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4

Fire tube boilers are limited to a maximum working pressure of

A. 0.17 MN/m²

B. 1.7 MN/m²

C. 17 MN/m²

D. 170 MN/m²

Correct Answer :

B. 1.7 MN/m²


Related Questions

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4

Water at pressure of 4 kg/cm² and 160°C temperature when exposed to atmosphere will

A. Boil

B. Flash i.e. get converted into steam

C. Remain as it was

D. Cool down

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4

In order to compare the capacity of boilers, the feed water temperature and working pressure are taken as

A. 50°C and normal atmospheric pressure

B. 50°C and 1.1 bar pressure

C. 100°C and normal atmospheric pressure

D. 100°C and 1.1 bar pressure

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4

Which of the following statement is correct?

A. The efficiency of steam turbines is greater than steam engines

B. A flywheel is a must for steam turbine

C. The turbine blades do not change the direction of steam issuing from the nozzle

D. The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades

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4

The evaporation of 15.653 kg of water per hour from and at 100°C is called

A. Evaporative capacity

B. Factor of evaporation

C. Equivalent evaporation

D. One boiler h.p.

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4

The height of chimney in a power plant is governed by

A. The draft to be created

B. Limitation of construction facilities

C. Control of pollution

D. Quantity of flue gases to be handled

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4

The steam enters the nozzle at a

A. High pressure and a low velocity

B. High pressure and a high velocity

C. Low pressure and a low velocity

D. Low pressure and a high velocity

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4

An ideal regenerative cycle is

A. Equal to Carnot cycle

B. Less than Carnot cycle

C. More than Carnot cycle

D. Could be anything

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4

The critical pressure ratio (p₂/p₁) is given by

A. (p₂/p₁) = [2/(n - 1)] n/(n + 1)

B. (p₂/p₁) = [2/(n + 1)] n/(n-1)

C. (p₂/p₁) = [(n - 1)/2] n + (1/n)

D. (p₂/p₁) = [(n + 1)/2] n - (1/n)

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4

When the speed of the crankshaft is between 100 r.p.m. and 250 r.p.m., the engine said to be a

A. Slow speed engine

B. Medium speed steam engine

C. High speed steam engine

D. None of these

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4

Efficiency of Rankine cycle can be increased by

A. Decreasing initial steam pressure and temperature

B. Increasing exhaust pressure

C. Decreasing exhausts pressure

D. Increasing the expansion ratio

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4

The stage efficiency (ηS) is given by (where ηB = Blading efficiency, and ηN = Nozzle efficiency)

A. ηS = ηB × ηN

B. ηS = ηB / ηN

C. ηS = ηN / ηB

D. None of these

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4

The high steam and low water safety valve is not used in

A. Cochran boiler

B. Cornish boiler

C. Lancashire boiler

D. Locomotive boiler

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4

The amount of water evaporated in kg per kg of fuel burnt is called

A. Evaporative capacity of a boiler

B. Equivalent evaporation from and at 100° C

C. Boiler efficiency

D. None of these

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4

A device in which some portion of waste heat of flue gases is recovered to heat the air before it passes to the furnace for combustion purpose, is known as

A. Superheater

B. Air-preheater

C. Economiser

D. Injector

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4

1 kg.m is equal to

A. 9.81 Joules

B. 102 Joules

C. 427 Joules

D. None of these

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4

While steam expands in turbines, theoretically the entropy

A. Remains constant

B. Increases

C. Decreases

D. Behaves unpredictably

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4

The numbers of fire tubes in a Cochran boiler are

A. 75

B. 115

C. 165

D. 225

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4

Sublimation region is the region where

A. Solid and vapour phases are in equilibrium

B. Solid and liquid phases are in equilibrium

C. Liquid and vapour phases are in equilibrium

D. Solid, liquid and vapour phases are in equilibrium

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4

Which is not correct statement about effect of sulphur in fuel?

A. It has heating value

B. It helps in electrostatic precipitation of ash in flue gases

C. It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low

D. It erodes furnace walls

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4

The state of vapour under saturation condition is described by

A. Pressure alone

B. Temperature alone

C. Pressure and temperature

D. Pressure and dryness fraction

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4

The ratio of the useful heat drop to the isentropic heat drop is called

A. Condenser efficiency

B. Nozzle efficiency

C. Boiler efficiency

D. Vacuum efficiency

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4

The diameter of cylindrical shell of the Lancashire boiler is of the order of

A. 1 to 1.25m

B. 1 to 1.75 m

C. 2 to 4 m

D. 1.75 to 2.75 m.

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4

The forced circulation of water does not take place in

A. LaMont boiler

B. Lancashire boiler

C. Velox boiler

D. Benson boiler

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4

The heat loss in a boiler takes place in the form of

A. Heat carried away by flue gases

B. Heat carried away by ash

C. Moisture present in fuel and steam formed by combustion of hydrogen in fuel

D. All of the above

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4

Heating wet steam at constant temperature is heating it at constant

A. Volume

B. Pressure

C. Entropy

D. Enthalpy

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4

The aim of a compound steam engine is

A. To reduce the ratio of expansion in each cylinder

B. To reduce the length of stroke

C. To reduce the temperature range in each cylinder

D. All of the above

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4

A nozzle is said to be a convergent nozzle

A. When the cross-section of the nozzle increases continuously from entrance to exit

B. When the cross-section of the nozzle decreases continuously from entrance to exit

C. When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit

D. None of the above

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4

The object of producing draught in a boiler is

A. To provide an adequate supply of air for the fuel combustion

B. To exhaust the gases of combustion from the combustion chamber

C. To discharge the gases of combustion to the atmosphere through the chimney

D. All of the above

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4

It is required to produce large amount of steam at low pressure. Which boiler should be used?

A. Pulverised fuel fired boiler

B. Cochran boiler

C. Lancashire boiler

D. Babcock and Wilcox boiler

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4

The discharge is __________ at critical pressure.

A. Zero

B. Minimum

C. Maximum

D. None of these