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National Maritime Center Providing Credentials to Mariners

U.S.C.G. Merchant Marine Exam

Assistant Engineer-Limited

Q611 Steam Plants

(Sample Examination)

of 24 Q611 Steam Plants

8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8

Choose the best answer to the following Multiple Choice Questions.

1. On a main propulsion turbine bearing, the readings obtained with a bridge gage represent the __________.

o (A) blade axial clearance o (B) Babbitt thickness • (C) oil clearance and bearing wear o (D) diaphragm tip clearance

If choice C is selected set score to 1.

2. Which of the following statements is correct regarding the start-up operation of a non-condensing turbine-driven feed pump?

o (A) Secure all drains prior to admitting any steam to avoid damage to traps. o (B) Keep the steam exhaust valve closed until steam is applied to ensure that the auxiliary

exhaust line pressure does not drop. o (C) Keep the pump casing vent valve closed until flow is established through the pump. • (D) Open the pump suction valve prior to admitting steam to the turbine.

If choice D is selected set score to 1.

3. Why should the fuel oil be recirculated before lighting off a cold boiler?

o (A) To allow the fuel strainers to thoroughly clean the fuel. o (B) To allow fuel pressure to buildup gradually. • (C) To heat the fuel enough for proper atomization. o (D) To ensure that all water is removed from the fuel.


4. As compared with a typical front fired boiler, which of the listed conditions represents an advantage of a top fired boiler?

• (A) More uniform heat distribution and gas dwell is obtained within the furnace. o (B) No division tube wall separating the convection and radiant sections of the furnace is ever

required. o (C) A lower fuel flow rate can be allowed, thus increasing economy. o (D) Superheating diaphragms may be omitted.

If choice A is selected set score to 1.


8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 5. Overheating of the generating tubes will occur when a boiler reaches its end point of __________.

o (A) combustion • (B) circulation o (C) moisture carryover o (D) evaporation

If choice B is selected set score to 1.

6. A pressure drop occurs across both the moving and fixed blades of a reaction turbine as a result of the __________.

• (A) moving and fixed blades being shaped to act as nozzles o (B) reversing blades causing a velocity drop with resultant pressure drop o (C) interstage diaphragms creating a nozzle effect in the steam flow o (D) conversion of the thermal energy to pressure energy always resulting in a pressure drop


7. When starting a turbo-generator, you must provide lube oil pressure to the governor power piston by means of __________.

• (A) the hand-operated or auxiliary lube oil pump o (B) a line from the gravity tank o (C) the main lube oil pump o (D) a line from the other generator


8. If a boiler is brought on the line with its steam pressure much higher than that of the boiler already on the line, there is danger of __________.

o (A) low water o (B) an overloaded superheater o (C) thermal shock • (D) priming and carryover


9. Excessive foaming in a steaming boiler can cause damage to the __________.

o (A) internal feed pipe o (B) economizer o (C) desuperheater • (D) superheater



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 10. Which of the types of superheaters listed has the flattest superheat temperature curve?

o (A) Convection • (B) Radiant-convection o (C) Radiant o (D) Conduction-convection


11. With vacuum up and the main propulsion turbine standing by while awaiting engine orders, it is necessary to roll the unit alternately ahead and astern every five minutes to __________.

o (A) warm the astern guarding valve and the low lube oil pressure throttle trip • (B) reduce the possibility of warping the turbine rotors o (C) distribute the gland sealing steam evenly throughout the glands o (D) slowly bring the lube oil and bearings to operating temperature


12. Proper use of the boiler surface blow will __________.

o (A) have no effect on boiler alkalinity o (B) remove most precipitated solids • (C) remove floating impurities from boiler water o (D) disrupt circulation in a steaming boiler


13. That portion of the steam drum, containing a manhole for internal access to the drum, for the purpose of cleaning, inspecting, and carrying out repairs, is called the __________.

o (A) wrapper sheet o (B) tube sheet • (C) drumhead o (D) end plate


14. Before placing the jacking gear in operation on a main turbine unit, you must always ensure that __________.

o (A) the gland seal steam system is operating • (B) the main lube oil system is operating o (C) the condensate system is operating o (D) the main salt water circulating pump is operating



