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Before attempting to put out a class “C” fire involving an electric-driven centrifugal pump, you should FIRST （）.
A . insulate your shoes
B . ground the fire hose
C . secure its power supply
D . start the fire pum
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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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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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The function of a centrifugal pump double volute casing is to （）.
A . reduce radial thrust to the impeller
B . double the liquid velocity through the pump when compared to a single volute
C . reduce hydraulic end thrust
D . provide the effect of multi-staging
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To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the （）.
A . shaft and impeller
B . motor and pump shaft
C . casing and impeller wearing rings
D . lantern ring and impeller
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On board supply vessels, a centrifuge is normally used to purify（）
A . cooling water
B . fuel oil
C . sea water
D . diesel intake air
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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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Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?（）
A . The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow
B . The pump packing gland overheats after short operating periods
C . The motor over-current protective device continually shuts the pump down
D . Pounding noises can be heard at the pump suction chest
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Which of the following statements is correct with regards to the operation of a centrifugal cargo pump?（）
A . Oil is discharged from the impeller through the outlet
B . Gravity causes the oil to flow toward the discharge
C . The self-priming feature of the centrifugal pump enables it to draw its own suction as it starts
D . The discharge capacity varies directly with the speed of the impeller
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A spring-loaded centrifugal flyweight governor responds to reduced engine load with an immediate increase in （）
A . pilot valve oil pressure
B . speeder spring force
C . compensation needle valve clearance
D . centrifugal force on the flyweight
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If fuel oil were being discharged from the waster outlet of a fuel oil disk type centrifuge, operated as separator, you should（）
A . remove the discharge ring
B . re-prime the purifier
C . the centrifuge to its proper speed
D . install an additional discharge ring
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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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Modern centrifuge designs enable continuous over a considerable period of timeThis is achieved by which is timed to discharge the sludge at regular intervals（）
A . an injection process
B . an ejection process
C . a separation process
D . a heating proce
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The cleaned heated oil, after passing through the centrifuges, is to be pumped to a （）.
A . settling tank
B . service tank
C . ballast tank
D . drain tank
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For many years marine centrifuges were designed for （） operation, that is the machines were run for a period during which solids accumulated in the bowlThe machine was stopped when the accumulated solids began to impair its performance.
A、purifying
B、batch
C、long period
D、temporary
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A refrigeration unit will tend to short cycle when operating （）.
A . under heavy loads
B . during hot gas defrost
C . under light loads
D . during starting conditio
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Which of the following problems will occur if a disk-type centrifugal lube oil purifier is not properly primed prior to admitting oil flow to the bowl?（）
A、Contamination of the lube oil by emulsification will result
B、The lube oil will not be subjected to the proper centrifugal force
C、The lube oil will overheat and flash
D、Oil will discharge from the heavy phase discharge port and be wasted.
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If you were operating a centrifugal water service pump with worn wearing rings, the （）.
A . pump would be very noisy
B . pump would vibrate excessively
C . pump would develop insufficient flow
D . stuffing box would leak excessively
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To operate a lathe, you should NOT wear ( ).
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Regulations concerning the operational control of a flight refer to
A、the specific duties of any required crewmember.
B、Exercising authority over initiating, conducting, or terminating a flight.
C、Exercising the privileges of pilot-in-command of an aircraft.
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Modern centrifuge designs enable continuous over a considerable period of timeThis is achieved by which is timed to discharge the sludge at regular intervals.
A.an injection process
B.an ejection process
C.a separation process
D.a heating process
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Dynamic pumps are classified as centrifugal or axial. axial pumps operate on the principle of centrifugal force.（）
是
否
