fuel oil to generate steam at maximum generating steam rate. These pump must be interconnected

Strainer must be arranged both suction and discharge pipe of burner oil pump, these strainers can be cleaned without stopping fuel supplying.

These strainer must be installed relief valve to reduce pressure before opened

Auxiliary boiler burner:

If these is other equipment ensuring for heating at sea going when auxiliary boiler stop then one firing device is permitted for this boiler.

76.  List the name and explain function of all main components of diesel oil system?

1. Fuel oil tanks: Storage tanks, settling tank, service tank, dirty oil tank, spill oil tank (overflow tank), sludge tank.

2. Transfer pumps.

A transfer pump is used to transfer fuel oil between tanks and supply fuel oil to the engines.

3. Fuel injection pumps.

 They create a high pressure of fuel oil before supplying to fuel injection valves.

4. Fuel injection valves.

Their duty is to atomize and distribute fuel oil over combustion chambers of the engines.

5. Filters.

The are two kinds of filter in the system, they are rough filter (strainer) and fine filter.

6. Heaters

Their function is to maintain proper viscosity of fuel oil. Either electric heaters or steam heaters are used in the system.

7. Purifiers.

They are used to separate water and sludge from fuel oil.

8. Pipe lines: Both high pressure and low-pressure pipes are used in the system.

9. Indicators, alarm devices.

77.  State the operational principle of a typical diesel oil system?

The typical diesel oil system (DO system).

DO system is used on small ships, for high-speed diesel engines or generator engines. Because viscosity of DO is low, a heater of DO is not required. However, DO may be heated before separating.

78.  List the name and explain function off all main components of heavy fuel oil system?

1-      DO settling tank

2-      DO service tank

3-      FO settling tank

4-      FO service tank

5-      Heater

6-      DO purifier

7-      FO purifier

8-      Venting tank

9-      Strainer

10-  DO burner pump

11-  FO burner pump

12-  Flow meter

13-  Rough filter

14-  Supply pump

15-  Circulating pump

16-  Fine filter

17-  Pressure regulating valve

79.  State the operational principle of a typical heavy fuel oil system?

The typical heavy fuel oil system (FO system).

FO system is mostly used on ships. When a heavy fuel oil system is used, a diesel oil system is also required. This is called “a two fuel system”. When the ship is in running up condition, FO is used for the main engine. On the other hand, when the ship is maneuvering, the main engine is switched over to DO.

Today, on some modern ships only FO is used. To maintain a proper temperature of FO in the fuel injection valves, FO must be continuously heated and circulated through the fuel injection valves even when the engine is stopping.

80.  State the functions of lubricating oil and lubricating oil system?

In fact, the lubricating oil is pumped into engines to carry out duties:

To lubricate working surfaces of the parts of an engine to reduce friction and wear.

To cool friction surfaces of the engine.

To clean working surfaces of all moving parts of the engine.

To safeguard metal surfaces from corrosion.

To fulfill these duties, the lubricating oil system must have following functions:

- To receive the lubricating oil (LO) into the ship.

- To store the lubricating oil in tanks.

- To transfer the lubricating oil between tanks.

- To separate water, sludge and dirties from the lubricating oil.

- To supply the lubricating oil to the friction surfaces of the engines.