Excessive oil foaming in the crankcase of a refrigeration compressor can result in （）.

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• Excessive piston ring wear in a diesel engine will cause（）

  A . high lube oil viscosity B . increased lube oil consumption C . low lube oil temperatures D . high firing pressure

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• 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

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• Production of mechanical foam by a portable in-line foam proportioner（）.

  A . increases the size of foam bubbles formed B . increases the rate of foam production C . improves the extinguishing properties of foam D . gives the nozzleman more freedom of movement，since it can be placed anywhere in the hose line

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• 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

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• What is an advantage of using foam in fire fighting?（）

  A . It is effective in controlling fire in flowing oil such as coming from a broken fuel line B . It absorbs heat from materials that could cause reignition C . Most foams can be used jointly with dry chemical extinguishing agents to attack a fire by two methods of extinguishment D . Once the surface is blanketed with foam and the fire is extinguished，no further foam is required

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• How does foam extinguish an oil fire?（）

  A . By cooling the oil below the ignition temperature B . By removing the fuel source from the fire C . By excluding the oxygen from the fire D . By increasing the weight of the oil

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• If a used lube oil analysis indicates excessive fuel dilution, the lube oil should be （）

  A . changed B . centrifuged C . filtered D . settled

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• In a refrigeration system, foaming of the crankcase oil may cause the （）.

  A . expansion valve to overfeed B . compressor to knock C . water regulating valve to fail D . crankcase drains to plug

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• In the common rail system, excessive pressure in the header may be caused by （）

  A . improper adjustment of the bypass valve B . a dribble in the fuel injection nozzle C . insufficient leak-off through injection nozzle packing D . a malfunctioning injection nozzle

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• Excessive scale formation in a distilling plant may result from （）.

  A . poor distillate quality B . reduced evaporator capacity C . low brine concentration D . improper vacuum regulatio

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• Excessive lube oil consumption can result from worn or broken（）

  A . piston rings B . valve guides C . valve seals D . all of the above

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• A portable foam fire extinguisher is placed in operation by（）

  A . turning it upside down B . pressing the foam lever C . squeezing the grip handle D . opening the hose valve

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• A four-stroke cycle, turbocharged, 1000 horsepower diesel engine has been operating under loadThe load suddenly increases, causing excessive black exhaust smoke, and a rapid rise in the lube oil temperatureIn response to this condition, you should:（）

  A . reduce load B . check your exhaust C . adjust cooling water temperature D . increase lube oil flow

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• A foam-type portable fire extinguisher would be most useful in combating a fire in（）.

  A . soild materials such as wood or bales of fiber B . flammable liquids C . a piece of electrical equipment D . combustible metallic solid

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• When an oil fire has been extinguished, the surface of the oil should be kept covered with foam to prevent （）.

  A . air from contacting the oil vapors B . permitting re-ignition boiling of the heated oil C . spontaneous combustion below the oil surface D . toxic fumes from escaping to the surface

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• 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

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• Excessive oil foaming in the crankcase of a refrigeration compressor at start up can cause（）.

  A . compressor damage from improper lubrication B . refrigerant absorption by the lubricant C . increased viscosity in the lubricant D . carbon deposit on the compressor suction valve

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• A foam-type portable fire extinguisher is most useful in fighting a fire in（）.

  A . generators B . oil drums C . the bridge controls D . combustible metal

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• A condition that can increase the foaming tendency of lube oil is （）

  A . excessively high oil temperatures B . water or moisture contamination C . fuel dilution D . life its cylinder relief vale

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• 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 wor

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• Which of the following conditions could be a cause of excessive fuel dilution of diesel engine lube oil?（）

  A . Leaking fuel injectors B . Lower than normal compression C . Delayed fuel injection D . All of the above are correct

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• 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

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