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

A . Reciprocating pump B . Screw pump C . Diffuser pump D . Water-ring pum

A . two or more impellers housed together in one casing and mounted on a single shaft B . a single stepped impeller mounted in a progressively staged casing C . a large radial clearance between the impeller and casing to prevent overheating due to D . an increase in the discharge velocity of the liquid with a corresponding decrease in pressure through the stage

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 . shaft and impeller B . motor and pump shaft C . casing and impeller wearing rings D . lantern ring and impeller

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 . 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 . executedin B . inspectedin C . check-in D . look-in

A . closed B . opened fully C . cracked open D . partly ope

A . an injection process B . an ejection process C . a separation process D . a heating proce

A . centrifugal pump is cheaper than reciprocating pump B . the size of centrifugal pump with same capacity is smaller than that of reciprocating pump C . centrifugal pump makes maintenance easier than reciprocating pump does D . all of the above

A . reduce fuel weight B . increase specific gravity C . separate fuel from lube oil D . reduce fuel viscosity

A . primarily to lubricate the shaft seals B . due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller C . to initially unload the pump by having its head pressure equal to discharge pressure D . in order to overcome the potential energy of water in the discharge line

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、purifying B、batch C、long period D、temporary

A . They are less expensive B . They are smaller for equivalent pumping ability C . They pump more cargo in less time D . All of the above

A . reclaims water B . purges air without losing refrigerant C . purges air with some loss of refrigerant D . purges lube oil from the refrigerant

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

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