更多"Excessive oil foaming in the crankc"的相关试题:
[单项选择]Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.
A. has continuously for a long period
B. suction pressure is below normal
C. oil level is below normal
D. starts after a long idle period
[单项选择]Foaming of the oil in a refrigeration compressor crankcase is caused by （）.
A. refrigerant boiling out of solution from the lube oil
B. liquid refrigerant flooding the compressor and system
C. lube oil viscosity being reduced by refrigerant dilution
D. compressor suction pressure suddenly increasing
[单项选择]A diesel engines crankcase oil level is found to be too high√ You should suspect that （）.
A. the engine was over filled
B. there might be a fuel leak
C. there might be a water leak
D. all of the above
[单项选择]Excessive circulation of the lubricating oil with the refrigerant in a refrigeration system will cause （）.
A. carbon deposits on the compressor suction valves
B. the evaporator temperature to increase
C. rapid corrosion of the thermal expansion valve
D. no operating problems
[单项选择]To avoid excessive pressures in the fuel oil filling system during bunkering, you should （）.
A. close the tank filling valves quickly
B. top off all tanks at the same time
C. rill completely all tanks to less than 95% full
D. reduce the loading rate when topping off
[单项选择]Before pumping up the crankcase oil,（） should be worked by hand to minimize corrosive action on the liners.
A. the indicators
B. the starting valves
C. the cylinder lubricators
D. the turning gear
[单项选择]Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.
A. using a slightly dirty air filter
B. using oil having an excessive viscosity
C. intercooler or after-cooler leaks
D. carrying the oil level higher than normal
[单项选择]Excessive lube oil consumption can result from worn or broken（）
A. piston rings
B. valve guides
C. valve seals
D. all of the above
[单项选择]Excessive lubricating oil consumption in a running diesel engine can be caused by （）
A. clogged lube oil piping
B. excessive valve-guide clearance
C. high lube oil viscosity
D. low lube oil temperature
[单项选择]Sludge may form in the lubricating oil crankcase of a reciprocating air conditioning compressor as a result of （）.
A. wax precipitation in the lube oil
B. contamination by dust, scale, or moisture
C. refrigerant bubbles in the lube oil
D. refrigerant reducing the lube oil viscosity
[单项选择]Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of （）
A. refrigerant bubbles in the lube oil
B. refrigerant reducing the lube oil viscosity
C. oxidation of the lube oil from overheating
D. reducing the floc or cloud point of the oil
[单项选择]If a used lube oil analysis indicates an excessive chromate content, this means （）
A. air filtration is inadequate
B. engine coolant leaking into the lube oil
C. fuel oil is leaking into the lube oil
D. the piston rings are excessively worn
[单项选择]If a used lube oil analysis indicates excessive fuel dilution, the lube oil should be （）
A. changed
B. centrifuged
C. filtered
D. settled
[单项选择]Internal combustion engine crankcase vent outlets must be equipped with （）
A. hinged rain guards
B. corrosion resistant flame screens
C. dipsticks for measuring oil levels
D. crankcase ventilation fans
[单项选择]In an operating refrigeration system low on refrigerant, a liquid line sight glass will（）
A. be clear
B. be blue
C. be light green
D. show bubbles
[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 terms of pressure and temperature in the refrigerant in the compressor, what happens to the primary?（）
A. its pressure and temperature are both lowered
B. its pressure and temperature are both raised
C. its pressure is lowered and its temperature is raised
D. its pressure is raised and its temperature is lowered
