What is an advantage of a gate valve over a butterfly valve ________．A.Less frequent maintenanceB.Faster operationC.CheaperD.More compact
What is an advantage of a gate valve over a butterfly valve ________．
A.Less frequent maintenance
B.Faster operation
C.Cheaper
D.More compact
相关考题：
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
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
What type of valve is used to direct the flow of hydraulic fluid?A.relief valveB.direction control valveC.stop valveD.pressure control valve
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
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
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
(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
单选题Which of the valves listed should be used either in the fully opened or the fully closed position?（）AA gate valveBA globe valveCAny check valveDAny needle valve
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?（）Athe direct acting relief valve is used for controlling lower flows and pressureBthe pilot operated relief valve is used for controlling higher flows and pressureCthe pilot operated relief valve is used for controlling lower flows and pressureDthe controlling accuracy of direct acting relief valve is worse than that of the pilot operated relief valve
单选题What type of valve is used to direct the flow of hydraulic fluid?（）ARelief valveBDirection control valveCStop valveDPressure control valve
单选题Which of the following statements concerning butterfly valves is correct?（）ASpecial tools are required for lapping or grindingBIt is impossible to throttle flow with a butterfly valveCTo close the valve, it is only necessary to turn the handle a quarter of a turnDThe butterfly valve should never be used in a freshwater system
单选题What is the function of thermostatic expansion valve in a compression refrigeration system?（）AnonexistentBfor controlling pressureCfor controlling superheatDfor controlling the solenoid valve
单选题Fire protection regulations for towing vessels require any fuel line subject to internal head pressure from fuel in the tank to（）.Abe fitted with a positive fuel shut-off valve located at the tankBhave a shut-off valve at the top of the tankChave a gate valve easily accessible in the space where the tank is locatedDhave a drain cock at the lowest point in the fuel line
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?（）AThe globe valve may be suitable for partially open operationBThe globe valve will give full bore flow with change of directionCThe gate valve gives full bore flow with change of directionDThe gate valve is suitable for full bore operation only
单选题A gate valve installed in a pipeline should be （）.Aused in either the fully dosed or fully opened positionBinstalled with the stem downCused for steam service onlyDused to throttle or regulate the flow of liquid
单选题What is the purpose of a striker plate? （）AProvides surface for applying force on machineryBProvides landing surface for the sounding bobCAbsorbs machinery vibrationDPrevents valve stem over-travel
单选题Valve lash, or clearance refers to the （）Aclearance between the top of the valve stem and the rocker armBcompression of the valve springsCclearance between the valve seat inserts and the headDout of roundness of the fuel injection cams
单选题A thermostatic expansion valve is properly controlling evaporator superheatAdjusting this valve to lower the superheat will result in a/an （）.Aevaporator pressure decreaseBevaporator coil over-feedCevaporator capacity increaseDexpansion valve diaphragm rupture
单选题To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the （）Asuction service valve as a vaporBsuction service valve as a liquidCdischarge service valve as a vaporDcharging valve as a liquid
单选题To add refrigerant to the high side of an air conditioning system, you should introduce the refrigerant through the （）.Adischarge service valve as a vaporBsuction service valve as a liquidCcharging valve as a liquidDcondenser purge valve as a vapor
单选题The advantage of a centrifugal pump as compared with a reciprocating pump is that （）.Adischarge is continuousBit has no internal valvesCupon accidental closing of discharge valve, excessive pressure will not build upDall of the above are true
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?（）AThe diameter of a disc is the same as the outer diameter of the pipeBWe can infer that the valve is opened or closed by rotating the spindleCA butterfly valve comprises a disc and a ring bodyDThe profile of the butterfly valve is a ring body
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.Aa check valveBa gate valveCa pressure reducing valveDa quick closing valve
单选题Valve cages are used on some large diesel engines to （）Areduce wear on the valve stemBpermit the use of alloy valve seat materialsCreduce heat transfer from the valve seatDfacilitate valve removal for servicing
单选题What is the purpose of a relief valve?（）Ato fill 2 tanks at the same timeBto use pump at a higher pressureCto return liquid to suction side if discharge valve is closedDAll of the above are true
单选题The direct acting mechanical governor used with some small diesel engines, controls fuel flow to the engine by（）Agovernor flyweight action on a pilot valve which controls fuel injectionBgovernor flyweight motion acting on fuel controls through suitable linkageCpositioning a butterfly valve in the fuel delivery system positioningDa servomotor piston attached to the fuel controls
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（）.AstopperBscreenCfilterDrestrictor