单选题As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into （）.AliquidBoily mixtureCemulsionDvapor
单选题
As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into （）.
A
liquid
B
oily mixture
C
emulsion
D
vapor
参考解析
解析：
暂无解析
相关考题：
If the head pressure of a reciprocating refrigeration compressor is excessiveA.the relief valve should open before the high pressure cutoutB.the relief valve should open and allow the excess refrigerant to flow to the receiverC.the high pressure cutout switch should operate before the relief valve opensD.you should close the discharging valve
The temperature of the refrigerant in the evaporator coil depends mostly upon the ___.A.refrigerant pressure in the evaporatorB.cooling water temperature to the condenserC.heat load in the refrigerator compartmentD.solenoid valve in the liquid line
To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the_______ .A.suction service valve as a vaporB.suction service valve as a liquidC.discharge service valve as a vaporD.charging valve as a liquid
If the superheat value of a thermostatic expansion valve is set too low, the _.A.the suction line will be abnormally cold and liquid may slug back to the compressorB.the suction line will be hot due to a reduced amount of refrigerant returning to the compressorC.the temperature of the refrigerant within the condenser will remain the sameD.the temperature of the refrigerant passing through the sub-cooler will decrease
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Which of the problems listed could be indicated if a sight glass in the refrigerant liquid line is full of bubbles?（）AProper refrigerant chargeBFaulty expansion valveCInsufficient refrigerantDSolenoid valve stuck open
单选题The thermal expansion valve controls the amount of refrigerant that is allowed to flow to the （）.AcompressorBcooling coilsCcondenserDreceiver
单选题If a refrigeration system compressor crankcase is sweating, you should （）.Aadd refrigerant to the systemBadjust the thermal expansion valve to the proper settingCadjust the float valve to the proper holding pressureDopen the hand expansion valve
单选题When you adjust a thermostatic expansion valve, （）.Arefrigerant must be bled off the sensing line before adjustments are madeBall refrigerant must be pumped into the receiver before adjustments are madeCtime must be allowed for conditions to stabilize in the evaporator before further adjustments are madeDall refrigerant must be routed through the dehydrator while changing the superheat setting
单选题As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into （）.AliquidBoily mixtureCemulsionDvapor
单选题In a compression refrigeration plant the refrigerant flows from the expansion valve and through the （） where it absorbs heat from the space being cooled and becomes a gas or vapor.AcompressorBcondenserCthrottle valveDevaporator
单选题A ruptured diaphragm in a thermostatic expansion valve will cause the valve to （）.AopenBcloseCremain in its positionDflood the evaporator with refrigerant
单选题A pressure drop through the refrigerant liquid line may cause （）.Asolenoid valve to seizeBcompressor to huntCformation of flash gas in the liquid lineDexpansion valve to freeze open
单选题The only means of removing the latent heat of condensation from a refrigerant in the normal refrigeration cycle is by （）.Apassing it through the expansion valveBcondensing refrigerant in the system condenserCpassing the gaseous refrigerant through the heat interchanger on the suction side of the compressorDmaintaining a high pressure on the systems receiver
单选题The compressed air is admitted to each cylinder through a cam operated by starting air valve when the piston has just passed its （）.ABDCBTDCCBBDCDATDC
单选题If the head pressure of a reciprocating refrigeration compressor is excessive, （）.Athe relief valve should open before the high pressure cutoutBthe relief valve should open and allow the excess refrigerant to flow to the receiverCthe high pressure cutout switch should operate before the relief valve opensDyou should close in on the suction valve
单选题If the head pressure is too high,（）Athe relief valve should open before the high-pressure cutoutBthe relief valve should open and let excess refrigerant go to receiverCthe high-pressure cutout switch should operate before the relief valve opensDclose in on the suction valve
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Both the temperature and the pressure of the refrigerant are increased in the （）.AcompressorBcondenserCevaporatorDexpansion valve
单选题To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the （）Asuction service valve as a vaporBsuction service valve as a liquidCdischarge service valve as a vaporDcharging valve as a liquid
单选题To add refrigerant to the high side of an air conditioning system, you should introduce the refrigerant through the （）.Adischarge service valve as a vaporBsuction service valve as a liquidCcharging valve as a liquidDcondenser purge valve as a vapor
单选题The thermostatic valve has a throttling action, that is to say the valve can（）Astop the refrigerant from flowingBforce the refrigerant to flowCcause the refrigerant pressure to riseDcause the refrigerant pressure to fall
单选题After passing through the expansion valve the refrigerant should be in the state of （）.AvaporBliquidCsolidDNone of the above is tree
单选题The principal purpose of sub-cooling liquid refrigerant prior to its entering the expansion valve is to （）.Aincrease the refrigerating effect, by decreasing the amount of flash gasBallow the refrigerant to enter the throttling device in a saturated conditionCincrease the refrigerating effect by increasing the amount of flash gasDminimize the temperature drop of the liquid as it passes through the solenoid valve to the outlet side
单选题A feeler or thermal bulb is used for the expansion valve to （）.Adetect the temperatureBdetect the pressureCheat the refrigerantDaccelerate the refrigerant
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In its simplest form the pressure reducing valve is opened or closed by （） which is balanced by the downstream pressure acting on a diaphragm.Aadjusting a nutBa pre-tensioned springCany springDupstream pressure
单选题When running a large, low-speed, main propulsion diesel engine on heavy fuel, which of the following precautions should be observed when switching back over to diesel oil?（）AThe diesel oil must never be allowed to mix with the heavy fuelBThe temperature of the fuel from the pre–heater should be gradually reduced after switching over the three–way valveCThe heating steam to the pre-heater should be secured as soon as the diesel fuel passes through the three-way valveDThe heating steam must be secured before the diesel oil passes through the three-way valve