Assessment Test

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1. C4 - Air compressor cylinder unloader enable the compressor to_______.

 

2. C4 - Which of the following statements regarding low pressure, reciprocating, air compressor valves is correct?

 

3. C4 - In a low pressure air compressor, the loss of volumetric efficiency normally results from _____.

 

4. C4 - In a large slow-speed propulsion diesel engine, the force applied to the piston is __________.

 

5. The expansion tank for the jacket cooling water which is a closed cooling type is used to ___________.

 
 

6. An eccentric reducer, used as a transition piece between a centrifugal pump suction flange and the suction piping flange, must be installed with the eccentric portion below the suction pipe centerline t

 
 

7. Inspection of a low pressure gear pump for cavitation will usually be indicated by a wear pattern _____.

 
 

8. When renewing the shaft packing on a centrifugal pump equipped with an external liquid sealing supply, you should _____?

 
 

9. Provision is to be made for ventilation of an enclosed diesel engine crankcase by means of a small _________

 
 

10. When installing a new rotary pump, the suction piping should ____

 
 

11. To prevent air pockets from forming in a centrifugal pump suction line installed angled from normal, any gate valve should be installed with the _

 
 

12. Burned gas from each cylinder is directed to the exhaust manifold which is part of__

 
 

13. The inlet pipe connection of dirty oil in disc type centrifugal purifier is located at the _

 
 

14. In a large, low-speed diesel engine the clearance between the piston crown and cylinder head is found to be excessive. In order to correct for this, you should ___

 
 

15. The thermostatic expansion valve of a refrigeration system is opened ____________.

 
 

16. On a medium pressure, differential piston, reciprocating air compressor, lubrication of the pistons/cylinders is usually accomplished

 
 

17. How can we quickly reduce high water level in a steaming boiler?

 
 

18. Which of the following procedures should be carried out to permit the continued operation of a crosshead engine with a leaky aftercooler?

 
 

19. An unloader is installed on an air compressor to

 
 

20. When air compressors are arranged for automatic operation, the cylinders can be unloaded during starting by

 
 

21. A centrifugal pump operating against a closed discharge valve has a/an __

 
 

22. Cylinder inlet valve failure in a low pressure air compressor can be caused by

 
 

23. One method of constructing large marine diesel engines and reducing the total engine frame weight is through

 
 

24. The static suction lift of a pump is the difference in elevation between the _

 
 

25. Which of the following methods applies to how a vacuum is created by a jet pump or an eductor?

 
 

26. The purpose of expansion valve is to__________.

 
 

27. A high reading at a salinity cell located in the loop seal between two stages of a flash type evaporator indicates_____.

 
 

28. Why is the discharge pressure of a herringbone gear pump steadier than the discharge pressure of a simple spur gear?

 
 

29. Which of the listed operations will cause an automatically controlled refrigeration compressor to restart?

 
 

30. If an air compressor is used to supply compressed air to outlets throughout the engine room and on deck of a vessel, the system is known as the _____.

 
 

31. In the refrigeration system, the refrigerant absorbs the latent heat of vaporization in the_

 
 

32. A squeaking sound occurring from within an operating reciprocating air compressor is an indication of___

 
 

33. The low pressure side of a refrigeration system is considered to exist from the

 
 

34. The function of seal cages, or lantern rings installed in the centrifugal pump stuffing boxes, is to _____.

 
 

35. Diesel engine jacket water is used in the fresh water distillation process as the __________.

 
 

36. A decrease in the condenser vacuum is found to be caused by a loss of the air ejector loop. To reestablish the loop seal, you should _____.

 
 

37. The demisters installed in a flash-type evaporator serve to _____.

 
 

38. What is the function of the aftercoolers installed in the diesel engine air intake system?

 
 

39. While at sea, the flash type evaporator is discharging the output to the boiler water reserve feed tanks. If it becomes necessary to reduce the evaporator feed water temperature to below 165oF, you should _____.

 
 

40. The capacity of a rotary pump, delivering a constant viscosity fluid, will decrease when the discharge pressure is increased, due to________.

 
 

41. The storage tank for liquid refrigerant in a refrigeration system is called _

 
 

42. Increasing the speed of a centrifugal pump will result in an increase in the pump capacity. Another means of increasing the total head pressure of a centrifugal pump is to increase the _____.

 
 

43. What common type of air heater is used in sectional headers of marine boilers?

 
 

44. Turbulence in the cylinder of a two-stroke/cycle main propulsion diesel engine is mainly created by __________.

 
 

45. The total static head of a system resisting the operation of a centrifugal pump is the difference in elevation between the _____.

 
 

46. The capacity of a rotary pump, when operated at a constant speed, will decrease with an increase in the pump _________.

 
 

47. The function of a centrifugal pump double volute casing is to _____.

 
 

48. Unloader in air compressor is use to_______

 
 

49. The purposes of an air compressor unloading device is to _____.

 
 

50. After the installation of new impeller wearing rings by pressing them onto the pump impeller hub, it is advisable to _____.

 
 

51. What component of the freshwater evaporator on board use to boil seawater, using the main engine jacket cooling water?

