DC 3RD CLASS BOILER COMPREHENSIVE EXAM UPDATED
QUESTIONS AND ANSWERS GRADED A+
✔✔______ is the ability of a material to return to its original shape after being deformed.
- ✔✔Resiliency
✔✔In a three-element feedwater regulating system, __________ are measured. -
✔✔steam flow, feedwater flow, and water level
✔✔A ________ is a highly efficient ion-exchange process in which resin is regenerated
with sulfuric acid in the first vessel and caustic soda in the second vessel -
✔✔demineralizer
✔✔The purpose of the diffuser in a boiler burner assembly is to ______. - ✔✔shield the
flame from the incoming air blast while allowing some mixing of fuel and air
✔✔How many horsepower are required to raise 3500 pounds to a height of 175 feet at
60% efficiency? - ✔✔31
✔✔A fuel tank contains 330,000 gallons of #4 fuel oil at 80°F. How many gallons would
it read if the temperature was raised to 95°F? Coefficient of expansion is .000345 -
✔✔331,708. (T1-T2) x #gals x CE
✔✔One row of fixed blading and one row of moving blading. - ✔✔A stage
✔✔A vaporstat control is sensitive to _____? - ✔✔pressure
✔✔A ______ in line heat exchanger installed in the deaerator which minimizes steam
loss to the atmosphere. - ✔✔vent condenser
✔✔A 300 HP motor is running at 1800 RPM and is at full load. The torque on the shaft
of the motor is_______. - ✔✔875. Tq=HP x 5262/ RPM
✔✔Repeated priming in a steam boiler can cause damage to the ____. -
✔✔Superheater
✔✔_______ is an alloy of chromium, cobalt, and tungsten used to treat the interior
components of valves to make them very hard and erosion resistant. - ✔✔stellite
✔✔A two element boiler feedwater regulator is controlled by_____. - ✔✔steam flow and
drum water level
, ✔✔The steam and water drum of a water tube boiler is 5' in diameter and has a bursting
pressure of 2500psi. The drum metal has a tensile strength of 65,000 psi with a joint
efficiency of 100%. The thickness of the drum metal is_____? - ✔✔1.25". t=MAWP x SF
x RAD/ TSX x Eff
✔✔Routine maintenance of boiler sliding feet should include - ✔✔wire brushing to
remove scale, rust and dirt
✔✔In a D-type boiler, what tubes would be located in the generating tube bank? -
✔✔Superheat support tubes
✔✔External feedwater treatment is accomplished by passing water through a ______? -
✔✔zeolite softener
✔✔Moving blading in which the space between blades is smaller at the exhaust than at
the inlet. Energy transfer in reaction blading results in a decrease in steam pressure and
velocity. - ✔✔Reaction blading
✔✔Before lighting off a boiler which has no steam pressure, which procedure would you
follow? - ✔✔Open the superheater vent, the drum air vent, the superheater drains, bring
water level in the drum to sufficient level, and purge furnace.
✔✔In normal practice, to correctly increase the blowdown of a nozzle reaction safety
valve, you should_____ring. - ✔✔Lower the adjusting
✔✔A _______ pump is a positive displacement pump. - ✔✔reciprocating
✔✔Changing a control device to a degree that is proportional to the need is called
_______ . - ✔✔Modulation
✔✔________ air supplied to a furnace controls the rate of combustion - ✔✔Primary
✔✔A scotch marine boiler can be easily recognized because it ______. - ✔✔Is
internally fired
✔✔Name a technique to reduce sulfur dioxide emissions from a coal fired power plant. -
✔✔Precombustion methods
✔✔The tubes in a straight tube water tube boiler are inclined ______. - ✔✔to increase
circulation
✔✔A lead sulfide cell is sensitive to______? - ✔✔Infrared rays
QUESTIONS AND ANSWERS GRADED A+
✔✔______ is the ability of a material to return to its original shape after being deformed.
- ✔✔Resiliency
✔✔In a three-element feedwater regulating system, __________ are measured. -
✔✔steam flow, feedwater flow, and water level
✔✔A ________ is a highly efficient ion-exchange process in which resin is regenerated
with sulfuric acid in the first vessel and caustic soda in the second vessel -
✔✔demineralizer
✔✔The purpose of the diffuser in a boiler burner assembly is to ______. - ✔✔shield the
flame from the incoming air blast while allowing some mixing of fuel and air
✔✔How many horsepower are required to raise 3500 pounds to a height of 175 feet at
60% efficiency? - ✔✔31
✔✔A fuel tank contains 330,000 gallons of #4 fuel oil at 80°F. How many gallons would
it read if the temperature was raised to 95°F? Coefficient of expansion is .000345 -
✔✔331,708. (T1-T2) x #gals x CE
✔✔One row of fixed blading and one row of moving blading. - ✔✔A stage
✔✔A vaporstat control is sensitive to _____? - ✔✔pressure
✔✔A ______ in line heat exchanger installed in the deaerator which minimizes steam
loss to the atmosphere. - ✔✔vent condenser
✔✔A 300 HP motor is running at 1800 RPM and is at full load. The torque on the shaft
of the motor is_______. - ✔✔875. Tq=HP x 5262/ RPM
✔✔Repeated priming in a steam boiler can cause damage to the ____. -
✔✔Superheater
✔✔_______ is an alloy of chromium, cobalt, and tungsten used to treat the interior
components of valves to make them very hard and erosion resistant. - ✔✔stellite
✔✔A two element boiler feedwater regulator is controlled by_____. - ✔✔steam flow and
drum water level
, ✔✔The steam and water drum of a water tube boiler is 5' in diameter and has a bursting
pressure of 2500psi. The drum metal has a tensile strength of 65,000 psi with a joint
efficiency of 100%. The thickness of the drum metal is_____? - ✔✔1.25". t=MAWP x SF
x RAD/ TSX x Eff
✔✔Routine maintenance of boiler sliding feet should include - ✔✔wire brushing to
remove scale, rust and dirt
✔✔In a D-type boiler, what tubes would be located in the generating tube bank? -
✔✔Superheat support tubes
✔✔External feedwater treatment is accomplished by passing water through a ______? -
✔✔zeolite softener
✔✔Moving blading in which the space between blades is smaller at the exhaust than at
the inlet. Energy transfer in reaction blading results in a decrease in steam pressure and
velocity. - ✔✔Reaction blading
✔✔Before lighting off a boiler which has no steam pressure, which procedure would you
follow? - ✔✔Open the superheater vent, the drum air vent, the superheater drains, bring
water level in the drum to sufficient level, and purge furnace.
✔✔In normal practice, to correctly increase the blowdown of a nozzle reaction safety
valve, you should_____ring. - ✔✔Lower the adjusting
✔✔A _______ pump is a positive displacement pump. - ✔✔reciprocating
✔✔Changing a control device to a degree that is proportional to the need is called
_______ . - ✔✔Modulation
✔✔________ air supplied to a furnace controls the rate of combustion - ✔✔Primary
✔✔A scotch marine boiler can be easily recognized because it ______. - ✔✔Is
internally fired
✔✔Name a technique to reduce sulfur dioxide emissions from a coal fired power plant. -
✔✔Precombustion methods
✔✔The tubes in a straight tube water tube boiler are inclined ______. - ✔✔to increase
circulation
✔✔A lead sulfide cell is sensitive to______? - ✔✔Infrared rays
