A.to raise water level
B.only while making steam
C.to remove scum
D.when fire are secured
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A.drop as the boiler warms up
B.rise as the boiler warms up
C.remain unchanged until the boiler is hot enough
D.rise and fall with the steam demand
A.filled with water
B.purged
C.cleared of air
D.None of the above is true
A.Safety valves
B.Water tubes
C.Steam stop valves
D.Blow down valves
A.water-tube
B.fire-tube
C.exhaust gas
D.None of the above is true
A.water-tube
B.fire-tube
C.exhaust gas
D.none of the above
最新試題
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
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Thermostatic expansion valves can be adjusted for （）.
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If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
When the steering gear is in operation, you should （）.
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