The diameter of a cylindrical shell of a Scotch marine boiler varies from
1.5 to 2 m
2.5 to 3.5 m
3.5 to 4.5 m
None of these
Correct Answer :
B. 2.5 to 3.5 m
Related Questions
In a glass tube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to
Water space also
Chimney
Steam space
Superheater
The capacity of induced draft fan compared to forced draft fan in a boiler is
Same
More
Less
Less or more depending on size of boiler
O₂ content in atmospheric air on weight basis is
21 %
23 %
30 %
40 %
The average operating pressure of Benson boiler is
100 bar
150 bar
200 bar
250 bar
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
Which of the following is steam dial?
Non-coking bituminous coal
Brown coal
Pulverised coal
Coking bituminous coal
Water boils when its vapour pressure
Equals that of the surroundings
Equals 760 mm of mercury
Equals to atmospheric pressure
Equals the pressure of water in the container
Efficiency of a thermal cycle increases by
Regeneration
Reheating of steam
Both (A) and (B)
Cooling of steam
While steam expands in turbines, theoretically the entropy
Remains constant
Increases
Decreases
Behaves unpredictably
The increase in pressure
Lowers the boiling point of a liquid
Raises the boiling point of a liquid
Does not affects the boiling point of a liquid
Reduces its volume
When the cross-section of a nozzle increases continuously from entrance to exit, it is called a
Divergent nozzle
Convergent nozzle
Convergent-divergent nozzle
None 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 high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks
180° to each other
90° to each other
0° to each other
None of these
A fusible plug is fitted in small boilers in order to
Avoid excessive build up of pressure
Avoid explosion
Extinguish fire if water level in the boiler falls below alarming limit
Control steam dome
In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
Velocity increases
Velocity decreases
Velocity remains constant
Pressure remains constant
The diameter of cylindrical shell of the Lancashire boiler is of the order of
1 to 1.25m
1 to 1.75 m
2 to 4 m
1.75 to 2.75 m.
The stage efficiency (ηS) is given by (where ηB = Blading efficiency, and ηN = Nozzle efficiency)
ηS = ηB × ηN
ηS = ηB / ηN
ηS = ηN / ηB
None of these
The height of chimney in a power plant is governed by
The draft to be created
Limitation of construction facilities
Control of pollution
Quantity of flue gases to be handled
The specific volume of steam with increase in pressure decreases
Linearly
Slowly first and then rapidly
Rapidly first and then slowly
Inversely
Heating wet steam at constant temperature is heating it at constant
Volume
Pressure
Entropy
Enthalpy
Which of the following is a water tube boiler?
Locomotive boiler
Cochran boiler
Cornish boiler
Babcock and Wilcox boiler
Steam turbines may be classified according to
Direction of steam flow
Number of stages
Mode of steam action
All of these
In a reaction turbine when the degree of reaction is zero, then there is
No heat drop in moving blades
No heat drop in fixed blades
Maximum heat drop in moving blades
Maximum heat drop in fixed blades
The diameters of fire tubes and superheater tubes in locomotive boiler are
47.5 mm, 130 mm
32.5 mm, 180 mm
65.5 mm, 210 mm
24.5 mm, 65 mm
The length of Cornish boiler is of the order of
24 m
35 m
57.5 m
79 m
In recuperative air preheaters, the heat is transferred
From a metal wall from one medium to another
From heating an intermediate material and then heating the air from this material
By direct mixing,
Heat is transferred by bleeding some gases from furnace
The effect of friction on the flow of steam through a nozzle is to
Decrease the mass flow rate and to increase the wetness of steam
Increase the mass flow rate and to increase the exit temperature
Decrease the mass flow rate and to decrease the wetness of steam
Increase the exit temperature without any effect on mass flow rate
The fire tubes in, a Coarran and Scottish marine boiler are
Horizontal
Vertical
Inclined
Both horizontal and vertical
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 %
The maximum heat loss is a boiler occurs due to
Moisture in fuel
Dry flue gases
Steam formation
Unburnt carbon