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单选题
Lube oil pumps taking suction from the sump of most small marine engines are usually （）.
A
of the diaphragm type
B
of the centrifugal type
C
of the positive displacement type
D
independently driven by electric motors
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Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of ______.A.refrigerant bubbles in the lube oilB.refrigerant reducing the lube oil viscosityC.oxidation(氧化) of the lube oil from overheatingD.reducing the floc or cloud point of the oil
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单选题A dirty diesel engine oil filter element can best be detected by （）.A
visual inspection of the elementsB
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单选题What is a function of the wearing rings used in most centrifugal pumps?（）A
Absorb erosion of high velocity discharge streamB
Seal pump shaft against entry of airC
Isolate the discharge side from the suction sideD
Dampen the turbulent discharge flow
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单选题The lube oil cooler is located after the lube oil filter in order for （）A
the filter to operate more efficientlyB
the lube oil cooler to be bypassedC
positive lube oil pump suction to be assuredD
galvanic action in the cooler to be minimized
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单选题A lube oil filter can be used to remove most contaminants from lube oilA contaminant which will remain in the lube oil after filtering is （）.A
acidB
fuel oilC
sedimentD
water
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单选题If the cooling water temperature and the lube oil temperature in a diesel engine are too high, the cause can be （）A
a dirty lube oil strainerB
internal water leaksC
an oil suction line restrictionD
excessive wears of the cooling water pump
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单选题In a bypass type lubrication system for a diesel engine, the dirty oil line to the centrifuge should be taken from the （）.A
lube oil pump suction lineB
lube oil pump discharge lineC
bottom of the lube oil sumpD
outlet from the lube oil header
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单选题The oil sump, a light welded design, is mounted on the engine block from below and sealed by （）A
O-ringB
gasketC
washerD
packing
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单选题A sudden decrease in the diesel engine lube oil viscosity could be an indication of（）A
loss of additives from the lube oilB
carbon deposits in the lube oilC
excessive centrifugingD
excessive fuel dilution
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单选题Which of the following conditions indicates the dilution of diesel engine lube oil by fuel oil?（）A
Water discharging from the water outlet of the lube oil purifierB
Fuel oil discharging from the water outlet of the lube oil purifierC
Lube oil discharging from the water outlet of the lube oil purifierD
A change in the lube oil viscosity
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单选题A lube oil sample taken from the main engine lube oil system has dark yellow opaque color.This is the result of （）A
water contaminationB
mixing oils of two widely different viscositiesC
overheatingD
aeration
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单选题Foaming of the oil in a refrigeration compressor crankcase is caused by （）.A
refrigerant boiling out of solution from the lube oilB
liquid refrigerant flooding the compressor and systemC
lube oil viscosity being reduced by refrigerant dilutionD
compressor suction pressure suddenly increasing
考题
单选题Which of the following problems will occur if a disk-type centrifugal lube oil purifier is not properly primed prior to admitting oil flow to the bowl?（）A
Contamination of the lube oil by emulsification will resultB
The lube oil will not be subjected to the proper centrifugal forceC
The lube oil will overheat and flashD
Oil will discharge from the heavy phase discharge port and be wasted
考题
单选题Which of the listed characteristics of lube oil are the most important to the engineer from an operational standpoint?（）A
Ash content, carbon residue, and gravityB
Viscosity, acidity, and demulsibilityC
Pour point, flash, point, and precipitation numberD
Auto-ignition point, viscosity index, and film strength
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单选题Demulsibility of a lube oil is defined as （）.A
the ability of oil to separate from waterB
the temperature at which oil flows rapidlyC
a measure of the water in a lube oil systemD
an emulsion of different grades of oil
考题
单选题Setting a sealing equipment astern on the tailshaft can’t （）A
prevent the seawater from intergratingB
prevent the lube oil from running out of the outside aboardC
strengthen the intencity of the sterntubeD
prevent the mud and sand from entering the lube oil system
考题
单选题Most pump manufacturers recommend that the suction piping dimension for centrifugal pumps be （）.A
one size smaller than the pump suction nozzleB
the same size as the pump suction nozzleC
one size larger than the pump suction nozzleD
installed with a short radius elbow at the pump
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单选题Which of the following operating procedures should be carried out immediately after any diesel engine is started?（）A
Take all exhaust temperature readingB
Check the sump oil levelC
Verify proper lube oil pressureD
All of the above
考题
单选题Which of the following statements concerning the lubrication of diesel propulsion engines used in vessels over 300 gross tons is most accurate?（）A
Lubrication systems using engine driven lube oil pumps do not require any additional independent arrangement when such arrangements have been proven reliableB
The use of engine driven pre-lube pumps is permitted on vessels with propulsion systems developing less than 500 shaft horsepowerC
When forced lubrication is used for propulsion engines, one independently driven stand-by pumps is to be provided in addition to the necessary pumps for normal operationD
Lubrication systems where two oil coolers are fitted require a minimum of two temperature control devices which may be actuated by similar sensors
考题
单选题Sludge formation in a diesel engine lube oil system is caused by（）A
carbonization of oils from the combustion chambersB
emulsions of lube oil and waterC
coagulation of unburned fuel below the piston ringsD
all of the above
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单选题Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of （）A
refrigerant bubbles in the lube oilB
refrigerant reducing the lube oil viscosityC
oxidation of the lube oil from overheatingD
reducing the floc or cloud point of the oil
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单选题The construction of the main propulsion engine lube oil sump should （）A
have no plating joints of 90B
retain the lube oil as long as possible before it recirculates through the systemC
provided drain/return lines that are no greater than 24 inches from the pump suctionD
be provided with only a perfectly horizontal bottom
考题
单选题Which harmful consequence may be the result of lube oil sludge accumulation? （）A
Clogged oil pump suction screensB
Increased oil operating temperaturesC
Sticking piston ringsD
All of the above
考题
单选题Most large, low-speed, main propulsion diesel engines use duplex lube oil strainer to （）A
decrease the time required between cleaningsB
removes all large and small foreign objectsC
ensure a positive flow of oil at all timesD
ensure that all lube oil has been treated twice
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