DC BOILER 1ST COMPREHENSIVE EXAM QUESTIONS AND
ANSWERS GRADED A+
✔✔How many inches of steam space in a cylinder of an engine 12"x28" and the stroke
is 5/8 of its full travel? - ✔✔1978. V=AxL V=3.14(6x6)x28x.625= 1978
✔✔What is the horsepower requirement of a pump that moves 2500 gpm of water
against a head of 475' if the pump is operating at 58% efficiency? - ✔✔516.8 HP=Head
x Weight/33000 x efficiency. (Head =475, Weight = 2500gpm x 8.33) (475x
20825)/19140
✔✔A ______ is the condition that is being controlled - ✔✔process variable
✔✔Although boiler tubes and boiler drums withstand the same pressure, the walls of
the boiler tubes are much thinner because ______. - ✔✔The tubes are much smaller in
diameter
✔✔A lead sulfide cell detects_____. - ✔✔Burner pilot and main flame
✔✔Which of the following indicates a malfunction in the DC heater? 1. The boiler
requires excessive amounts of oxygen absorbing chemicals.
2.Water and steam are entering the DC heater at the same temperature. - ✔✔Both 1 &
2
✔✔______ is the plasticity exhibited by a material under tension loading. - ✔✔Ductility
✔✔In a pressure atomizing fuel oil-burner, atomization of fuel is produced by the
_______. - ✔✔Burner tip and high pressure fuel
✔✔The ends of boiler tubes are secured to headers by______. - ✔✔Expanding
✔✔A_______ is a process condition that must be met before a certain action may be
taken. - ✔✔Permissive
✔✔______ 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
ANSWERS GRADED A+
✔✔How many inches of steam space in a cylinder of an engine 12"x28" and the stroke
is 5/8 of its full travel? - ✔✔1978. V=AxL V=3.14(6x6)x28x.625= 1978
✔✔What is the horsepower requirement of a pump that moves 2500 gpm of water
against a head of 475' if the pump is operating at 58% efficiency? - ✔✔516.8 HP=Head
x Weight/33000 x efficiency. (Head =475, Weight = 2500gpm x 8.33) (475x
20825)/19140
✔✔A ______ is the condition that is being controlled - ✔✔process variable
✔✔Although boiler tubes and boiler drums withstand the same pressure, the walls of
the boiler tubes are much thinner because ______. - ✔✔The tubes are much smaller in
diameter
✔✔A lead sulfide cell detects_____. - ✔✔Burner pilot and main flame
✔✔Which of the following indicates a malfunction in the DC heater? 1. The boiler
requires excessive amounts of oxygen absorbing chemicals.
2.Water and steam are entering the DC heater at the same temperature. - ✔✔Both 1 &
2
✔✔______ is the plasticity exhibited by a material under tension loading. - ✔✔Ductility
✔✔In a pressure atomizing fuel oil-burner, atomization of fuel is produced by the
_______. - ✔✔Burner tip and high pressure fuel
✔✔The ends of boiler tubes are secured to headers by______. - ✔✔Expanding
✔✔A_______ is a process condition that must be met before a certain action may be
taken. - ✔✔Permissive
✔✔______ 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