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 15. An auxiliary turbine boiler feed pump should normally be stopped by __________.

o (A) increasing the load on the driven unit o (B) closing the exhaust valve slightly • (C) actuating the throttle hand tripping device o (D) rotating the hand lube oil pump backwards


16. The FIRST step in breaking vacuum on a main turbine unit should be to __________.

o (A) secure the steam to the gland seal system o (B) stop the main circulating pump o (C) stop the main condensate pump • (D) secure the steam to the main air ejector


17. As lube oil absorbs moisture its dielectric strength can be expected to __________.

o (A) increase with a decrease in viscosity o (B) increase with an increase in viscosity o (C) remain the same • (D) decrease


18. Which of the following statements is true concerning lube oil coolers?

• (A) The pressure of the oil is greater than that of the cooling water. o (B) Magnets are installed in the tube sheets to remove metal particles. o (C) The pressure of the oil is less than that of the cooling water. o (D) The temperature of the oil is less than that of the cooling water.


19. Which of the following statements represents the function of a turbine gland exhaust condenser?

o (A) Directs the gland exhaust from the turbine sealing glands to the air ejector suction. o (B) Recovers condensate from the gland leakage around the ahead and astern throttle valves. • (C) Assists in preheating the condensate before it enters the DC heater. o (D) Recovers condensate formed at the gland seal exhaust leakoff.



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 20. Which of the listed conditions can cause high superheater outlet steam temperature in an automated

boiler?

o (A) Insufficient excess air. • (B) Operating with a bypassed economizer. o (C) Excessive heat transfer in the control desuperheater. o (D) High water level in the steam drum.


21. If the main and standby lube oil service pumps of the main engine fail while underway at sea, __________.

o (A) the turbine bearings will immediately fail o (B) emergency lubrication can be supplied through the use of the hand pump o (C) the reduction gear bearings will immediately fail • (D) an emergency supply of oil in the gravity tank will provide time to crash stop the turbine and

gears


22. To assure a long service life for boiler refractory materials after installation, the most effective method is to __________.

o (A) maintain a high furnace temperature at all times • (B) avoid rapid temperature changes and follow recommended operating procedures o (C) properly secure refractory with anchor bolts o (D) patch refractory with plastic chrome ore


23. A common method of preheating main turbine lube oil prior to rolling over the main unit would be to ________.

o (A) bypass the lube oil gravity tank o (B) run both the lube oil pumps simultaneously • (C) operate the lube oil purifier on the main lube oil sump o (D) slightly increase gland sealing steam pressure


24. Which of the following types of bearings are used as line shaft bearings?

o (A) Rigidly mounted, radial sleeve o (B) Segmental, pivoted-shoe thrust o (C) Tapered roller, split type radial • (D) Ring-oiled, Babbitt-faced, spherical seat, shell



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 25. The boiler feedwater control valve varies the unity relationship between steam and water flow during

periods of __________.

o (A) steady boiler load o (B) minimum boiler load o (C) overload operation • (D) load change


26. The correct radial clearances between the rotor and the casing in a propulsion turbine are maintained by the turbine __________.

o (A) interstage packing o (B) thrust bearing • (C) journal bearings o (D) diaphragms


27. A sample of boiler water can be chemically tested for alkalinity by initially adding a few drops of phenolphthalein and then slowly titrating the water sample until the __________.

o (A) sample color changes from clear to pink • (B) sample color changes from pink to clear o (C) entire concentration of chlorides have been neutralized o (D) water sample pH reaches 10.5


28. An advantage of using boiler furnace studded waterwall tubes packed with refractory is that __________.

o (A) thinner tubes can be used • (B) the use of dense firebricks is not required o (C) thicker tubes are required o (D) lower quality steel can be used


29. To safely decrease the boiler firing rate, you should always reduce the fuel pressure __________.

• (A) before reducing the forced draft pressure o (B) after reducing the forced draft pressure o (C) by opening the oil recirculating valve o (D) by opening the fuel pump relief valve



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 30. The automatic recirculating valve in the main condensate recirculating line is controlled by a

temperature sensor which is located at the __________.

