网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
Air entering an air-cooled refrigeration system is indicated by （）.
A
frosting of the liquid line
B
higher than normal head pressure
C
a clear sight glass
D
abnormally cold reefer boxes
参考答案
参考解析
解析：
暂无解析
更多 “单选题Air entering an air-cooled refrigeration system is indicated by （）.A frosting of the liquid lineB higher than normal head pressureC a clear sight glassD abnormally cold reefer boxes” 相关考题
考题
When adding oil to a refrigeration system, precautions must be taken to ensure thatA.the compressor suction pressure is not too highB.all air is purged from the pump and charging fittingsC.the high pressure cutout switch is held open to prevent accidental startingD.the condenser is completely shutdown first
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
考题
Air trapped in the hydraulic fluid of a steering system may be indicated byA.the steering pumps overspeedingB.a jammed open relief valveC.a constantly occurring improper rudder responseD.excessive ram pressure
考题
In the refrigeration system, a shortage of refrigerant is indicated byA.the compressor short cycling on high pressure cut out switchB.high suction pressureC.high head pressureD.bubbles in the sight glass
考题
You are in a tropical port．The refrigeration machinery on a container loaded with air-cooled fruit fails．It cannot be repaired for 18 to 24 hours．Which step should you take to reduce the temperature rise and spoilage of the fruit ________．A.Discharge a cylinder of nitrogen into the containerB.Shade the container and periodically hose it downC.Seal any ventilation openings and add dry iceD.Spread ice over the top layer and in any voids within the container
考题
单选题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
考题
单选题Air trapped in the hydraulic fluid of a steering system would be indicated by（）A
an improper rudder responseB
hammering noises in the equipment or transmission linesC
popping or sputtering noisesD
all the above
考题
单选题Air trapped in the hydraulic fluid of a steering system should be indicated by （）.A
the pump over-speedingB
an improper rudder responseC
bubbles in the sight glassD
ram relief valves lifting
考题
单选题When adding oil to a refrigeration system, precautions must be taken to ensure that （）.A
the compressor suction pressure is not too highB
all air is purged from the pump and charging fittingsC
the high pressure cutout switch is held open to prevent accidental startingD
the condenser is completely shutdown first
考题
单选题Refrigerant is normally sub-cooled in a refrigeration or air conditioning system condenser to （）.A
maintain adequate coil back pressureB
prohibit flashing in the liquid lineC
reduce refrigerant volume in the systemD
reduce compressor discharge line loading
考题
单选题Air or noncondensable gas is removed from a refrigeration system by a （）A
separating chamberB
system of bafflesC
purge valveD
vacuum reducing valve
考题
单选题Air trapped in the hydraulic fluid of a steering system may be indicated by（）A
the steering pumps overspeedingB
a jammed open relief valeC
a constantly occurring improper rudder responseD
excessive ram pressure
考题
单选题The presence of air in the condenser of a refrigeration system will （） the condensing pressure.A
increaseB
reduceC
maintain constantD
None of the above is true
考题
单选题（）are supplied by main switchboard directly.A
Suez Canal searchlight, air compressor and air conditioning compressorB
Air compressor, boiler blower and refrigeration plantC
Boiler blower, Suez Canal searchlight and refrigeration plantD
Suez canal searchlight, air compressor and boiler blower
考题
单选题In the refrigeration system, a shortage of refrigerant is indicated by （）.A
the compressor short cycling on high pressure cut out switchB
high suction pressureC
high head pressureD
bubbles in the sight glass
考题
单选题A liquid sight flow indicator in a refrigeration system is examined and gas bubbles are noted in motion with the fluid flowThis means （）.A
the system is fully chargedB
there is air leaking in from the condenserC
ice crystals are forming in the refrigerantD
the system contains less than a full charge of refrigerant
考题
单选题What is NOT a function of the air supply of a covered lifeboat?（）A
Provides air for engine combustionB
Pressurizes water spray systemC
Provides air for passenger respirationD
Prevents smoke and other noxious fumes from entering craft
考题
单选题Which of the listed operating conditions would have the greatest effect on the volumetric efficiency of an operating reciprocating air compressor?（）A
The density of the air entering the compressorB
The temperature of the air entering the compressorC
The designed rotating speed of the compressorD
A leaking head gasket
考题
单选题Excessive clearances in the main or crank-pin bearings will sometimes be indicated by （） before any bearing knock is heard.A
loss of flow in the fuel systemB
loss of pressure in the air systemC
loss of flow in the lubricating systemD
loss of pressure in the lubricating system
考题
单选题An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.A
oil foaming in the compressorB
higher than normal suction and discharge pressures with a higher box temperatureC
higher than normal discharge pressure with a normal box temperatureD
the compressor to run continuously
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Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）A
Sub-cooled liquidB
Sub-cooled vaporC
Superheated vaporD
Liquid
考题
单选题The accumulation of air and other non-condensable gases in a refrigeration system will （）.A
cause a loss of the liquid sealB
create a vapor lock in the liquid receiverC
collect in the condenserD
cause foaming of the oil in the crankcase
考题
单选题While troubleshooting a refrigeration system for low head pressure, liquid refrigerant flooding back from the evaporator is determined to be the causeIt may be necessary to （）.A
change the expansion valve adjustmentB
readjust the water regulating valve to increase the flow of waterC
purge air from the condenserD
clean the waterside of the condenser
考题
单选题A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）A
purge lube oil from the liquid refrigerantB
recover water purged from the systemC
separate foul gases from the receiverD
purge non-condensable gases without losing refrigerant
考题
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 （）.A
control air systemB
forced draft air systemC
supply air systemD
ships service air system
考题
单选题You are in a tropical port. The refrigeration machinery on a container loaded with air-cooled fruit fails. It cannot be repaired for 18 to 24 hours. Which step should you take to reduce the temperature rise and spoilage of the fruit?（）.A
Discharge a cylinder of nitrogen into the containerB
Shade the container and periodically hose it downC
Seal any ventilation openings and add dry iceD
Spread ice over the top layer and in any voids within the container
热门标签
最新试卷