9. Refrigerant is circulated through a refrigeration system by the ______. A. compressor B. condenser C. expansion valve D. evaporator 10. In a compressor refrigeration plant the refrigerant flows from the expansion valve and through the ________ where it absorbs heat from the space being cooled and becomes a gas or vapor. A. compressor B. condenser C. throttle valve D. evaporator
11. Moisture should be kept out of an R-12 system because it tends to cause _______. A. icing of the automatic controls
B. embrittlement of some parts of the automatic controls C. sludge in the lubricating oil D. all of the above
12. A feeler or thermal bulb is used for the expansion valve to ______.
A. detect the temperature B. detect the pressure C. heat the refrigerant D. accelerate the refrigerant
13. When adding oil to a refrigeration system, precautions must be taken to ensure that ______.
A. the compressor suction pressure is not too high
B. all air is purged from the pump and charging fittings
C. the high pressure cutout switch is held open to prevent accidental starting D. the condenser is completely shutdown first
14. “Flooding back” is a condition where the liquid refrigerant ______.
A. vaporizes in the condenser B. reaches the compressor through the suction line
C. flashes in the liquid line D. condenses in the receiver 15. Zinc rods are installed on the ______in the refrigeration system.
A. liquid strainer B. liquid receiver C. saltwater condenser D. evaporator
16. Air entering an air-cooled refrigeration system is indicated by ______.
A. frosting of the liquid line B. higher than normal head pressure
C. a clear sight glass D. abnormally cold reefer boxes
17. Ammonia when used as a refrigerant is valuable because of its high efficiency, it is however ____.
A. toxic B. flammable C. explosive D. all of the above
18. If a refrigeration compressor will not start, the reason may be ______. A. the pressure regulating valve is not closing B. an excessive lack of refrigerant in the system
C. badly leaking discharge valves D. worn piston rings
19. In a refrigeration system, if the cooling water to the condenser fails, the ______. A. box temperature solenoid valve will close B. expansion valve will close
C. compressor will shutdown D. king valve will open
20. If liquid refrigerant accidentally comes in contact with the eyes, ______immediately.
A. rub the eyes B. irritate the eyes
C. wash the eyes with a heavy boric acid solution D. obtain medical help 21. The certificate for the refrigerating plant will ______soon. I?d like to extend its validation now.
A. update B. finish C. outdated D. expire
22. If a refrigeration system were short of refrigerant, the condition would result in ______.
A. continuous running of the compressor B. high suction pressure C. high discharge pressure
D. short cycling of the compressor on the water failure switch 23. The purpose of the low pressure cutout switch is to______. A. maintain liquid refrigerant at the suction of the compressor B. maintain a preset suction pressure to the compressor
C. start and stop the compressor at preset operating pressures D. operate at minimum efficiency
24. When a refrigeration compressor is in the 'off' cycle, the thermal expansion valve will______.
A. always be wide open when the compressor restarts B. continue to operate as if the system were in operation
C. remain open until evaporator pressure equalizes, then close until the compressor restarts
D. always be completely closed until the compressor restarts
25. A ship designed for carrying goods requiring refrigeration is called_____.
A. REEFER B. RO/RO SHIP C. CONTAINER D. TANKER
26. A non-return valve in the air delivery line near to the compressor must be ______type similar to the compressor discharge valve.
A. the low inertia B. the high inertia C. the low velocity D. the high velocity
27. Every liquid has a pressure at which will vaporize and this pressure varies with temperature. The word “ which” means ______.
A. a liquid B. a pressure C. a temperature D. none of the above
Lesson 21
Air Conditioning System
单项选择题：
1. The quantity of cooled air delivered by an air conditioning unit should _______ the sum of the quantity of air re-circulated to the unit and the quantity mechanically exhausted.
2.
3. 4.
5.
6.
7.
8.
9.
A. balance B. not balance C. be more than D. be less than
Most air conditioning units have _______ for adjusting the ratio of re-circulated fresh air. Care must be taken not to reduce the fresh air so that stuffiness or smells arise.
A. catch plates B. dampers C. regulating valves D. fans For the intermediate condition, thermostats must be correctly set _______. A. by trial and error B. by and large C. automatically D. very easily Sludge may form in the crankcase of an air conditioning compressor as a result of ______.
A. bubbling refrigerant B. overheating and oxidation
C. lowered operating temperatures D. reducing the cloud or flash point The temperature at which water vapor in the atmosphere begins to condense is called the ______.
A. dew point temperature B. condensation temperature C. psychometric temperature D. absolute humidity temperature
For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?
