A spur gear pump should be operated with the discharge valves ______.A.slightly openedB.throttledC.fully openedD.halfway opened
A spur gear pump should be operated with the discharge valves ______.
A.slightly opened
B.throttled
C.fully opened
D.halfway opened
相关考题：
While on watch in the engine room, you hear a continuous sounding of the general alarm. Which of the following actions should you take?A.Make an entry in the official logbookB.Open the master control valves on the fixed CO2 systemC.Start the fire pump and check discharge pressureD.Secure auxiliary condenser overboard discharge
If it becomes necessary to pump bilges while a vessel is in port, which of the following procedures should be followed?A.Pump only if the discharge is led to a shore tank or bargeB.Pump only during the hours of darknessC.Pump only on the outgoing tideD.Pump only as much as is necessary
If you must pump bilges while a vessel is in port，you should pump only ______．A.If discharge is led to a shore tank or bargeB.During the hours of darknessC.On the outgoing tideD.As much as is necessary
Which method should be used to warm up the pump turbines prior to discharge ________．A.Lock the turbine rotor and slowly bleed in steam until operating temperature is reachedB.Run the pump at high speed with the discharge valves closedC.Run the turbine at slow speed with the pump disconnectedD.Shut the discharge valve and run the pump at slow speed
All of the following steps are taken in starting a centrifugal pump，EXCEPT to ______．A.Set the relief valveB.Check the lubrication systemC.Vent the pump casingD.Open the pump suction and discharge valves
单选题When the desired rudder angle is attained by a typical double mm electro-hydraulic steering gear,the（）.Aram relief valves bypass oil to stop rudder movementBsix-way valve shifts to the neutral flow positionCsteering pump electric motor is de - energized by the transfer switchDfollow-up gear takes the hydraulic pump off stroke
单选题When the helm demands a 20°right rudder movement from an electro-hydraulic steering gear, which of the listed actions will be the FIRST action to happen when this rudder position is attained?（）AThe six-way valve opensBThe steering service pump motor is stoppedCThe follow-up gear takes the pump off strokeDThe cylinder relief valves bypass oil to the suction side the pump
单选题If a centrifugal bilge pump were continually operated with the discharge valve closed the （）.Amotor overload would openBrelief valve would openCpump would eventually overheatDmotor would overheat
单选题Hydraulically, servo-operated, automatic, change over valves, utilized in a two ram hydraulic steering gear, serve to（）Aallow an alternate main pump to start in the fully loaded condition thus developing immediate full torqueBprevent either main pump from being hydraulically motored when idle by cross pressure flowCprevent both units from operating simultaneously which could result in doubling the flow of oil and pressure leading to over pressurization of the systemDall of the above
单选题Which of the following will be the advantage of a centrifugal pump as compared with a reciprocating pump?（） (1) Its discharge is continuous (2) It has no internal valves (3) Upon accidental closing of discharge valve, excessive pressure will not build upA（1），（2）B（2），（3）C（1），（2），（3）D（2）only
单选题An advantage of a helical gear pump over a simple gear pump is that the helical gear pump is capable of （）.Amaintaining a steadier speedBdelivering liquids over greater distancesCoperating for longer periods of timeDproducing a smoother discharge flow
单选题Which method should be used to warm up the pump turbines prior to discharge（）.ALock the turbine rotor and slowly bleed in steam until operating temperature is reachedBRun the pump at high speed with the discharge valves closedCRun the turbine at slow speed with the pump disconnectedDShut the discharge valve and run the pump at slow speed
单选题If the discharge valves on a refrigeration compressor are leaking badly, the compressor should （）.Arun continuouslyBnot startChave high discharge pressureDshort cycle on the high pressure switch
单选题Which of the following is NOT true according to the passage?（）ABoth the main steering gear and the auxiliary steering gear should be operatedBThe alarms fitted to the remote control system should be operatedCThe emergency generator compartment should be checkedDThe communication system between the bridge and the steering gear compartment should be operated
单选题Most pump manufacturers recommended that the discharge piping for centrifugal pumps be （）.Aone size larger than the pump discharge nozzleBthe same size as the pump discharge nozzleCone size smaller than the pump discharge nozzleDinstalled with a short radius elbow at the pump
单选题Which of the following pumps will build up a bursting pressure or stall their motors if the discharge valves are closed?（） (1) gear (2) centrifugal (3) screwA（1）and（2）B（1），（2）and（3）C（1）and（3）D（2）and（3）
单选题All of the following steps are taken in starting a centrifugal pump，EXCEPT to（）.Aset the relief valveBcheck the lubrication systemCvent the pump casingDopen the pump suction and discharge valves
单选题A diesel engine should not be operated at low loads for long periods of time because（）Aheavy carbon deposits will buildup on the valves and in the exhaustBfuel dilution is increased at low loadCexhaust valves may be damagedDall of the above
单选题If the engine does start on air, but combustion does not immediately begin, the cause may not be （）.Alow compressionBfailure of the fuel pump to discharge fuelCincorrect timing of fuel pumpDturning gear being still on
单选题While on watch in the engine room, you hear a continuous sounding of the general alarmWhich of the following actions should you take?（）AMake an entry in the official logbookBOpen the master control valves on the fixed CO2 systemCStart the fire pump and check discharge pressureDSecure auxiliary condenser overboard discharge
单选题To operate a centrifugal fire pump at reduced capacity, you should （）.Areadjust the relief valveBthrottle the suction lineCthrottle the discharge valveDopen the priming line
单选题Which of the listed statements is correct concerning the starting of centrifugal pumps?（）AThey should always be started with the discharge valve closedBThey should always be started with the discharge valve openedCA priming pump is always required to flood the impeller suctionDThey should always be started with the sealing line valves closed
单选题If fuel oil were being discharged from the waster outlet of a fuel oil disk type centrifuge, operated as separator, you should（）Aremove the discharge ringBre-prime the purifierCthe centrifuge to its proper speedDinstall an additional discharge ring
单选题If a centrifugal pump were continually operated with the discharge valve closed, the （）.Amotor controller overload would openBpump would eventually overheatCrelief valve would continuously cycle openDmotor would overheat
单选题When starting a centrifugal pump, the discharge valve should be （）.AclosedBopened fullyCcracked openDpartly open
单选题With reference to operating a four-ram steering gear system under emergency conditions, which one of the following statements is incorrect?（）AOnly one pump should be used at any timeBThe ship speed should be reduced to 70% of the normalCWatch keeping of the steering gear should be increasedDLimitations of the steering gear should be logged but the bridge need not be informed
单选题A spur gear pump should be operated with the discharge valves （）.Aslightly openedBthrottledCfully openedDhalfway opened