更多"If the discharge valves on a refrig"的相关试题:
[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]In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low alloy steels because （）.
A. the beveled edges of the intake valves provide for serf-centering during seating
B. intake valves utilize stellite-coated valve seat inserts which reduce wear
C. the volume of air passing through intake valves is less than the volume of air passing through exhaust valves
D. intake valves are less affected to the corrosive action of exhaust gases
[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]A （） in the air delivery line near to each compressor is essential.
A. butterfly valve
B. globe valve
C. gate valve
D. non-return valve
[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]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]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
[单项选择]Which of the listed refrigeration system components keeps the refrigerant circulating through the system?（）
A. Expansion valve
B. Condenser
C. Evaporator
D. Compressor
[单项选择]Short cycling of a refrigeration compressor refers to （）.
A. frequently grounding out
B. frequently starting and stopping
C. running too fast
D. running too slow
[单项选择]If the refrigeration compressor crankcase is sweating, the cause may be due to （）.
A. a shortage of refrigerant
B. the compressor running continuously
C. liquid refrigerant returning to the compressor
D. the compressor short cycling on the high pressure cutout
[单项选择]The refrigeration system low pressure cutout switch is actuated by （）.
A. an electric system manager
B. a sensing bulb at the tail coil of the evaporator
C. pressure changes in the suction line
D. failure of the king solenoid valve
[单项选择]Personnel working with refrigeration systems, and subject to the exposure of refrigerants should wear （）.
A. face shield
B. a respirator
C. rubber gloves
D. an all purpose gas mask
[单项选择]If a refrigeration compressor is running continuously without lowering temperature as normal in the refrigerator, the trouble may be （）.
A. excessive condenser cooling water
B. warm food in the refrigerator
C. a shortage of refrigerant
D. s shortage of compressor oil
[单项选择]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 adjustment
B. readjust the water regulating valve to increase the flow of water
C. purge air from the condenser
D. clean the waterside of the condenser
[单项选择]In a vapor compression refrigeration the evaporating pressure is maintained constant by the action of the （）, which removes vapor from the evaporator at the same rate at which it is formed.
A. evaporator
B. compressor
C. condenser
D. none of the above
[单项选择]In a compression refrigeration plant the refrigerant is under low pressure in the （） and under high pressure in the （）.
A. compressor；condenser
B. condenser；evaporator
C. throttle valve；evaporator
D. evaporator；condenser
[单项选择]Saltwater is typically provided to a refrigeration system to （）.
A. cool the expansion valve
B. prevent refrigerant superheating
C. condense the refrigerant gas
D. prevent motor overheating
