Sealing in pump shaft is achieved by means of the （）.

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• The purpose of the wearing rings used in a centrifugal pump is to （）.

  A . prevent an internal explosion in the pump when it is overheated B . enable a visual inspection of the pump while it is running C . insure a proper alignment of the pump coupling to the driver D . accommodate for friction between the impeller and the easing

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• It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong directionThis would cause the pump （）.

  A . head capacity to improve B . discharge to be reversed C . efficiency to decrease D . slippage to decrease

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• As for a hydraulic vane pump, which of the following is in contact with the vanes during working: （） (1)the rotor (2)the pump shaft (3)the external surface of the housing

  A . (1) only B . (2) only C . (1) and (2) D . (1),(2)and(3)

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• Which of the following actions should be taken if during a routine maintenance inspection of a centrifugal pump, localized scoring on a pump shaft sleeve is detected?（）

  A . Correct the cause of the scoring and repair the sleeve or replace with a new one B . Reassemble the unit and provide more water leak off for proper lubrication C . Check for parallel alignment of the sleeve radial faces to the sleeve bores D . Reassemble the unit and adjust the governor to obtain a slower speed

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• The usual symptoms of cavitation in a centrifugal pump is （）.

  A . noise and vibration B . an increase in discharge pressure C . an increase in suction pressure D . lifting of the relief valve

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• Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.

  A . cavitation B . electrolysis C . abrasion D . corrosio

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• The pressure head of a pump is given in the unit of （）.

  A . kg B . MPa C . meter fluid column D . None of the above is true

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• What is a function of the wearing rings used in most centrifugal pumps?（）

  A . Absorb erosion of high velocity discharge stream B . Seal pump shaft against entry of air C . Isolate the discharge side from the suction side D . Dampen the turbulent discharge flow

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• To absorb the wear resulting from impeller rotation and abrasives in the liquid, a centrifugal pump is usually fitted with （）.

  A . lantern rings B . bearings C . easing volutes D . wearing ring

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• When in operation, it is unavoidable that a small amount of oil （） through leakage, and in order to compensate for these leaks the system is connected to a feed pump.

  A . escapes B . overheats C . expands D . accelerate

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• In general, the oil mist defectors include a base plate with air blast pumpThe function of air blast pump is to （）crankcase.

  A . supply clean air to the measuring compartment of the units for more accuracy B . generaate the pressure required for the extraction of the oil mist from the C . generate the pressure required for the extraction of the oil mist from the crankcase D . supply clean air to the measuring track of the units for more accuracy

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• When the tail-shaft is drawn from a vessel in dry-dock, which of the following inspections is required to be carried out?（）

  A . The propeller hub taper and shaft keyway should be inspected for cracks or corrosion B . The stern bearing alignment with the stern frame should be checked C . The interior of the stern tube should be inspected for leaks D . The shaft liner should be removed and inspected

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• In a vacuum boiling evaporator, the fresh water generated is pumped out by （）.

  A . a brine pump B . an air ejector C . a feed water pump D . a condensate pum

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• Increasing the speed of a centrifugal pump will result in an increase in its capacity in its capacityAnother means of increasing the capacity pump is to increase the（）

  A . diameter of the discharge piping, with all other factors remaining the same B . diameter of the suction piping, with all other factors remaining the same C . width of the impeller only D . diameter of the impeller

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• The usual number of single-acting pistons used in a variable stroke axial-piston pump is （）.

  A、3 or 5 B、5 or 7 C、7 or 9 D、9 or 11

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• The plunger in the fuel injector pump, usually operated by a （）, is driven up and down when working.

  A . crankshaft B . camshaft C . piston rod D . rack and pinio

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• The pressure head of a water pump is given in the unit of （）.

  A . kg B . MPa C . mH20 D . None of the above

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• The plunger in a jerk pump is rotated until the release port is uncoveredIf the port remains uncovered all of the time, which of the listed operations will occur?（）

  A . No fuel will be delivered B . The maximum effective stroke will be attained C . The fuel delivered to the cylinder will be excessive D . The injection nozzle will overheat and carbonize

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• When the tilting box of a variable stroke axial-piston pump is perpendicular to the pump shaft, which of the following conditions will exist?（）

  A . The pistons reciprocate B . The ‘B’ end cylinder barrel rotates C . There is no fluid flow D . Power is transmitted hydraulically

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• The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.

  A . assist in a quick cutoff of fuel injection B . allow oil backflow from the injector to the helix C . reduce fuel oil pressure between injection strokes D . meter the quantity of fuel delivered

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• The static suction lift of a pump is the difference in elevation between the （）.

  A . centerline of the pump and the level of the liquid in the suction well when the source of liquid is below the pump B . centerline of the pump and the suction liquid level when the source of liquid is above the pump C . centerline of the pump and the level of the discharge liquid D . liquid levels of the suction and discharge

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• When possible，what is the FIRST step in fighting an engine fuel-pump fire which results from a broken fuel line?（）

  A . Secure all engine room doors，hatches，and vents B . Close the fuel line valve C . Check the spread of the fire with foam D . Cast the barge off the wharf

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• Your vessel is taking on fuel oil when a small leak develops in the hose and you have ordered the pumping stoppedBefore resuming pumping，you should（）.

  A . notify the terminal superintendent B . place a large drip pan under the leak and ping the scuppers C . repair the hose with a patch D . replace the hose

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• In a typical fuel oil system, the oil is stored in tanks in the double bottom from which it is pumped to （） and heated.

  A . a service tank B . a collecting tank C . a sump D . a settling tank

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