The shell of the Cochran boiler is made hemispherical
To give maximum space and strength
To withstand the pressure of steam inside the boiler
Both (A) and (B)
None of the above
Correct Answer :
C. Both (A) and (B)
Related Questions
Carbonisation of coal is the process of
Pulverising coal in inert atmosphere
Heating wood in a limited supply of air at temperatures below 300°C
Strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel
Binding the pulverised coal into briquettes
The function of a valve rod is
To provide reciprocating motion to the slide valve
To convert reciprocating motion of the piston into rotary motion of the crank
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To provide simple harmonic motion to the D-slide valve
The indicated thermal efficiency is defined as the
Ratio of thermal efficiency to the Rankine efficiency
Ratio of brake power to the indicated power
Ratio of heat equivalent to indicated power to the energy supplied in steam
Product of thermal efficiency and Rankine efficiency
Tertiary air is the air used to
Provide air around burners for obtaining optimum combustion
Transport and dry the coal
Cool the scanners
Convert CO (formed in lower zone of furnace) into CO₂ at higher zone.
With increase in load, radiant superheater has
Drooping characteristic
Linear characteristic
Rising characteristic
Flat characteristic
The selection of type and size of a steam boiler depends upon
The power required and working pressure
The geographical position of the power house
The fuel and water available
All of the above
The natural draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is
0.007 bar
0.053 bar
0.06 bar
0.067 bar
If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
Throttling calorimeter
Separating calorimeter
Combined separating and throttling calorimeter
Bucket calorimeter
For burning 1 kg of carbon to CO as per chemically correct combustion, amount of air required is
1 kg
4/3 kg
8/3 kg
2 kg
The missing quantity per stroke is equal to
Cylinder feed indicated mass of steam
Cylinder feed + indicated mass of steam
Mass of cushion steam + indicated mass of steam
Mass of cushion steam + cylinder feed
With increase in load, convection superheater has
Drooping characteristic
Linear characteristic
Rising characteristic
Flat characteristic
Which of the following statement is wrong?
The factor of evaporation for all boilers is always greater than unity.
The amount of water evaporated in kg per kg of fuel burnt is called equivalent evaporation from and at 100° C.
The ratio of heat actually used in producing the steam to the heat liberated in the furnace is called boiler efficiency.
None of the above
The chimney draught varies with
Climatic conditions
Temperature of furnace gases
Height of chimney
All of these
Which of the following statement is correct?
A horizontal steam engine requires less floor area than a vertical steam engine
The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure
The compound steam engines are generally non-condensing steam engines
All of the above
Latent heat of dry steam at atmospheric pressure is equal to
539 kcal/ kg
539 BTU/ lb
427 kcal/ kg
100 kcal/ kg
Which is not the correct statement about moisture in coal?
Inherent moisture and surface moisture are different things
In some coals moisture may be present up to 40%
Some moisture in coal helps in better burning which is not possible with completely dry coal
It increases thermal efficiency
The efficiency of reaction turbine is maximum when (where α = Angle made by the absolute velocity V at inlet)
Vb = 0.5 V cosα
Vb = V cos α
Vb = 0.5 V² cosα
Vb = V² cosα
In case of condensing steam engines, the pressure of steam in the cylinder during exhaust stroke is _________ the atmospheric pressure.
Equal to
Lower than
Higher than
None of these
Steam engine operates on
Carnot cycle
Joule cycle
Stirling cycle
Brayton cycle
The draught produced by a steam jet issuing from a nozzle placed in the ash-pit under the fire grate of the furnace is called
Induced steam jet draught
Chimney draught
Forced steam jet draught
None of these
In water wall furnace, the heat is transferred to the water walls by
Convection
Radiation
Conduction
Radiation and conduction
Steam turbines may be classified according to
Direction of steam flow
Number of stages
Mode of steam action
All of these
Locomotive type' boiler is
Horizontal multi-tubular water tube boiler
Water wall enclosed furnace type
Vertical tubular fire tube type
Horizontal multi-tubular fire tube type
The fittings mounted on the boiler for its proper and safe functioning is a
Water level indicator
Pressure gauge
Safety valve
All of these
The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is
Less
More
Equal
May be less or more depending on temperature
O₂ content in atmospheric air on volume basis is
21 %
23 %
30 %
40 %
Pour point of fuel oil is the
Lowest temperature at which oil will flow under set condition
Storage temperature
Temperature at which fuel is pumped through burners
Temperature at which oil is transported
The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)
V = 44.72 hd K
V = 44.72 K hd
V = 44.72 K hd
V = 44.72 K hd
The turbine blades are
Straight
Circular
Curved
None of these