DC Boiler Exam Prep 2023 (Formulas and constants used for the DC 3rd class boiler exam) QUESTIONS WITH COMPLETE SOLUTIONS

DC BOILER EXAM PREP 2015
QUESTIONS AND ANSWERS



Area6of6a6rectangle-6ans---6Length6x6Width

Area6of6a6Circle-6ans---6.78546x6Diameter²

Volume6of6a6Box-6ans---6Length6x6Width6x6Height

Volume6of6a6Cylinder-6ans---6.78546x6Diameter²6x6Length

Circumference6of6a6Circle-6ans---6π6x6Diameter

Unit6of6Force-6ans---6Pound6(lb)

Formula6for6Force-6ans---6Pressure6÷6Area

Unit6of6Work-6ans---6in-lb6or6ft-lb

Formula6for6Work-6ans---6Force6x6Distance

Unit6of6Power-6ans---6ft-lb/min

Formula6for6Power-6ans---6=6Work6÷6Time6
or6(Force6x6Distance)6÷6Time

Formula6for6Mechanical6Horsepower-6ans---6=6Power6÷633,0006ft-lb/min

Fahrenheit6to6Celsius-6ans---6°C6=6(°F6-632)6÷61.8

Celsius6to6Fahrenheit-6ans---6°F6=6(1.86x6°C)6-632

Fahrenheit6to6Rankine-6ans---6°R6=6°F6+6460

Celsius6to6Kelvin-6ans---6K6=6°C6+273.15

Charles'6First6Law-6ans---6Volume16/6Pressure16=6Volume26/6Pressure2

Charles'6Second6Law-6ans---6Pressure16/6Temperature16=6Pressure26/6Temperature2

, Boyle's6Law-6ans---6Pressure16x6Volume16=6Pressure26x6Volume2

General6Gas6Law-6ans---6(Pres16x6Vol1)/6Temp16=6(Pres26x6Vol2)/Temp2

Formula6for6Levers-6ans---6Resistance6x6DistanceR6=6Effort6x6DistanceE

Formula6for6Inclined6Planes-6ans---6Force6x6Length6=6Resistance6x6Height

Formula6for6Wheel6&6Axel-6ans---6Force6x6DistanceF6=6Resistance6x6DistanceR

Torque-6ans---6Force6x6Radius

Safe6Working6Pressure6of6a6Riveted6Boiler6(SWP)-6ans---
6(Area6of6Staybolt6x6Stress6Constant6of6Staybolt)6÷6Area6Covered6by6Staybolt6or6=6(a6x6C

)6÷6A

Area6Covered6by6Staybolt-6ans---6=6Pitch6x6Pitch

Longitudinal6Stress-6ans---6(P6x6D6x6L)6/62t
P6=6Pressure
D6=6Diameter
L6=6Length
t6=6thickness6of6steel

Boiler6Heating6Surface6(tubes)6=-6ans---6=6C6x6L6x6#
C6=6Circumference6of6tubes
L6=6Length6of6tubes
#6=6Number6of6tubes
HS6=6π6x6Diameter6x6Length6x6Number6of6Tubes

Watts6per6Boiler6Horsepower-6ans---67466Watts

Horsepower6formula-6ans---6=6ft-lb/min6÷6330006ft-lb/min

ft-lb6formula6for6a6pump-6ans---6=6gpm6x68.336x6head6(ft)

Factor6of6Evaporation6(FE)6=-6ans---6=6[Hs6-6(tfw-32)]6÷6970.3
Hs6=6Enthalpy6of6steam
tfw6=6temperature6of6feed6water

Latent6Heat6of6Vaporization6for6Water-6ans---6970.36Btu/lb

Latent6Heat6of6Fusion6for6Water-6ans---61446Btu/lb

16Boiler6Horsepower6=6x6lbs6of6steam6generator6per6hour-6ans---634.56lbs/hr