Fuel Systems
The device labeled "B", shown in the illustration is known as the __________. Illustration MO-0112.
centripetal pump chamber cover
The port "X" shown in the illustration allows water to enter the adjoining chamber. During what cycle of operation will this occur? Illustration MO-0112.
Sludge discharge cycle
Which of the listed types of gasket material should be used on high pressure fuel oil lines on a diesel engine?
Soft copper
The device labeled "H", shown in the illustration is referred to as the __________. Illustration MO-0112.
centrifugation chamber bottom gasket
On a slow-speed diesel engine vessel equipped with an ALCAP fuel oil purification system, what would be a symptom of an opening solenoid valve leaking by?
An increase in the rate at which the purifier sludge tank is rising.
The diesel engine shown in the illustration has the highest fuel pressure developed in the part labeled __________. Illustration MO-0003.
E
The device labeled "A", shown in the illustration, is known as the __________. Illustration MO-0112.
regulating ring
An immediate repair is required if a leak occurs in the high pressure fuel piping between the injection pump and fuel nozzle because of the __________.
serious fire hazard
All alarms occurring on the control unit of the device shown in the illustration will __________. Illustration MO-0127.
shut off the oil feed to the separator
The gasket "U" shown in the illustration, is used to seal the liquid space below the __________. Illustration MO-0112.
sliding piston
Item "O" of the device shown in the illustration is the __________. Illustration MO0112.
spindle nut
As shown in the illustration, the viscosimeter would be used to directly control the output of which of the following components? Illustration MO-0077.
Final heaters.
During the change over period from residual to distillate fuel the final fuel filters clog at a decreasing time interval. What is the most likely cause?
Incompatibility of the fuels resulting in asphaltenes of the residual fuel precipitating out.
Which of the following conditions would be the most probable cause for the 'low oil temperature after preheater' LED indicators, as shown in the illustration, to be illuminated? Illustration MO-0127.
Incorrect steam control valve setting.
After removing the bowl hood of the device shown in the illustration, excessive quantities of sludge are visible. Which of the following statements represents the approach to rectify the situation? Illustration MO-0112.
Disassemble the entire unit, clean all components, replace any defective gaskets and use the proper lubricants where required.
The wear liner shown in the illustration is indicated by the letter __________. Illustration MO-0112.
"R"
Using the graph shown in the illustration, the oil being separated has a specific gravity of .87 kg/dm3 at 72.5°C. What will be the specific gravity if the temperature is lowered to 40°C? Illustration MO-0113.
0.892 kg/dm3
From the graph shown in the illustration, determine the size of the regulating ring required for the proper operation of the fuel oil centrifuge if the fuel oil specific gravity is 0.9 kg/dm3 at 68°F, and the separating temperature is 158°F. Illustration MO-0113.
110 mm
From the graph shown in the illustration, if the separating temperature required is to be 167°F, and the specific gravity of the oil is .98 kg/dm3 at 59°F, what size regulating ring is required? Illustration MO-0113.
92 mm
Which of the labeled figures illustrated, represents the correct alignment mark relationships of a properly reassembled centrifuge bowl? Illustration MO-0022.
A
The temperature of the contaminated fuel oil fed to the centrifuge shown in the illustration should be __________. Illustration MO-0012.
203°F to less than 212°F
What operational difficulties are associated with fuel incompatibility?
Frequent clogging of final fuel filters and sticking/scuffing of fuel pump plungers and nozzles.
Which of the following statements describes "N" shown in the illustration?
Illustration MO-0112.?the centrifuge disc stack
Where does the shoot cycle operating liquid first come in contact with the rotating forces of the device shown in the illustration? Illustration MO-0112.
In the opening chamber labeled "L".
How is oil supplied to the device shown in the illustration Illustration MO-0127.
In this arrangement an independent pump is utilized.
The device shown in the illustration can be automatically or manually desludged. The closing sequence at the end of the desludging cycle is initiated by opening which of the labeled components listed below? Illustration MO-0012.
Q
When changing over from residual to distillate fuel on a slow-speed diesel main engine, what is a good guideline to follow regarding the change over?
Rate of temperature change of fuel to the engine should not exceed 2 degrees C per minute.
In pre-treating fuel oil on a motor vessel, what would you consider the most important factor to prevent high temperature corrosion on an engine's combustion components?
Run one centrifuge as a purifier at a reduced rate to minimize water, especially salt water, in the fuel.
The discharge nozzle shown in the illustration, is indicated by the letter __________. Illustration MO-0112.
S
When changing over from residual to distillate fuel on a slow-speed diesel propelled vessel, you should limit the rate of temperature change of the fuel in order to prevent what operational difficulty?
Seizing and scuffing of fuel pump plungers and injector needle valves due to thermal effects on close clearance components.
Which of the listed substances can be satisfactorily removed from diesel fuel by centrifuging?
Sludge
Which of the following statements describes what will occur if the annular spaces, indicated by the letter "K" of the device shown in the illustration, became restricted? Illustration MO0112.
The bowl will fail to close when starting and the unit will not shoot when operating.
Which of the following statements is accurate concerning the vibration sensing device used with the separator shown in the illustration? Illustration MO-0127.
The detector mechanism consists of an armature suspended on a flexure pivot and restrained from motion by a permanent magnet acting through a small air gap.
If the separating temperature is to remain constant, what is the relationship between the specific gravity of the oil and the required size of the regulating ring? Illustration MO-0113.
