Assessment Test


1. Which of the following statements represents the main difference between a stuffing box gland and a mechanical seal for sealing the shaft of a centrifugal pump?


2. Which of the materials listed is used as the dynamic seal material on mechanical seals installed on most centrifugal pumps used in water service?


3. Why are removable sleeves installed on centrifugal pump shafts?


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


5. Which type of pump would normally be used to transfer fairly large quantities of fluids at relatively low pressures?


6. Which of the pumping systems listed for use aboard ship will most likely use a propeller type pump?


7. One of the main differences between a propeller pump and a centrifugal pump is the absence of a __________.


8. The suction-force principle of operation is a typical characteristic of __________.


9. If you have a duplex, single acting, reciprocating pump making 140 strokes/minute with a 3" diameter cylinder, and a 12" stroke with a 94% volumetric efficiency, what is the capacity of this pump?


10. To safely remove the piston rod packing from the steam end of a reciprocating pump, you should __________.


11. Which of the lubricants listed is the best to use on a reciprocating pump rod?


12. The first step when resetting the slide valves on a duplex reciprocating pump is to __________.


13. When repacking a reciprocating pump with more than four rings of packing, the packing is cut square, installed with the ends abutted, and each succeeding ring staggered with the butted ends __________.


14. Which of the listed types of steam end piston rod packing should be used in a steam reciprocating pump?


15. A spur gear pump should be operated with the discharge valves __________.


16. Excessive lost motion in the valve mechanism of a duplex reciprocating pump will cause the __________.


17. When the danger of freezing exists, all steam driven reciprocating pumps and deck equipment should be __________.


18. An inadequate reciprocating bilge pump discharge is most often caused by __________.


19. Which of the following conditions would prevent a steam reciprocating pump from delivering its rated capacity?


20. A pounding noise occurring in one cylinder of a steam reciprocating general service pump could be caused by __________.


21. When piston rod packing persists in leaking on a reciprocating steam pump, the cause may be ___


22. When securing a steam reciprocating pump, which of the valves listed should remain open?


23. You suspect a problem with the centrifugal fire pump on your ship, and begin to slowly close the discharge valve. Your suspicion is confirmed when the


24. A centrifugal bilge pump requires priming __________.


25. The simplest method to use for determining if a centrifugal pump is operating as designed, is to __________.


26. Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?


27. A centrifugal pump may fail to deliver water when first started if the __________.


28. Charring or glazing of the inner circumference of the packing rings in a centrifugal pump, is caused by __________.


29. If a centrifugal pump were continually operated with the discharge valve closed, the __________.


30. Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by __________.


31. The total length of stroke in a reciprocating steam pump can be adjusted by __________.


32. Which of the listed reciprocating pump parts control the position of the pilot slide valve?


33. Which of the listed devices is used to control the admission of steam to the steam cylinder of a reciprocating pump?


34. Which of the following is NOT an identifiable characteristic of a steam reciprocating pump?


35. Which of the following valve arrangements permits the reciprocating pump liquid piston to take suction from the suction chamber, and simultaneously discharge through the discharge chamber during the up and down strokes?


36. The three basic parts of any eductor are the nozzle, the suction chamber, and the __________.


37. A distinguishing feature of an eductor, when compared to other pumps, is the __________.


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


39. The flame screens installed on sewage system tank vents prevent explosions by __________.


40. Which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flush water at ambient air pressure and temperature?


41. A constant pressure range is maintained in the potable water system of many vessels by using __


42. A vessel is in compliance with federal regulations regarding the discharge of sewage by __________.


43. Expansion tanks when used in a ship's low temperature hot water heating system may be of the open or closed type. In a closed type system, what would be the normal temperature range of the water?


44. (What type of pump is invariably used as a circulator in a hydronic heating system?


45. What statement is true concerning a one-pipe hydronic heating system?


46. What statement is true concerning a two-pipe hydronic heating system?


47. It is absolutely essential that hydronic heating system hot water piping be kept free of air. Assuming that a system is initially properly filled with water, what is the primary source of air contamination?


48. What advantage does a 4-pipe hydronic heating/cooling heating system have over a 2-pipe hydronic heating/cooling system?


