The gear and screw pumps are classified as______.

试卷相关题目

• 1A feed pump for an auxiliary boiler might lose suction if the ______.

  A.boiler water level is low

  B.feed-water is too hot

  C.boiler steam demand is low

  D.feed-water is too cold

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• 2A firebox explosion in an automatically fired auxiliary boiler may be the result of ______.

  A.excessive purging before lighting off

  B.insufficient trail for ignition period

  C.a faulty transformer in the ignition circuit

  D.insufficient purging after lighting off

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• 3The water in a steaming auxiliary boiler should be tested daily for ______.

  A.dissolved oxygen

  B.chlorides

  C.sludge

  D.dissolved nitrogen

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• 4______continuously extract the crankcase atmosphere, via a pipe system, and move it past a sensitive and accurate opacity (不透明)measuring track.

  A.The oil mist detectors

  B.The smoke detectors

  C.An oily water monitor

  D.Oil discharge monitoring and controlling system

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• 5The maximum pressure developed by a waste heat boiler is determined by the main engine exhaust ______.

  A.gas composition

  B.gas temperature

  C.pressure

  D.timing

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• 6The pressure of a liquid leaving the pump can be referred to as the ______.

  A.total head

  B.discharge head

  C.net positive suction head

  D.suction head

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• 7Which of the valves listed will be cycled from fully open to fully closed when the handle is turned 90 degree、

  A.A rising stem gate valve

  B.A globe stop valve

  C.A check valve

  D.A butterfly valve

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• 8A pump shaft that is bent or distorted should normally be ______.

  A.repaired by a suitable welding process

  B.straightened by applying heat and torsion

  C.reconditioned by metallizing and machining

  D.replaced with a satisfactory spare

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• 9A centrifugal pump may fail to deliver water when first started if the ______.

  A.water seal pipe is plugged

  B.pump is not primed

  C.seal ring is improperly located

  D.impeller is flooded

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• 10Which of the following conditions must exist for heat to flow from one object to another、

  A.The two objects must be in physical contact.

  B.The two objects must be the same size.

  C.There must be an existing temperature differential.

  D.There must be an existing weight differential.

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