网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
A centrifugal pump may fail to deliver water when first started if the ______.
A.water seal pipe is plugged
B.pump is not primed
C.seal ring is properly located
D.impeller is flooded
参考答案
更多 “ A centrifugal pump may fail to deliver water when first started if the ______.A.water seal pipe is pluggedB.pump is not primedC.seal ring is properly locatedD.impeller is flooded ” 相关考题
考题
When started, a complete oily water separating unit is first filled ______. The oily water mixture is then pumped through the inlet pipe into the coarse separating compartment.A.with dirty waterB.with clean waterC.by oily waterD.by mixed water
考题
If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause may be ______.A.high steam pressure in the boilerB.abnormally high feed-water temperatureC.abnormally high boiler water temperatureD.steam demand exceeding feed pump capacity
考题
What is the function of wearing rings found on some centrifugal pumps ________．A.Absorb erosion of high velocity discharge streamB.Seal pump shaft against entry of airC.Isolate the outlet side from the inlet sideD.Dampen the turbulent discharge flow
考题
What prevents water running along the shaft of a leaking centrifugal pump from entering the shaft bearing ________．A.Shaft sealB.Water flingerC.Drain holeD.Lantern ring
考题
单选题If a centrifugal pump vibrates and is noisy when operating, the cause could be （）.A
worn gland sealing shaftB
worn wearing ringsC
a bent shaftD
reversed pump coupling
考题
单选题The function of a centrifugal pump double volute casing is to （）.A
reduce radial thrust to the impellerB
double the liquid velocity through the pump when compared to a single voluteC
reduce hydraulic end thrustD
provide the effect of multi-staging
考题
单选题A water pump can not supply water after startingIt may be caused by （）.A
closed discharge valveB
broken pipe lineC
worn shaftD
both A and B
考题
单选题A centrifugal bilge pump requires priming （）.A
primarily to lubricate the shaft sealsB
due to the inability of this type of pump to lift water to cover the suction (eye) of the impellerC
to initially unload the pump by having its head pressure equal to discharge pressureD
in order to overcome the potential energy of water in the discharge line
考题
单选题The main propulsion diesel engine jacket water temperature rises above normal, with the raw water sea suction and the expansion tank water level being normalWhich of the following problems is most likely the cause?（）A
Faulty thermostatic bypass valveB
Eroded zinc pencils in the heat exchangerC
Steam formation in the expansion tankD
Excessive leakage from jacket water pump seal
考题
单选题Domestic water pump is started automatically by （） which operates as the water level falls to a predetermined level.A
a level controllerB
a temperature switchC
a pressure switchD
a floating ball
考题
单选题Before attempting to put out a class “C” fire involving an electric-driven centrifugal pump, you should FIRST （）.A
insulate your shoesB
ground the fire hoseC
secure its power supplyD
start the fire pump
考题
单选题One of the main functions of wearing rings, as used in a centrifugal pump, is to （）.A
maintain radial alignment between the pump impeller and casingB
absorb all impeller shaft end thrustC
prevent water leakage to the atmosphereD
prevent wear of the pump casing and/or impeller
考题
单选题（）is used in typical marine pattern self-contained unit.A
a water cooled condenserB
a slop tankC
a expansion tankD
a centrifugal pump
考题
单选题The purpose of the wearing rings used in a centrifugal pump is to （）.A
prevent an internal explosion in the pump when it is overheatedB
enable a visual inspection of the pump while it is runningC
insure a proper alignment of the pump coupling to the driverD
accommodate for friction between the impeller and the easing
考题
单选题Which of the listed statements is correct concerning the starting of centrifugal pumps?（）A
They should always be started with the discharge valve closedB
They should always be started with the discharge valve openedC
A priming pump is always required to flood the impeller suctionD
They should always be started with the sealing line valves closed
考题
单选题In order to properly remove air from the casing of a centrifugal pump when starting, the pump should have a （）.A
positive headB
negative suction headC
mechanical sealD
vent valve attached to the casing at the top of the volute
考题
单选题The most suitable pump for oily water separator feed duties is （）.A
a reciprocating pumpB
a vane pumpC
a centrifugal pumpD
a triple screw pump
考题
单选题A centrifugal pump may fail to deliver water when first started if the （）.A
water seal pipe is pluggedB
pump is not primedC
seal ring is improperly locatedD
impeller is flooded
考题
单选题When started, a complete oily water separating unit is first filled （）The oily water mixture is then pumped through the inlet pipe into the coarse separating compartment.A
with dirty waterB
with clean waterC
by oily waterD
by mixed water
考题
单选题Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?（）A
The pump delivers full capacity when started, but gradually slackens off toan abnormally low flowB
The pump packing gland overheats after short operating periodsC
The motor over-current protective device continually shuts the pump downD
Pounding noises can be heard at the pump suction chest
考题
单选题Which of the materials listed is used as the dynamic seal material on mechanical seals installed on most centrifugal pumps used in water service?（）A
CopperB
Copper and carbonC
CarbonD
Bronze
考题
单选题To thoroughly pump out the bilges using a horizontally mounted centrifugal pump, the （）.A
pump must always be primedB
volute must impart a radial and rotary motion of the water suction sideC
connection must guide the liquid to the lantern ringsD
stuffing box should not be allowed any water leakage
考题
单选题When starting a centrifugal pump, the discharge valve should be （）.A
closedB
opened fullyC
cracked openD
partly open
考题
单选题The separating effect of oil separator is not very good, the reason may be（）A
too little seal waterB
improper gravity discC
oil discharging pump not working very wellD
low water level of the working water
考题
单选题Water accumulation in the cylinder of a secured engine is an indication that the （）A
soft water pump was not secured along with the engineB
jacket water thermostat has failedC
cylinder liner may be crackedD
raw water pump is over-speeding just prior to engine shutdown
考题
单选题If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause maybe （）.A
high steam pressure in the boilerB
abnormally high feed water temperatureC
abnormally high boiler water temperatureD
steam demand exceeding feed pump capacity
考题
单选题A centrifugal pump can’t supply water after startingYou should check （）.A
priming waterB
power supplyC
packing glandD
bearing lubrication
热门标签
最新试卷