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）
单选题
Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by （）.
A
a compressed packing gland
B
lantern tings between the packing rings
C
a liquid seal
D
the stuffing box gland
参考答案
参考解析
解析：
暂无解析
更多 “单选题Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by （）.A a compressed packing glandB lantern tings between the packing ringsC a liquid sealD the stuffing box gland” 相关考题
考题
When using a fuel with a higher than normal sulfur content in an auxiliary four stroke diesel engine, you mayA.maintain higher than normal jacket water temperatureB.change the lube oil more frequently than normalC.maintain a higher air-box temperature than normalD.maintain a higher air-box pressure than normal
考题
Positive displacement, helical gear pumps are well suited for pumping oil becauseA.stuffing boxes eliminate the leakage problems usually associated with other gear pumpsB.it is not necessary to closely maintain design clearances with this pumpC.they are essentially self-priming and produce a high suction liftD.these pumps are designed with extreme tooth angles
考题
Which of the following statements represents an advantage of an electromagnetic clutch?A.Large misalignments can be tolerated between the shaft and engine couplingB.Slip is held to a minimum when reversing shaft rotationC.Engine torsional vibrations to the driven shaft are eliminatedD.It aids in maintaining power factor
考题
Which of the following components provides a direct source of seawater for the fire main system?A.Rose boxB.Sea chestC.Sluice(闸式) valveD.Fire pump stuffing box
考题
Leakage of hydraulic fluid from around the shaft of a hydraulic motor may be caused by ______.A.permanent loss of pump suctionB.worn shaft sealsC.high level in the oil sumpD.low motor RPM
考题
In the event of the cylinder starting valve leakage ______would pass into the air pipes and ignite the oil deposited.A.cooling waterB.vapor from the boilerC.starting airD.hot gases
考题
单选题Shaft sealing in a centrifugal pump can be effected by （）.A
the mechanical sealB
packed stuffing boxesC
either A or BD
neither A nor B
考题
单选题On opposite ends of a single shaft of a turboblower are a gas driven （）and a air compressor, which are sealed each other.A
charge air receiverB
scavenging air beltC
turbineD
air cooler
考题
单选题Which of the following components provides a direct source of seawater for the fire main system?（）A
Rose boxB
Sea chest or spool pieceC
Sluice valveD
Fire pump stuffing box
考题
单选题Which of the following statements represents an advantage of an electromagnetic clutch?（）A
Large misalignments can be tolerated between the shaft and engine couplingB
Slip is held to a minimum when reversing shaft rotationC
Engine torsion vibrations to the driven shaft are eliminatedD
It aids in maintaining power factor
考题
单选题The dew point temperature is（）.A
always higher than the air temperatureB
always lower than the air temperatureC
equal to the difference between the wet and dry bulb temperaturesD
the temperature at which the air is saturated with water vapor
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If over a period of weeks the air-box pressure of a turbo-charged, diesel engine, operating at full load, appears to be dropping off, the cause can be （）.A
open air-box drainsB
loss of cooling water to the diffuserC
gradual fouling of the air filtersD
improperly timed exhaust valves
考题
单选题（） of the A-frames there is a strong cast iron frame called the scavenging air box.A
At the topB
At the bottomC
In the topD
In the bottom
考题
单选题Leakage of hydraulic fluid from around the shaft of a hydraulic motor may be caused by（）A
permanent loss of pump suctionB
worn shaft sealsC
high level in the oil sumpD
low motor RPM
考题
单选题Some pumps use packing as sealing glandThe gland should be （）.A
slack enough to allow slight leakage of fluidB
slightly clockedC
brought up tight so as not to allow any leakageD
fitted with a relief valve
考题
单选题In the event of the cylinder starting valve leakage （） would pass into the air pipes and ignite the oil deposited.A
cooling waterB
vapor from the boilerC
starting airD
hot gases
考题
单选题When the tilting box of a variable stroke axial-piston pump is perpendicular to the pump shaft, which of the following conditions will exist?（）A
The pistons reciprocateB
The ‘B’ end cylinder barrel rotatesC
There is no fluid flowD
Power is transmitted hydraulically
考题
单选题Which condition indicates the air side fouling of an after-cooler on a turbocharged diesel engine?（）A
An increased air temperature differential between the cooler inlet and outletB
A decrease in the air pressure differential across the coolerC
Excessive condensate forming in the air boxD
A decrease in the air temperature differential between the cooler inlet and outlet
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Each piston stuffing box is provided with two sealing rings and three（）A
packingsB
piston ringsC
distributor ringsD
scraper rings
考题
单选题Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.A
a high suction headB
rotating ringsC
badly worn bearingsD
a loose stuffing box gland
考题
单选题Some vessels are equipped with a water lubricated stern robeWhen at sea, operating under normal conditions, the water service valve from the ships saltwater system to the bearing should be （）.A
closed, and no leakage permitted across the shaft packingB
closed, and only slight leakage permitted across the shaft packingC
open, and no leakage permitted across the shaft packingD
open, and only slight leakage permitted across the shaft packing
考题
单选题The shaft and spare parts（） should be well greased in order to avoid corrosion.A
in the store roomB
in the cylinderC
in the scavenge air boxD
in the water box
考题
单选题The packing installed in the pump stuffing box is lubricated by （）.A
gravity and feed oil cupsB
grease cupsC
hand during installationD
leakage through the stuffing box
考题
单选题When occurring a fire in the scavenge air box, the following measures should be taken except for（）A
reducing speed to SLOW and asking bridge for permission to stopB
stopping the fuel oil supplyC
switching-on the auxiliary blowersD
putting the scavenge air box fire extinguishing equipment into function
考题
单选题When using a fuel with a higher than normal sulfur content in an auxiliary diesel engine, you should（）A
maintain higher than normal jacket water temperatureB
change the lube oil more frequently than normalC
maintain a higher air-box temperature than normalD
maintain a higher air-box pressure than normal
热门标签
最新试卷