In a furnace employing forced draught compared to induced draught __________

In a furnace employing forced draught as compared to induced draught,

A

Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced

B

The fan operates hot and hence blades are liable to corrosion and erosion

C

Positive pressure exists in the furnace

D

None of these

For the same draught produced the power of induced draught fan as compared to forced draught fan is

A

less

B

more

C

same

D

not predictable

Power required in case of forced draught as compared to induced draught (for the same draught produced) is

A

Same

B

Less

C

More

D

Either more or less; depends on the flue gas density

Why is induced draught considered better than the forced draught?

A

Because power requirement is high for forced draught

B

Maintenance of induced draught fan is costlier

C

Forced draught is less efficient

D

Forced draught produces less amount of speed of air

Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300° ) may be reduced by about __________ percent as compared to the use of atmospheric combustion air.

A

5

B

10

C

20

D

35

Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400°C results in saving of about __________ percent furnace oil as compared to its combustion with atmospheric air, if the flue gas outlet temperature from the soaking pit is 1200°C.

A

5

B

60

C

20

D

40

Consider the following statements for an induction furnace: 1. High-frequency current is generally used for the furnace working. 2. There is less loss of alloying elements due to oxidation. 3. Pronounced stirring action of molten metal occurs inside the furnace. 4. Slag cover is essential for the efficient working of the furnace. Which of the above statements are correct?

A

1, 3 and 4 only

B

2, 3 and 4 only

C

1, 2 and 3 only

D

1, 2, 3 and 4

A balanced draught boiler furnace employs __________ draught fan.

A

Induced

B

Forced

C

Both A & B

D

Neither A nor B

Statement: Resonance is a special case of forced vibration in which the nature and frequency of vibration of the body are the same as the impressed frequency and the amplitude of forced vibration, is maximum. Reason: The amplitude of forced vibrations of a body increases with an increase in the frequency of the externally impressed periodic force.

A

Both statement and reason are true and the reason is the correct explanation of the statement

B

Both statement and reason are true but the reason is not the correct explanation of the statement

C

Statement is true, but the reason is false

D

Statement and reason are false

What is installed to transfer air into furnace in forced draught system?

A

Air blower

B

Tuyeres

C

Draft gauges

D

Cyclone separator

In a furnace employing forced draught compared to induced draught __________

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