单选题An air compressor can be unloaded at start-up by （）.Aholding the discharge valve openBrelieving the intercooler pressure to the atmosphereCusing an enlarged, permanently opened clearance expansion spaceDa pre-charged accumulator
单选题
An air compressor can be unloaded at start-up by （）.
A
holding the discharge valve open
B
relieving the intercooler pressure to the atmosphere
C
using an enlarged, permanently opened clearance expansion space
D
a pre-charged accumulator
参考解析
解析：
暂无解析
相关考题：
Low compressor head pressure in a refrigeration system can be caused by ___.A.insufficient condenser cooling waterB.excessive condenser cooling waterC.air in the refrigeration systemD.excessive refrigerant in the system
In a chilled(冷的) water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by ______.A.increasing refrigerant pressure in the coilB.increasing chilled water flow through the coolerC.sub-cooling the refrigerant in the condenserD.superheating the refrigerant in the compressor
单选题Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.Ausing a slightly dirty air filterBusing oil having an excessive viscosityCintercooler or after-cooler leaksDcarrying the oil level higher than normal
单选题Air blowing from the intake air filter of an operating air compressor indicates （）.Abroken inlet valvesBbroken discharge valvesCpulsations in the air distribution systemDoverloading of the air distribution system
单选题On opposite ends of a single shaft of a turboblower are a gas driven （）and a air compressor, which are sealed each other.Acharge air receiverBscavenging air beltCturbineDair cooler
单选题The unloading system on an air compressor will （）.Aincrease compressor discharge pressure on demandBincrease compressor operating speed as necessaryCallow the motor to turn the compressor opposed only by frictionDreduce the compressor frictional load when starting
单选题In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）Abroken valve springsBtight drive beltsChigh line voltageDair in the system
单选题（）are supplied by main switchboard directly.ASuez Canal searchlight, air compressor and air conditioning compressorBAir compressor, boiler blower and refrigeration plantCBoiler blower, Suez Canal searchlight and refrigeration plantDSuez canal searchlight, air compressor and boiler blower
单选题Broken valve strips in an operating low pressure, air compressor will cause （）.Aan immediate crankcase explosionBoil contamination in the compressed airCa decrease in compressor capacityDno immediate loss of the compressed air capacity
单选题In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by （）.Aincreasing refrigerant pressure in the coilBincreasing chilled water flow through the coolerCsub-cooling the refrigerant in the condenserDsuperheating the refrigerant in the compressor
单选题Before starting an air compressor, It should be （）.AunloadedBprimedCfilled with waterDgreased
单选题Which of the following problems can cause an above normal air temperature to develop in the intake manifold of a turbocharged and after-cooled diesel engine?（）AFaulty turbocharger turbine diffuser ringBFaulty turbocharger compressor ringCInsufficient cooling water flowDClogged air intake filters
单选题An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.Aoil foaming in the compressorBhigher than normal suction and discharge pressures with a higher box temperatureChigher than normal discharge pressure with a normal box temperatureDthe compressor to run continuously
单选题The air compressor pumps air to the （）.Aexpansion tankBcombustion chamberCair receiverDevaporator
单选题The air compressor pumps air to the （）.Aair cylinderBcombustion chamberCsteam drumDexpansion tank
单选题The air filter is fixed in the （） of an air compressor.Ainlet pipeBoutlet pipeCinter coolerDafter cooler
单选题The air charge leaving an intercooler, or after-cooler of an air compressor can be expected to be （）.AsuperheatedBsuper-cooledCat or below the dew pointDAll of the above
单选题If an air compressor is used to supply compressed air to outlets throughout the engine room and on deck of a vessel, the system is known as the （）.Acombustion control air systemBsupply air systemCships service air systemDlow pressure deck air system
单选题An un-loader is installed on an air compressor to （）.Abypass the high pressure stage to the low pressure stage on 100% of the air compressors in serviceBprevent excessive inter-stage pressure buildupCcontrol compressor discharge pressureDremove all but the frictional load during starting
单选题Starting air for auxiliary engines may be taken directly from the main reservoirs or through （）.Aan auxiliary reservoirBa controlling air bottleCan emergency air compressorDa main air compressor
单选题Air compressor cylinder un-loaders enable the compressor to （）.Avary their speed according to temperature and loadBstart and come up to speed before air compression beginsCchange speed according to overload demandsDreduce compressed air charge density
单选题A knocking sound emitted from an unloaded air compressor is probably caused by （）.Adamaged intake valvesBexcessively tight mounting boltsCinsufficient cylinder lubricationDa loose piston
单选题The loss of （） from an air compressor could lead to an overheated air discharge and possibly an explosion in the pipelines leading to the air reservoir.Alubricating oilBcompressed airCcooling waterDsealing ring
单选题If an air compressor is used to supply air primarily to the combustion control system and other pneumatic controllers, the entire system is known as the （）.Acontrol air systemBforced draft air systemCsupply air systemDships service air system
单选题“This increase in charge air density is accomplished on most modern diesel engine types by use of exhaust gas turbo-charging, in which a turbine wheel driven by exhaust from the engine is rigidly coupled to a centrifugal type air compressor” According to this sentence, we can know that increases density（）, drives the compressor directly（）Aa modern diesel engine；a turbine wheelBa modem diesel engine；exhaust gasesCa compressor；an exhaust gas turbochargerDa compressor；a turbine wheel