单选题Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?（）APressure-reducing valveBUnloading valveCCounterbalance valveDPressure-relief valve
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 valve
B
Unloading valve
C
Counterbalance valve
D
Pressure-relief valve
参考解析
解析：
暂无解析
相关考题：
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
Which of the listed devices is used to measure pressure and convert it to an electrical signal?A.TransducerB.ReducerC.TransformerD.Rectifier
单选题（） are used to limit the pressure in any particular portion and mainly control the pressure after the valve.ARelief valvesBCheck valvesCSafety valvesDReducing valve
单选题Which of the conditions listed would cause simultaneous high cylinder firing pressure and low exhaust temperature?（）AImproper fuel rack positioningBLengthy opening of the exhaust valveCExcessively early injection timingDExtended light load operation
单选题The device used for low-pressure control and high-pressure cutout on a compressor is called a（）AcutoutBpressure controllerCcontroller switchDcutout switch
单选题Which of the valves listed should be used either in the fully opened or the fully closed position?（）AA gate valveBA globe valveCAny check valveDAny needle valve
单选题Which of the valves listed is NOT considered to be a hydraulic system directional control valve?（）ASpring-centered valveBUnloading valveCThree-position valveDTwo-position valve
单选题In the design of hydraulic piping and equipment consideration is given to minimize turbulence in the hydraulic fluid, as this will cause（）Amolecular fluid vibrationBenergy lossesCwide pressure variationsDmechanical damage to control valves
单选题For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?（）AChilled water system supply temperatureBChilled water system return temperatureCCompressor discharge temperatureDCompressor suction pressure
单选题Which of the following methods is used to prevent throttling of compressed air through the diesel engine air starting valves?（）AHolding the valve open for a long periodBIncreasing the starting air pressure usedCOpening the stating air valve quicklyDReducing the starting air valve size
单选题The series of valves used to control the return flow in well control operations is called the（）.Avalve assemblyBstandpipe manifoldCaccumulator manifoldDchoke manifold
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?（）ALow compression pressure and high exhaust temperatureBLow firing pressure and high exhaust temperatureCLow compression pressure and low exhaust temperatureDLow firing pressure and low exhaust temperature
单选题Which of the listed devices is used to measure pressure and convert it to an electrical signal?（）ATransducerBReducerCTransformerDRectifier
单选题Check value is used to control （）Adirection of oil flowBback pressure of return oilCbypass of filterDhigh pressure overflow
单选题In order to distribute the side pressures over a wide area of the cylinder walls and liners, which of the listed types of pistons are used in modem low pressure air compressors?（）ADifferentialBTrunkCBarrelDValve-in-head
单选题Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）Adouble bottom fuel oil tank temperatureBheater supply steam flowCpressure of the fuel supplied to the burnersDattemperator steam flow in the heater discharge circuit
单选题The arrangement and shape of the cams on a diesel engine camshaft directly control which of the listed groups of operating conditions?（）Aspeed, torque, and horsepower productionBfiring order, valve timing, and valve liftCfuel consumption, efficiency, and cylinder pressureDscavenge pressure, compression ratio, and exhaust pressure
单选题Differential needle valves used in fuel injectors are directly closed by（）Acam actionBspring forceCfuel oil pressureDfiring pressure
单选题Compensated flow control or constant flow valves are used in hydraulic systems to（）Acompensate for major leaks in the systemBmaintain the original fluid viscosityCallow for changes in pressure and temperature within the systemDassure constant fluid temperature
单选题Diesel engine automated control systems may utilize sensing devices of dual function, with sensing ranges providing both alarm and engine shut down capability.Which of the key points would only require an alarm sensor?（）ALube oil pressure and temperatureBjacket water pressure and temperatureCEngine over-speedDLube oil sump level
单选题In a refrigeration system, which of the following statements describes the actions occurring when a solenoid valves, used in conjunction with an unloader head is energized?（）AThe solenoid valves directs high pressure gas to the valve lifting device raising the suction valve off its seat and causing one specific cylinder to become unloadedBThe solenoid valves directs high pressure gas to the underside of the unloading piston, causing it to rise and allowing the recirculating ports to be openedCWhen the solenoid valve becomes energized, the valve ports become closed, allowing discharge pressure to build up above the piston, shifting it and causing it to unloadDThe solenoid valve allows the refrigerant to pass from the suction chamber to the top of the unloader piston, causing the piston to lift and unload the cylinder
单选题Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）AThermal expansion valve frozen openBSuction gas heat exchanger bypassedCCondenser clogged or fouledDHigh pressure cutout switch inoperative
单选题Which of the listed devices would be installed at a control system air pressure reducing station?（）AMoisture separatorBVacuum breakerCLubricatorDNon-return valve
单选题Which of the listed failures, occurring in an automated diesel generator system, should cause an audible alarm at the engine room control station?（）ALow cooling water outlet temperatureBHigh lube oil pressureCLow lube oil temperatureDLow starting air pressure