更多"Zinc rods are installed in the refr"的相关试题:
[单项选择]When it is necessary to open a refrigeration system for repairs and the system will be open for more than a few minutes, the open ends of the system should be （）.
A. dehydrated
B. purged
C. plugged
D. evacuated
[单项选择]Accidental grounds in a shipboard electrical system must be repaired as soon as possible as they will （）
A. result in immediate power outages
B. damage circuit breakers
C. appear on the ground detection system
D. damage insulation and may cause outages
[单项选择]Refrigeration system compressor crankcase sweating is an indication of （）.
A. insufficient lube oil circulating through the system
B. excessive circulation of lube oil through the system
C. insufficient refrigerant in the system
D. an overworked compressor
[单项选择]In a closed diesel engine freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the （）.
A. suction pressure regulator
B. thermostatic bypass valve
C. sea water temperature
D. water level in the expansion tank
[单项选择]Water allowed to accumulate in the hydraulic system oil will cause an oxidation process producing by- products which are normally （）.
A. gums, acids, and varnishes
B. removed by cellulose type filters
C. neutralized by oil additives
D. not removed by absorbent filters
[单项选择]SOLAS regulations require that the inert gas system shall be capable of delivering inert gas with an oxygen content of not more than what percentage?（）
A. 5%
B. 8%
C. 6%
D. 3%
[单项选择]Insufficient refrigerant in a refrigeration plant may result in （）.
A. high discharge pressure
B. frosting of the crankcase
C. high temperature of the overboard water
D. low suction pressure of compressor
[单项选择]Some refrigeration systems have chemical moisture indicators installed in conjunction with the sight glass in the liquid lineIf excess moisture is present in the system, the indicator will （）
A. activate the driers
B. change color
C. secure the compressor
D. add a predetermined amount of liquid drier
[单项选择]Badly leaking refrigeration compressor discharge valves will cause（）.
A. overfeeding of the expansion valve
B. damage to the condenser
C. constant running of the compressor
D. flooding of the receiver
[单项选择]A refrigeration system contaminated with moisture can be affected by （）.
A. acid formation
B. sludge formation
C. ice in the expansion valve
D. All of the above
[单项选择]Refrigerant is circulated through a refrigeration system by the （）.
A. compressor
B. condenser
C. expansion valve
D. evaporator
[单项选择]In North America the majority of the weather systems move from（）.
A. north to south
B. south to north
C. east to west
D. west to east
[单项选择]Sludge formation in a diesel engine lube oil system is caused by（）
A. carbonization of oils from the combustion chambers
B. emulsions of lube oil and water
C. coagulation of unburned fuel below the piston rings
D. all of the above
[单项选择]In a combination chain and wire rope mooring system，the anchor chain is deployed at the anchor end of the line to（）.
A. increase fatigue life of the system
B. reduce the time to retrieve the line
C. increase the holding power
D. reduce the catenary
[单项选择]The car will be guided by a differential GPS system that corrects errors（）in global positioning satellite signals.
A. arising
B. rise
C. raise
D. arouse
[单项选择]An orifice-check valve placed in a hydraulic system is used to（）
A. regulate the fluid flow in either direction
B. restrict movement of hydraulic fluid in one direction, but allow free movement in the other direction
C. allow free movement of hydraulic fluid in both directions
D. allow a restricted fluid flow in one direction only
[单项选择]Because of the reduced （）in the distillation system, some of the sea water boils as it flows through the tubes of the evaporator.
A. pressure
B. temperature
C. density
D. volume
[单项选择]A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of（）.
A. a shortage of refrigerant in the system
B. air in the system
C. an accumulation of liquid refrigerant in the crankcase
D. a shortage of oil in the crankcase
