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
The valve that prevents water from backing out of the boiler into the feed line is the（）.
A
bottom-blow valve
B
skin valve
C
feed-check valve
D
feed-stop valve
参考答案
参考解析
解析：
暂无解析
更多 “单选题The valve that prevents water from backing out of the boiler into the feed line is the（）.A bottom-blow valveB skin valveC feed-check valveD feed-stop valve” 相关考题
考题
In a()boiler the hot gases from the furnace pass gases from the furnace pass water is on the outside.
A.water-tubeB.fire-tubeC.exhaust gasD.composite
考题
what chemicals did you use to treat the boiler water ?when you test alkalinity and acidity of water in boiler by pH test paper ? the result shows the boiler water is in acidiity . please describe what the possible cause is .
考题
Which statement is correct about HTTP trickling?()
A. It prevents the HTTP client or server from timing-out during an antivirus updateB. It prevents the HTTP client or server from timing-out during antivirus scanning.C. It is an attack.D. It is used to bypass antivirus scanners.
考题
The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to______.A.precipitate(使沉淀) silica （硅石）from solutionB.reduce corrosion in the heating coilC.prevent clogging and erosion in the coilD.maintain zero water hardness
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
Which statement is correct about HTTP trickling?（）A、It prevents the HTTP client or server from timing-out during an antivirus updateB、It prevents the HTTP client or server from timing-out during antivirus scanning.C、It is an attack.D、It is used to bypass antivirus scanners.
考题
单选题The perforated，elevated bottom of the chain locker，which prevents the chains from touching the main locker bottom and allows seepage water to flow to the drains，is called a（）.A
cradleB
draftC
harpingD
manger
考题
单选题What is NOT a function of the steam drum of a marine water-tube boiler（）.A
Receives saturated steam from the generating tubesB
Serves as a reservoir of boiler feed waterC
Holds internal fittings for separation of moisture from steamD
Collects steam exhausted from the turbines
考题
单选题Black smoke coming from a boiler can be caused by （）.A
low water levelB
high water levelC
excessively high fuel pressureD
low oil temperature
考题
单选题Which of the following statements concerning the water tube and fire tube boilers is not true?（）A
natural circulation of the water in the water tube boiler is better than that in the fire tube boilerB
for the same output the water tube boiler will carry less mass of water compared with the fire tube boilerC
the water tube boiler will cost shorter time for steam raisingD
the water tube boiler require lower skill in operating and maintaining
考题
单选题In readying an auxiliary water-tube boiler for a routine hydrostatic test, which of the following procedures should be undertaken prior to filling the boiler with fresh water?（）A
The safety valve escape piping should be disconnected from the valve body and a blank insertedB
The boiler vent valves should be openedC
All hand-hole/manhole covers should be tightened up as much as possible to preclude any leaksD
All of the above
考题
单选题The rate of heat transfer in a water-tube auxiliary boiler can be increased by （）.A
operating the boiler at less than normal water levelB
installing fins on the firesides of water-tubesC
increasing the amount of excess air to the burnersD
treating the boiler water with chemical oxygen scavengers
考题
单选题In readying an auxiliary water-tube boiler for a routine hydrostatic test, which of the following procedures should be undertaken prior to filling the boiler with fresh water?（）A
The safety valve escape piping should be disconnected from the valve body and a blank insertedB
The boiler vent valves should be openedC
All handhole/manhole covers should be tightened up as much as possible to preclude any leaksD
All of the above
考题
单选题The（）enables water to be blow down or emptied from the boilerIt may be used when partially or completely emptying the boiler.A
main stem stop valveB
auxiliary steam stop valveC
feed check or control valveD
blow down valve
考题
单选题Bottom blow valves are installed on auxiliary water-tube boilers to （）A
remove suspended and precipitated solids from the boiler waterB
completely drain the boiler in an emergency situationC
prevent hardened scale deposits in the water drumD
remove floating impurities from the oily water surface
考题
单选题In a （） boiler the hot gases from the furnace pass through the tubes while the water is on the outside.A
water-tubeB
fire-tubeC
exhaust gasD
None of the above is true
考题
单选题What does blowing tubes accomplish?（）A
Eliminates unburned fuel oil residues from the fireboxB
Increases boiler efficiencyC
Flushes away mineral deposits inside the water tubesD
Cleans soot deposits from the inside of the stack
考题
单选题Aburned exhaust valve may be detected by a higher than normal （）A
firing pressureB
exhaust temperature from a particular cylinderC
cooling water temperatureD
compression pressure
考题
单选题Which statement is correct about HTTP trickling?（）A
It prevents the HTTP client or server from timing-out during an antivirus updateB
It prevents the HTTP client or server from timing-out during antivirus scanning.C
It is an attack.D
It is used to bypass antivirus scanners.
考题
单选题Water level controllers of the boiler must be kept operable to protect external steam-using plant from water “（）” danger.A
carry offB
carry downC
carry onD
carry over
考题
单选题If in doubt as to the true water level when a boiler is being oil-fired, you should （）.A
take no measuresB
extinguish the fire as soon as possibleC
feed water to the boilerD
open the blow down valve
考题
单选题The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to（）A
precipitate silica from solutionB
reduce corrosion in the heating coilC
prevent clogging and erosion in the coilD
maintain zero water hardness
考题
单选题While troubleshooting a refrigeration system for low head pressure, liquid refrigerant flooding back from the evaporator is determined to be the causeIt may be necessary to （）.A
change the expansion valve adjustmentB
readjust the water regulating valve to increase the flow of waterC
purge air from the condenserD
clean the waterside of the condenser
考题
单选题Impurities from the boiler water surface can be removed through the （）.A
safety valveB
blow down valveC
scum valveD
feed check valve
考题
单选题Bottom blow valves are installed on auxiliary water-tube boilers to （）A
completely drain the boiler in an emergencyB
prevent sludge from forming in the drumC
remove floating impurities from the boiler water surfaceD
remove settled solids from the water drum
考题
单选题Black smoke coming from a boiler can be caused by （）.A
low water levelB
low oil pressureC
excessively high fuel pressureD
an improper air/fuel ratio
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
热门标签
最新试卷
