单项选择题
The starting air bottle should be pumped up to maximum pressure by the （） before start of the engine.
A.air compressor
B.refrigeration compressor
C.vacuum pump
D.purifier
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相关考题
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单项选择题
The process during which liquid containing a reasonable amount of sensible heat at a particular pressure immediately changes into steam after admitted to a chamber at a lower pressure is called （）.
A.boiling off
B.flash evaporation
C.condensation
D.none of the above -
单项选择题
When distilling salt water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.
A.to cut down the amount of cooling water needed
B.to prevent an excess amount of cooling water from being discharged to the bilges
C.to supply hot water to the evaporator for more economical operation
D.None of the above is tree -
单项选择题
When distilling sea water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.
A.to decrease scale formation
B.for better cooling effect
C.for more economical purpose
D.to raise vacuum
