WorksheetsMachine Foundation and Chimney ELEMENTS
Total questions: 43
Worksheet time: 22mins
Foundations are preferably built of concrete in the proportion of what measure of Portland cement: sand: crushed stones?
1 : 2 : 5
2 : 4 : 6
2 : 3 : 5
1 : 2 : 4
For design stability, the center of gravity of the total combined engine, driven equipment, and foundation should be kept ______.
anywhere
above the foundation top
in line with surface of the foundation
below the foundation top
The machine foundation must have a factor of safety of
4
5
6
7
The diesel engine foundation safe soil bearing pressure is:
4890 kg/cm2
4500 kg/cm2
4490 kg/cm2
4125 kg/cm2
Anchor bolts in a machine foundation should be embedded in concrete of at least how many time of the bolt diameter
15
20
30
25
As a good practical rule, the foundation depth may be taken as how many times of the engine stroke?
2.2 to 3.2
3.2 to 4.2
2.5 to 3.5
3.5 to 4.5
To secure the belts embedded within the foundation, the distance of the edges of the foundation from the bedplate must be ______.
120 mm to 300 mm
150 mm to 330 mm
100 mm to 280 mm
200 mm to 380 mm
The weight of the foundation is how many times of the weight of the engine?
4 to 5 times
3 to 5 times
2 to 3 times
4 to 6 times
To eliminate transmission of vibration, the foundation should be isolated from floor slabs or building footings at least how many mm around its perimeter?
15
20
25
30
The minimum vertical distance from the floor or soil level to the top edge of the foundation must be around ____.
150 mm
100 mm
200 mm
120 mm
There shall be no foundation bolts less than _____.
12 mm in diameter
16 mm in diameter
18 mm in diameter
20 mm in diameter
The weight of steel bar reinforcements should be how many times the weight of the foundation
1/2 % to 1 %
1 % to 1.5 %
3 % to 5 %
3.2 % to 4.2 %
Concrete foundation should have steel bar reinforcements placed vertically and horizontally to avoid
breaking
thermal cracking
melting
vibration
Foundation bolts of specified size should be use and surrounded by pipe sleeve with an inside diameter of at least how many times the diameter of the anchor bolt?
3
4
5
6
For a diesel engine's foundation, in pouring a concrete mixture, it should be poured :
one time
two times
three times
four times
For foundations of steam turbine, the concrete mixture should be _____.
1 : 2 : 4
1 : 3 : 5
1 : 2 : 3
1 : 3 : 4
The steam turbine foundation should be designed to support the machine load plus how many percent for impact, condenser load, floor loads and dead loads?
15
20
25
30
Which of the following rely on the stack effect to draw off combustion gases?
Natural draft
Forced draft
Induced draft
Balanced draft
Fans located before the furnace that are used to supply air for burning.
Natural draft
Forced draft
Induced draft
Balanced draft
Forced draft fans are run at relatively high speeds in the range of :
1200 to 1800 rpm
1000 to 1600 rpm
1500 to 2000 rpm
900 to 1500 rpm
Chimneys that rely on natural draft are sometimes referred to as
natural chimney
gravity chimney
normal chimney
stack
Forced draft fans create a positive pressure of
0.5 to 2.5 kPa
1.0 to 3.0 kPa
2.0 to 4.0 kPa
0.2 to 2.2 kPa
Fans that are used to draw combustion products through the furnace bed, stack, and pollution control system by injecting air into the stack after combustion.
Natural draft
Forced draft
Induced draft
Balanced draft
The term used when the static pressure is equal to the atmospheric pressure
Natural draft
Forced draft
Induced draft
Balanced draft
In order to keep combustion products inside the combustion chamber and stack system, balanced draft system may actually operate with a slight
negative pressure
positive pressure
positive and negative pressures
absolute pressure
The static pressure drop due to friction through the boiler and stack.
draft loss
available draft
stack effect
fan boost
The difference between the theoretical draft and the draft loss
draft loss
available draft
stack effect
fan boost
In a balanced system, the available draft is:
unity
zero
100
infinite
The total pressure supplied by the fan at maximum operating conditions
net rating or fan boost
draft loss
available draft
stack effect
Generally the higher the chimney
the smaller the stack effect
the greater the stack effect
stack effect is zero
stack effect approaches unity
Modern stacks are seldom built higher than
60 m
50 m
40 m
30 m
Most stacks are built of height less than
60 m
50 m
40 m
30 m
The average flue gas temperature is
the temperature entering the stack
the temperature leaving the stack
the temperature halfway up the stack
the sum of temperatures
The coefficient of velocity is approximately
0.30 to 0.50
0.40 to 0.60
0.20 to 0.40
0.50 to 0.70
For realistic problems, the achievable stack effect probably should be considered to be :
75 % of the ideal
80 % of the ideal
equal to the ideal
half the ideal
Guyed stacks seldom exceed
1.83 m in diameter
2.83 m in diameter
1.45 m in diameter
2.45 m in diameter
The angle between the stack and the guy wire is usually
30 degrees
45 degrees
60 degrees
75 degrees
Guyed stacks height seldom exceed
30.48 m
34.80 m
43.80 m
48.30 m
The maximum unit pressure of turbine and generator on the reinforced concrete should not exceed
17.62 kg/cm2
18.62 kg/cm2
16.62 kg/cm2
19.62 kg/cm2
In guyed steel stacks, the angle between wires in a set of three is:
120 deg.
110 deg.
135 deg.
145 deg.
Guys are usually applied in how many sets?
1 to 3
2 to 4
3 to 5
4 to 6
The empirical coefficient e in a machine foundation if not given is assumed
0.11
0.25
0.32
0.15
The term suction units is used with
Natural draft
Forced draft
Induced draft
Balanced draft