49. Water hammer in a steam heating system can be caused by __________.


50. Which of the following guidelines is considered to reflect good design practices for shipboard steam heating systems?


51. What type of fan is most commonly used in ducted air-conditioning systems?


52. What type of centrifugal fan is characterized by the highest operating efficiency?


53. What pressure drop across an air-conditioning filter is indicative of a need to replace or clean the filter as appropriate?


54. Concerning air-conditioning system steam heating coils, what statement is true?


55. Concerning air-conditioning system hot-water heating coils, what statement is true?


56. What type of heating coil is generally preferred in heating spaces with electronic equipment?


57. What statement is true concerning steam-heated, hot-water heated, or electric- heated convectors?


58. Concerning air-conditioning system dry-expansion cooling coils, what statement is true?


59. Concerning cargo-hold dehumidification, what statement is true?


60. Which statement is true concerning a liquid desiccant cargo-hold dehumidification system?


61. What statement is true concerning a liquid desiccant cargo-hold dehumidification system?


62. With regard to the cooling and heating coils and humidification and regeneration chambers of a liquid cargo-hold dehumidification system, which statement is true?


63. What is the primary advantage of transverse bow and stern tunnel thrusters when installed on ships?


64. Which set of operating conditions would be most problematic in terms of the deterioration of the insulation resistance of the drive motor of an electric motor driven transverse tunnel bow thruster?


65. The gears used for virtually all marine propulsion reduction gear sets are of what type?


66. Of the following propulsion modes, which one would operate with a geared-drive featuring a single reduction?


67. What is an example of an epicyclic gear?


68. For a parallel axis single reduction gear, what statement is true?


69. Which of the listed reduction gear sets has the input and output shafts in-line with one another?


70. Which of the following couplings or clutches would be able to prevent the transmission of torsional vibrations from an engine to a reduction gear?


71. Which of the following couplings or clutches allows, within limits, a certain degree of slip?


72. Concerning main propulsion reduction gears, what statement is true?


73. What is a shipboard application for a worm gear drive?


74. Of the following propulsion modes, which one would operate with a geared-drive featuring a double reduction?


75. The basic function of the centrifugal pump impeller is to __________.


76. The primary function of a centrifugal pump volute is to __________.


77. Which of the following statements is true concerning centrifugal pumps?


78. Which of the following statements is true concerning centrifugal pumps?


79. Which of the listed types of seals is used effectively for pumps handling toxic or highly flammable liquids that cannot be permitted to escape into the atmosphere?


80. Which of the listed parts is used in a lobe-type rotary pump to allow for wear on the lobe edges?


81. One disadvantage of using a mechanical shaft seal instead of mechanical packing is that __________.


82. The output volume of a positive fixed displacement pump can be changed only by __________.


83. Why should the use of metallic or semi-metallic packing hooks or pullers be avoided on bronze or brass shafts, rods, plungers, or sleeves?


84. What should be done if localized scoring is discovered on a pump shaft sleeve during routine maintenance inspection?


85. When repacking a stuffing box fitted with a lantern ring, which of the following precautions should be observed?


86. When installing a mechanical shaft seal on a pump, it is important to ______.


87. A centrifugal pump gradually develops insufficient discharge pressure. What corrective action is required?


88. A pump shaft that is bent or distorted should normally be __________.


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


90. The capacity of a gear type rotary pump, when operated at a constant speed, will decrease with an increase in the pump __________.


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


92. How does the viscosity of a fluid being pumped affect the operation of a spur gear pump?


93. Positive displacement, helical gear pumps are well suited for pumping oil because __________.


94. The pressure of a liquid leaving the pump can be referred to as the __________.


95. If the existing vapor pressure is subtracted from the indicated pressure at the pump suction, the remainder is the


96. A pump is defined as a device that __________.


97. Which of the following terms is used to identify the pressure of a liquid entering a centrifugal pump?


98. Water leaking from a pump packing gland is kept away from the bearing housing by the use of __________.


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


100. Permanent centrifugal pump shaft damage due to erosion, corrosion, and wear at the stuffing box is usually prevented by


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