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Most pump manufacturers recommended that the discharge piping for centrifugal pumps be ().
A . one size larger than the pump discharge nozzle
B . the same size as the pump discharge nozzle
C . one size smaller than the pump discharge nozzle
D . installed with a short radius elbow at the pum
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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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The pump used to send the bilge water into the oily water separator()the mixture because this might create finer oil particles.
A . should agitate
B . should not agitate
C . should mix up
D . should not add u
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()uses one or two high pressure pumps for all the cylinders with one more standby, while()have a separate high-pressure pump for each cylinder.
A . A common rail engine;conventional engines
B . A conventional engine;common rail engines
C . A marine diesel engine;most other engines
D . A two-stroke engine;four-stroke engine
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Which features of a centrifugal pump reduce the need for renewing worn impellers and pump casings?()
A . Close radial clearance between impeller hub and casing
B . Low rotational speed of impeller
C . Removable end plate
D . Replaceable impeller and casing 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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When installed for bilge pumping or ballast duty, centrifugal pumps require a () to remove air from the suction pipe.
A . air chamber
B . head lank
C . primer
D . prime mover
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The simplest method to use for determining if a centrifugal pump is operating as designed, is to ().
A . closely observe the pump discharge temperature
B . close off the discharge valve, and watch for a rise in pressure
C . momentarily close off the suction valve, and watch for a rise in pressure
D . use a clamp on ammeter and compare the readings to past record
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The minimum number and capacity of bilge pumps and fire pumps and their distributing within the ship is governed by ().
A . Classification Society Rules
B . National requirements
C . The IMO International Convention for the Safety of Life at Sea
D . All of the above
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The motor for the fresh water pump ().
A . need to repair
B . need to be repaired
C . needs to repair
D . needs repairing
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The exhaust valve opens before bottom dead center in a four stroke engine to() Ⅰ.allow for blow down Ⅱ.Reduce pumping losses
A . Ⅰ only
B . Ⅱ only
C . both Ⅰ and Ⅱ
D . neither Ⅰ nor Ⅱ
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If a bilge pump failed to build up discharge pressure, you should check for ().
A、The requirement for the oil content of bilge water discharged is 15 ppm.
B、No discharge in sensitive waters.
C、Any discharge in sensitive waters.
D、International, national or local requirements have to be observed.
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As for a hydraulic single action vane pump, the inner wall of the stator is usually of () shape.
A . circular
B . elliptical
C . rectangular
D . hexago
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The fire pumps must be capable of delivering a total quantity of water at a defined head, not less than () of the total bilge pumping capacity.
A . one-third
B . two-thirds
C . one-fourth
D . two-fourth
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Which of the fuel injection systems listed uses a spring loaded differential spray needle valve and individual pump for each cylinder?()
A . Common-rail injection
B . Air injection
C . Jerk pump injection
D . Distribution injectio
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The bilge system has been performing well; however, the aft starboard engine room bilgewell suddenly fails to be pumped outWhich of the following should be done first to determine the cause?()
A、Open the bilge pump for inspection
B、Remove each of the manifold valves
C、Remove only the manifold valve to the affected bilge-well
D、Attempt to pump out another bilge well to determine if the entire system is affected.
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You are unable to pump out the aft starboard engine room bilge well that is fouled, with one foot of water over the top of the bilge well, what action should be carried out?()
A . Send the wiper into the well with only a scoop and pail
B . Remove the bilge manifold valve and attempt to back flush the line
C . Simultaneously operate all available bilge pumps
D . It is only necessary to transfer half the contents of a drum of degreaser into the bilge well
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Which of the equipment listed is most effective in processing bilge slops for overboard discharge?()
A . 100PPM oily water separator
B . Assembling the lube oil purifier as a separator and aligning bilge overboard
C . A 15PPM oily water separator
D . A magnetic duplex strainer
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When fire pumps are used for other than firefighting service,each pipe connecting the other service (except for branch lines used for deck washing) must have a().
A . check valve installed in the line
B . shut off valve at a manifold near the pump
C . quick disconnect union within ten feet of the pump
D . regulator in the line set at 125 psi
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On modern ships, centrifugal pump with a self-primer has replaced reciprocating pump as bilge pump because()
A . centrifugal pump is cheaper than reciprocating pump
B . the size of centrifugal pump with same capacity is smaller than that of reciprocating pump
C . centrifugal pump makes maintenance easier than reciprocating pump does
D . all of the above
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A centrifugal bilge pump requires priming ().
A . primarily to lubricate the shaft seals
B . due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller
C . to initially unload the pump by having its head pressure equal to discharge pressure
D . in order to overcome the potential energy of water in the discharge line
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If the pump for a hydraulic anchor windlass is overheating, the cause may be ().
A . excessive drive motor speed
B . excessive pump discharge pressure
C . too low of a tilting box angle
D . insufficient drive motor speed
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If an operating bilge pump is developing good vacuum, but is unable to discharge any water, which of the following problems is the most probable cause?()
A . The wearing rings are excessively worn
B . The suction strainer is clogged
C . The discharge valve is clogged
D . The shaft is wor
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The exhaust valve opens before bottom dead center in a four stroke engine to______Iallow for blow down IIReduce pumping losses
A.I only
B.II only
C.both I and II
D.neither I nor II