DC 1st Class Boiler Exam
Questions and Answers 100%
Correct
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
Questions and Answers 100%
Correct
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