• (A) air ejector condensate discharge o (B) condensate inlet to the main air ejectors o (C) main condensate pump suction o (D) main condensate pump discharge


31. If it should become necessary to abandon a compartment because of the danger of a large steam leak on a boiler, which of the following actions represents the best avenue of escape?

o (A) Escape through another compartment on a higher level. o (B) Use fire room elevator to an upper deck. • (C) Escape through another compartment on a lower level. o (D) Escape by way of a fire room ladder to the outer deck.


32. A pilot valve and servomotor are utilized in mechanical-hydraulic governing systems on a turbo-generator unit in order to __________.

o (A) provide a means of maintaining a constant load on the turbine unit • (B) provide sufficient force to operate large steam lifting beam control valves o (C) allow parallel operation with zero speed droop o (D) provide a means of maintaining constant output voltage


33. The base ring shown in the illustration is identified by the letter __________. Illustration SE-0012

o (A) A o (B) E o (C) C • (D) D


34. The advantage of installing waterwall tubes in a boiler furnace is to __________.

• (A) permit higher combustion rates o (B) increase heat transfer to the mud drum o (C) decrease the flow of gases through the furnace o (D) increase the flow of gases through the furnace



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 35. If the water level in one boiler of a two boiler plant rapidly falls out of sight, which of the following

actions should be carried out FIRST?

• (A) Secure the fuel oil to that boiler. o (B) Secure the steam stop to that boiler. o (C) Blowdown the gage glass. o (D) Raise the feed pump pressure.


36. Steam tables can be used to obtain the __________.

• (A) values for properties of water and steam vapor at various conditions o (B) mechanical efficiency of the main unit o (C) steam generating capacity of a vessel's boilers o (D) specific fuel consumption under steady steaming conditions


37. In the illustration of a typical ship service turbo-generator control system, the handle labeled "B" is used to _______________. Illustration SE-0009

o (A) pump up the lube oil manifold • (B) reset the overspeed trip o (C) bypass the governor control o (D) roll over the high-speed pinion


38. Excessive accumulation of carbon deposits on a boiler burner throat ring and diffuser could result in __________.

o (A) a reduced boiler fuel oil pressure o (B) increased heat transfer and overheating o (C) too much excess combustion air • (D) a decrease in boiler efficiency


39. According to the data given in the illustration, which of the following would be the physical state of the fluid at a gage vacuum of 29.00 inches Hg, and 85.21 degrees Fahrenheit? Illustration SG-0026

o (A) Subcooled liquid. o (B) Saturated liquid. • (C) Superheated vapor. o (D) Mixture of saturated liquid and vapor.



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 40. The component labeled "II", as shown in the illustration, is called the __________. Illustration SE-

0013

o (A) first reduction gear • (B) high-speed pinion o (C) second reduction pinion o (D) second reduction gear


41. An excess pressure governor is a special type of control device which would normally be found on a __________.

o (A) forced draft fan o (B) main circulator pump • (C) turbine-driven feed pump o (D) low-pressure propulsion turbine


42. The items labeled "D" and "M" as indicated on the illustration are commonly called ________. Illustration SG-0020

o (A) cork gaskets o (B) glass inserts o (C) face plates • (D) mica sheets


43. To obtain the best mixing of air and fuel with a fuel oil atomizer, you need to adjust the __________.

o (A) primary and secondary air cones for desired air flow o (B) total air volume admitted to the boiler furnace o (C) diffuser to the desired flow • (D) atomizer position using the distance piece


44. When a boiler water test indicates a pH value of 6, you should __________.

• (A) chemically treat to raise the pH to normal level o (B) begin a continuous boiler blowdown o (C) check the DC heater for possible malfunction o (D) chemically treat to lower the pH to normal level



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 45. Which of the following items should be checked each time the firing rate or forced draft pressure is

adjusted?

o (A) Atomizing steam pressure • (B) Smoke periscope o (C) Fuel oil suction pressure o (D) Fuel oil heater inlet temperature


46. Which of the devices listed is generally used to engage the main engine turning gear to the high-pressure turbine high-speed pinion?

