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
A cutoff valve in the fire-main system of a ship may be closed to protect the portion of the system on an exposed deck from（）.
A
damage from crane operations
B
being used for wash down purposes
C
accidental diversion of flow to wrong location
D
freezing
参考答案
参考解析
解析：
暂无解析
更多 “单选题A cutoff valve in the fire-main system of a ship may be closed to protect the portion of the system on an exposed deck from（）.A damage from crane operationsB being used for wash down purposesC accidental diversion of flow to wrong locationD freezing” 相关考题
考题
第二组Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.The passage is mainly aboutA.crankcase explosionB.scavenge box fireC.starting air pipeD.the danger of explosion in the starting air system
考题
To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the_______ .A.suction service valve as a vaporB.suction service valve as a liquidC.discharge service valve as a vaporD.charging valve as a liquid
考题
单选题If a refrigeration system compressor crankcase is sweating, you should （）.A
add refrigerant to the systemB
adjust the thermal expansion valve to the proper settingC
adjust the float valve to the proper holding pressureD
open the hand expansion valve
考题
单选题General radio communications in the global system are those between（）concerning the management and operation of the ships and may have impact on their safety.A
SAR party and the ship in distressB
SAR authorities and the ship in distress and survival craftC
A ship station and any coast stationD
Ship stations and shore-based communication network
考题
单选题If the operating element of a thermostatic valve installed in a diesel engine cooling system malfunctions, it may result in （）A
a low level in the engine expansion tankB
excessively high coolant pressureC
improper temperaturesD
malfunctioning of the jacket water heater
考题
单选题What is the function of thermostatic expansion valve in a compression refrigeration system?（）A
nonexistentB
for controlling pressureC
for controlling superheatD
for controlling the solenoid valve
考题
单选题On a ship，the possibility of a blowout makes which type of diesel engine shutdown desirable?（）A
Overspeed tripB
Air inlet shut-off valveC
Water injectorD
Fuel cutoff valve
考题
单选题In a refrigeration system, foaming of the crankcase oil may cause the （）.A
expansion valve to overfeedB
compressor to knockC
water regulating valve to failD
crankcase drains to plug
考题
单选题A pressure drop through the refrigerant liquid line may cause （）.A
solenoid valve to seizeB
compressor to huntC
formation of flash gas in the liquid lineD
expansion valve to freeze open
考题
单选题The emergency bilge suction or bilge injection valve is used to prevent （） of the ship.A
proceedingB
overloadingC
collisionD
flooding
考题
单选题The purpose of the purge valve at the top of the condenser in a refrigerating system is to（）A
remove any air that may accumulate in the systemB
take out unpleasant fumes from the refrigerantC
vent off excess refrigerant in an emergencyD
permit opening the refrigerating system for cleaning and inspecting
考题
单选题When ship in the dock repairing, engine department should emphasize on the inspection of（）A
sea valve chest, sect valve, thrusterB
bilge motherboard, steering and the shaft systemC
sea water systemD
fresh water system
考题
单选题Which system may be useful for messages，such as local storm warnings or a shore-to-ship distress alert，for which it is inappropriate to alert all ships in the satellite coverage area?（）A
NAVTEXB
EGCC
AMVERD
DSC
考题
单选题Which of the following statements is TRUE regarding automatic identification systems (AIS) ? （）A
AIS may be used to make passing arrangements via ship-to-ship text messaging thus relieving a vessel operator from sounding whistle signals or making contact via radiotelephoneB
AIS may be used to make passing arrangements via ship-to-ship text messaging but a vessel operator is still required to sound whistle signals unless the arrangement is made via radiotelephoneC
AIS cannot be used to make passing arrangements because the system does not have the ability to communicate from ship-to-ship in this mannerD
AIS cannot be used to make passing arrangements because the use of the ship-to-ship text messaging feature in this way is prohibited
考题
单选题Moisture in a refrigeration system can cause （）.A
freezing the expansion valve closedB
corrosion of system pipingC
improper temperature regulationD
all of the above
考题
单选题The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.A
assist in a quick cutoff of fuel injectionB
allow oil backflow from the injector to the helixC
reduce fuel oil pressure between injection strokesD
meter the quantity of fuel delivered
考题
单选题To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the （）A
suction service valve as a vaporB
suction service valve as a liquidC
discharge service valve as a vaporD
charging valve as a liquid
考题
单选题To add refrigerant to the high side of an air conditioning system, you should introduce the refrigerant through the （）.A
discharge service valve as a vaporB
suction service valve as a liquidC
charging valve as a liquidD
condenser purge valve as a vapor
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Each part of the fire-main system located on an exposed deck must be（）.A
protected against freezingB
locked to prevent theftC
numbered sequentiallyD
pressurized at all times
考题
单选题In a refrigeration system, if the cooling water to the condenser fails, the（）.A
box temperature solenoid valve will closeB
expansion valve will closeC
compressor will shutdownD
king valve will open
考题
单选题General radio communications in the global system may（）ship’s safety.A
be responsible forB
have an impact onC
commandD
give a guidance to
考题
单选题To correct the condition of slugging and flooding back in a refrigeration system, it may be necessary to （）.A
re-adjust the discharge pressureB
clean the expansion valve screenC
add refrigerantD
adjust the expansion valve
考题
单选题The low pressure side of a refrigeration system is considered to exist from the （）.A
expansion valve to the compressorB
receiver to the expansion coilC
expansion valve to the evaporatorD
condenser to the expansion valve
考题
单选题A branch line valve of a fire extinguishing system on a ship must be marked with the（）.A
maximum pressure allowed at that branchB
name of the space or spaces which it servesC
date of the last maintenance inspectionD
pressure needed to maintain an effective stream at that point
考题
单选题A pressure drop in the liquid line of a refrigeration system may cause（）A
the solenoid valve to seizeB
the compressor to huntC
flash gas to form in the liquid lineD
the expansion valve to freeze open
考题
单选题Control valves of a CO2 system may be located within the protected space when（）.A
it is impractical to locate them outsideB
there is also a control valve outsideC
the CO2 cylinders are also in the spaceD
an automatic heat-sensing trip is installed
热门标签
最新试卷
