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What is an advantage of a gate valve over a butterfly valve ________．
A.Less frequent maintenance
B.Faster operation
C.Cheaper
D.More compact
参考答案
更多 “ What is an advantage of a gate valve over a butterfly valve ________．A.Less frequent maintenanceB.Faster operationC.CheaperD.More compact ” 相关考题
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The globe valve has a bulbous body, housing a valve seat and screw down plug or disc arranged at right angles to the axis of the pipeAccording to the above sentence, which of the following statements is not true?A.The profile of the valve is like a globeB.The valve seat is set into the bulbous bodyC.The plug or disc of the valve is made vertical to the axis of the pipeD.The valve seat is located at right side of the plug or disc
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A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the superheat will result in a/anA.evaporator pressure decreaseB.evaporator coil over-feedC.evaporator capacity increaseD.expansion valve diaphragm rupture
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What type of valve is used to direct the flow of hydraulic fluid?A.relief valveB.direction control valveC.stop valveD.pressure control valve
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The valve on the discharge side of a cargo pump on a tank vessel will usually be a ______.A.butterfly valveB.spectacle valveC.check valveD.globe valve
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In the piping systems of a vessel，what type of valve gives the least resistance to fluid flow when fully open ________．A.Globe valveB.Butterfly valveC.Gate valveD.Packless valve
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What is an advantage of diesel over steam turbine propulsion ________．A.Less fuel consumption per SHPB.Diesel fuel costs less than bunker C or its equivalentC.Less routine maintenance requiredD.Less weight per SHP
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(APS2000)以下哪个LRU的线路故障不会导致“MAINT”灯亮（）A、SPEED SENSORB、THERMOCOUPLEC、MAIN FUEL VALVED、BLEED SERVO VALVE
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单选题Which of the valves listed should be used either in the fully opened or the fully closed position?（）A
A gate valveB
A globe valveC
Any check valveD
Any needle valve
考题
单选题Which one of following statement is not true concerning the suitable sites of the direct acting relief valve and the pilot operated relieve valve?（）A
the direct acting relief valve is used for controlling lower flows and pressureB
the pilot operated relief valve is used for controlling higher flows and pressureC
the pilot operated relief valve is used for controlling lower flows and pressureD
the controlling accuracy of direct acting relief valve is worse than that of the pilot operated relief valve
考题
单选题What type of valve is used to direct the flow of hydraulic fluid?（）A
Relief valveB
Direction control valveC
Stop valveD
Pressure control valve
考题
单选题Which of the following statements concerning butterfly valves is correct?（）A
Special tools are required for lapping or grindingB
It is impossible to throttle flow with a butterfly valveC
To close the valve, it is only necessary to turn the handle a quarter of a turnD
The butterfly valve should never be used in a freshwater system
考题
单选题What is the function of thermostatic expansion valve in a compression refrigeration system?（）A
nonexistentB
for controlling pressureC
for controlling superheatD
for controlling the solenoid valve
考题
单选题Fire protection regulations for towing vessels require any fuel line subject to internal head pressure from fuel in the tank to（）.A
be fitted with a positive fuel shut-off valve located at the tankB
have a shut-off valve at the top of the tankC
have a gate valve easily accessible in the space where the tank is locatedD
have a drain cock at the lowest point in the fuel line
考题
单选题Unlike the globe valve, gate valves give full bore flow without change of direction, such a valve is not suitable to partially open operationAccording to the above sentence, which of the following statements is not true?（）A
The globe valve may be suitable for partially open operationB
The globe valve will give full bore flow with change of directionC
The gate valve gives full bore flow with change of directionD
The gate valve is suitable for full bore operation only
考题
单选题A gate valve installed in a pipeline should be （）.A
used in either the fully dosed or fully opened positionB
installed with the stem downC
used for steam service onlyD
used to throttle or regulate the flow of liquid
考题
单选题What is the purpose of a striker plate? （）A
Provides surface for applying force on machineryB
Provides landing surface for the sounding bobC
Absorbs machinery vibrationD
Prevents valve stem over-travel
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单选题Valve lash, or clearance refers to the （）A
clearance between the top of the valve stem and the rocker armB
compression of the valve springsC
clearance between the valve seat inserts and the headD
out of roundness of the fuel injection cams
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单选题A thermostatic expansion valve is properly controlling evaporator superheatAdjusting this valve to lower the superheat will result in a/an （）.A
evaporator pressure decreaseB
evaporator coil over-feedC
evaporator capacity increaseD
expansion valve diaphragm rupture
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单选题To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the （）A
suction service valve as a vaporB
suction service valve as a liquidC
discharge service valve as a vaporD
charging valve as a liquid
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单选题To add refrigerant to the high side of an air conditioning system, you should introduce the refrigerant through the （）.A
discharge service valve as a vaporB
suction service valve as a liquidC
charging valve as a liquidD
condenser purge valve as a vapor
考题
单选题The advantage of a centrifugal pump as compared with a reciprocating pump is that （）.A
discharge is continuousB
it has no internal valvesC
upon accidental closing of discharge valve, excessive pressure will not build upD
all of the above are true
考题
单选题A butterfly valve consists basically of a disc pivoted across the bore of a ring body having the same radial dimensions as the pipe in which it is fitted.According to the above sentence, which of the following statements is not true?（）A
The diameter of a disc is the same as the outer diameter of the pipeB
We can infer that the valve is opened or closed by rotating the spindleC
A butterfly valve comprises a disc and a ring bodyD
The profile of the butterfly valve is a ring body
考题
单选题To maintain the down stream pressure within defined limits over a range of flow and despite any changes in supply pressure, （） is fitted.A
a check valveB
a gate valveC
a pressure reducing valveD
a quick closing valve
考题
单选题Valve cages are used on some large diesel engines to （）A
reduce wear on the valve stemB
permit the use of alloy valve seat materialsC
reduce heat transfer from the valve seatD
facilitate valve removal for servicing
考题
单选题What is the purpose of a relief valve?（）A
to fill 2 tanks at the same timeB
to use pump at a higher pressureC
to return liquid to suction side if discharge valve is closedD
All of the above are true
考题
单选题The direct acting mechanical governor used with some small diesel engines, controls fuel flow to the engine by（）A
governor flyweight action on a pilot valve which controls fuel injectionB
governor flyweight motion acting on fuel controls through suitable linkageC
positioning a butterfly valve in the fuel delivery system positioningD
a servomotor piston attached to the fuel controls
考题
单选题A device fitted over the discharge opening on a relief valve consisting of one or two woven wire fabrics is called a flame（）.A
stopperB
screenC
filterD
restrictor
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