51. An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called __________ furnace.
52. Turndown ratio of a burner gives an idea of the __________ in the furnace.
53. In low or standard frequency induction furnace, heat is produced by the
54. Which furnace employs natural draft ?
55. Test specimen for determination of refractoriness under load (RUL) of a refractory is heated in a
56. Regenerators compared to the recuperators for the same duty
57. Regenerators are used for waste heat recovery in
58. Which of the following furnaces will have maximum thermal efficiency ?
59. Heat transfer takes place through a liquid medium surrounding the submerged material under heating, in case of a/an
60. The heating capacity of muffle furnace depends on the
61. Which of the following is a batch furnace ?
62. In a heating process, a heat flow diagram in which the quantities of heat in the various items of a heat balance are represented by the width of a band is called the
63. Maximum thermal efficiency of boiler may be about __________ percent.
64. Rotary kilns are used in the
65. The method of Lobo and Evans is concerned with the calculation of the
66. Reverberatory furnace is used for
67. Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent.
68. In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by
69. Which of the following is a directly fired intermittant furnace ?
70. Dampers are located
71. Protective gas used in the annealing furnace for steel coil comprises of
72. Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of
73. Scaling of furnace stock is reduced by __________ in flue gas.
74. __________ furnace is not an electric furnace.
75. Forced recirculation of furnace gases is practised