單項選擇題The packing installed in the pump stuffing box is lubricated by （）.

A.gravity and feed oil cups
B.grease cups
C.hand during installation
D.leakage through the stuffing box


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1.單項選擇題The steam coils in a high pressure evaporator used for saltwater service should be de-scaled with （）.

A.a needle gun
B.soap and water
C.a wire brush
D.a chipping hammer

2.單項選擇題Which of the listed chemicals can be routinely used to maintain the hygienic quality of potable water?（）

A.Hydrochloric acid
B.Chlorine
C.Sulfuric acid
D.Zinc chromate

4.單項選擇題If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably（）.

A.excessive pump speed
B.excessive suction head
C.worn wearing rings
D.gross pump misalignment

5.單項選擇題Which of the following statements is correct relative to distillation plant operation?（）

A.Distillation is the process of boiling seawater to produce vapor which is condensed into fresh water
B.Evaporation is the second part of the distillation process where brine is removed
C.Brine is the result of condensed sea water vapor
D.Distillate is the product resulting from the evaporation of fresh water vapor