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25 Cards in this Set
- Front
- Back
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1) The waterside of a flat-glass boiler gauge glass is protected from the etching action of steam by ---
(A) polyethlene (B) asbestos (C) sheet mica (D) graphite |
(C) sheet mica
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2) When air or the products of combustion are caused to flow to or through a boiler by maintaining them at a progressively increasing subatmospheric pressure, the draft system is said to be under ---
(A) induced draft (B) forced draft (C) balanced draft (D) both forced and induced draft |
(A) induced draft
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3) When air or the products of combustion are caused to flow to or through a unit by maintaining them at a pressure above atmospheric, the draft system is said to be under ---
(A) induced draft (B) forced draft (C) balanced draft (D) both forced and induced draft |
(B) forced draft
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4) In a controlled circualtion boiler ---
(A) positive circulation cannot take place until heat is applied (B) the limited natural circulation head requires the use of large-diameter waterwall tubes (C) the wall thickness of the waterwall tubes is generally greater than fo other boiler types (D) operating pressure in excess of 2400 psig may be used |
(D) operating pressure in excess of 2400 psig may be used
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5) All of the below but one describe a method of circulation in water-tube boilers ---
(A) natural (B) controlled (C) once-through (D) horizontal-return tube |
(D) horizontal-return tube
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6) Of the below statements, the one having the most effect on circulation in a natural circulation boiler is ---
(A) difference in density between steam and water (B) height of steam drum (C) ambient temperature (D) diameter of waterwall tubes |
(A) difference in density between steam and water
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7) A type of boiler design which uses a recirculation pump between the drum and the waterwalls is called ---
(A) natural circulation (B) scotch type (C) controlled circulation (D) once-through |
(C) controlled circulation
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8) The amount of refactory and firebrick needed in boilers has been reduced through the use of ---
(A) better tube metal (B) waterwall tubes (C) higher pressures (D) larger furnaces |
(B) waterwall tubes
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9) The use of preheated combustion air ---
(A) speeds up combustion (B) improve combustion at low loads (C) increases efficiency (D) all three |
(D) all three
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10) Which one of the following statements is not true regarding the operation of auxiliary air heaters?
(A) steam coils are used to transfer heat to the incoming air (B) they indirectly control the temperature of the flue gas leaving the air preheater (C) they are often bypassed when operating at low unit loads (D) they are often bypassed when burning low percentage sulphur fuel |
(C) they are often bypassed when operating at low unit loads
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11) Recirculated gas is used to control the steam temperature to the turbine. It effect within the boiler is to --
(A) increase the firing rate (B) lower the boiler efficiency by 20 percent (C) change the pattern of heat absorption (D) increase the gas weight up the stack |
(C) change the pattern of heat absorption
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12) A type of waterwall construction which provides the most effective means for maintaining a gas-tight boiler casing is the ---
(A) welded membrane wall (B) stud-tube wall (C) tangent-tube wall (D) welded outer casing |
(A) welded membrane wall
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13) The purpose of the turbine bypass system in super critical boiler units is to provide a means for ---
(A) furnace wall protection (B) initial feedwater heating and deaeration (C) protecting the unit during startup and shutdown (D) all three of the above |
(D) all three of the above
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14) In most natural circulation type boilers, the flue gas enters the economizer ---
(A) after leaving the air preheater (B) after leaving the secondary superheater (C) before passing through the primary reheater (D) after leaving the secondary superheater and before entering the primary superheater |
(B) after leaving the secondary superheater
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15) For every 10 - 11 degrees F increase in feedwater temperature picked up in the economizer the boiler efficiency increases about ---
(A) 10 percent (B) 5 percent (C) 3 percent (D) 1 percent |
(D) 1 percent
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16) The term surface attemperator, when applied to the steam temperature control, refers to ---
(A) mixing feedwater directly with the steam for desuperheating (B) bypassing steam back to the economizer (C) diverting part of the superheated steam from the primary superheater to a heat exchanger submerged in one of the boiler drums (D) desuperheating the steam at the turbine throttle by the direct method |
(C) diverting part of the superheated steam from the primary superheater to a heat exchanger submerged in one of the boiler drums
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17) The primary function of the steam drum is to ---
(A) contains the purification equipment (B) introduce chemicals for feedwater treatment (C) provide suction head for the feed pump (D) separate the steam from the mixture of water and steam discharged to it |
(D) separate the steam from the mixture of water and steam discharged to it
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18) An air preheater ---
(A) improve boiler efficiency by maintaining high exit gas temperatures (B) improves boiler efficiency only when combustion air temperatures are kept below 300 degrees F (C) improves combustion only at low loads (D) will increase boiler efficiency about 2 1/2 percent for every drop in exit gas temperature when using either oil or gas |
(D) will increase boiler efficiency about 2 1/2 percent for every drop in exit gas temperature when using either oil or gas
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19) Tie bars and buckstay arrangements are often provided at corner connections of the boiler furnace to ---
(A) maintain tube alignment (B) support the casing insulation (C) prevent the rupture of boiler tubes during a boiler explosion (D) absorb the additional loading placed on boiler walls by furnace puffs or other abnormal variations in furnace pressure |
D) absorb the additional loading placed on boiler walls by furnace puffs or other abnormal variations in furnace pressure
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20) A boiler safety valve is set to lift at 2450 psig. It resets at 2364. The percentage of blowdown is most nearly ---
(A) 2.0 percent (B) 2.5 percent (C) 3.0 percent (D) 3.5 percent |
(D) 3.5 percent
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21) From the methods shown below, select the one that is not an accepted way for connecting boiler tubes to drums or headers ---
(A) expanding (B) threading and seal welding (C) expanding and seal welding (D) butt welding |
(B) threading and seal welding
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22) The main reason for washing the boiler furnace and gas passes is to ---
(A) improve heat transfer (B) reduce the draft losses (C) reduce tube exfoliation (D) reduce sulfatrioxide gas concentration in the flue gas |
(A) improve heat transfer
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23) When reinstalling a boiler manhole cover ---
(A) alway make sure the drum and cover match-marks are lined up (B) gaskets are required only if the mating surfaces are badly pitted (C) yoke bars should not be removed until cover is fully seated by water pressure (D) use a 0.008 inch feeler gauge |
(A) alway make sure the drum and cover match-marks are lined up
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24) Which of the below statements is not true regarding boiler hydrostatic tests?
(A) pressure is always 1 1/2 times the designed pressure (B) used to test for leaks (C) water should be between 70 - 90 degrees F (D) usually given following acid cleaning |
A) pressure is always 1 1/2 times the designed pressure
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25) The relieving capacity of a safety valve most nearly means ---
(A) the pressure at which the valve opens (B) the amount of steam in lbs/hr a valve can discharge at a pressure 6 percent higher than the set popping pressure (C) the difference in pressure between opening and closing of the valve (D) the pressure at which the valve closes |
(B) the amount of steam in lbs/hr a valve can discharge at a pressure 6 percent higher than the set popping pressure
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