A. Chilled water system supply temperature. B. Chilled water system return temperature. C. Compressor discharge temperature. D. Compressor suction pressure..
A re-heater in an air conditioning system functions to ______. A. control inlet air temperature B. control inlet air volume
C. maintain relative humidity at 15%
D. restore conditioned air temperature to a comfortable level
In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by ______. A. increasing refrigerant pressure in the coil
B. increasing chilled water flow through the cooler C. sub-cooling the refrigerant in the condenser D. superheating the refrigerant in the compressor
Sludge may form in the lubricating oil crankcase of a reciprocating air conditioning compressor as a result of ______. A. wax precipitation in the lube oil
B. contamination by dust, scale, or moisture C. refrigerant bubbles in the lube oil
D. refrigerant reducing the lube oil viscosity
Lesson 22
Oil Pollution Prevention
单项选择题：
1. Most marine biological sewage treatment plants consists of all the following statements except ________. A. aeration tanks B. settling tanks C. disinfection agent D. anaerobic bacteria
2. A number of biological sewage treatment plants are in use at sea but nearly all work on what is called the extended aeration process. Basically this consists of oxygenating the liquor by bubbling air through it. According to the above two sentences, the word “this” means ______. A. a sewage treatment plant B. the extended aeration process C. the liquor D. the bubbling air
3. Here some oil in the oily water separator, as a result of its lower ______, will separate and rise into the oil collection space. A. temperature B. viscosity C. density D. velocity
4. 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 water B. with clean water C. by oily water D. by mixed water
5. In a complete oil / water separator, more oil will separate out onto the underside of these plates and travel outwards until it is free to rise into the oil collecting space. What?s the meaning of “it” in the sentence above? A. a separator B. oil C. water D. an oil collecting space
6. _________ is the breakdown of surface tension between oil droplets in an oil water mixture which causes them to join and increase in size. A. Wear B. Contaminating C. Coalescence D. Coarse separating
7. The remaining oil/water mixture now flows down into the fine separating compartment and moves slowly between the _______ in the Turbulo separator. A. catch plates B. swash plates C. cover plates D. bedplates 8. The ______is fitted on an oily water separator.
A. sliding bowl bottom B. gravity disc C. bowl D. liquid level detector
9. The oil sludge is burnt in the ______onboard. I?ll show you the ashes.
A. boiler B. main engine C. auxiliary engine D. incinerator 10. The bilge system has been performing well; however, the aft starboard engine room bilge-well suddenly fails to be pumped out. Which of the following should be done first to determine the cause? A. Open the bilge pump for inspection. B. Remove each of the manifold valves.
C. Remove only the manifold valve to the affected bilge-well.
D. Attempt to pump out another bilge well to determine if the entire system is
affected.
11. 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 water B. with clean water C. by oily water D. by mixed water
12. Here some oil in the oily water separator, as a result of its lower ______,will separate and rise into the oil collection space.
A. temperature B. viscosity C. density D. velocity
13. The most common type of containment device for spilled oil on the water is the use of ______.
A. straw B. booms C. skimmers D. chemical dispersants 14. In a complete oil/water separator, more oil will separate out onto the underside of these plates and travel outwards until it is free to rise into the oil collecting space. What?s the meaning of “it” in the sentence above?
A. a separator B. oil C. water D. an oil collecting space
15. An oil water monitor is required in order to measure ______.
A. the oil content in water B. the water content in fuel oil C. the water level in bilge well D. the oil level in bilge well
16. Oil water separators are used to ensure that ships don't discharge oil when ______bilge water.
A. to pump off B. being pumped C. pumping out D. it pumping out
17. A high rate of separation between oil and water is favored by______.
A. large size of oil globule B. low temperature C. high viscosity D. high flow rate
18. Oil Record Book Part I shall be provided to every oil tanker of 150 tons gross tonnage and above and every ship of 400 tons gross tonnage and above, ______oil tankers, to record relevant machinery space operations.
A. as well as B. as long as C. rather than D. other than 19. If one of the bilge system manifold valves does not properly seat, the ______. A. bilge well connected to that valve, plus the second bilge well being pumped will be completely emptied
B. bilge system will lose vacuum and prevent the other bilges from being pumped out
C. bilge well aft connected to that valve will siphon(虹吸) its contents to the forward bilge wells
D. discharge pressure will be too high.
20. Placing a filter on the ______of an oily water separator will “polish” the discharge but overloading must be avoided.
A. suction side B. discharge side C. by-pass pipe D. sampling pipe
21. When started, a complete oily water separating unit is first filled ______.The oily