2023 update DC BOILER/STATIONARY Third
testing questions with complete
solutions/100% Scores!!
The component in which liquid vapor by absorbing heat is called? - -
Evaporator
-Select the best answer electrical grounding method? - -Metal stake drive 8
foot into the ground.
-A _____ valve should be used for throttling purpose? - -Globe
-What is the acceptable range for residual sodium sulfite in the boiler
maintain? - -30-70
-What is the BTU content of a gallon of #4? - -146,000
-What does a zeolite water softener system use as a means of regeneration?
- -Brine
-What are the 4 steps for a Zeolite Rejuvenation water softener process? - -
Back wash
Backwash, brine, rinse, service
-Where is medium temperature is liquid found? - -Condenser
-Where is high temperature vapor found? - -At the discharge of the
compressor or condenser
-What stays are used to support the burner chamber in a scotch marine
boiler? - -Diagonal Stays
-What type of safety valve is this? - -( Full) Crosby nozzle-type safety valve.
Page 365 BOG
-What type of safety valve is this? - -( Full) Crosby nozzle-type safety valve.
Page 365 BOG
-Where do you found superheat reading? - -Take suction line pressure
Cross reference using a P/T Chart
Get tail coil Temperature
Subtract cross references temperature from tail coil temperature
Result will be superheat
, -Name the wire that connects all component of a system to a physical
ground or water pipe? - -Grounding Electrode Conductor
-Where do get sub-cooling reading? - -Take liquid line pressure
Cross reference to temperature using a P/T Chart
Get liquid line temperature
Subtract actual temperature from cross referenced temperature
Result is sub-cooling
-On the boilers that have both Quick opening and Screw type blow down
valves, the Quick opening valve must be located? - -Closest to the boiler and
followed by the screw type valve
-High pressure boilers equipped with Quick opening and Screw type valves
are blown down how? - -By opening the Quick opening valve first and closing
it Last. Page 403 BOG
-ASME Code defines a slow opening valve as what? - -One requiring at least
5 full 360 degree turns between full open and close position. Page 374
-A 300 Horsepower boiler operating at 100psi has an average load of 75%
with 80% condensate return and 5% blow down. The treatment provides a
chemical which costs $8.75 per gallon, and will treat 600 gallon. Find the
amount of the chemical needed for the day period, and the cost of the
chemical for a 30 days period? - -Water In = Water Out
Makeup + Condensate Return = Evaporator + Blow Down
Average Evaporator Rate = 300 x 34.5 pph x .75% load = 7762, 50 pph
Gallons per Month = 1634..33 x 24 x 30 = 141, 252.24 gallons per
month
Chemical needed = 141,252.24 gallon / 600 gallon = 235, 40 gallon
Cost per month = 235, 40 gallon x 8.75 = $2,059.75
, -During a 24 hours operation how often should you check the water level? -
-Once per shift
-A 15 psi steam boiler produces 8000 pound of steam per hour. The
Minimum pipe size for the pipe leaving the boiler is___12__inches.
(Density is 0.037 lbs/ft3)
Equation: - -D = 12 (C/d/h /.7854)
D = 12 (.037/60) = 3,603.60
D = .ft = 3,927
D = 3.603.,927 = 0.917647058
D = 0.957938963 * 12
D = 11.49 OR 12 "pipe
-The boiler steam line is 350 Feet long. During start-up the pipe is heated
From 60 F to 350 F. The 350 F. The pipe wills expand__7.92__inches
Due to the change in temperature
Equation: - -(T 1 - T2) x L x .0000065
(350 - 60) x 350 x .0000065
290 x 350 x 12 x .0000065 = 7.92
-A 12" pipe filled with water to a height of 250 feet will have a pressure of
_________at the bottom of the pipe?
Equation:
P = FT / 2.31 - -250 feet / 2.31 = 108.22
-A "5" pipe filled with water to a height of 75 feet will have a pressure of
_________at
The bottom of the pipe?
Equation:
P = FT / 2.31 - -75 feet / 2.31 = 32.46
-What is the flow rate, in gallons per minute, of water flowing through a 8'
pipe
At a velocity of 7 feet per second? - -GPM = V X D²
0.4085
GPM = 7 x (8 x 8)
0.4085
GPM = 448
0.4085
GPM = 1096.69 gpm
-What is the flow rate, in gallons per minute, of water flowing through a 4'
pipe At a velocity of 12 feet per second? - -GPM = V X D²
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