DC 1st Class Boiler exam with correct
answers
Moving blading in which space between blades is the same size at the blading inlet, and the blading
outlet. - ANSWER -Impulse Blading
To blowdown a boiler equipped with a quick opening and slow opening valve on the bottom blowdown
line, the_________. - ANSWER -quick opening valve is opened first and closed last.
Hardness of water is the measurement in ppm of ________ and ________ in the water. - ANSWER -
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? - ANSWER -HP=5.1 HP= (Head in Feet) x (Weight
in Lbs.)/ 33,000 x Efficiency
a duplex double-acting reciprocating feed water pump has____ - ANSWER -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. - ANSWER -Selective Catalytic Reduction
Spalling in a boiler occurs in the ____? - ANSWER -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 ______? - ANSWER -Pyrolysis
What is the primary purpose of using wet scrubbers? - ANSWER -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_______? - ANSWER -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. - ANSWER -Reverse osmosis
The airflow switch at the burner fan housing______. - ANSWER -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? - ANSWER -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? - ANSWER -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 - ANSWER -process variable
Although boiler tubes and boiler drums withstand the same pressure, the walls of the boiler tubes are
much thinner because ______. - ANSWER -The tubes are much smaller in diameter
A lead sulfide cell detects_____. - ANSWER -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. - ANSWER -Both 1 & 2
______ is the plasticity exhibited by a material under tension loading. - ANSWER -Ductility
In a pressure atomizing fuel oil-burner, atomization of fuel is produced by the _______. - ANSWER -
Burner tip and high pressure fuel
The ends of boiler tubes are secured to headers by______. - ANSWER -Expanding
answers
Moving blading in which space between blades is the same size at the blading inlet, and the blading
outlet. - ANSWER -Impulse Blading
To blowdown a boiler equipped with a quick opening and slow opening valve on the bottom blowdown
line, the_________. - ANSWER -quick opening valve is opened first and closed last.
Hardness of water is the measurement in ppm of ________ and ________ in the water. - ANSWER -
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? - ANSWER -HP=5.1 HP= (Head in Feet) x (Weight
in Lbs.)/ 33,000 x Efficiency
a duplex double-acting reciprocating feed water pump has____ - ANSWER -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. - ANSWER -Selective Catalytic Reduction
Spalling in a boiler occurs in the ____? - ANSWER -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 ______? - ANSWER -Pyrolysis
What is the primary purpose of using wet scrubbers? - ANSWER -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_______? - ANSWER -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. - ANSWER -Reverse osmosis
The airflow switch at the burner fan housing______. - ANSWER -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? - ANSWER -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? - ANSWER -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 - ANSWER -process variable
Although boiler tubes and boiler drums withstand the same pressure, the walls of the boiler tubes are
much thinner because ______. - ANSWER -The tubes are much smaller in diameter
A lead sulfide cell detects_____. - ANSWER -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. - ANSWER -Both 1 & 2
______ is the plasticity exhibited by a material under tension loading. - ANSWER -Ductility
In a pressure atomizing fuel oil-burner, atomization of fuel is produced by the _______. - ANSWER -
Burner tip and high pressure fuel
The ends of boiler tubes are secured to headers by______. - ANSWER -Expanding
