The diameter of fire tubes in Cochran boiler is of the order of
2 cm
6 cm
8 cm
12 cm
Correct Answer :
B. 6 cm
Related Questions
The draught may be produced by a
Mechanical fan
Chimney
A steam jet
All of these
Lancashire boiler is a
Stationary fire tube boiler
Stationary water tube boiler
Water tube boiler with natural/forced circulation
Mobile fire tube boiler
The ratio of the clearance volume to the swept volume is called
Cut-off ratio
Expansion ratio
Clearance ratio
None of these
Which of the following statement is wrong?
The critical pressure gives the velocity of steam at the throat equal to the velocity of sound.
The flow in the convergent portion of the nozzle is subsonic.
The flow in the divergent portion of the nozzle is supersonic.
To increase the velocity of steam above sonic velocity (supersonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary.
Parson's turbine is a
Simple impulse turbine
Simple reaction turbine
Impulse-reaction turbine
None of these
The diagram factor is the ratio of the
Area of the actual indicator diagram to the area of theoretical indicator diagram
Actual workdone per stroke to the theoretical workdone per stroke
Actual mean effective pressure to the theoretical mean effective pressure
Any one of the above
The artificial draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
Blow off cock in a boiler is used 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 high pressure boiler is one, which produces steam at a pressure more than
Atmospheric pressure
5 kg/cm²
10 kg/cm²
7580 kg/cm²
In a Tandem type compound engine, the high pressure and low pressure cylinders
Have common piston rod
Are set at 90°
Have separate piston rods
Are set in V-arrangement
Which is not correct statement about pulverised fuel firing?
High burning rate is possible
Heat release can be easily controlled
Fuel burns economically
It is the best technique for burning high ash content fuel having low fusion ash
Water tube boilers are
Internally fired
Externally fired
Internally as well as externally fired
None of these
A device used to increase the temperature of saturated steam without raising its pressure, is called
Blow off cock
Fusible plug
Superheater
Stop valve
The size of a boiler drum in pulverised fuel fired boiler, as its size and capacity, (steam pressure and flow ratings) increase
Increases
Decreases
Remains unchanged
Increases/decreases depending on steam temperature requirements
The flow through a nozzle is regarded as
Constant volume flow
Constant pressure flow
Isothermal flow
Isentropic flow
The function of an eccentric 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
Stage efficiency is also known as
Diagram efficiency
Nozzle efficiency
Gross efficiency
None of these
An ideal regenerative cycle is
Equal to Carnot cycle
Less than Carnot cycle
More than Carnot cycle
Could be anything
Green coal, in order to be burnt, must be
Heated sufficiently
Burnt in excess air
Heated to its ignition point
Burnt as powder
The amount of water evaporated in kg per kg of fuel burnt is called
Evaporative capacity of a boiler
Equivalent evaporation from and at 100° C
Boiler efficiency
None of these
Proximate analysis of fuel is determination of percentage of
Carbon, hydrogen, nitrogen, sulphur, moisture
Fixed carbon, ash, volatile matter, moisture
Higher calorific value
Lower calorific value
The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.
Same
Less
More
None of these
Sulphur content of fuels is very important to the plant operators because it
Has high heating value
Retards electric precipitation
Promotes complete combustion
Has highly corrosive effect
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
The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)
Remains constant
Decreases
Increases
None of these
The function of a safety valve is
To blow off steam when the pressure of steam inside the boiler exceeds the working pressure
To indicate the water level inside the boiler to an observer
To measure pressure of steam inside the steam boiler
None of the above
Willian's law states that the steam consumption per hour provided with a throttled governor is proportional to (where I.P. = Indicated power)
1/(I.P)
1/(I.P)²
I.P.
(I.P.)²
The chimney draught varies with
Climatic conditions
Temperature of furnace gases
Height of chimney
All 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
By compounding the expansion of steam in two or more cylinders, the length of stroke
Does not change
Increases
Decreases
None of these