DC 3RD CLASS BOILER CORE EXAMINATION SET
QUESTIONS AND ANSWERS GRADED A+
✔✔A boiler operated with a pressure of 350 psi; boiler drum is 12' long and has a
diameter of 5'; what is the total force acting on the boiler drum? - ✔✔11,474,610
TF= P x (area of head + area of drum)
✔✔In a pressure atomizing burner, the atomization of the oil is accomplished by______.
- ✔✔Sprayer plate and tip
✔✔A _______ boiler is an electric power generation system that uses both a gas
turbine-driven generator and a steam drives generator. - ✔✔Combined -cycle
✔✔Alkalinity of boiler water may be raised by adding______. - ✔✔caustic soda
✔✔In a jet condenser______. - ✔✔water and steam mix
✔✔What provides circulation to the water wall tubes? - ✔✔Downcomers
✔✔All of the following are components of a secondary refrigeration system except
______? - ✔✔receiver. ( diffuser, cooling coils, expansion tank)
✔✔What is the advantage of the "bent tube" method of installing tubes in a boiler? -
✔✔A comparatively greater amount of holes can be placed in a given area of the tube
sheet.
✔✔ Moving blading in which space between blades is the same size at the blading inlet,
and the blading outlet. - ✔✔Impulse Blading
✔✔To blowdown a boiler equipped with a quick opening and slow opening valve on the
bottom blowdown line, the_________. - ✔✔quick opening valve is opened first and
closed last.
✔✔Hardness of water is the measurement in ppm of ________ and ________ in the
water. - ✔✔calcium and magnesium
✔✔A pump delivers 175 gallons per minute against a pressure of 55 psi; the suction
pressure is 15 psi. If a pump is 80% efficient, what is the horsepower needed? -
✔✔HP=5.1 HP= (Head in Feet) x (Weight in Lbs.)/ 33,000 x Efficiency
✔✔a duplex double-acting reciprocating feed water pump has____ - ✔✔two steam
Pistons 2 to 2 2/2 times larger in area than the water piston
, ✔✔Name a technique to control the nitrous oxide emissions. - ✔✔Selective Catalytic
Reduction
✔✔Spalling in a boiler occurs in the ____? - ✔✔Combustion chamber
✔✔A technology in which solid waste is heated in an oxygen starved atmosphere to
break down the solids into a gas is called ______? - ✔✔Pyrolysis
✔✔What is the primary purpose of using wet scrubbers? - ✔✔To remove sulfur dioxides
✔✔The thermal efficiency of a boiler with a stack temperature of 750°F and and a
furnace temperature of 3200°F is_______? - ✔✔75% ((3200-750)/3200) x 100
✔✔________is a water-purification process in which the water to be treated is
pressurized and applied against the surface of a semipermeable membrane. -
✔✔Reverse osmosis
✔✔The airflow switch at the burner fan housing______. - ✔✔Ensures the primary air
fan is functioning
✔✔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
QUESTIONS AND ANSWERS GRADED A+
✔✔A boiler operated with a pressure of 350 psi; boiler drum is 12' long and has a
diameter of 5'; what is the total force acting on the boiler drum? - ✔✔11,474,610
TF= P x (area of head + area of drum)
✔✔In a pressure atomizing burner, the atomization of the oil is accomplished by______.
- ✔✔Sprayer plate and tip
✔✔A _______ boiler is an electric power generation system that uses both a gas
turbine-driven generator and a steam drives generator. - ✔✔Combined -cycle
✔✔Alkalinity of boiler water may be raised by adding______. - ✔✔caustic soda
✔✔In a jet condenser______. - ✔✔water and steam mix
✔✔What provides circulation to the water wall tubes? - ✔✔Downcomers
✔✔All of the following are components of a secondary refrigeration system except
______? - ✔✔receiver. ( diffuser, cooling coils, expansion tank)
✔✔What is the advantage of the "bent tube" method of installing tubes in a boiler? -
✔✔A comparatively greater amount of holes can be placed in a given area of the tube
sheet.
✔✔ Moving blading in which space between blades is the same size at the blading inlet,
and the blading outlet. - ✔✔Impulse Blading
✔✔To blowdown a boiler equipped with a quick opening and slow opening valve on the
bottom blowdown line, the_________. - ✔✔quick opening valve is opened first and
closed last.
✔✔Hardness of water is the measurement in ppm of ________ and ________ in the
water. - ✔✔calcium and magnesium
✔✔A pump delivers 175 gallons per minute against a pressure of 55 psi; the suction
pressure is 15 psi. If a pump is 80% efficient, what is the horsepower needed? -
✔✔HP=5.1 HP= (Head in Feet) x (Weight in Lbs.)/ 33,000 x Efficiency
✔✔a duplex double-acting reciprocating feed water pump has____ - ✔✔two steam
Pistons 2 to 2 2/2 times larger in area than the water piston
, ✔✔Name a technique to control the nitrous oxide emissions. - ✔✔Selective Catalytic
Reduction
✔✔Spalling in a boiler occurs in the ____? - ✔✔Combustion chamber
✔✔A technology in which solid waste is heated in an oxygen starved atmosphere to
break down the solids into a gas is called ______? - ✔✔Pyrolysis
✔✔What is the primary purpose of using wet scrubbers? - ✔✔To remove sulfur dioxides
✔✔The thermal efficiency of a boiler with a stack temperature of 750°F and and a
furnace temperature of 3200°F is_______? - ✔✔75% ((3200-750)/3200) x 100
✔✔________is a water-purification process in which the water to be treated is
pressurized and applied against the surface of a semipermeable membrane. -
✔✔Reverse osmosis
✔✔The airflow switch at the burner fan housing______. - ✔✔Ensures the primary air
fan is functioning
✔✔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
