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单选题
In a （） boiler the water flows through the inside of the tubes while the hot gases pass around the outside.
A
water-tube
B
fire-tube
C
exhaust gas
D
none of the above
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The fuel supply system to an automatic auxiliary boiler, will be automatically shutdown if the boiler()
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what chemicals did you use to treat the boiler water ?when you test alkalinity and acidity of water in boiler by pH test paper ? the result shows the boiler water is in acidiity . please describe what the possible cause is .
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If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause may be ______.A.high steam pressure in the boilerB.abnormally high feed-water temperatureC.abnormally high boiler water temperatureD.steam demand exceeding feed pump capacity
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The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to______.A.precipitate(使沉淀) silica （硅石）from solutionB.reduce corrosion in the heating coilC.prevent clogging and erosion in the coilD.maintain zero water hardness
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单选题The most common cause of scale formation in an auxiliary boiler is （）A
concentrations of calcium sulfate in the boiler waterB
fuel oil in the feed waterC
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单选题You should frequently compare drum-mounted and remote-reading water level indicators（） between these have contributed to failures because of overheating through shortage of water, when a boiler was being oil-fired.A
descriptionsB
discrepanciesC
differentD
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单选题Because of the reduced （） in the distillation system, some of the sea water boils as it flows through the tubes of the evaporator.A
pressureB
temperatureC
densityD
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单选题Which of the following statements concerning the water tube and fire tube boilers is not true?（）A
natural circulation of the water in the water tube boiler is better than that in the fire tube boilerB
for the same output the water tube boiler will carry less mass of water compared with the fire tube boilerC
the water tube boiler will cost shorter time for steam raisingD
the water tube boiler require lower skill in operating and maintaining
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单选题The rate of heat transfer in a water-tube auxiliary boiler can be increased by （）.A
operating the boiler at less than normal water levelB
installing fins on the firesides of water-tubesC
increasing the amount of excess air to the burnersD
treating the boiler water with chemical oxygen scavengers
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单选题请阅读 Passage 1，完成第 21~25小题。Passage 1These days，many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool，but they can also damage the environment.Since they use a lot of electricity，for instance，they contribute indirectly to global warming.In addition，the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons，or CFCs，that are believed to damage the Earth's ozone layer.Recently，though，a system has been built in the city of Toronto，Canada，that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings，water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building，it gradually becomes warmer.Finally，it reaches the roof ，where it is left to cool down naturally in a water tower.After that it is returned to the chillers，where the cycle begins again.Toronto lies on the shore of Lake Ontario，one of North America's Great Lakes，and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth，the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However，the water from the lake is not pumped directly into the air-conditioning systems.Instead，it is used to cool the water that is already inside the air-conditioning systems.After that，the lake water is added to the city's ordinary water supply.Enwave，the company that developed this deep-lake cooling system，says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used，no damage can be caused to the ozone layer.Not every city is located next to a large lake，but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What is the function of the chillers in a traditional air-conditioning system?A
They pump the air continuously to the units in each room.B
They lower the temperature of the water in the system.C
They help the water cool down naturally on the roof .D
They gradually clean the water as it flows through the building.
考题
单选题Bottom blow valves are installed on auxiliary water-tube boilers to （）A
remove suspended and precipitated solids from the boiler waterB
completely drain the boiler in an emergency situationC
prevent hardened scale deposits in the water drumD
remove floating impurities from the oily water surface
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单选题A distorted furnace in a fire-tube auxiliary boiler may be the result of （）A
firing for extended periods in the low fire modeB
overheating, due to waterside depositsC
varying the water level above the crown sheetD
carrying excessive alkalinity in the boiler water
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单选题In a diesel engine, an integral liner is one in which the cooling water （） Ⅰ.flows through the cylinder liner jackets Ⅱ.touches the outer side of the linerA
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Ⅱ onlyC
both Ⅰ and ⅡD
neither Ⅰ and Ⅱ
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单选题In a （） boiler the hot gases from the furnace pass through the tubes while the water is on the outside.A
water-tubeB
fire-tubeC
exhaust gasD
None of the above is true
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单选题In （）, hot diesel engine jacket water passes over the stack and heats the sea water passing through the tubes.A
a flash generatorB
a flash evaporatorC
a vacuum boiling evaporatorD
a boiler
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单选题What does blowing tubes accomplish?（）A
Eliminates unburned fuel oil residues from the fireboxB
Increases boiler efficiencyC
Flushes away mineral deposits inside the water tubesD
Cleans soot deposits from the inside of the stack
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单选题Because of the reduced （） in the vacuum boiling evaporator, some of the sea water boils as it flows through the tubes.A
temperatureB
water levelC
pressureD
rate of flow
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单选题请阅读 Passage 1，完成第 21~25小题。Passage 1These days，many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool，but they can also damage the environment.Since they use a lot of electricity，for instance，they contribute indirectly to global warming.In addition，the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons，or CFCs，that are believed to damage the Earth's ozone layer.Recently，though，a system has been built in the city of Toronto，Canada，that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings，water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building，it gradually becomes warmer.Finally，it reaches the roof ，where it is left to cool down naturally in a water tower.After that it is returned to the chillers，where the cycle begins again.Toronto lies on the shore of Lake Ontario，one of North America's Great Lakes，and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth，the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However，the water from the lake is not pumped directly into the air-conditioning systems.Instead，it is used to cool the water that is already inside the air-conditioning systems.After that，the lake water is added to the city's ordinary water supply.Enwave，the company that developed this deep-lake cooling system，says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used，no damage can be caused to the ozone layer.Not every city is located next to a large lake，but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What happens in the end to the water from Lake Ontario?A
It is used by the residents of Toronto.B
It is returned to a place deep in the lake.C
It is cooled down before being used again.D
It is added to the water inside air-conditioning systems.
考题
单选题The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to（）A
precipitate silica from solutionB
reduce corrosion in the heating coilC
prevent clogging and erosion in the coilD
maintain zero water hardness
考题
单选题Impurities from the boiler water surface can be removed through the （）.A
safety valveB
blow down valveC
scum valveD
feed check valve
考题
单选题When steam is being raised on a boiler, the water level will normally （）.A
drop as the boiler warms upB
rise as the boiler warms upC
remain unchanged until the boiler is hot enoughD
rise and fall with the steam demand
考题
单选题The water level in the gauge glass when a boiler is operating is （） when the boiler is shut down.A
lower thanB
higher thanC
belowD
equal to
考题
单选题Excessive alkalinity of the water in an auxiliary boiler can cause （）.A
caustic embrittlement of the boiler metalB
acidic corrosion of the boiler metalC
hard scale deposits on the boiler tubesD
etching of the heat exchange surfaces
考题
单选题Bottom blow valves are installed on auxiliary water-tube boilers to （）A
completely drain the boiler in an emergencyB
prevent sludge from forming in the drumC
remove floating impurities from the boiler water surfaceD
remove settled solids from the water drum
考题
单选题If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause maybe （）.A
high steam pressure in the boilerB
abnormally high feed water temperatureC
abnormally high boiler water temperatureD
steam demand exceeding feed pump capacity
考题
单选题In a （） boiler the water flows through the inside of the tubes while the hot gases pass around the outside.A
water-tubeB
fire-tubeC
exhaust gasD
none of the above
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