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
What is the purpose of pressure-vacuum relief valves ________．
A.Regulation of discharge pressure from cargo pumps
B.Maintaining constant velocity in cargo lines
C.Regulation of suction head on cargo pumps
D.To maintain a tank or void at atmospheric pressure
相关考题：
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
Badly leaking refrigeration compressor discharge valves will cause ______.A.overfeeding of the expansion valveB.damage to the condenserC.constant running of the compressorD.flooding of the receiver
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
Which method should be used to warm up the pump turbines prior to discharge ________．A.Lock the turbine rotor and slowly bleed in steam until operating temperature is reachedB.Run the pump at high speed with the discharge valves closedC.Run the turbine at slow speed with the pump disconnectedD.Shut the discharge valve and run the pump at slow speed
What is the purpose of the relief valve of a cargo pump ________．A.Provides for the removal of vaporsB.Allows two or more tanks to be filled at the same timeC.Provides for the emergency shutdown of the pumpD.Permits the return of cargo to the suction side of the pump
All of the following steps are taken in starting a centrifugal pump，EXCEPT to ______．A.Set the relief valveB.Check the lubrication systemC.Vent the pump casingD.Open the pump suction and discharge valves
单选题What is the purpose of pressure-vacuum relief valves? （）ARegulation of discharge pressure from cargo pumpsBMaintaining constant velocity in cargo linesCRegulation of suction head on cargo pumpsDTo maintain a tank or void at atmospheric pressure
单选题Cargo pump relief valves are piped to the（）.Acargo pump pressure gaugesBcrossover lines interconnecting two pumpsCsuction side of pumpsDatmosphere through pump vents
单选题The purpose of the safety relief valves installed on an auxiliary boiler is to （）.Arelieve excess fuel oil pressure during the “off” fire cycleBadmit water to the dry pipeCthrottle the forced draft fan output for proper combustionDreduce excess steam pressure in the boiler
单选题After installing a new hydraulic pump in a system, what special attention should be given to the hydraulic system?（）AThe relief valves in the system should be readjustedBThe filters and strainers should be checked frequentlyCAll system pressure should be readjustedDThe system should be drained and renewed with a fluid of different operating characteristics
单选题Badly leaking refrigeration compressor discharge valves will cause（）.Aoverfeeding of the expansion valveBdamage to the condenserCconstant running of the compressorDflooding of the receiver
单选题Which method should be used to warm up the pump turbines prior to discharge（）.ALock the turbine rotor and slowly bleed in steam until operating temperature is reachedBRun the pump at high speed with the discharge valves closedCRun the turbine at slow speed with the pump disconnectedDShut the discharge valve and run the pump at slow speed
单选题If the discharge valves on a refrigeration compressor are leaking badly, the compressor should （）.Arun continuouslyBnot startChave high discharge pressureDshort cycle on the high pressure switch
单选题All of the following steps are taken in starting a centrifugal pump，EXCEPT to（）.Aset the relief valveBcheck the lubrication systemCvent the pump casingDopen the pump suction and discharge valves
单选题Overload protection on hydraulic system is provided by the use of （）.Astop valvesBpressure relief valvesCbalance valvesDregulating speed valves
单选题The usual symptoms of cavitation in a centrifugal pump is （）.Anoise and vibrationBan increase in discharge pressureCan increase in suction pressureDlifting of the relief valve
单选题Blow-off of the relief valves of the engines cylinders may be caused by （）.Atoo low leadBwater in fuelCtoo tight springDleakage
单选题What is the purpose of the intake/exhaust valves in a diesel engine? （）AThey regulate the combustion cycleBThey supply cooling waterCThey synchronize the ignition sparkDThey supply and regulate the lubricant flow
单选题To operate a centrifugal fire pump at reduced capacity, you should （）.Areadjust the relief valveBthrottle the suction lineCthrottle the discharge valveDopen the priming line
单选题A relief valve for a cargo pump is generally installed（）.Aafter the discharge valveBbetween the pump and discharge valveCafter the suction valveDbetween the pump and suction valve
单选题Bad valves operation of the reciprocating air compressors can be detected by observation of （）.Athe discharge temperature lowBthe discharge temperature highCthe discharge pressure riseDthe inter-stage pressure low
单选题What is the purpose of a relief valve?（）Ato fill 2 tanks at the same timeBto use pump at a higher pressureCto return liquid to suction side if discharge valve is closedDAll of the above are true
单选题The major difference between the discharge and suction valves installed in most low pressure, reciprocating air compressors is that（）Aone valve seats upwards, while the other seats downwardsBthe reed valves used on the discharge are made substantially thicker and heavier than the suction valvesCthe suction valve springs exert a greater tension than the discharge valve springsDthe discharge valve springs exert a greater tension than the suction valve springs
单选题Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by（）.Aleaky discharge valves on the LP cylinderBleaky discharge valves on the HP cylinderCinsufficient intercooler coolingDlow ambient air pressure
单选题How should cargo tank hatches be protected when the ullage opening is open and the tank not gas free?（）.AWith gooseneck ventsBWith warning signsCWith flame screensDWith pressure-vacuum relife valves
单选题A spur gear pump should be operated with the discharge valves （）.Aslightly openedBthrottledCfully openedDhalfway opened
单选题A device fitted over the discharge opening on a relief valve consisting of one or two woven wire fabrics is called a flame（）.AstopperBscreenCfilterDrestrictor