Related Questions

Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C.
A 770
B 570
C 270
D 70
With increase in the porosity, thermal spalling resistance of fireclay brick
A increases
B decreases
C remains same
D may increase or decrease
Spalling hammer is used for
A Driving wooden headed chisels
B Rough dressing of stones
C Carving of stones
D Breaking small projection of stones
To resist spalling tendency, a refractory should have
A Greater diffusivity
B Low specific heat
C Low thermal co-efficient of expansion
D All of the above
Spalling resistance of a refractory can not be increased by
A Increasing its porosity
B Using a coarser grog during its manufacture
C Decreasing its thermal co-efficient of expansion
D Making it denser
Spalling of a refractory means its
A Softening
B Fracture due to uneven expansion at high temperature
C Resistancce to compressive loads
D Resistance to chemical action of gases and molten fluxes
Spalling tendency of refractories is reduced by increasing its
A Porosity
B Specific gravity
C Thermal conductivity
D Strength
Coal is pulverised before burning in large capacity boiler furnaces mainly to
A Ensure its complete combustion
B Facilitate easy ash removal
C Enhance its calorific value
D Provide trouble free operation
Which of the following furnaces will have maximum thermal efficiency?
A Soaking pits
B Walking beam reheating furnace
C Boiler furnace
D Rotary kilns
Thermal efficiency of furnaces can be improved by
A Waste heat recovery from flue gas
B Minimising heat losses from furnace walls
C Maintaining proper draught
D All of the above

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