Steam Flashcards
Why is superheated steam used in the main propulsion turbines instead of saturated steam?
(a) Less specific energy available per pound of steam.
(b) Greater heat energy available per pound of steam.
(c) Higher pressure available than saturated steam.
(d) Lower required specific volume than saturated steam.
(b) Greater heat energy available per pound of steam.
As steam accomplishes work in an engine or turbine, the pressure of the steam is reduced because it __________.
(a) becomes saturated again
(b) diminishes in volume
(c) expands in volume
(d) becomes superheated again
(c) expands in volume
The device illustrated is referred to as a/an \_\_\_\_\_\_\_\_\_\_ . GS-0048 A inverted bucket trap B upright bucket trap C "P" type trap D none of the above
A inverted bucket trap
The function of the device illustrated is to __________ . GS-0048
A control steam input to a heat exchanger
B control condensate output from a heat exchanger
C provide on/off control of drain pump
D provide air purging of low pressure refrigeration or air conditioning systems
B control condensate output from a heat exchanger
The trap illustrated operates as a __________ . GS-0005
A thermostatic bellows type steam trap
B thermodynamic bellows type steam trap
C thermostatic bi-metalic bellows type steam trap
D thermodynamic float type steam trap type steam trap
A thermostatic bellows type steam trap
The quantity of condensate passing through the illustrated steam trap will be reduced as the __________ . GS-0005
A amount of vapor contained in “A” decreases
B amount of liquid contained in “A” increases
C amount of vapor pressure contained in “A” increases
D vapor pressure of the liquid contained in “A” decreases
C amount of vapor pressure contained in “A” increases
[“A” will expand, pushing “C” closer into “D,” restricting flow of condensate.]
What statement representing the primary purpose of a steam trap is true?
(a) By draining the low point of a horizontal run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer.
(b) By draining the high point of a horizontal run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer.
(c) By draining the high point of a vertical run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer.
(d) By draining the low point of a horizontal run of steam piping, a steam trap is used primarily to insure good heat transfer efficiency.
(a) By draining the low point of a horizontal run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer.
In order for a steam trap to be effective in accomplishing its intended purpose, what statement is true regarding its installation?
(a) The steam trap should never be painted, but should be covered with insulation.
(b) The steam trap should be painted to reduce corrosion and should be covered with insulation.
(c) The steam trap should be painted to reduce corrosion but should never be covered with
insulation.
(d) The steam trap should never be painted and should never be covered with insulation.
(d) The steam trap should never be painted and should never be covered with insulation.
The most critical period of main turbine operation is during cold start-up, rather than hot shutdown because __________.
(a) harmonic vibrations associated with critical speed can easily be reached during start-up
(b) the danger of blade erosion damage from dry steam impingement is greater during start-up
(c) lubricant film thickness during start-up is considerably less than the dimensions of gear
surface irregularities
(d) differential expansion can result from the temperature difference between the rotor and rotor casing
(d) differential expansion can result from the temperature difference between the rotor and rotor casing
If “E” is moved closer to the top of “B” as shown in the illustration, the __________ . GS-0002
A efficiency of the heat exchanger operation will be increased
B point of condensation will be moved closer to the steam inlet of the heat exchanger
C point of condensation will be moved closer to the condensate outlet of the heat exchanger
D steam pressure set point will automatically be increased
B point of condensation will be moved closer to the steam inlet of the heat exchanger
Referring to the illustrated bellows-type thermostatic steam trap, what statement is true concerning its operation? GS-0005
A When the bellows comes into contact with relatively cool condensate, the vapor within the bellows condenses resulting in bellows contraction and valve opening.
B When the bellows comes into contact with relatively hot steam, the vapor within the bellows condenses resulting in bellows contraction and valve opening.
C When the bellows comes into contact with relatively cool condensate, the liquid within the bellows vaporizes resulting in bellows expansion and valve closing.
D When the bellows comes into contact with relatively hot steam, the liquid within the bellows vaporizes resulting in bellows contraction and valve opening.
A When the bellows comes into contact with relatively cool condensate, the vapor within the bellows condenses resulting in bellows contraction and valve opening.
Which of the listed types of steam traps operates on the principle that hot water flashes to steam when its vapor pressure is rapidly reduced? A Ball float B Thermostatic C Bimetallic D Impulse
D Impulse
The gravity tank in a gravity lube oil system serves to __________.
(a) settle lube oil prior to purifying
(b) maintain oil supply for several minutes to bearings should the lube oil service pump fail
(c) store heated lube oil
(d) supply the lube oil service pump with a positive suction head
(b) maintain oil supply for several minutes to bearings should the lube oil service pump fail
Which of the following conditions is indicated by oil flowing through a lube oil gravity tank overflow sight glass?
(a) Turbine bearing failure has occurred.
(b) Insufficient oil is being pumped to the gravity tank.
(c) Excessive oil is stored in the gravity tank.
(d) Sufficient oil flow is being supplied to the gravity tank.
(d) Sufficient oil flow is being supplied to the gravity tank.