o (A) Manually operated band brake o (B) Quill shaft o (C) Sleeve coupling • (D) Manually operated sliding jaw clutch


47. How many Curtis stages are contained in the turbine shown in the illustration? Illustration SE-0003

• (A) 1 o (B) 2 o (C) 3 o (D) only a reaction turbine stage is shown


48. As steam first enters the main propulsion turbine, which of the following energy conversions takes place?

o (A) mechanical to thermal • (B) potential to kinetic o (C) chemical to thermal o (D) thermal to chemical


49. A turbine assembly in which steam flows in series through a high-pressure turbine and then on to a low-pressure turbine, with both turbines driving a common reduction gear through separate shafts, is classified as _________.

o (A) tandem compound o (B) dual series o (C) tandem, double flow • (D) cross compound



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 50. The boiler main feed stop-check valve is located nearest the __________.

• (A) main feedwater regulator inlet o (B) DC heater feedwater outlet o (C) boiler water drum inlet o (D) first stage feedwater heater outlet


51. While underway, vacuum in the main condenser is primarily caused by the __________.

• (A) condensing of the exhausting steam o (B) after condenser loop seal o (C) main air ejector o (D) suction drawn by the condensate pump


52. What is the cause of "laning" in a boiler tube bank?

• (A) Excessive slag accumulation on the tubes o (B) Low fuel oil pressure o (C) Reduced furnace volume o (D) Insufficient air flow


53. In any governor there is a small range of speed in which no corrective action occurs. This speed range is called the governor deadband and is caused by __________.

o (A) excessive sensitivity in the governor control valve o (B) speed droop designed into the governor system • (C) friction in the governor linkage and control valve o (D) speeder spring surge in the governor servomotor system


54. After routine blowing of tubes at sea, there should be a decrease in the __________.

o (A) CO2 in the stack gas o (B) fuel oil temperature o (C) excess air required for complete combustion • (D) stack temperature



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 55. A boiler is to be secured in port. After the burners have been secured, the forced draft fan and air

registers should be secured __________.

• (A) after any oil on the furnace floor has been burned off and cleared of combustion gases o (B) after at least 1 hour has elapsed, after carrying out these securing procedures o (C) after 30 minutes has elapsed, after carrying out these procedures o (D) immediately after carrying out the former procedures


56. If manual control of the water level in a steaming boiler is required, the proper method of control is with the auxiliary feed __________.

o (A) stop valve o (B) pump pressure control o (C) pump speed control • (D) stop-check valve


57. The greatest resistance to heat transfer from the fireside to the waterside of a water-tube boiler takes place in the __________.

o (A) soot buildup directly on the tube exterior o (B) moving water and steam inside the tube o (C) steel tube wall itself • (D) gas film layer surrounding the tube


58. Which type of packing is primarily utilized to control steam leakage from the casing of a modern auxiliary turbine?

• (A) labyrinth o (B) Teflon o (C) dovetail o (D) carbon


59. The minimum feedwater inlet temperature to a boiler economizer is determined by the __________.

o (A) superheater outlet temperature • (B) dew point temperature of the stack gas o (C) surface area of the third stage heater o (D) radiant heat transfer in the furnace



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 60. You are standing watch in the engine room of a steam vessel. You should blow down a gage glass

periodically to __________.

o (A) maintain the proper water level in the steam drum o (B) provide water samples for the second assistant o (C) test the feedwater stop-check valve • (D) remove any sediment that has accumulated


61. When heated, fuel oil will __________.

o (A) increase in specific gravity o (B) increase in viscosity • (C) expand in volume o (D) have a higher specific heat


62. Shrouding on impulse turbine blading is held in place by __________.

• (A) peening the tenons o (B) circumferential dovetails o (C) seal welding o (D) locking keys


63. Which color burner flame would indicate too much excess air?

o (A) Yellowish orange • (B) Incandescent white o (C) Orange red o (D) Bright red


64. Which of the coupling types listed is shown in the illustration? Illustration SE-0001

o (A) Claw o (B) Pin • (C) Gear o (D) Solid



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 65. Which of the following statements represents the significance of the differential pressure existing

between the nozzle block and steam chest of a turbo-generator equipped with a lifting beam mechanism?

o (A) The pressure differential eliminates the possibility of valve binding in the lifting beam. o (B) The pressure differential requires the installation of a special biasing spring to open the

valves. • (C) The pressure differential assists in seating the valves when the lifting beam is lowered. o (D) The pressure differential necessitates the use of a special balance piston.


