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单选题
What is TRUE of pressure/vacuum valves? （）
A
They are designed to provide for the flow of small volumes of tank atmospheres caused by thermal variations in a cargo tank
B
They should operate in advance of the pressure/vacuum breakers
C
They should be kept in good working order by regular inspection and cleaning
D
All of the above
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更多 “单选题What is TRUE of pressure/vacuum valves? （）A They are designed to provide for the flow of small volumes of tank atmospheres caused by thermal variations in a cargo tankB They should operate in advance of the pressure/vacuum breakersC They should be kept in good working order by regular inspection and cleaningD All of the above” 相关考题
考题
Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?A.Pressure-reducing valveB.Unloading valveC.Counterbalance valveD.Pressure-relief valve
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After installing a new hydraulic pump in a system, what special attention should be given to the hydraulic system?A.The relief valves in the system should be readjustedB.The filters and strainers should be checked frequentlyC.All system pressure should be readjustedD.The system should be drained and renewed with a fluid of different operating characteristics
考题
How should cargo tank hatches be protected when the ullage opening is open and the tank NOT gas free?A.With gooseneck ventsB.With warning signsC.With flame screensD.With pressure-vacuum relief valves
考题
What is TRUE of pressure/vacuum valves?A.They are designed to provide for the flow of small volumes of tank atmospheres caused by thermal variations in a cargo tankB.They should operate in advance of the pressure/vacuum breakersC.They should be kept in good working order by regular inspection and cleaningD.All of the above
考题
What best describes for how long a gas-free test is good ________．A.For as long as is indicated on the gas-free certificateB.For the instant that it is madeC.Until valves in line with the tank or compartment are reopenedD.Until changes in temperature or pressure affect the vapor content in the space
考题
What is the purpose of pressure-vacuum relief valves ________．A.Regulation of discharge pressure from cargo pumpsB.Maintaining constant velocity in cargo linesC.Regulation of suction head on cargo pumpsD.To maintain a tank or void at atmospheric pressure
考题
单选题Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?（）A
Pressure-reducing valveB
Unloading valveC
Counterbalance valveD
Pressure-relief valve
考题
单选题What is the purpose of pressure-vacuum relief valves? （）A
Regulation of discharge pressure from cargo pumpsB
Maintaining constant velocity in cargo linesC
Regulation of suction head on cargo pumpsD
To maintain a tank or void at atmospheric pressure
考题
单选题To avoid excessive surge pressure when bunkering, you should （）A
bunker at a normal rateB
check for kinks in hoseC
close valves slowlyD
shut valves before topping off
考题
单选题Most hydraulic steering gears are fitted with relief valves which（）A
function when the rudder is amidshipsB
relieve excess whip pressure from the hydraulic oil systemC
protect the piping assembly from external rudder shockD
relieve excessive telemotor pressure
考题
单选题After installing a new hydraulic pump in a system, what special attention should be given to the hydraulic system?（）A
The relief valves in the system should be readjustedB
The filters and strainers should be checked frequentlyC
All system pressure should be readjustedD
The system should be drained and renewed with a fluid of different operating characteristics
考题
单选题If a refrigeration compressor were short cycling on the low pressure cutout switch, the probable cause for this might be the （）.A
system was overcharged with refrigerantB
high pressure switch was improperly adjustedC
expansion valve strainers were fouledD
suction valves were leaking slightly
考题
单选题The loss of the diesel engine cylinder air charge through leaky valves, piston rings, worn or scored liners, would be indicated by which of the following sets of conditions?（）A
Low compression pressure and high exhaust temperatureB
Low firing pressure and high exhaust temperatureC
Low compression pressure and low exhaust temperatureD
Low firing pressure and low exhaust temperature
考题
单选题The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch， One reason for this could be the （）.A
system is low on refrigerantB
high pressure cutout switch is improperly adjustedC
discharge valves are leaking slightlyD
discharge valves are leaking excessively
考题
单选题The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch（）A
system is overcharged with refrigerantB
system is low on refrigerantC
discharge valves are leaking excessivelyD
discharge valves are leaking slightly
考题
单选题Low pressure air is usually taken through （） or pressure regulators to a low pressure reservoir supplying a ring main through driers.A
globe valvesB
butterfly valvesC
gate valvesD
reducing valves
考题
单选题Starting air valves are held firmly on their seats by（）A
cam rollers on the camshaftB
spring forceC
air pressure on top of the valve differential pistonD
air pressure on the bottom of the valve differential piston
考题
单选题Differential needle valves used in fuel injectors are directly closed by（）A
cam actionB
spring forceC
fuel oil pressureD
firing pressure
考题
单选题Which one of the followings might not be employed to create vacuum for flash type evaporator? （）A
high-pressure steam-driven air-ejectorB
motor-driven vacuum pumpC
water-motivated air eductorD
centrifuge pump
考题
单选题If one of the bilge system manifold valves does not properly seat, the （）A
bilge well connected to that valve, plus the second bilge well being pumped will be completely emptiedB
bilge system will lose vacuum and prevent the other bilges from being pumped outC
bilge well aft connected to that valve will siphon its contents to the forward bilge wellsD
discharge pressure will be too high
考题
单选题The lifting pressure of （） is set in the presence of a Surveyor it is locked and cannot be changed.A
fuel valves of main engineB
injector pump of main engineC
safety valves of marine boilerD
safety valves of a reciprocating pump
考题
单选题Bourdon Tube is probably the most commonly used （） measuring instrument.A
the absolute pressureB
the gauge pressureC
the vacuum pressureD
the differential pressure
考题
单选题Thermostatic expansion valves can be adjusted for （）.A
suction pressure onlyB
head pressure onlyC
superheat onlyD
suction pressure and box temperature
考题
单选题Bad valves operation of the reciprocating air compressors can be detected by observation of （）.A
the discharge temperature lowB
the discharge temperature highC
the discharge pressure riseD
the inter-stage pressure low
考题
单选题A vacuum is initially established in the first and second stages of a low pressure evaporator by the use of （）A
vacuum drag from the auxiliary condensate systemB
individual vacuum pumpsC
a single non-condensing air ejectorD
a two stage air ejector
考题
单选题Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by（）.A
leaky discharge valves on the LP cylinderB
leaky discharge valves on the HP cylinderC
insufficient intercooler coolingD
low ambient air pressure
考题
单选题Most solenoid valves are actuated by （）.A
a springB
an electromagnetC
the force of gravityD
refrigerant pressure
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