61. In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is
40%
25%
50%
80%
90%.
Correct answer: (D) 80%
62. In designing air preheater, the important design consideration is that
approach temperature should be as low as possible
handling and maintenance should be easier
heat transfer area should be optimum
stack gases should not be cooled to the dew point
none of the above.
Correct answer: (D) stack gases should not be cooled to the dew point
63. In forced circulation type boiler
heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
feed pump is employed to supplement natural circulation in water wall type furnace
water is converted into steam in one pass without any recirculation
water is heated in a large number of tubes.
Correct answer: (D) water is converted into steam in one pass without any recirculation
64. In forced recirculation type boiler,
heating takes place at bottom and the water supplied at bottom gets converted into the mixture of'steam bubbles and hot water which rise to drum
water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
feed pump is employed to supplement natural circulation in water wall type furnace
water is converted into steam in one pass without any recirculation
heating of water takes place in stages.
Correct answer: (C) feed pump is employed to supplement natural circulation in water wall type furnace
65. In locomotive boiler, maximum steam pressure is limited to
1 kg/cm2
5 kg/cm2
10 kg/cm2
18 kg/cm2
31 kg/cm2.
Correct answer: (D) 18 kg/cm2
66. In locomotives, the draught is produced by
chimney
induced draft fan
both combined (a) and (b)
steam jet draught
none of the above.
Correct answer: (D) steam jet draught
67. In natural circulation type boiler,
heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
water is supplied in durm and through down-comers located in atmospheric conditon it passes to the water wall and rises to drum in the form of mixture of water and steam
feed pump is employed to supplement natural circulation in water wall type furnace
water is converted into steam in one . pass without any recirculation
water is fed at atmospheric pressure.
Correct answer: (A) heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
68. In ordetjo obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will
remain unaffected
improve (c) worsen
may improve/worsen depending on size
unpredictable.
none of the above.
Correct answer: (C) may improve/worsen depending on size
69. In regenerative air preheater, the heat is transferred
from a metal wall from one medium to another
from heating an intermediateanaterial and then heating the air from this material
by direct mixing
heat is transferred by bleeding some gas from furnace
none of the above.
Correct answer: (B) from heating an intermediateanaterial and then heating the air from this material
70. In water wall furnace, the heat is transferred to the water-walls by