safety valve
blow down valve
scum valve
feed check valve
第1题:
In a ______boiler the hot gases from the furnace pass through the tubes while the water is on the outside.
A.water-tube
B.fire-tube
C.exhaust gas
D.Composite
第2题:
The separation of impurities and water from ______is essential for good combustion of diesel engines.
A.lube oil
B.fuel oil
C.turbine oil
D.grease
第3题:
It can be learned from the passage that about four billion years ago ______.
A. the earth was in molten state
B. the earth surface temperature was above 100℃
C. the earth surface temperature was below 100℃
D. rain water could remain on the earth
43.答案为B。根据第一段最后一句及第二段内容可知,雨水在地表温度降到水的沸点以下才能停在地表,由此可知大约在四十亿年前,地表温度应在沸点以上。
第4题:
main stern stop valve
auxiliary steam stop valve
scum valve
blow down valve
第5题:
第6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(使沉淀) silica (硅石)from solution
B.reduce corrosion in the heating coil
C.prevent clogging and erosion in the coil
D.maintain zero water hardness
第7题:
The general circulation of the surface water in Mediterranean is ______.
A.counter-clockwise
B.clockwise
C.from east to west
D.from north to south
第8题:
A.water-tube
B.fire-tube
C.exhaust gas
D.composite
第9题:
seawater contamination
frequent surface blows
dissolved oxygen deaeration
frequent bottom blows
第10题:
will be modulated in proportion
will be modulated in proportion and integral
will be modulated in proportion and differential
will not be modulated at all