Chapter 16 ( Machine Foundation & Chimney )

Question 1

Foundation are preferably built of concrete in the proportion of what measure of Portland cement: sand : crushee stones?

Answer 1

1 : 2 : 4

Question 2

For design stability, the center of gravity of the total combined engine, drive equipment and foundation should be kept ______

Answer 2

below the foundation top

Question 3

The machine foundation must have a factor safety of ___

Answer 3

5

Question 4

Diesel engine foundation safe soil bearing pressure is:

Answer 4

4,890 kg/cm²

Question 5

Anchor bolts in a machine foundation should

Answer 5

30

Question 6

As a good practical rule, the foundation depth may be taken as how many times of the engine stroke?

Answer 6

3.2 to 4.2

Question 7

To secure the belts embedded within the foundation, the distance of the edges of the foundation from the bedplate must be ______

Answer 7

120 mm to 300mm

Question 8

Weight of the machine foundation is how many time the weight of the engine

Answer 8

3 to 5 times

Question 9

To eliminate transmission of vibration, the foundation should be isolated from floor slabs or building footings at least how many mm around its perimeter?

Answer 9

25 mm

Question 10

Minimum vertical distance from the floor to the top edge of foundation

Answer 10

120 mm

Question 11

There shall be no foundation bolts less than ____

Answer 11

12 mm in diameter

Question 12

Weight of steel bar reinforcements should be how many times the weight of the foundation

Answer 12

1/2 % to 1%

Question 13

Concrete foundation should have steel bar reinforcements placed vertically and horizontally to avoid _____

Answer 13

Thermal Cracking

Question 14

Foundations bolt length should be at least how many times the anchor bolt diameter?

Answer 14

18 times

Question 15

Foundation bolts of specified size should be used and surrounded by a pipe sleeve with an inside diameter of at least how many times the diameter of the anchor bolt?

Answer 15

3

Question 16

For a diesel engine’s foundation, in pouring a concrete mixture, it should be poured:

Answer 16

one time

Question 17

For foundations of steam turbine, the concrete mixture should be ____

Answer 17

1 : 2 : 4

Question 18

The steam turbine foundation should be designed to support the machine load plus how many percent for impact, condenser loaf, floor loads and dead loads?

Answer 18

25 %

Question 19

Which of the following draft rely on the stack effect to draw off combustion gases?

Answer 19

Natural Draft

Question 20

Fans located before the furnace that are used to supply air for burning.

Answer 20

Forced Draft

Question 21

Forced draft fans run at relatively high speeds in what range:

Answer 21

1200 - 1800 RPM

Question 22

Chimneys that rely on natural draft are referred as:

Answer 22

Gravity Chimney

Question 23

Force draft fans create a positive pressure of:

Answer 23

0.5 to 2.5 kPa

Question 24

Fans that are used to draw combustion products through the furnace bed, stack and pollution control system injecting air into the stack after combustion

Answer 24

Induced Draft

Question 25

The term used when the static pressure is equal to the atmospheric pressure

Answer 25

Balanced Draft

Question 26

In order to keep combustion products inside the combustion chamber and stack system, balanced draft system may actually operate with a slight _____

Answer 26

negative pressure

Question 27

the static pressure drop due to friction through the boiler

Answer 27

draft loss

Question 28

The difference between the theoretical draft and the draft loss

Answer 28

Available draft

Question 29

In a balanced system, the available draft is _____

Answer 29

Zero

Question 30

The total pressure supplied by the fan at maximum operating conditions

Answer 30

net rating or fan boost

Question 31

Generally, The higher the chimney, the ______

Answer 31

the greater the stack effect

Question 32

Modern stacks are seldom built higher than ____

Answer 32

60 m

Question 33

Most stacks are built of height less than _____

Answer 33

30 m

Question 34

The average flue gas temperature is_____

Answer 34

the temperature halfway up the stack

Question 35

Coefficient of velocity is approximately:

Answer 35

0.30 to 0.50

Question 36

For realistic problems, the achievable stack effect probably should be considered to be:

Answer 36

80% of the ideal

Question 37

Guyed stacks seldom exceed:

Answer 37

1.83 m in diameter

Question 38

The angle between the stack and the guy wire is :

Answer 38

60 degrees

Question 39

Guyed stacks HEIGHT seldom exceed:

Answer 39

30.48 m

Question 40

Maximum unit pressure of turbine and generator on the reinforced concrete

Answer 40

17.62 kg/cm²

Question 41

In guyed steel stacks, the angle between wires in a set of three is:

Answer 41

120 degrees

Question 42

Guys are usually applied in how many sets ?

Answer 42

1 to 3

Question 43

The empirical coefficient (e) in machine foundation if not given is ____

Answer 43

0.11

Question 44

The term suction units is used with

Answer 44

Induced Draft