Centrifugal casting is suitable to produce ( ).

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

A . noise and vibration B . an increase in discharge pressure C . an increase in suction pressure D . lifting of the relief valve

A . cavitation B . electrolysis C . abrasion D . corrosio

A . Impurities B . Lube oil C . Gasoline D . Diesel fuel

A . Absorb erosion of high velocity discharge stream B . Seal pump shaft against entry of air C . Isolate the discharge side from the suction side D . Dampen the turbulent discharge flow

A . being shrunk into B . to be shrunk into C . to be shrunk with D . shrinking into

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

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

A . directly increase the pressure of the liquid being pumped B . directly increase the velocity of the liquid being pumped C . convert the potential energy of the liquid to kinetic energy D . separate air from the liquid being pumped

A . drill holes through the heavy side of the impeller until it balances B . weld counterweights to the light side of the impeller C . remove metal from the heavy side by machining in a lathe D . acid wash and serape the heavy side until it balance

A . They are self-priming B . Decreasing the speed of rotation will decrease the discharge pressure C . Opening the discharge valve wider will increase the discharge pressure D . All of the above

A . flame temperature B . fuel oil C . air movement D . gas force

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

A . displaying code letter Y (Yankee) B . sounding five short blasts on his whistle C . displaying code numeral 5 D . sounding one prolonged blast on his whistle

A . They should always be started with the discharge valve closed B . They should always be started with the discharge valve opened C . A priming pump is always required to flood the impeller suction D . They should always be started with the sealing line valves closed

A . greater high temperature strength B . better heat conductivity C . greater weight per cubic inch D . increased resistance to wear

A . They are particularly suited for pumping high viscosity fluids B . They are started with the discharge valve opened C . The flow of liquid is developed by imparting energy due to the rotation of an impeller D . They are always mounted in a horizontal positio

A . cylinder liner B . cylinder cover C . the gear box D . the scavenging box

A.They are particularly suited for pumping high viscosity fluids B.They are started with the discharge valve opened C.The flow of liquid is developed by imparting energy due to the rotation of an impeller D.They are always mounted in a horizontal position

A．展子虔 Zhan Ziqian B．李思训 Li Sixun C．王墨 Wang Mo D．王维 Wang Wei