Bottom blow valves are installed on auxiliary water-tube boilers to __________.
(a) completely drain the boiler in an emergency
(b) prevent sludge from forming in the steam drum
(c) remove floating impurities from the boiler water surface
(d) remove settled solids from the water drum
(d) remove settled solids from the water drum
Proper use of the boiler surface blow will __________ .
A remove most precipitated solids
B remove floating impurities from boiler water
C disrupt circulation in a steaming boiler
D have no effect on boiler alkalinity
B remove floating impurities from boiler water
Which of the following statements concerning fire-tube boilers is correct?
(a) Combustion gases flow through the tubes.
(b) Flames impinge on the tubes.
(c) Combustion occurs in the tubes.
(d) Water flows through the tubes.
(a) Combustion gases flow through the tubes.
The boiler shown in the illustration would be classed as __________. MO-0064
(a) two-pass, water-tube
(b) two-pass, scotch marine
(c) single-pass, fire-tube, scotch marine
(d) forced circulation, coil-type
(c) single-pass, fire-tube, scotch marine
[Fire-tube = the fire is in the tubes.]
Fusible plugs are installed in fire-tube boilers to __________.
(a) provide a means of draining the boiler
(b) warn the engineer of low water level
(c) cool the crown sheet at high firing rates
(d) open the burners’ electrical firing circuits
(b) warn the engineer of low water level
A photoelectric cell installed in an automatically fired auxiliary boiler burner management system __________.
(a) opens the burner circuit upon sensing a flame failure
(b) detects a flame failure by monitoring radiant heat from glowing refractory
(c) requires mechanical linkage to secure the burner fuel supply
(d) must be bypassed at low firing rates
(a) opens the burner circuit upon sensing a flame failure
Auxiliary boilers are divided into several classifications, one of which is __________.
(a) water-tube supercritical circulation
(b) water-tube forced circulation
(c) fire-tube controlled circulation
(d) fire-tube express circulation
(b) water-tube forced circulation
The solenoid valves in the fuel oil supply line to an automatically fired auxiliary boiler, are automatically closed by __________.
(a) a decrease in feed temperature
(b) high furnace air pressure
(c) high steam pressure
(d) low steam pressure
(c) high steam pressure
The action of water circulating within a natural circulation boiler, is the direct result of \_\_\_\_\_\_\_\_\_\_ . A furnace flame radiation B tube wall conduction C gas convection D water density differences
D water density differences
Water circulates in a natural circulation boiler due to the __________.
A difference in tube length and diameter
B angle of inclination
C difference in density between the water and the steam/water mixture
D difference between the heights of the boiler drums
C difference in density between the water and the steam/water mixture
Auxiliary boilers can be classified as \_\_\_\_\_\_\_\_\_\_ . A water-tube natural circulation boilers B fire-tube boilers C water-tube forced circulation boilers D all of the above
D all of the above
To minimize metal corrosion, boiler water is best kept __________.
(a) slightly acidic
(b) neutral
(c) fairly acidic
(d) alkaline
(d) alkaline
Although accurate tests of boiler water for dissolved oxygen are difficult to obtain on board ship, you can be fairly certain of proper oxygen removal by __________.
(a) maintaining a normal level of scavenging agents
(b) maintaining low boiler water pH
(c) testing frequently for total dissolved solids
(d) giving the boiler frequent surface blows
(a) maintaining a normal level of scavenging agents
When a boiler water test indicates a pH value of 6, you should __________.
(a) chemically treat to raise the pH to normal level
(b) check the DC heater for possible malfunction
(c) begin a continuous boiler blow down
(d) chemically treat to lower the pH to normal level
(a) chemically treat to raise the pH to normal level
Flame scanners are used with boiler combustion control systems to monitor flame quality and to __________.
(a) secure the fuel oil service pump in the event of a floor fire
(b) regulate the fuel/air ratio controller for more efficient combustion
(c) shut off the fuel supply if flame failure is detected
(d) secure the forced draft fan in the event of a flame failure
(c) shut off the fuel supply if flame failure is detected
In the water level electrode assembly, shown in the illustration, the feed pump should restart when the level of the water reaches the position indicated by arrow ‘____’. MO-0047
(a) B
(b) C
(c) E
(d) D
(b) C
The auxiliary boiler feed water level control shown in the illustration, utilizes __________ .
A two position differential gap action
B proportional action
C proportional plus reset action
D proportional plus reset plus rate action
A two position differential gap action
In the auxiliary diesel engine, shown in the illustration, the __________. Illustration MO- 0006
(a) governor is linked to the fuel injection pump by vertical linkage
(b) explosion relief doors are clearly visible on both sides of the crankcase
(c) camshaft rotates at the same speed as the crankshaft
(d) engine oil filter is outboard of the electric starter
(a) governor is linked to the fuel injection pump by vertical linkage
Which of the listed refractory materials can be used in an area directly exposed to the highest heat in the furnace?
(a) Baffle mix
(b) Insulating block
(c) Insulating brick
(d) Firebrick
(d) Firebrick