 
 

52. A salinity indicating system functions on the basic principle of measuring the____.

 
 

53. Component of an engine used to increase scavenging air is called _

 
 

54. Irregular feeding or surging of the feedwater supply to a low pressure distilling plant may be attributed to _____.

 
 

55. A recirculating, or bleed off line is installed on a centrifugal pump in order to ___

 
 

56. In a refrigeration system, the amount of superheat absorbed by the refrigerant is adjusted at the

 
 

57. The high pressure side of the refrigeration systems starts from the ___

 
 

58. During the operation of the flash-type evaporator, the distillate flow meter indicates the output has dropped by more than 50% from the previous day. With the exception of the three-way valve diverting the distillate output to the bilge once every hour,

 
 

59. If a centrifugal pump operating with a positive suction head vibrates, or becomes noisy, the cause could be __

 
 

60. Refrigerant is circulated through a refrigeration system by the ___________.

 
 

61. If an air compressor is used to supply air primarily to the combustion control system and other pneumatic controllers, the entire system is known as the _____.

 
 

62. Integral water jacket liners use O-rings near the bottom of the liner. These O-rings serve to

 
 

63. What could be the probable cause if a generator engine charge air pressure becomes lower than normal?

 
 

64. Short cycling of a refrigeration compressor refers to_____________.

 
 

65. Air leaking into a flash type distilling plant could occur through_______.

 
 

66. One advantage of dry cylinder liners used in a diesel engine is the ____________

 
 

67. A mooring winch should be equipped with mechanical brakes capable of holding_____.

 
 

68. It is possible to mount a double suction centrifugal pump impeller with the vanes facing the wrong direction. This would cause the pump _

 
 

69. The separation chamber of the purifier is called

 
 

70. Which of the following statements is true concerning the overall efficiency of air compressors?

 
 

71. If an air compressor intercooler pressure rises above normal, it usually indicates _

 
 

72. A compressor operating with an accumulation of dust and grease on the surfaces of an intercooler would result in _________. I. a decrease in volumetric efficiency of the compressor II. higher volume of air to be discharged to the receiver

 
 

73. Which of the following statements is true concerning V-belt drives for reciprocating air compressors? I. Belts generally stretch slightly during the first few months of use II. Excessively tight belts will overload the bearings III. Belts are generally replaced as a set

 
 

74. When air compressors are arranged for automatic operation, the cylinders can be unloaded during starting by _____. I. bypassing the discharge to suction II. fitting depressors which hold the suction valve plates on their seats III. step unloading the cylinders in a multicylinder machine

 
 

75. A compressor operating with an accumulation of dust and grease on the surface of an intercooler would result in _____. I. a high consumption of lube oil II. higher than normal air pressure in the reciever

 
 

76. What would be the result of throttling the suction valve to the point where the flow was less than that recommended by a centrifugal pump manufacture? I. The discharge head would be reduced II. The pump would begin to cavitate

 
 

77. What would be the probable cause if a pump were unable to maintain necessary discharge pressure to a system? I. failure of the internal parts of the pump II. failure of the pump relief valve spring

 
 

78. What would be the result of throttling the suction valve to the point where the flow was less than that recommended by a centrifugal pump manufacturer? I. The designed discharge head would be reduced II. The packing life would be greatly reduced

 
 

79. What would be the result of throttling the suction valve to the point where the flow was less than that recommended by the centrifugal pump? I. The designed total net head would be reduced II. The pump would begin to cavitate

 
 

80. In a diesel engine, an integral liner is one in which the cooling water _______. I. flows through the cylinder liner jackets II. Touches the outer side of the liner

 
 

81. Parts of the pump used to maintain the alignment of the pump are____

 
 

82. The inability to maintain proper vacuum in a submerged tube evaporator can be caused by

 
 

83. Which units of measurement are commonly used to express pump suction head values when calculating pump capacities and hydraulic horsepower?

 
 

84. Operating a rotary gear pump far below its rated speed when handling low viscosity liquids, will cause its volumetric efficiency to __

 
 

85. Fluctuations in the pressure and temperature of the steam supplied to the first-effect of a low pressure submerged tube distilling plant will cause

 
 

86. An air compressor is equipped with an intercooler and an aftercooler to__________

 
 

87. If a reciprocating air compressor has a knock occurring in frequency with its operating RPM, the cause is probably ____________.

 
 

88. If you hear a ‘crackling’ sound coming from a salt water centrifugal pump casing, the most probable cause of the noise would be

 
 

89. While operating a two-stage flash-type evaporator, designed to operate in sea water of 70oF, the current seawater temperature is 50oF, while the salt water feed temperature is maintained at 170oF. The three-way solenoid valve trips, directing the distillate pump discharge to the bilge. Which of the following conditions is the probable cause for this occurrence?

 
 

90. It is a form of energy which crosses the boundary of a system during a change of state produced by a difference of temperature between the system and its surroundings.

 
 

91. The high pressure cut-out switch will stop the refrigeration compressor when there is______.

 
 

92. The heat gained per pound of refrigerant in the evaporator is known as the___

 
 

93. When renewing spiral packaging in a centrifugal pump stuffing box, after the packing is firmly seated, the packing gland nuts should be ___

 
 

94. Which combination of the main shaft segments listed below, that are located furthest from the main engine, are connected by the inboard stern tube shaft coupling?

 
 

95. The liquid indicator sight glass is generally located in the ____________

 
 

96. To prevent overheating and scoring of the shaft after repacking the stuffing box, which of the following procedures should be carried out?

 
 

97. One of the main functions of wearing rings, as used in a centrifugal pumps, is to _

 
 

98. C4 - Cylinder oil is used for _________.

 

99. C4 - Condensers located in the various stages of the flash evaporator are cooled by_________.

 

100. C4 - A material use to protect the internal parts of air compressor from solid particles which can be sucked along with fresh air is called____.

 


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