True/False
Indicate whether the
statement is true or false.
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1.
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Nonpositive displacement compressors are also called dynamic compressors.
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2.
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The minimum operating pressure of a pneumatic system is determined by the
minimum pressure requirements of the machinery being supplied.
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3.
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Reciprocating piston compressors are the most common design for small to medium
sized commercial compressors.
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4.
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Single piston designs can generate pressures up to 200 psi.
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5.
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Vacuum pumps are basically air compressors that are operated in reverse.
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6.
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Vacuum generators are not reliable.
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7.
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Vacuum generators require lubrication.
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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8.
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Determine the actual drive power required to drive a compressor that delivers
100 scfm at 150 psig. The overall efficiency of the compressor is 75%.
a. | 28.22 hp | d. | 29.8 hp | b. | 0.5 hp | e. | not enough information | c. | 11250
hp |
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9.
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Determine the drive power required to drive a compressor that delivers 6.25
standard  at 1000 kPa. The overall efficiency of
the compressor is 75%. a. | 45.5kW | d. | 49.1kW | b. | 48.1 kW | e. | not enough information | c. | 6250kW |
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10.
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A compressor unit is required to proved a flow of 100 scfm to a system for 15
minutes while the compressor sits idle. What size receiver tank is required. The system
must operate between 90 and 120 psig.
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11.
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A compressor unit is required to proved a flow of 3.0 standard 
to a system for 15 minutes while the compressor sits idle. What size receiver tank is
required. The system must operate between 600 and 750 kPa guage. a. | 450.8 | c. | 45.2 | b. | 112.5 | d. | 30.3  |
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12.
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Determine the time to recharge a 300  receiver tank from 100 to
130 psig if the compressor delivery flow is 150 scfm. Assume the demand remains constant at 50
scfm during this time. a. | 6.12 minutes | c. | 12.24 minutes | b. | 5.25 minutes | d. | 5 minutes |
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13.
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Determine the time to recharge a 8  receiver tank from 600 to
700 kPa guage if the compressor delivery flow is 2.5 standard  .
Assume the demand remains constant at 1.0 standard  during this
time. a. | 3.2 minutes | c. | 2.5 minutes | b. | 18.75 minutes | d. | 5.28 minutes |
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Completion
Complete each
statement.
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14.
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In a typical pneumatic power unit, the compressor fills the receiver tank with
air up to some predetermined ____________ pressure and then shuts down.
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15.
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When pressure drops to a predetermined minimum, the compressor automatically
starts up and charges the receiver back upto the maximum pressure. This process is known a
________ a compressor.
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16.
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Positive displacement pumps operate by opening up a cavity to draw in fluid,
then closing the cavity to ______ the fluid.
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17.
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Nonpositive displacement pumps function by imparting a ___________ to the
fluid.
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18.
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Three designs of positive displacement compressors are prevalent in industry:
reciprocating piston, rotary vane, and rotary _________.
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19.
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As the crankshaft is rotated, the _______ reciprocate, alternately drawing in
atmospheric air and pushing out compressed air.
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20.
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A rotary vane compressor is very similar to the unbalanced vane pump. As
the rotor spins, the vanes are kept in contact with the houseing by _________ force and therefore
extend and retract.
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21.
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A rotary _________ compressor compresses air between two intermeshing
screws.
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22.
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Compressure units must be sized to supply sufficient pressure and flow to the
system under all __________ conditions.
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23.
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Compressor input power, like hydraulic pump input power, depends on pressure and
________.
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24.
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Air compressors are one of the largest consumers of industrial
__________.
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25.
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____________ pumps evacuate air from one side of an object, allowing atmospheric
pressure to act on the opposite side.
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26.
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Vacuum generators use a _________ to create a vacuum.
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27.
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The throat is designed so that the pressure drops below ____________ pressure,
creating a vacuum.
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Matching
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a. | receiver tank | c. | compressor | b. | prime mover |
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28.
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An electric motor, gas or diesel engine.
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29.
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An air pump that compresses air.
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30.
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A pressure source from which the system can draw as dictated by the flow
demand.
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a. | pressure switch | c. | cut-in | b. | cut-out |
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31.
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The pressure at which the compressor turns on.
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32.
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The pressure at which the compressor turns off.
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33.
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A device that automatically senses the pressure.
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a. | rotary screw | c. | rotary vane | b. | reciprocating
piston |
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34.
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35.
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36.
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