66. The leakage of air into the pump casing by way of the packing gland of a condensate pump, is prevented by __________.

• (A) a water seal line to the packing gland o (B) the vacuum in the pump suction o (C) an air seal line from the compressed air line o (D) special packing in the stuffing box


67. During normal operation of a main propulsion turbine, the lube oil supply temperature to the bearings should be maintained at approximately __________.

o (A) 60°F o (B) 72°F • (C) 120°F o (D) 135°F


68. Vent condensers are usually an integral part of deaerating feed heaters and serve to condense __________.

o (A) the gases liberated by the deaeration process o (B) only steam vented from high-pressure steam traps o (C) steam vented from high-pressure steam glands • (D) the steam vapor entrained with the non-condensable gases



8/30/2017

U.S.C.G. Merchant Marine Exam Assistant Engineer-Limited Q611 Steam Plants Illustrations: 8 69. As found in a basic pneumatic automatic combustion control system, the function of a standardizing

relay is to __________.

• (A) introduce a control for maintaining constant steam pressure regardless of boiler load o (B) introduce a control for maintaining constant superheated steam temperature regardless of

boiler load o (C) control the boiler drum water level within acceptable limits regardless of the load o (D) provide a backup means for manual control of the system


70. The component labeled "F" as shown in the illustration is __________. Illustration SG-0007

o (A) a permanently installed Orsat apparatus o (B) one of the retractable soot blower elements o (C) a regenerative air heater • (D) one of the main burner assemblies



8/30/2017


12/8/2016

SE-0001

Adapted for testing purposes only BLANK, Introduction to

Naval Engineering, Second Edition

Copyright © 1985 by the United States Naval Institute

Further reproduction prohibited without permission



12/21/2016

SE-0009

Adapted for testing purposes only from Machinist’s Mate 3 & 2

NAVEDTRA 14151




12/23/2016

SE-0012

Adapted for testing purposes only from Machinist’s Mate 3 & 2

NAVEDTRA 14151




11/22/2016

SG-0020

Adapted for testing purposes only from POLSEN, Fundamentals of Steam Generators as

Applied to Marine Propulsion Power Plants

Copyright © 1969 by School of Marine Engineering & Navigation




12/5/2016

SG-0026

Properties of Saturated Steam

Vacuum Inches

of Hg Gage

Temperature

°C

Temperature

°F

29.51 11.74 53.14

29.41 15.17 59.30

29.31 18.04 64.47

29.21 20.52 68.93

29.11 22.70 72.86

29.00 24.66 76.38

28.90 26.43 79.58

28.70 29.56 85.21

28.49 32.27 90.08

28.29 34.66 94.38

28.09 36.80 98.24

27.88 38.74 101.74

27.48 42.18 107.92

27.06 45.14 113.26

26.66 47.77 117.99

26.26 50.13 122.23

25.85 52.27 126.08

25.44 54.23 129.62

25.03 56.05 132.89

24.63 57.74 135.94

24.22 59.33 138.79

23.81 60.82 141.48

22.79 64.21 147.57

21.78 67.21 152.97

20.76 69.91 157.83

19.74 72.36 162.24

18.72 74.61 166.30

17.70 76.70 170.06

16.69 78.64 173.56

15.67 80.47 176.85

14.65 82.14 179.86

13.63 83.81 182.86

12.61 85.36 185.64

11.60 86.82 188.28

10.58 88.22 190.80

9.56 89.57 193.21

7.52 92.08 197.75

5.49 94.42 201.96

3.45 96.60 205.88

1.42 98.64 209.56

Adapted for testing purposes only

Further reproduction prohibited without permission of 24 Q611 Steam Plants

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