The chimney draught varies with
Climatic conditions
Temperature of furnace gases
Height of chimney
All of these
Correct Answer :
D. All of these
Related Questions
The diameter of tubes for natural circulation boiler as compared to controlled circulation boilers is
More
Less
Same
Could be more or less depending on other factors
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.
In a throttling process
Heat transfer takes place
Work is done by the expanding steam
Internal energy of steam changes
None of the above
Boiler parameters are expressed by
Tonnes/hr. of steam
Pressure of steam in kg/cm²
Temperature of steam in °C
All of the above
The cylinder condensation or missing quantity may be reduced by
The efficient steam jacketing of the cylinder walls
Superheating the steam supplied to the engine cylinder
Keeping the expansion ratio small in each cylinder
All of the above
The crown of the fire box is made hemispherical in order to
Give maximum space
Give maximum strength
Withstand pressure inside boiler
Resist intense heat in fire box
The fittings mounted on the boiler for its proper and safe functioning is a
Water level indicator
Pressure gauge
Safety valve
All of these
Fire tube boilers are those in which
Flue gases pass through tubes and water around it
Water passes through the tubes and flue gases around it
Forced circulation takes place
Tubes are laid vertically
The object of producing draught in a boiler is
To provide an adequate supply of air for the fuel combustion
To exhaust the gases of combustion from the combustion chamber
To discharge the gases of combustion to the atmosphere through the chimney
All of the above
One kg of steam sample contains 0.8 kg dry steam; Its dryness fraction is
0.2
0.8
1.0
0.6
The diameter of Cornish boiler is of the order of
12 m
1.52.5 m
23 m
2.53.5 m
Which of the following is a fire tube boiler?
Lancashire boiler
Babcock and Wilcox boiler
Yarrow boiler
None of these
A packaged boiler is one in which various parts like firing equipment, fans, feed pumps and automatic controls are
Supplied by same manufacturer loose and assembled at site
Supplied mounted on a single base
Purchased from several parties and packed together at site
Packaged boiler does not exist
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
If the critical pressure ratio for steam is 0.546, then the steam is initially
Wet steam
Dry saturated steam
Superheated steam
None of these
Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
Increases
Decreases
Remain unaffected
First increases and then decreases
The steam temperature with increase in load in case of a boiler fitted with radiation superheater
Increases
Decreases
Remain unaffected
First increases and then decreases
Which is not correct statement about the function of furnace?
To provide proper conditions for continuous complete combustion
Mix fuel with air and ignite
Separate ash from coal
Maintain heat supply to prepare and ignite the incoming fuel
An economiser in a boiler
Increases steam pressure
Increases steam flow
Decreases fuel consumption
Decreases steam pressure
The critical pressure ratio for initially dry saturated steam is
0.546
0.577
0.582
0.601
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
Cut-off ratio is the ratio of
Swept volume to the volume at cut-off
Volume at cut-off to the clearance volume
Volume at cut-off to the swept volume
Clearance volume to the volume at cut-off
Which type of boiler can meet rapid changes of load?
Vertical fire tube type
Horizontal fire tube type
Horizontal water tube type
Forced circulation type
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
When the nozzle operates with the maximum mass flow, the nozzle is said to be
Choked
Under-damping
Over-damping
None of these
Which of the following is correct? (Where pa = Actual mean effective pressure, pm = Theoretical mean effective pressure, and K = Diagram factor)
pa = pm/K
pa = pm × K
pa = K/pm
pa = pm + K
The principal function of a stop valve is to
Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
Increase the temperature of saturated steam without raising its pressure
The function of a flywheel is
To convert reciprocating motion of the piston into rotary motion
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To prevent fluctuation of speed
To keep the engine speed uniform at all load conditions
The blade friction in the impulse turbine reduces the velocity of steam by __________ while it passes over the blades.
10 to 15 %
15 to 20 %
20 to 30 %
30 to 40 %
The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called
Blading efficiency
Nozzle efficiency
Stage efficiency
Mechanical efficiency