The larger sized regulating rings are designed to be used with oils of lower specific gravities.
The unit shown in the illustration is beginning the sludge discharge cycle. The operating liquid solenoid valve has been energized and space "J" is filling up. Which of the following actions should occur next? Illustration MO-0112.
The liquid enters via port "X" into the opening space with the net resultant force causing the piston slide to move down.
If item "F" begins leaking during operation, which of the following operating conditions will NOT occur? Illustration MO-0112.
The oil/water interface will remain in the same neutral position.
As Chief Engineer of a slow speed diesel engine vessel equipped with an ALCAP fuel oil purification system. You note a definite increase in the rate at which the purifier sludge tank is rising. One of the first items to check on your system would be which of the following?
The opening water solenoid for leak through.
Which of the following statements represents the working principle of the water transducer used with the separator shown in the illustration? Illustration MO-0127.
The probe and sensor measure the dielectric constant through capacitive reactance of the process fluid.
Your ship is equipped with ALCAP heavy fuel oil purifiers. The watchstander reports excessive water drained from the fuel oil service tank. Which component should he check?
The water transducer located in the clean oil discharge line.
What terminates the sludge discharge cycle of the device shown in the illustration? Illustration MO-0112.
The solenoid valve closes, allows the water in the opening chamber to bleed off through "S", and the sliding piston moves upward due to the force developed in area "J".
During the normal operation of the centrifuge shown in the illustration, the operating liquid solenoid and bypass valves for the cleaning cycle should be in which position? Illustration MO-0112.
The solenoid valve is closed and the bypass valve is closed.
Which factor determines the size of the ring dam for a fuel oil centrifugal purifier?
The specific gravity of the fuel.
How may water be removed from the bowl of the separator as shown in the illustration? Illustration MO-0127.
The water may be removed through the water drain valve or through the sludge ports during the sludge discharge cycle.
As shown in the illustration, which of the following conditions would be responsible for a "low pressure in oil outlet" alarm to be indicated? Illustration MO-0127.
Throughput too low
What is used as the primary operating medium during the sludge discharge cycle, shown in the illustration? Illustration MO-0112.
Water
When tightening the lock ring "G" of the device shown in the illustration, two events are simultaneously accomplished. Which of the following statements represents these events? Illustration MO-0112.
When tightened, the lock ring allows for movement of the sliding piston and positions the sliding piston within the bowl bottom.
Heavy fuel oil used in the system shown in the illustration, will have the lowest viscosity __________. Illustration MO-0058.
at the main engine fuel oil header
The principal hazard to personnel when using a diesel engine fuel nozzle tester is _______.
blood poisoning
The purpose of the interlocked three-way valve shown in the illustration is to __________. Illustration MO-0058.
change fuel from heavy to light oil or vice-versa while insuring that oil is returned to the proper day tank
For a continuous operation diesel engine, a duplex filter unit would be the best arrangement because __________.
changing filter elements would not interrupt engine operation
During normal operation, the liquid retained in space 'J' of the device shown in the illustration is __________. Illustration MO-0112.
directly forcing the sliding piston upward to keep the bowl closed
In the device shown in the illustration, the component lettered "A" is the ________. Illustration MO-0012.
dirty oil input port
When reassembling the bowl of the centrifuge, shown in the illustration, the alignment mark on the locking ring passes the bowl cover mark in excess of the manufacturer's specifications. This is due to __________. Illustration MO-0012.
excessive wear of the locking ring and/or bowl threads
While operating the fuel oil centrifuge shown in the illustration, the fuel oil is being continuously ejected with the sludge and the seal water. The probable cause is the __________. Illustration MO-0012.
gravity disk inside diameter is too large
Whether using a centrifuge or a simple filter, oil cleaning and filtration will be the most effective when the oil is at a __________.
high temperature and a low viscosity
The area indicated by the letter "L" of the device shown in the illustration is properly called the __________. Illustration MO-0112.
injection chamber
The greatest difference between the centrifuge bowl shown in the illustration and that of a tubular bowl, with straight, vertical, interior surfaces, is that the illustrated unit __________. Illustration MO-0012.
is self desludging
The system shown in the illustration utilizes a water transducer which is __________. Illustration MO-0127.
located in the oil outlet piping
The replacement piping for diesel engine high pressure fuel systems must be the same length and diameter as the original piping to __________.
maintain specified injection characteristics
To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of ______.
monel metal or stainless steel
If the bowl of a disk type centrifugal purifier when operated as a separator is not primed, the __________.
oil will be lost through the water discharge ports
The area indicated by the letter "W", shown in the illustration is correctly termed the __________. Illustration MO-0112.
opening chamber
While operating the fuel oil centrifuge shown in the illustration, the bowl fails to open for sludge ejection. The probable cause is that __________. Illustration MO-0012.
the seal ring on the operating slide is defective
The force developed by the liquid within space "J" of the device shown in the illustration depends upon __________. Illustration MO-0112.
the speed of the bowl and the condition of seal "U"
For optimum results, centrifugal purification of heavy fuel oil should be accomplished with the fuel at the lowest practicable __________.
throughput
The device labeled "D", as shown in the illustration, is the bowl __________. Illustration MO-0112.
top
The item indicated by the letter "F" of the device shown in the illustration is the __________. Illustration MO-0112.
upper bowl gasket
The device labeled 'C' shown in the illustration is known as the __________. Illustration MO-0112.
upper locking ring
